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Rodent models of lymphocyte migration
seminars in I M M U N OL OG Y, Vol 11, 1999: pp. 85]93 Article No. smim.1999.0164, available online at http:rrwww.idealibrary.com on
Rodent models of lymphocyte migration Anna A. Kulidjian†, Robert InmanU and Thomas B. Issekutz‡ Transendothelial migration is thought to proceed in several sequential overlapping steps, each mediated by a distinct family of adhesion molecules ŽFigure 1.. The initial interaction of lymphocytes with the vascular endothelium is transient and low in affinity, resulting in the rolling of cells on the vascular endothelium. Rolling is followed by lymphocyte activation, firm adhesion, and finally, transmigration.5 The initial rolling interaction is thought to be mediated by the binding of the selectin family of adhesion molecules to their glycoprotein ligands,5 and possibly by adhesion mediated through the a 4 family of integrins.6,7 Cytokine activation of rolling lymphocytes is thought to increase the affinity of surface integrins, which mediate firm adhesion and transmigration.5 In addition, as recently suggested for neutrophils and monocytes, lymphocyte transmigration also may be mediated through the platelet endothelial cell adhesion molecule-1 ŽPECAM1. }PECAM-1 interaction ŽCD31..8 This review will summarize how rodent models are used to study the molecular mechanisms of lymphocyte migration in vivo by giving examples of current knowledge obtained through rodent models. It will also discuss some of the advantages and limitations of existing rodent models as tools in understanding molecular mechanisms of lymphocyte migration.
The ability of leukocytes to migrate out of blood into tissues enables them to perform their surveillance functions. Understanding the molecular mechanisms by which this migration is accomplished has the potential of unveiling new methods of regulating immune responses. The existing knowledge of rodent physiology and the recent development of knockout mice makes rodents attractive models for studying the mechanisms of leukocyte migration in vivo. This review considers the existing rodent models in light of the knowledge gained from them in lymphocyte migration, and in addition, shows the advantages and limitations of using rodent models in studying lymphocyte migration. Key words: in vivo animal models r T lymphocytes r leukocytes r recruitment r adhesion molecules Q1999 Academic Press
Introduction LYMPHOCYTES ACCOMPLISH their surveillance functions by actively recirculating cells from blood to tissues or lymph nodes, and through lymphatics back into blood.1,2 During inflammation, lymphocyte migration out of blood into tissue intensifies, with naive and memory T lymphocytes migrating from blood into inflamed tissue, and from there into regional lymph nodes.2 ] 4 The rate-limiting step in this migration is that of lymphocytes from blood passing through the endothelial lining of the vessel into the tissue. Understanding the key molecular processes mediating this transendothelial migration could be an important step toward modulating inflammatory responses.
The rodent models Rodents are well established in research by virtue of their size, relative ease of husbandry, short reproductive cycle, and ease of handling. Various inbred strains of rats and mice, with relatively well understood characteristics and known MHC haplotypes are easily obtainable commercially. In addition, the recent development of knockout gene technology in mice has increased the range of experiments that can be carried out in rodents. Furthermore, most blocking monoclonal antibodies ŽmAbs., the widely used tool for studying the functions of adhesion molecules,
U
From the Departments of Medicine and Immunology, University of Toronto and Toronto Western Hospital, Toronto M5T 2S8, Canada, †Department of Immunology, Faculty of Medicine, Medical Sciences Building, University of Toronto, Toronto, ON M5S 1A8, Canada and ‡Department of Paediatrics, IWK Grace Health Centre, Halifax B3S 3G9, Canada Q1999 Academic Press 1044-5323r 99r 020085q 09 $30.00r 0
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Figure 1. The multistep model of leukocyte recruitment from the blood.
have been developed for rats and mice. Rodents thus serve as ideal animal models for investigating the molecular mechanisms of lymphocyte migration. Various rodent models have been developed to study the migration of lymphocytes. In vivo investigations often make use of mAbs blocking the function of adhesion receptors to determine their role in lymphocyte migration. A common criticism of this method is that mAbs may be exerting non-specific effects, either by activating cells through their cognate receptor, or by aggregating cells through Fc]Fc receptor interactions. The recent development of adhesion molecule deficient mice offers an alternative to mAb studies. These, however, may also be problematic, as such animals may have compensatory alterations in the expression of adhesion molecules as compared to the wild-type. Comparative studies carried out in parallel using mAbs and knockout mice, minimize these potential problems. Various methods are used to assess lymphocyte migration. Histological observations, ear or foot pad swelling measurements, direct counting of cells in peritoneal exudates, intravital microscopy, and labeling of leukocytes are among the most common methods of assessment. Depending on the stage of the migration being investigated and the leukocyte popu-
lation studied, some methods are more useful than others. Histological observations are carried out using dyes or markers to selectively visualize the leukocyte population of interest. This method allows visualization of cells which have completed extravasation, and to some degree allows a discrimination of cell types in the infiltrate. However, if cells migrate poorly, this method can not distinguish the affected stages of migration. Moreover, since T cells often represent only a small fraction of the cellular infiltrate, they are not easily quantifiable histologically in rodents. Consequently, T lymphocyte accumulation in rodents has been frequently measured indirectly, such as by measuring ear thickness and foot pad swelling in contact hypersensitivity reactions. This method is based on the observation that swelling, a measure of the plasma leakage out of blood vessels, directly correlates with the numbers of migrated leukocytes in contact sensitivity reactions in rodents. Recently it has been shown that such is not always the case.9 Furthermore, since contact hypersensitivity reactions in mice are predominantly infiltrated by neutrophils, this assay is not an accurate measure of T lymphocyte accumulation. The counting of T cells in peritoneal inflammatory exudates, although a direct way of measuring T cell
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migration, represents migration to a single tissue compartment, and may not be representative of the T cell migration to other tissues. Another common method of studying lymphocyte migration is intravital microscopy. This method allows direct visualization of cells in circulation, providing an excellent means of studying the rolling and arrest stages of leukocyte migration. It is less effective for quantitating leukocytes which have completed extravasation, and is inadequate for differentiating lymphocytes from other cells in circulation.10 The use of radiolabeled spleen T lymphocytes, a method used both in rats and mice, offers a substantial advantage over other methods, since T cell migration can be studied to various inflammatory stimuli in many different organs. T lymphocyte populations of interest are selectively radiolabeled and their migration to tissues measured using radiation counters. This method allows for more quantitative studies. It also allows several leukocyte populations to one inflammatory reaction to be studied concurrently. A wide range of inflammatory models have been established in rodents. The most commonly used are inflammatory agent induced reactions, microbial infections, delayed type hypersensitivity responses ŽDTH., allograft rejection, and injury mediated inflammation. This article focuses on the in vivo roles of adhesion molecules postulated or shown to be involved in T lymphocyte migration to inflammatory reactions. The brief discussion on the structural characteristics and specificities of these molecules should be supplemented by any of several excellent reviews on this topic.11 ] 15
cells, as well as on neutrophils, monocytes and eosinophils.17 L-selectin glycoprotein ligands are the peripheral node addressins ŽPNAd., glycosylation-dependent cell adhesion molecule-1 ŽGLyCAM-1 ., CD34, and murine mucosal lymphoid addressin MAdCAM, identified by MECA-79 mAb.18,19 L-selectin on human but not mouse neutrophils also binds to both P-selectin and E-selectin. 20,21 The role of L-selectin in in vivo T lymphocyte migration to inflammatory reactions has been suggested by experiments which showed that anti-Lselectin mAb reduced lymphocyte accumulation in the inflamed peritoneum by 90%, and that in Lselectin-deficient mice lymphocyte migration to the thioglycolate inflamed peritoneum is inhibited by 70%.22,23 Furthermore, L-selectin-deficient mice have impaired delayed-type hypersensitivity reactions, as measured by the decreased ear swelling response in the model of contact hypersensitivity reaction to oxazolone. More studies are needed to determine the extent of the contribution by L-selectin to lymphocyte migration in other inflammatory sites. More importantly L-selectin contribution relative to other adhesion molecules needs further investigation. E-selectin E-selectin is induced on cultured human endothelial cells after stimulation with interleukin-1 ŽIL-1 . and TNF-a , and was shown to be involved in the adhesion of neutrophils.24 IFN-g was also shown to induce E-selectin expression on human dermal microvascular cells in vitro.25 Unlike P-selectin, E-selectin expression requires de novo synthesis and therefore is delayed after cell stimulation. The specific glycoprotein ligands on leukocytes have not been fully identified. However, human Lselectin, the b 2 integrins, and mouse protein ESL-1 on neutrophils have been reported to bind to Eselectin.20,26,27 Another protein ligand is the cutaneous lymphocyte antigen ŽCLA., expressed on a subset of human CD4q T lymphocytes.28 CLA expressing T cells comprise 80]90% of T cells in chronic skin inflammatory reactions, but - 5% of T cells in extracutaneous chronic inflammatory sites.29 It is because of these observations that E-selectin has been proposed to be an adhesion molecule responsible for recruiting T lymphocyte to skin inflammation.30 In addition, T cell clones grown from the skin of atopic patients bind E-selectin in vitro, further supporting
Selectins Selectins are a family of calcium-dependent adhesion molecules implicated in mediating the initial interaction of leukocytes with vascular endothelial cells. Three members, L-selectin, P-selectin and E-selectin, have been identified.13 L-selectin L-selectin was originally identified in mice by the mAb MEL-14, a blocking mAb to L-selectin, which nearly abolished lymphocyte migration to the peripheral lymph nodes.16 It is expressed on virtually all naive lymphocytes and on a portion of memory T
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expression and T cell migration to TNF-a .41 These findings strongly suggest an essential role for Eselectin in T cell migration to TNF-a . However, our results indicated that E-selectin is involved but not essential for T cell migration to TNF-a . P-selectin and other adhesion molecules seem to be able to substitute for E-selectin function, as functional absence Žeither by mAb treatment or in selectin-deficient animals. of either E-selectin or P-selectin alone did not affect T cell migration to TNF-a , whereas blocking both resulted in partial inhibition of T cell migration. Another possible candidate is VCAM-1, an activation inducible endothelial adhesion molecule. TNF-a induces VCAM-1 expression on endothelial cells,42 and VCAM-1 supports tethering and rolling of T cells in vitro via VLA-4. 43 Some in vivo studies, however, suggest that this interaction supports rolling but not tethering of leukocytes.44,45 It remains to be determined which adhesion molecules are involved in T cell migration to TNF-a . This result only begins to show the complexity of in vivo T lymphocyte migration to inflammation, clearly demonstrating the importance of studying adhesion molecules in the context of leukocyte migration to various stimuli.
the role of E-selectin in targeting T cells to the inflamed skin.31 Direct evidence for the role of E-selectin in in vivo T lymphocyte migration comes from blocking antibody studies. Anti-E-selectin mAbs have been shown to partially inhibit the intensity of peripheral blood lymphocyte recruitment to DTH reactions in pigs,32 and to tuberculin DTH reactions in some Macaque monkeys.33 Anti-E-selectin mAbs have also been shown to partially inhibit the migration of cultured CD4q Th1 cells to sites of contact hypersensitivity reactions in the skin of mice.34 Although antibody studies have shown a role for E-selectin in T lymphocyte migration, in E-selectin-deficient mice contact sensitivity reactions were histologically similar to those in wild-type mice, in that intensity of the cellular infiltrate was unaffected.35,36 In these mice, rolling of leukocytes, the majority of which are probably granulocytes, was also not altered after TNF-a stimulation.35 To investigate the role of E-selectin in lymphocyte migration further, we studied T cell migration to intradermally injected inflammatory cytokines IFN-g and TNF-a and an inflammatory agent Con A. We used radiolabeled spleen T lymphocytes, and studied the role of E-selectin by using anti-E-selectin blocking mAbs and E-selectin knockout mice. Anti-Eselectin treatment significantly inhibited T cell migration to all of the stimuli except TNF-a . In Eselectin-deficient mice, T lymphocyte migration was also inhibited to all stimuli except TNF-a ŽKulidjian et al, manuscript in preparation.. These results suggest that E-selectin may be used by T cells migrating to inflammatory reactions in the skin, probably to mediate the initial rolling interaction with the endothelium. Yet, E-selectin is probably not the exclusive mediator of T lymphocyte entry into inflamed skin, as in both anti-E-selectin-treated and Eselectin-deficient mice T cell migration to skin lesions was only partially inhibited. Alternatively, this result may also point to a population of spleen T lymphocytes that are independent of E-selectin for their migration to skin. The finding that T cell migration to a TNF-a stimulus was not inhibited in anti-E-selectin-treated or E-selectin-deficient mice was unexpected. TNF-a has been shown to be a potent inducer of E-selectin expression on dermal vascular endothelial cells both in vitro and in vivo.24,37,38 TNF-a also attracts large numbers of T lymphocytes when injected intradermally in mice ŽKulidjian et al, manuscript in preparation., and in other animals.39 ] 41 Furthermore, Binns et al have shown a correlation between E-selectin
P-selectin P-selectin is stored in cytoplasmic granules: in agranules of platelets46 and in Weibel]Palade bodies of endothelial cells.47 P-selectin is rapidly transported to the surface of the cells upon stimulation with thrombin, histamine, TNF-a , IFN-g and IL-1. 48 ] 50 Only two protein ligands for P-selectin have been identified thus far: one is the P-selectin glycoprotein ligand ŽPSGL-1 . on myeloid cells and T cells;51 the other, the L-selectin on neutrophils which binds to both P-selectin and E-selectin. T cells express functional ligands for P-selectin, as in vitro they roll efficiently on immobilized P-selectin in flow chambers.52 Recently, P-selectin-deficient animals were shown to have decreased CD4q T cell numbers in contact hypersensitivity reactions9 and anti-P-selectin mAb was reported to partially inhibit the migration of cultured mouse Th1 CD4q T cells to contact hypersensitivity reactions in mice.34 Together these studies demonstrate P-selectin involvement in in vivo migration of at least some T cells. However, Tang T. et al, recently showed that in P-selectin-deficient mice, mononuclear cell accumulation in the inflamed cerebrospinal fluid is not in88
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Lymphocyte function associated antigen-1 (LFA-1 )
hibited in 24 h.53 Furthermore, P-selectin-deficient mice reject allogeneic skin grafts normally, a function dependent on T lymphocyte migration into the grafted tissue.54 In our model also P-selectin by itself appeared to play a relatively minor role in T lymphocyte migration to skin inflammation in this model. Anti-P-selectin mAb had no effect on in vivo T cell migration to all of the intradermally injected inflammatory agents. Furthermore, T cell migration in P-selectin-deficient mice was largely unaffected. Yet, blocking E-selectin in addition to P-selectin inhibited T cell recruitment into the inflammatory sites further than with E-selectin absence alone, and for the first time inhibited T cell migration to TNF-a . Thus P-selectin contributes to, but is not essential for, T cell migration to inflamed tissue in our model. The results regarding the use of P-selectin by T lymphocytes seem intuitively paradoxical. Austrup et al demonstrated partial inhibition of cultured Th1 cell migration to contact sensitivity reaction with antiP-selectin treatment. However, these T cells were cultured in vitro and stimulated to develop a Th1 or Th2 cytokine profile, before being injected in vivo. Hence, their requirement for P-selectin may be different from that of spleen T cells in our experiments, or those involved in allograft rejection or migrating to cerebrospinal fluid. The observed difference in P-selectin utilization by T cells in the contact sensitivity mouse model used by Subramaniam et al versus the model used in our experiments may be related to the inflammatory agent used to elicit skin inflammation: contact sensitizing agent oxazolone versus intradermally injected cytokines and Con A.
LFA-1 ŽCD11arCD18. is a member of the b 2 ŽCD18. integrin subfamily of adhesion molecules.55 LFA-1 is expressed on the surface of all lymphocytes.55 Three ligands have been identified to date: ICAM-1, ICAM-2 and ICAM-3. 56 ] 58 ICAM-1 and ICAM-2 on endothelial cells bind to LFA-1 on T lymphocytes, and this adhesion increases in avidity with T cell activation by MCP-1 and RANTES chemokines.5 ICAM-1 is a protein expressed in low levels on vascular endothelial cells, and it is also present on some T lymphocytes, monocytes and NK cells. IL-1, TNF-a and IFN-g markedly increase ICAM-1 expression on endothelial cells.59,60 ICAM-2 is constituitively expressed on endothelial cells.57 LFA-1 was one of the first receptors reported to mediate lymphocyte adhesion to endothelial cells in vitro, and lymphocyte migration in vivo.61,62 An in vivo role for LFA-1 in T lymphocyte migration to inflammatory reactions was demonstrated in various animal models of inflammation. LFA-1 blockade strongly inhibits T lymphocyte migration to cutaneous DTH reactions and IFN-g , TNF-a and LPS-induced inflammatory reactions.63,64 The importance of LFA-1 varies with the T cell population studied. For example, anti-LFA-1 treatment has been shown to inhibit T lymphocyte migration to cutaneous inflammatory reactions by 80%, while the migration of activated T lymphocytes derived from an inflammatory exudate was only mildly inhibited by the antiLFA-1 treatment.63,65 T cell migration to cutaneous inflammation is only partially inhibited in the absence of LFA-1. The remainder of the migration seems to be mediated by the VLA-4 integrin, since blocking both VLA-4 in addition to LFA-1 abolishes T cell migration to inflammatory reactions in the skin.63 Recently, ICAM-1-deficient mice were generated. These mice have increased numbers of circulating blood lymphocytes and partially inhibited contact hypersensitivity reactions.66,67 Further studies are required to understand the relative importance of LFA1 ligands in mediating T cell migration and such animals will be valuable in this pursuit. Although LFA-1 is essential to T lymphocyte migration to inflammatory reactions in the skin, in other inflammatory settings it may be less important. For example, anti-LFA-1 treatment alone does not inhibit T cell migration to inflamed joints in rat adjuvant arthritis,40 and lymphoblast migration into the para-
The integrins and T lymphocyte migration Integrins are a family of transmembrane cell adhesion molecules consisting of non-covalently linked, heterodimeric a and b chains. Each b chain may associate with several different a subunits and some a subunits can associate with different b subunits. Within the integrin family only three members have been shown to be involved in lymphocyte migration: b 2 leukocyte integrin LFA-1 ŽCD11arCD18., b 1 integrin VLA-4 Ž a 4 b 1 , CD49drCD29., and LPAM1 a 4 b 7 . Two of these, LFA-1 and VLA-4, have been demonstrated to be important mediators of T lymphocyte migration to inflammatory reactions. 89
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site-infected gut.68 Anti-LFA-1 treatment, however, does inhibit inflammation in the acute rabbit arthritis.69 These experiments demonstrate that LFA-1 involvement depends not only on the activation status of the T lymphocyte, but also on the inflammatory organ and the type of inflammation studied, and emphasizes the importance of studying the in vivo function of adhesion molecules in the context of different inflammatory stimuli. In conclusion, LFA-1 is essential for the migration of T lymphocytes to lymphoid organs and inflammatory reactions, and its function is of particular importance for the migration of resting T cells.
migration to antigen induced hypersensitivity reactions in the bronchial wall.82 Hence VLA-4 is essential for T cell migration to inflammatory reactions in many tissues, and appears to be involved in migration of both resting and activated T cells. When both LFA-1 and VLA-4 are blocked by mAb’s T lymphocyte migration to skin inflammation-induced by intradermal injection of IFN-g and tuberculin DTH is inhibited by more than 98%,63 demonstrating that both LFA-1 and VLA-4 mediate part of T lymphocyte migration to skin inflammation, and no other adhesion molecule can substitute for their function. Interestingly, the combined LFA-1 and VLA-4 blockade does not completely inhibit T cell migration to some other inflamed tissues. For example, the combined treatment with anti-LFA-1 and anti-VLA-4 did not significantly prolong heart allograft survival beyond that seen in anti-LFA-1 treatment alone,83 indicating that in some inflammatory settings other molecules are capable of mediating T cell migration, or a population independent of LFA-1 and VLA-4 integrins migrates to these sites. In conclusion studies reviewed here demonstrate the importance and usefulness of rodent models in studying the mechanisms of lymphocyte migration. Though much remains to be understood in how the leukocyte migration is accomplished, rodent models serve as a valuable resource for deciphering the molecular basis of cell migration.
Very late activation antigen-4 (VLA-4 ) VLA-4 ŽCD49drCD29. is a member of the b 1 integrin family of adhesion molecules. It is expressed on lymphocytes, monocytes, eosinophils, mast cells, and in low levels on neutrophils.70 ] 72 VLA-4 has several ligands, vascular cell adhesion molecule-1 ŽVCAM-1 . and the CS-1 fragment of fibronectin being important in leukocyte migration. VCAM-1 expressing endothelial cells support the adhesion of blood lymphocytes through a VLA-4 mediated mechanism,73,74 and endothelial cells expressing fibronectin containing CS-1 support binding of T lymphocytes.75 Normally endothelial cells do not express VCAM-1. TNF-a , IL-1, IL-4 and LPS can stimulate endothelial cells to express VCAM-1. 42,59,76 Most of our understanding of the in vivo role of VLA-4 in T lymphocyte migration derives from blocking mAb studies, because VCAM-1 is important in embryo uterine implantation resulting in VCAM-1 knockout being a lethal mutation.77 mAb studies have shown a role for VLA-4 in T lymphocyte migration to sites of inflammation. VLA-4 blockade by TA-2 mAb inhibited blood T lymphocyte migration to cutaneous DTH reactions and IFN-g , TNF-a and LPS-induced inflammation by approximately 60%. VLA-4 blockade was effective at inhibiting the migration of both resting and activated T cells.78 VLA-4 is also important in T cell migration to inflammatory reactions in tissues other than skin. Anti-VLA-4 treatment alone inhibits T cell migration to inflamed joints in the adjuvant arthritis model.40 Anti-VLA-4 treatment inhibits T cell mediated neurologic damage in experimental allergic encephalomyelitis ŽEAE. 79 and T cell migration to the central nervous system.80 Blockade of VLA-4 also inhibits T cell migration to allergen-induced tracheal inflammation81 and T cell
Acknowledgements We would like to thank Aiyappa Palecanda for his critical reading of the manuscript, and Ara Kulidjian for his editorial assistance.
References 1. Gowans JL, Knight EJ Ž1964. The recirculation of lymphocytes in the rat. Proc R Soc London Ser B 159:257]282 2. Smith JB, McIntosh GH, Morris B Ž1970. The traffic of cells through tissues: a study of peripheral lymph in sheep. J Anat 107:87]100 3. MacKay CR, Marston W, Dudler L Ž1992. Altered patterns of T cell migration through lymph nodes and skin following antigen challenge. Eur J Immunol 22:2205]2210 4. Issekutz TB, Chin W, Hay JB Ž1980. Lymphocyte traffic through granulomas: difference in the recovery of indium111-labeled lymphocytes in afferent and efferent lymph. Cell Immunol 20:79]86 5. Springer TA Ž1994. Traffic signals for lymphocyte recirculation and leukocyte emigration: The multistep paradigm. Cell 76:301]314
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6. Jones DA, McIntire LV, Smith CW, Picker LJ Ž1994. A two-step adhesion cascade for T cellrendothelial cell interactions under flow conditions. J Clin Invest 94:2443]2450 7. Alon R, Kassner PD, Carr MW, Finger EB, Hemler ME, Springer TA Ž1995. The integrin VLA-4 supports tethering and rolling in flow on VCAM-1. J Cell Biol 128:1243 8. Muller WA, Weigl SA, Deng X, Phillips DM Ž1993. PECAM-1 is required for transendothelial migration of leukocytes. J Exp Med 178:449]460 9. Subramaniam M, Saffaripour S, Watson SR, Mayadas TN, Hynes RO, Wagner DD Ž1995. Reduced recruitment of inflammatory cells in a contact hypersensitivity response in P-selectin-deficient mice. J Exp Med 181:2277]2282 10. Kunkel EJ, Ley K Ž1996. Distinct phenotype of E-selectin-de ficient mice. E-selectin is required for slow leukocyte rolling in vivo. Circ Res 79:1196]1204 11. Bevilacqua MP, Butcher E, Furie BC, Gallatin M, Gimbrone M, Harlan JM, Kishimoto K, Lasky LA, McEver RP, Paulson J et al Ž1991. Selectins: A family of adhesion receptors. Cell 67:233 12. Vestweber D Ž1996. Ligand-specificity of the selectins. J Cell Biochem 61Ž4.:585]591 13. Bevilacqua MP, Nelson RM Ž1993. Selectins. J Clin Invest 91:379]387 14. Larson RS, Springer TA Ž1990. Structure and function of leukocyte integrins. Immunol Rev 114:181 15. Sonnenberg A Ž1993. Integrins and their ligands. Curr Top Microbiol Immunol 184:7]35 16. Gallatin WM, Weissman IL, Butcher EC Ž1983. A cell-surface molecule involved in organ-specific homing of lymphocytes. Nature 304:30]34 17. Lewinsohn DM, Bargatze RF, Butcher EC Ž1987. Leukocyteendothelial cell recognition: evidence of a common molecular mechanism shared by neutrophils, lymphocytes, and other leukocytes. J Immunol 138:4313]4321 18. Streeter PR, Rouse BT, Butcher EC Ž1988. Immunohistologic and functional characterization of a vascular addressin involved in lymphocyte homing into peripheral lymph nodes. J Cell Biol 107:1853]1862 19. Carlos TM, Harlan JM Ž1994. Leukocyte-endothelial adhesion molecules. Blood 84:2068]2101 20. Picker LJ, Warnock RA, Bums AR, Doerschuk CM, Berg EL, Butcher EC Ž1991. The neutrophil selectin LECAM-1 presents carbohydrate ligands to the vascular selectins ELAM-1 and GMP-140. Cell 66:921]933 21. Zollner O, Lenter MC, Blanks JE, Borges E, Steegmaier M, Zerwes HG, Vestweber D Ž1997. L-selectin from human, but not from mouse neutrophils binds directly to E-selectin. J Cell Biol 136:707]716 22. Pizcueta P, Luscinskas FW Ž1994. Monoclonal antibody blockade of L-selectin inhibits mononuclear leukocyte recruitment to inflammatory sites in vivo. Am J Pathol 145:461]469 23. Tedder TF, Steeber DA, Pizcueta P Ž1995. L-selectin-deficient mice have impaired leukocyte recruitment into inflammatory sites. J Exp Med 181:2259]2263 24. Bevilacqua MP, Pober JS, Mendrick DL, Cotran RS, Gimbrone MAJ Ž1987. Identification of an inducible endothelialleukocyte adhesion molecule. Proc Natl Acad Sci USA 84:9238 25. Lee KH, Chung KY, Koh YJ Ž1995. Memory T lymphocytes’ adherence to interferon gamma-activated human dermal microvascular endothelial cells via E-selectin. J Dermatol Sci 10Ž2.:166]175 26. Levinovitz A, Muhlhoff J, Isenmann I, Vestweber D Ž1993. ¨ Identification of a glycoprotein ligand for E-selectin on mouse myeloid cells. J Cell Biol 121:449]459 27. Kotovuori P, Tontti E, Pigott R, Shepherd M, Kiso M, Hasegawa A, Renkonen R, Nortamo P, Altieri DC, Gahmberg CG Ž1997. The vascular E-selectin binds to the leukocyte integrins CD11rCD18. Glycobiology 3Ž2.:131]136
28. Berg EL, Yoshino T, Rott LS, Robinson MK, Warnock RA, Kishimoto TK, Picker LJ, Butcher EC Ž1991. The cutaneous lymphocyte antigen is a skin lymphocyte homing receptor for the vascular lectin endothelial cell]leukocyte adhesion molecule 1. J Exp Med 174:1461]1466 29. Picker LJ, Michie SA, Rott LS, Butcher EC Ž1990. A unique phenotype of skin-associated lymphocytes in humans: Preferential expression of the HECA-452 epitope by benign and malignant T cells at cutaneous sites. Am J Pathol 136:1053]1068 30. Picker LJ, Kishimoto TK, Smith CW, Warnock RA, Butcher EC Ž1991. ELAM-1 is an adhesion molecule for skin-homing T cells. Nature 349:796]799 31. Rossiter H, Van Reijsen F, Mudde GC, Kalthoff F, Carla AFM, Bruijnzeel-Koomen, Picker LJ, Kupper TS Ž1994. Skin disease-related T cells bind to endothelial selectins: expression of cutaneous lymphocyte antigen ŽCLA. predicts E-selectin but not P-selectin binding. Eur J Immunol 24:205]210 32. Binns RM, Whyte A, Licence ST, Harrison AA, Tsang YT, Haskard DO, Robinson MK Ž1996. The role of E-selectin in lymphocyte and polymorphonuclear cell recruitment into cutaneous delayed hypersensitivity reactions in sensitized pigs. J Immunol 157:4094]4099 33. Silber A, Newman W, Sasseville VG, Pauley D, Beall D, Walsh DG, Ringler W Ž1994. Recruitment of lymphocytes during cutaneous delayed hypersensitivity in nonhuman primates is dependent on E-selectin and vascular cell adhesion molecule 1. J Clin Invest 93:1554]1563 34. Austrup F, Vestweber D, Borges E, Lohning M, Brauer R, Herz U, Renz H, Hallmann R, Scheffold A, Radbruch A et al Ž1997. P- and E-selectin mediate recruitment of T-helper-1 but not T-helper-2 cells into inflamed tissues. Nature 385:81]83 35. Labow MA, Norton CR, Rumberger JM, Lombard-Gillooly KM, Shuster DJ, Hubbard J, Bertko R, Knaack PA, Terry RW, Harbison MI, Ž1994. Characterization of E-selectin-deficient mice: demonstration of overlapping function of the endothelial selectins. Immunity 1:709]720 36. Staite ND, Justen JM, Sly LM, Beaudet AL, Bullard DC Ž1996. Inhibition of delayed-type contact hypersensitivity in mice deficient in both E- selectin and P- selectin. Blood 88Ž8.:2973]2979 37. Henseleit U, Steinbrink K, Goebeler M, Roth J, Vestweber D, Sorg C, Sunderkotter C Ž1996. E-selectin expression in experimental models of inflammation in mice. J Pathol 180:317]325 38. Whyte A, Licence ST, Robinson MK, van der Lienden K Ž1996. Lymphocyte subsets and adhesion molecules in cutaneous inflammation induced by inflammatory agonists: Correlation between E-selectin and gamma delta TcRŽq. lymphocytes. Lab Invest 75Ž3.:439]449 39. Issekutz TB Ž1990. Effects of six different cytokines on lymphocyte adherence to microvascular endothelium and in vivo lymphocyte migration in the rat. J Immunol 144: 2140]2146 40. Issekutz TB, Issekutz AC Ž1991. T lymphocyte migration to arthritic joints and dermal inflammation in the rat: Differing migration patterns and the involvement of VLA-4. Clin Immunol Immunopathol 61:436]447 41. Binns RM, Licence ST, Harrison AA, Keelan ET, Robinson MK, Haskard DO Ž1996. In vivo E-selectin upregulation correlates early with infiltration of PMN, later with PBL entry: MAbs block both. Am J Physiol 270:H183]193 42. Thornhill MH, Wellicome SM, Mahiouz DL, Lanchbury JSS, Kyan-Aung U, Haskard DO Ž1991. Tumor necrosis factor combines with IL-4 or IFN-gamma to selectively enhance endothelial cell adhesiveness for T cells: The contribution of vascular cell adhesion molecule-1-dependent and independent binding mechanisms. J Immunol 146:592]598 43. Berlin C, Bargatze RF, Campbell JJ, Von Andrian UH, Szabo
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R. Inman
44.
45.
46.
47.
48.
49. 50.
51.
52.
53.
54.
55. 56. 57. 58.
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MC, Hasslen SR, Nelson RD, Erlandsen SL, Butcher EC Ž1995. Alpha 4 integrins mediate lymphocyte attachment and rolling under physiologic flow. Cell 80:413]422 Johnston B, Issekutz TB, Kubes P Ž1996. The alpha 4integrin supports leukocyte rolling and adhesion in chronically inflamed postcapillary venules in vivo. J Exp Med 183: 1995]2006 Kanwar S, Bullard DC, Hickey MJ, Smith CW, Beaudet AL, Wolitzky BA, Kubes P Ž1997. The association between alpha4-integrin, P-selectin, and E-selectin in an allergic model of inflammation. J Exp Med 185:1077]1087 Stenberg PE, McEver RP, Shuman MA, Jacques YV, Bainton DF Ž1985. A platelet alpha-granule membrane protein ŽGMP140. is expressed on the plasma membrane after activation. J Cell Biol 101:880 McEver RP, Beckstead JH, Moore KL, Marshall-Carlson L, Bainton DF Ž1989. GMP-140, a platelet alpha-granule membrane protein, is also synthesized by vascular endothelial cells and is localized in Weibel]Palade bodies. J Clin Invest 84:92]99 Weller A, Isenmann S, Vestweber D Ž1992. Cloning of the mouse endothelial selectins. Expression of both E- and Pselectin is inducible by tumor necrosis factor alpha. J Biol Chem 267:15176]15183 Wagner DD Ž1993. The Weibel]Palade body: the storage granule for von Willebrand factor and P-selectin. Thromb Haemost 70:105]110 Todoroki N, Watanabe Y, Akaike T, Katagiri Y, Tanoue K, Yamazaki H, Tsuji T, Toyoshima S, Osawa T Ž1991. Enhancement by IL-1 and IFN-gamma of platelet activation: adhesion to leukocytes via GMP-140rPADGEM protein ŽSD62.. Biochem Biophys Res Commun 179:756]761 Moore KL, Stults NL, Diaz S, Smith DF, Cummings RD, Varki A, McEver RP Ž1992. Identification of a specific glycoprotein ligand for P-selectin ŽCD62. on myeloid cells. J Cell Biol 118:445]456 Alon R, Rossiter H, Wang X, Springer TA, Kupper TS Ž1994. Distinct cell surface ligands mediate T lymphocyte attachment and rolling on P and E selectin under physiological flow. J Cell Biol 127:1485]1495 Tang T, Frenette PS, Hynes RO, Wagner DD, Mayadas TN Ž1996. Cytokine-induced meningitis is dramatically attenuated in mice deficient in endothelial selectins. J Clin Invest 97:2485]2490 Tang ML, Hale LP, Steeber DA, Tedder TF Ž1997. L-selectin is involved in lymphocyte migration to sites of inflammation in the skin: delayed rejection of allografts in L-selectin-defi cient mice. J Immunol 158:5191]5199 Arnaout MA Ž1990. Structure and function of the leukocyte adhesion molecules CD11rCD18. Blood 75:1037]1050 Marlin D, Springer TA Ž1987. Purified intercellular adhesion molecule-1 ŽICAM-1 . is a ligand for lymphocyte function-associated antigen 1 ŽLFA-1 .. Cell 51:813]819 Staunton DE, Dustin ML, Springer TA Ž1989. Functional cloning of ICAM-2, a cell adhesion ligand for LFA-1 homologous to ICAM-1. Nature 339:61]64 De Fougerolles AR, Springer TA Ž1992. Intercellular adhesion molecule 3, a third adhesion counter-receptor for lymphocyte function-associated molecule 1 on resting lymphocytes. J Exp Med 175:185]190 Pober JS, Gimbrone MAJ, Lapierre LA, Mendrick DL, Fiers W, Rothlien R, Springer TA Ž1986. Overlapping patterns of activation of human endothelial cell by interleukin-1, tumor necrosis factor and immune interferon. J Immunol 137: 1893]1896 Dustin ML, Rothlein R, Bhan AK, Dinarello CA, Springer TA Ž1986. Induction by IL-1 and interferon-g: Tissue distribution, biochemistry, and function of a natural adherence molecule ŽICAM-1 .. J Immunol 137:245]254
61. Haskard DO, Cavender DE, Beatty PG, Springer TA, Ziff M Ž1986. T lymphocyte adhesion to endothelial cells: mechanisms demonstrated by anti-LFA-1 monoclonal antibodies. J Immunol 137:2901]2906 62. Hamann A, Jablonski -WD, Duijvestijn A, Butcher EC, Baisch H, Harder R, Thiele HG Ž1988. Evidence for an accessory role of LFA-1 in lymphocyte-high endothelium interaction during homing. J Immunol 140:693]699 63. Issekutz TB Ž1993. Dual inhibition of VLA-4 and LFA-1 maximally inhibits cutaneous delayed-type hypersensitivity-induced inflammation. Am J Pathol 143:1286]1293 64. Issekutz TB Ž1995. In vivo blood monocyte migration to acute inflammatory reactions, IL-1 a , TNFa , IFN-t , and C5a utilizes LFA-1, Mac-1 and VLA-4: The relative importance of each integrin. J Immunol 154:6533]6540 65. Issekutz TB Ž1992. Inhibition of lymphocyte endothelial adhesion and in vivo lymphocyte migration to cutaneous inflammation by TA-3, a new monoclonal antibody to rat LFA-1. J Immunol 149:3394]3402 66. Sligh JD, Ballantyne CM, Rich SS, Hawkins HK, Smith CW, Bradley A, Beaudet AL Ž1993. Inflammatory and immune responses are impaired in mice deficient in intercellar adhesion molecule 1. Proc Natl Acad Sci USA 90:8529]8533 67. Xu H, Gonzalo JA, St. Pierre Y, Williams IR, Kupper TS, Cotran RS, Springer TA, Gutierrez-Ramos J-C Ž1994. Leukocytosis and resistance to septic shock in intercellular adhesion molecule 1-deficient mice. J Exp Med 180:95]109 68. Bell RG, Issekutz TB Ž1993. Expression of a protective intestinal immune response can be inhibited at three distinct sites by treatment with anti-a 4 integrin. J Immunol 151:4790]4802 69. Jasin HE, Lightfoot E, Davis LS, Rothlein R, Faanes RB, Lipsky PE Ž1992. Amelioration of antigen-induced arthritis in rabbits treated with monoclonal antibodies to leukocyte adhesion molecules. Arthritis Rheum 35:541]549 70. Hemler ME, Elices MJ, Parker C, Takada Y Ž1990. Structure of the integrin VLA-4 and its cell]cell and cell]matrix adhesion functions. Immunol Rev 114:45 71. Kubes P, Niu X, Smith CW, Kehrli Jr ME, Reinhardt PH, Woodman RC Ž1995. A novel b 1-dependent adhesion pathway on neutrophils: a mechanism invoked by dihydrocytochalasin B or endothelial transmigration. FASEB J 9:1103]1111 72. Issekutz TB, Miyasaka M, Issekutz AC Ž1996. Rat blood neutrophils express very late antigen 4 and it mediates migration to arthritic joint and dermal inflammation. J Exp Med 183:2175]2184 73. Elices MJ, Osborn L, Takada Y, Crouse C, Luhowskyj S, Hemler ME, Lobb RR Ž1990. VCAM-1 on activated endothelium interacts with the leukocyte integrin VLA-4 at a site distinct from the VLA-4rfibronectin binding site. Cell 60:577]584 74. Issekutz TB, Wykretowicz A Ž1991. Effect of a new monoclonal antibody, TA-2, that inhibits lymphocyte adherence to cytokine stimulated endothelium in the rat. J Immunol 147:109]116 75. Elices MJ, Tsai V, Strahl D, Goel AS, Tollefson V, Arrhenius T, Wayner EA, Gaeta FC, Fikes JD, Firestein GS Ž1994. Expression and functional significance of alternatively spliced CS1 fibronectin in rheumatoid arthritis microvasculature. J Clin Invest 93:405]416 76. Rice GE, Munro JM, Bevilacqua MP Ž1990. Inducible cell adhesion molecule 110 ŽINCAM-110 . is an endothelial receptor for lymphocytes. A CD11rCD18-independent adhesion mechanism. J Exp Med 171:1369]1374 77. Gurtner GC, Davis V, Li H, McCoy MJ, Sharpe A, Cybulski MI Ž1995. Targeted disruption of the murine VCAM1 gene: essential role of VCAM-1 in chorioallantoic fusion and placentation. Genes Dev 9:1]14 78. Issekutz TB Ž1991. Inhibition of in vivo lymphocyte migration to inflammation and homing to lymphoid tissues by the TA-2
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monoclonal antibody: A likely role for VLA-4 in vivo. J Immunol 147:4178]4184 79. Yednock TA, Cannon C, Fritz LC, Sanchez-Madrid F, Steinman L, Karin N Ž1992. Prevention of experimental autoimmune encephalomyelitis by antibodies against a 4b 1 integrin. Nature 356:63]66 80. Issekutz TB Ž1992. Effect of anti-LFA-1 and anti-VLA-4 on T lymphocyte migration to skin, joint, and CNS inflammation and lymph nodes. Int Cong Immunol 8:288 81. Nakajima H, Sano H, Nashimura T, Yoshida S, lwamoto T
Ž1994. Role of VCAM-1rVLA-4 and ICAM-1rLFA-1 interactions in antigen induced eosinophil and T cell recruitment into the tissue. J Exp Med 179:1145]1154 82. Pretolani M, Ruffie C, Lapa e Silva JR, Joseph D, Lobb RR, Vargaftig B Ž1994. Antibody to very late activation antigen 4 prevents antigen-induced bronchial hyperactivity and cellular infiltration in the guinea pig. J Exp Med 180:795]805 83. Paul LC, Davidoff A, Issekutz TB Ž1993. The efficacy of LFA-1 and VLA-4 antibody treatment in rat vascularized cardiac allograft rejection. Transplantation 55:1196]1199
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Rodent models of lymphocyte migration Anna A. Kulidjian†, Robert InmanU and Thomas B. Issekutz‡ Transendothelial migration is thought to proceed in several sequential overlapping steps, each mediated by a distinct family of adhesion molecules ŽFigure 1.. The initial interaction of lymphocytes with the vascular endothelium is transient and low in affinity, resulting in the rolling of cells on the vascular endothelium. Rolling is followed by lymphocyte activation, firm adhesion, and finally, transmigration.5 The initial rolling interaction is thought to be mediated by the binding of the selectin family of adhesion molecules to their glycoprotein ligands,5 and possibly by adhesion mediated through the a 4 family of integrins.6,7 Cytokine activation of rolling lymphocytes is thought to increase the affinity of surface integrins, which mediate firm adhesion and transmigration.5 In addition, as recently suggested for neutrophils and monocytes, lymphocyte transmigration also may be mediated through the platelet endothelial cell adhesion molecule-1 ŽPECAM1. }PECAM-1 interaction ŽCD31..8 This review will summarize how rodent models are used to study the molecular mechanisms of lymphocyte migration in vivo by giving examples of current knowledge obtained through rodent models. It will also discuss some of the advantages and limitations of existing rodent models as tools in understanding molecular mechanisms of lymphocyte migration.
The ability of leukocytes to migrate out of blood into tissues enables them to perform their surveillance functions. Understanding the molecular mechanisms by which this migration is accomplished has the potential of unveiling new methods of regulating immune responses. The existing knowledge of rodent physiology and the recent development of knockout mice makes rodents attractive models for studying the mechanisms of leukocyte migration in vivo. This review considers the existing rodent models in light of the knowledge gained from them in lymphocyte migration, and in addition, shows the advantages and limitations of using rodent models in studying lymphocyte migration. Key words: in vivo animal models r T lymphocytes r leukocytes r recruitment r adhesion molecules Q1999 Academic Press
Introduction LYMPHOCYTES ACCOMPLISH their surveillance functions by actively recirculating cells from blood to tissues or lymph nodes, and through lymphatics back into blood.1,2 During inflammation, lymphocyte migration out of blood into tissue intensifies, with naive and memory T lymphocytes migrating from blood into inflamed tissue, and from there into regional lymph nodes.2 ] 4 The rate-limiting step in this migration is that of lymphocytes from blood passing through the endothelial lining of the vessel into the tissue. Understanding the key molecular processes mediating this transendothelial migration could be an important step toward modulating inflammatory responses.
The rodent models Rodents are well established in research by virtue of their size, relative ease of husbandry, short reproductive cycle, and ease of handling. Various inbred strains of rats and mice, with relatively well understood characteristics and known MHC haplotypes are easily obtainable commercially. In addition, the recent development of knockout gene technology in mice has increased the range of experiments that can be carried out in rodents. Furthermore, most blocking monoclonal antibodies ŽmAbs., the widely used tool for studying the functions of adhesion molecules,
U
From the Departments of Medicine and Immunology, University of Toronto and Toronto Western Hospital, Toronto M5T 2S8, Canada, †Department of Immunology, Faculty of Medicine, Medical Sciences Building, University of Toronto, Toronto, ON M5S 1A8, Canada and ‡Department of Paediatrics, IWK Grace Health Centre, Halifax B3S 3G9, Canada Q1999 Academic Press 1044-5323r 99r 020085q 09 $30.00r 0
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Figure 1. The multistep model of leukocyte recruitment from the blood.
have been developed for rats and mice. Rodents thus serve as ideal animal models for investigating the molecular mechanisms of lymphocyte migration. Various rodent models have been developed to study the migration of lymphocytes. In vivo investigations often make use of mAbs blocking the function of adhesion receptors to determine their role in lymphocyte migration. A common criticism of this method is that mAbs may be exerting non-specific effects, either by activating cells through their cognate receptor, or by aggregating cells through Fc]Fc receptor interactions. The recent development of adhesion molecule deficient mice offers an alternative to mAb studies. These, however, may also be problematic, as such animals may have compensatory alterations in the expression of adhesion molecules as compared to the wild-type. Comparative studies carried out in parallel using mAbs and knockout mice, minimize these potential problems. Various methods are used to assess lymphocyte migration. Histological observations, ear or foot pad swelling measurements, direct counting of cells in peritoneal exudates, intravital microscopy, and labeling of leukocytes are among the most common methods of assessment. Depending on the stage of the migration being investigated and the leukocyte popu-
lation studied, some methods are more useful than others. Histological observations are carried out using dyes or markers to selectively visualize the leukocyte population of interest. This method allows visualization of cells which have completed extravasation, and to some degree allows a discrimination of cell types in the infiltrate. However, if cells migrate poorly, this method can not distinguish the affected stages of migration. Moreover, since T cells often represent only a small fraction of the cellular infiltrate, they are not easily quantifiable histologically in rodents. Consequently, T lymphocyte accumulation in rodents has been frequently measured indirectly, such as by measuring ear thickness and foot pad swelling in contact hypersensitivity reactions. This method is based on the observation that swelling, a measure of the plasma leakage out of blood vessels, directly correlates with the numbers of migrated leukocytes in contact sensitivity reactions in rodents. Recently it has been shown that such is not always the case.9 Furthermore, since contact hypersensitivity reactions in mice are predominantly infiltrated by neutrophils, this assay is not an accurate measure of T lymphocyte accumulation. The counting of T cells in peritoneal inflammatory exudates, although a direct way of measuring T cell
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migration, represents migration to a single tissue compartment, and may not be representative of the T cell migration to other tissues. Another common method of studying lymphocyte migration is intravital microscopy. This method allows direct visualization of cells in circulation, providing an excellent means of studying the rolling and arrest stages of leukocyte migration. It is less effective for quantitating leukocytes which have completed extravasation, and is inadequate for differentiating lymphocytes from other cells in circulation.10 The use of radiolabeled spleen T lymphocytes, a method used both in rats and mice, offers a substantial advantage over other methods, since T cell migration can be studied to various inflammatory stimuli in many different organs. T lymphocyte populations of interest are selectively radiolabeled and their migration to tissues measured using radiation counters. This method allows for more quantitative studies. It also allows several leukocyte populations to one inflammatory reaction to be studied concurrently. A wide range of inflammatory models have been established in rodents. The most commonly used are inflammatory agent induced reactions, microbial infections, delayed type hypersensitivity responses ŽDTH., allograft rejection, and injury mediated inflammation. This article focuses on the in vivo roles of adhesion molecules postulated or shown to be involved in T lymphocyte migration to inflammatory reactions. The brief discussion on the structural characteristics and specificities of these molecules should be supplemented by any of several excellent reviews on this topic.11 ] 15
cells, as well as on neutrophils, monocytes and eosinophils.17 L-selectin glycoprotein ligands are the peripheral node addressins ŽPNAd., glycosylation-dependent cell adhesion molecule-1 ŽGLyCAM-1 ., CD34, and murine mucosal lymphoid addressin MAdCAM, identified by MECA-79 mAb.18,19 L-selectin on human but not mouse neutrophils also binds to both P-selectin and E-selectin. 20,21 The role of L-selectin in in vivo T lymphocyte migration to inflammatory reactions has been suggested by experiments which showed that anti-Lselectin mAb reduced lymphocyte accumulation in the inflamed peritoneum by 90%, and that in Lselectin-deficient mice lymphocyte migration to the thioglycolate inflamed peritoneum is inhibited by 70%.22,23 Furthermore, L-selectin-deficient mice have impaired delayed-type hypersensitivity reactions, as measured by the decreased ear swelling response in the model of contact hypersensitivity reaction to oxazolone. More studies are needed to determine the extent of the contribution by L-selectin to lymphocyte migration in other inflammatory sites. More importantly L-selectin contribution relative to other adhesion molecules needs further investigation. E-selectin E-selectin is induced on cultured human endothelial cells after stimulation with interleukin-1 ŽIL-1 . and TNF-a , and was shown to be involved in the adhesion of neutrophils.24 IFN-g was also shown to induce E-selectin expression on human dermal microvascular cells in vitro.25 Unlike P-selectin, E-selectin expression requires de novo synthesis and therefore is delayed after cell stimulation. The specific glycoprotein ligands on leukocytes have not been fully identified. However, human Lselectin, the b 2 integrins, and mouse protein ESL-1 on neutrophils have been reported to bind to Eselectin.20,26,27 Another protein ligand is the cutaneous lymphocyte antigen ŽCLA., expressed on a subset of human CD4q T lymphocytes.28 CLA expressing T cells comprise 80]90% of T cells in chronic skin inflammatory reactions, but - 5% of T cells in extracutaneous chronic inflammatory sites.29 It is because of these observations that E-selectin has been proposed to be an adhesion molecule responsible for recruiting T lymphocyte to skin inflammation.30 In addition, T cell clones grown from the skin of atopic patients bind E-selectin in vitro, further supporting
Selectins Selectins are a family of calcium-dependent adhesion molecules implicated in mediating the initial interaction of leukocytes with vascular endothelial cells. Three members, L-selectin, P-selectin and E-selectin, have been identified.13 L-selectin L-selectin was originally identified in mice by the mAb MEL-14, a blocking mAb to L-selectin, which nearly abolished lymphocyte migration to the peripheral lymph nodes.16 It is expressed on virtually all naive lymphocytes and on a portion of memory T
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expression and T cell migration to TNF-a .41 These findings strongly suggest an essential role for Eselectin in T cell migration to TNF-a . However, our results indicated that E-selectin is involved but not essential for T cell migration to TNF-a . P-selectin and other adhesion molecules seem to be able to substitute for E-selectin function, as functional absence Žeither by mAb treatment or in selectin-deficient animals. of either E-selectin or P-selectin alone did not affect T cell migration to TNF-a , whereas blocking both resulted in partial inhibition of T cell migration. Another possible candidate is VCAM-1, an activation inducible endothelial adhesion molecule. TNF-a induces VCAM-1 expression on endothelial cells,42 and VCAM-1 supports tethering and rolling of T cells in vitro via VLA-4. 43 Some in vivo studies, however, suggest that this interaction supports rolling but not tethering of leukocytes.44,45 It remains to be determined which adhesion molecules are involved in T cell migration to TNF-a . This result only begins to show the complexity of in vivo T lymphocyte migration to inflammation, clearly demonstrating the importance of studying adhesion molecules in the context of leukocyte migration to various stimuli.
the role of E-selectin in targeting T cells to the inflamed skin.31 Direct evidence for the role of E-selectin in in vivo T lymphocyte migration comes from blocking antibody studies. Anti-E-selectin mAbs have been shown to partially inhibit the intensity of peripheral blood lymphocyte recruitment to DTH reactions in pigs,32 and to tuberculin DTH reactions in some Macaque monkeys.33 Anti-E-selectin mAbs have also been shown to partially inhibit the migration of cultured CD4q Th1 cells to sites of contact hypersensitivity reactions in the skin of mice.34 Although antibody studies have shown a role for E-selectin in T lymphocyte migration, in E-selectin-deficient mice contact sensitivity reactions were histologically similar to those in wild-type mice, in that intensity of the cellular infiltrate was unaffected.35,36 In these mice, rolling of leukocytes, the majority of which are probably granulocytes, was also not altered after TNF-a stimulation.35 To investigate the role of E-selectin in lymphocyte migration further, we studied T cell migration to intradermally injected inflammatory cytokines IFN-g and TNF-a and an inflammatory agent Con A. We used radiolabeled spleen T lymphocytes, and studied the role of E-selectin by using anti-E-selectin blocking mAbs and E-selectin knockout mice. Anti-Eselectin treatment significantly inhibited T cell migration to all of the stimuli except TNF-a . In Eselectin-deficient mice, T lymphocyte migration was also inhibited to all stimuli except TNF-a ŽKulidjian et al, manuscript in preparation.. These results suggest that E-selectin may be used by T cells migrating to inflammatory reactions in the skin, probably to mediate the initial rolling interaction with the endothelium. Yet, E-selectin is probably not the exclusive mediator of T lymphocyte entry into inflamed skin, as in both anti-E-selectin-treated and Eselectin-deficient mice T cell migration to skin lesions was only partially inhibited. Alternatively, this result may also point to a population of spleen T lymphocytes that are independent of E-selectin for their migration to skin. The finding that T cell migration to a TNF-a stimulus was not inhibited in anti-E-selectin-treated or E-selectin-deficient mice was unexpected. TNF-a has been shown to be a potent inducer of E-selectin expression on dermal vascular endothelial cells both in vitro and in vivo.24,37,38 TNF-a also attracts large numbers of T lymphocytes when injected intradermally in mice ŽKulidjian et al, manuscript in preparation., and in other animals.39 ] 41 Furthermore, Binns et al have shown a correlation between E-selectin
P-selectin P-selectin is stored in cytoplasmic granules: in agranules of platelets46 and in Weibel]Palade bodies of endothelial cells.47 P-selectin is rapidly transported to the surface of the cells upon stimulation with thrombin, histamine, TNF-a , IFN-g and IL-1. 48 ] 50 Only two protein ligands for P-selectin have been identified thus far: one is the P-selectin glycoprotein ligand ŽPSGL-1 . on myeloid cells and T cells;51 the other, the L-selectin on neutrophils which binds to both P-selectin and E-selectin. T cells express functional ligands for P-selectin, as in vitro they roll efficiently on immobilized P-selectin in flow chambers.52 Recently, P-selectin-deficient animals were shown to have decreased CD4q T cell numbers in contact hypersensitivity reactions9 and anti-P-selectin mAb was reported to partially inhibit the migration of cultured mouse Th1 CD4q T cells to contact hypersensitivity reactions in mice.34 Together these studies demonstrate P-selectin involvement in in vivo migration of at least some T cells. However, Tang T. et al, recently showed that in P-selectin-deficient mice, mononuclear cell accumulation in the inflamed cerebrospinal fluid is not in88
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Lymphocyte function associated antigen-1 (LFA-1 )
hibited in 24 h.53 Furthermore, P-selectin-deficient mice reject allogeneic skin grafts normally, a function dependent on T lymphocyte migration into the grafted tissue.54 In our model also P-selectin by itself appeared to play a relatively minor role in T lymphocyte migration to skin inflammation in this model. Anti-P-selectin mAb had no effect on in vivo T cell migration to all of the intradermally injected inflammatory agents. Furthermore, T cell migration in P-selectin-deficient mice was largely unaffected. Yet, blocking E-selectin in addition to P-selectin inhibited T cell recruitment into the inflammatory sites further than with E-selectin absence alone, and for the first time inhibited T cell migration to TNF-a . Thus P-selectin contributes to, but is not essential for, T cell migration to inflamed tissue in our model. The results regarding the use of P-selectin by T lymphocytes seem intuitively paradoxical. Austrup et al demonstrated partial inhibition of cultured Th1 cell migration to contact sensitivity reaction with antiP-selectin treatment. However, these T cells were cultured in vitro and stimulated to develop a Th1 or Th2 cytokine profile, before being injected in vivo. Hence, their requirement for P-selectin may be different from that of spleen T cells in our experiments, or those involved in allograft rejection or migrating to cerebrospinal fluid. The observed difference in P-selectin utilization by T cells in the contact sensitivity mouse model used by Subramaniam et al versus the model used in our experiments may be related to the inflammatory agent used to elicit skin inflammation: contact sensitizing agent oxazolone versus intradermally injected cytokines and Con A.
LFA-1 ŽCD11arCD18. is a member of the b 2 ŽCD18. integrin subfamily of adhesion molecules.55 LFA-1 is expressed on the surface of all lymphocytes.55 Three ligands have been identified to date: ICAM-1, ICAM-2 and ICAM-3. 56 ] 58 ICAM-1 and ICAM-2 on endothelial cells bind to LFA-1 on T lymphocytes, and this adhesion increases in avidity with T cell activation by MCP-1 and RANTES chemokines.5 ICAM-1 is a protein expressed in low levels on vascular endothelial cells, and it is also present on some T lymphocytes, monocytes and NK cells. IL-1, TNF-a and IFN-g markedly increase ICAM-1 expression on endothelial cells.59,60 ICAM-2 is constituitively expressed on endothelial cells.57 LFA-1 was one of the first receptors reported to mediate lymphocyte adhesion to endothelial cells in vitro, and lymphocyte migration in vivo.61,62 An in vivo role for LFA-1 in T lymphocyte migration to inflammatory reactions was demonstrated in various animal models of inflammation. LFA-1 blockade strongly inhibits T lymphocyte migration to cutaneous DTH reactions and IFN-g , TNF-a and LPS-induced inflammatory reactions.63,64 The importance of LFA-1 varies with the T cell population studied. For example, anti-LFA-1 treatment has been shown to inhibit T lymphocyte migration to cutaneous inflammatory reactions by 80%, while the migration of activated T lymphocytes derived from an inflammatory exudate was only mildly inhibited by the antiLFA-1 treatment.63,65 T cell migration to cutaneous inflammation is only partially inhibited in the absence of LFA-1. The remainder of the migration seems to be mediated by the VLA-4 integrin, since blocking both VLA-4 in addition to LFA-1 abolishes T cell migration to inflammatory reactions in the skin.63 Recently, ICAM-1-deficient mice were generated. These mice have increased numbers of circulating blood lymphocytes and partially inhibited contact hypersensitivity reactions.66,67 Further studies are required to understand the relative importance of LFA1 ligands in mediating T cell migration and such animals will be valuable in this pursuit. Although LFA-1 is essential to T lymphocyte migration to inflammatory reactions in the skin, in other inflammatory settings it may be less important. For example, anti-LFA-1 treatment alone does not inhibit T cell migration to inflamed joints in rat adjuvant arthritis,40 and lymphoblast migration into the para-
The integrins and T lymphocyte migration Integrins are a family of transmembrane cell adhesion molecules consisting of non-covalently linked, heterodimeric a and b chains. Each b chain may associate with several different a subunits and some a subunits can associate with different b subunits. Within the integrin family only three members have been shown to be involved in lymphocyte migration: b 2 leukocyte integrin LFA-1 ŽCD11arCD18., b 1 integrin VLA-4 Ž a 4 b 1 , CD49drCD29., and LPAM1 a 4 b 7 . Two of these, LFA-1 and VLA-4, have been demonstrated to be important mediators of T lymphocyte migration to inflammatory reactions. 89
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site-infected gut.68 Anti-LFA-1 treatment, however, does inhibit inflammation in the acute rabbit arthritis.69 These experiments demonstrate that LFA-1 involvement depends not only on the activation status of the T lymphocyte, but also on the inflammatory organ and the type of inflammation studied, and emphasizes the importance of studying the in vivo function of adhesion molecules in the context of different inflammatory stimuli. In conclusion, LFA-1 is essential for the migration of T lymphocytes to lymphoid organs and inflammatory reactions, and its function is of particular importance for the migration of resting T cells.
migration to antigen induced hypersensitivity reactions in the bronchial wall.82 Hence VLA-4 is essential for T cell migration to inflammatory reactions in many tissues, and appears to be involved in migration of both resting and activated T cells. When both LFA-1 and VLA-4 are blocked by mAb’s T lymphocyte migration to skin inflammation-induced by intradermal injection of IFN-g and tuberculin DTH is inhibited by more than 98%,63 demonstrating that both LFA-1 and VLA-4 mediate part of T lymphocyte migration to skin inflammation, and no other adhesion molecule can substitute for their function. Interestingly, the combined LFA-1 and VLA-4 blockade does not completely inhibit T cell migration to some other inflamed tissues. For example, the combined treatment with anti-LFA-1 and anti-VLA-4 did not significantly prolong heart allograft survival beyond that seen in anti-LFA-1 treatment alone,83 indicating that in some inflammatory settings other molecules are capable of mediating T cell migration, or a population independent of LFA-1 and VLA-4 integrins migrates to these sites. In conclusion studies reviewed here demonstrate the importance and usefulness of rodent models in studying the mechanisms of lymphocyte migration. Though much remains to be understood in how the leukocyte migration is accomplished, rodent models serve as a valuable resource for deciphering the molecular basis of cell migration.
Very late activation antigen-4 (VLA-4 ) VLA-4 ŽCD49drCD29. is a member of the b 1 integrin family of adhesion molecules. It is expressed on lymphocytes, monocytes, eosinophils, mast cells, and in low levels on neutrophils.70 ] 72 VLA-4 has several ligands, vascular cell adhesion molecule-1 ŽVCAM-1 . and the CS-1 fragment of fibronectin being important in leukocyte migration. VCAM-1 expressing endothelial cells support the adhesion of blood lymphocytes through a VLA-4 mediated mechanism,73,74 and endothelial cells expressing fibronectin containing CS-1 support binding of T lymphocytes.75 Normally endothelial cells do not express VCAM-1. TNF-a , IL-1, IL-4 and LPS can stimulate endothelial cells to express VCAM-1. 42,59,76 Most of our understanding of the in vivo role of VLA-4 in T lymphocyte migration derives from blocking mAb studies, because VCAM-1 is important in embryo uterine implantation resulting in VCAM-1 knockout being a lethal mutation.77 mAb studies have shown a role for VLA-4 in T lymphocyte migration to sites of inflammation. VLA-4 blockade by TA-2 mAb inhibited blood T lymphocyte migration to cutaneous DTH reactions and IFN-g , TNF-a and LPS-induced inflammation by approximately 60%. VLA-4 blockade was effective at inhibiting the migration of both resting and activated T cells.78 VLA-4 is also important in T cell migration to inflammatory reactions in tissues other than skin. Anti-VLA-4 treatment alone inhibits T cell migration to inflamed joints in the adjuvant arthritis model.40 Anti-VLA-4 treatment inhibits T cell mediated neurologic damage in experimental allergic encephalomyelitis ŽEAE. 79 and T cell migration to the central nervous system.80 Blockade of VLA-4 also inhibits T cell migration to allergen-induced tracheal inflammation81 and T cell
Acknowledgements We would like to thank Aiyappa Palecanda for his critical reading of the manuscript, and Ara Kulidjian for his editorial assistance.
References 1. Gowans JL, Knight EJ Ž1964. The recirculation of lymphocytes in the rat. Proc R Soc London Ser B 159:257]282 2. Smith JB, McIntosh GH, Morris B Ž1970. The traffic of cells through tissues: a study of peripheral lymph in sheep. J Anat 107:87]100 3. MacKay CR, Marston W, Dudler L Ž1992. Altered patterns of T cell migration through lymph nodes and skin following antigen challenge. Eur J Immunol 22:2205]2210 4. Issekutz TB, Chin W, Hay JB Ž1980. Lymphocyte traffic through granulomas: difference in the recovery of indium111-labeled lymphocytes in afferent and efferent lymph. Cell Immunol 20:79]86 5. Springer TA Ž1994. Traffic signals for lymphocyte recirculation and leukocyte emigration: The multistep paradigm. Cell 76:301]314
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6. Jones DA, McIntire LV, Smith CW, Picker LJ Ž1994. A two-step adhesion cascade for T cellrendothelial cell interactions under flow conditions. J Clin Invest 94:2443]2450 7. Alon R, Kassner PD, Carr MW, Finger EB, Hemler ME, Springer TA Ž1995. The integrin VLA-4 supports tethering and rolling in flow on VCAM-1. J Cell Biol 128:1243 8. Muller WA, Weigl SA, Deng X, Phillips DM Ž1993. PECAM-1 is required for transendothelial migration of leukocytes. J Exp Med 178:449]460 9. Subramaniam M, Saffaripour S, Watson SR, Mayadas TN, Hynes RO, Wagner DD Ž1995. Reduced recruitment of inflammatory cells in a contact hypersensitivity response in P-selectin-deficient mice. J Exp Med 181:2277]2282 10. Kunkel EJ, Ley K Ž1996. Distinct phenotype of E-selectin-de ficient mice. E-selectin is required for slow leukocyte rolling in vivo. Circ Res 79:1196]1204 11. Bevilacqua MP, Butcher E, Furie BC, Gallatin M, Gimbrone M, Harlan JM, Kishimoto K, Lasky LA, McEver RP, Paulson J et al Ž1991. Selectins: A family of adhesion receptors. Cell 67:233 12. Vestweber D Ž1996. Ligand-specificity of the selectins. J Cell Biochem 61Ž4.:585]591 13. Bevilacqua MP, Nelson RM Ž1993. Selectins. J Clin Invest 91:379]387 14. Larson RS, Springer TA Ž1990. Structure and function of leukocyte integrins. Immunol Rev 114:181 15. Sonnenberg A Ž1993. Integrins and their ligands. Curr Top Microbiol Immunol 184:7]35 16. Gallatin WM, Weissman IL, Butcher EC Ž1983. A cell-surface molecule involved in organ-specific homing of lymphocytes. Nature 304:30]34 17. Lewinsohn DM, Bargatze RF, Butcher EC Ž1987. Leukocyteendothelial cell recognition: evidence of a common molecular mechanism shared by neutrophils, lymphocytes, and other leukocytes. J Immunol 138:4313]4321 18. Streeter PR, Rouse BT, Butcher EC Ž1988. Immunohistologic and functional characterization of a vascular addressin involved in lymphocyte homing into peripheral lymph nodes. J Cell Biol 107:1853]1862 19. Carlos TM, Harlan JM Ž1994. Leukocyte-endothelial adhesion molecules. Blood 84:2068]2101 20. Picker LJ, Warnock RA, Bums AR, Doerschuk CM, Berg EL, Butcher EC Ž1991. The neutrophil selectin LECAM-1 presents carbohydrate ligands to the vascular selectins ELAM-1 and GMP-140. Cell 66:921]933 21. Zollner O, Lenter MC, Blanks JE, Borges E, Steegmaier M, Zerwes HG, Vestweber D Ž1997. L-selectin from human, but not from mouse neutrophils binds directly to E-selectin. J Cell Biol 136:707]716 22. Pizcueta P, Luscinskas FW Ž1994. Monoclonal antibody blockade of L-selectin inhibits mononuclear leukocyte recruitment to inflammatory sites in vivo. Am J Pathol 145:461]469 23. Tedder TF, Steeber DA, Pizcueta P Ž1995. L-selectin-deficient mice have impaired leukocyte recruitment into inflammatory sites. J Exp Med 181:2259]2263 24. Bevilacqua MP, Pober JS, Mendrick DL, Cotran RS, Gimbrone MAJ Ž1987. Identification of an inducible endothelialleukocyte adhesion molecule. Proc Natl Acad Sci USA 84:9238 25. Lee KH, Chung KY, Koh YJ Ž1995. Memory T lymphocytes’ adherence to interferon gamma-activated human dermal microvascular endothelial cells via E-selectin. J Dermatol Sci 10Ž2.:166]175 26. Levinovitz A, Muhlhoff J, Isenmann I, Vestweber D Ž1993. ¨ Identification of a glycoprotein ligand for E-selectin on mouse myeloid cells. J Cell Biol 121:449]459 27. Kotovuori P, Tontti E, Pigott R, Shepherd M, Kiso M, Hasegawa A, Renkonen R, Nortamo P, Altieri DC, Gahmberg CG Ž1997. The vascular E-selectin binds to the leukocyte integrins CD11rCD18. Glycobiology 3Ž2.:131]136
28. Berg EL, Yoshino T, Rott LS, Robinson MK, Warnock RA, Kishimoto TK, Picker LJ, Butcher EC Ž1991. The cutaneous lymphocyte antigen is a skin lymphocyte homing receptor for the vascular lectin endothelial cell]leukocyte adhesion molecule 1. J Exp Med 174:1461]1466 29. Picker LJ, Michie SA, Rott LS, Butcher EC Ž1990. A unique phenotype of skin-associated lymphocytes in humans: Preferential expression of the HECA-452 epitope by benign and malignant T cells at cutaneous sites. Am J Pathol 136:1053]1068 30. Picker LJ, Kishimoto TK, Smith CW, Warnock RA, Butcher EC Ž1991. ELAM-1 is an adhesion molecule for skin-homing T cells. Nature 349:796]799 31. Rossiter H, Van Reijsen F, Mudde GC, Kalthoff F, Carla AFM, Bruijnzeel-Koomen, Picker LJ, Kupper TS Ž1994. Skin disease-related T cells bind to endothelial selectins: expression of cutaneous lymphocyte antigen ŽCLA. predicts E-selectin but not P-selectin binding. Eur J Immunol 24:205]210 32. Binns RM, Whyte A, Licence ST, Harrison AA, Tsang YT, Haskard DO, Robinson MK Ž1996. The role of E-selectin in lymphocyte and polymorphonuclear cell recruitment into cutaneous delayed hypersensitivity reactions in sensitized pigs. J Immunol 157:4094]4099 33. Silber A, Newman W, Sasseville VG, Pauley D, Beall D, Walsh DG, Ringler W Ž1994. Recruitment of lymphocytes during cutaneous delayed hypersensitivity in nonhuman primates is dependent on E-selectin and vascular cell adhesion molecule 1. J Clin Invest 93:1554]1563 34. Austrup F, Vestweber D, Borges E, Lohning M, Brauer R, Herz U, Renz H, Hallmann R, Scheffold A, Radbruch A et al Ž1997. P- and E-selectin mediate recruitment of T-helper-1 but not T-helper-2 cells into inflamed tissues. Nature 385:81]83 35. Labow MA, Norton CR, Rumberger JM, Lombard-Gillooly KM, Shuster DJ, Hubbard J, Bertko R, Knaack PA, Terry RW, Harbison MI, Ž1994. Characterization of E-selectin-deficient mice: demonstration of overlapping function of the endothelial selectins. Immunity 1:709]720 36. Staite ND, Justen JM, Sly LM, Beaudet AL, Bullard DC Ž1996. Inhibition of delayed-type contact hypersensitivity in mice deficient in both E- selectin and P- selectin. Blood 88Ž8.:2973]2979 37. Henseleit U, Steinbrink K, Goebeler M, Roth J, Vestweber D, Sorg C, Sunderkotter C Ž1996. E-selectin expression in experimental models of inflammation in mice. J Pathol 180:317]325 38. Whyte A, Licence ST, Robinson MK, van der Lienden K Ž1996. Lymphocyte subsets and adhesion molecules in cutaneous inflammation induced by inflammatory agonists: Correlation between E-selectin and gamma delta TcRŽq. lymphocytes. Lab Invest 75Ž3.:439]449 39. Issekutz TB Ž1990. Effects of six different cytokines on lymphocyte adherence to microvascular endothelium and in vivo lymphocyte migration in the rat. J Immunol 144: 2140]2146 40. Issekutz TB, Issekutz AC Ž1991. T lymphocyte migration to arthritic joints and dermal inflammation in the rat: Differing migration patterns and the involvement of VLA-4. Clin Immunol Immunopathol 61:436]447 41. Binns RM, Licence ST, Harrison AA, Keelan ET, Robinson MK, Haskard DO Ž1996. In vivo E-selectin upregulation correlates early with infiltration of PMN, later with PBL entry: MAbs block both. Am J Physiol 270:H183]193 42. Thornhill MH, Wellicome SM, Mahiouz DL, Lanchbury JSS, Kyan-Aung U, Haskard DO Ž1991. Tumor necrosis factor combines with IL-4 or IFN-gamma to selectively enhance endothelial cell adhesiveness for T cells: The contribution of vascular cell adhesion molecule-1-dependent and independent binding mechanisms. J Immunol 146:592]598 43. Berlin C, Bargatze RF, Campbell JJ, Von Andrian UH, Szabo
91
R. Inman
44.
45.
46.
47.
48.
49. 50.
51.
52.
53.
54.
55. 56. 57. 58.
59.
60.
MC, Hasslen SR, Nelson RD, Erlandsen SL, Butcher EC Ž1995. Alpha 4 integrins mediate lymphocyte attachment and rolling under physiologic flow. Cell 80:413]422 Johnston B, Issekutz TB, Kubes P Ž1996. The alpha 4integrin supports leukocyte rolling and adhesion in chronically inflamed postcapillary venules in vivo. J Exp Med 183: 1995]2006 Kanwar S, Bullard DC, Hickey MJ, Smith CW, Beaudet AL, Wolitzky BA, Kubes P Ž1997. The association between alpha4-integrin, P-selectin, and E-selectin in an allergic model of inflammation. J Exp Med 185:1077]1087 Stenberg PE, McEver RP, Shuman MA, Jacques YV, Bainton DF Ž1985. A platelet alpha-granule membrane protein ŽGMP140. is expressed on the plasma membrane after activation. J Cell Biol 101:880 McEver RP, Beckstead JH, Moore KL, Marshall-Carlson L, Bainton DF Ž1989. GMP-140, a platelet alpha-granule membrane protein, is also synthesized by vascular endothelial cells and is localized in Weibel]Palade bodies. J Clin Invest 84:92]99 Weller A, Isenmann S, Vestweber D Ž1992. Cloning of the mouse endothelial selectins. Expression of both E- and Pselectin is inducible by tumor necrosis factor alpha. J Biol Chem 267:15176]15183 Wagner DD Ž1993. The Weibel]Palade body: the storage granule for von Willebrand factor and P-selectin. Thromb Haemost 70:105]110 Todoroki N, Watanabe Y, Akaike T, Katagiri Y, Tanoue K, Yamazaki H, Tsuji T, Toyoshima S, Osawa T Ž1991. Enhancement by IL-1 and IFN-gamma of platelet activation: adhesion to leukocytes via GMP-140rPADGEM protein ŽSD62.. Biochem Biophys Res Commun 179:756]761 Moore KL, Stults NL, Diaz S, Smith DF, Cummings RD, Varki A, McEver RP Ž1992. Identification of a specific glycoprotein ligand for P-selectin ŽCD62. on myeloid cells. J Cell Biol 118:445]456 Alon R, Rossiter H, Wang X, Springer TA, Kupper TS Ž1994. Distinct cell surface ligands mediate T lymphocyte attachment and rolling on P and E selectin under physiological flow. J Cell Biol 127:1485]1495 Tang T, Frenette PS, Hynes RO, Wagner DD, Mayadas TN Ž1996. Cytokine-induced meningitis is dramatically attenuated in mice deficient in endothelial selectins. J Clin Invest 97:2485]2490 Tang ML, Hale LP, Steeber DA, Tedder TF Ž1997. L-selectin is involved in lymphocyte migration to sites of inflammation in the skin: delayed rejection of allografts in L-selectin-defi cient mice. J Immunol 158:5191]5199 Arnaout MA Ž1990. Structure and function of the leukocyte adhesion molecules CD11rCD18. Blood 75:1037]1050 Marlin D, Springer TA Ž1987. Purified intercellular adhesion molecule-1 ŽICAM-1 . is a ligand for lymphocyte function-associated antigen 1 ŽLFA-1 .. Cell 51:813]819 Staunton DE, Dustin ML, Springer TA Ž1989. Functional cloning of ICAM-2, a cell adhesion ligand for LFA-1 homologous to ICAM-1. Nature 339:61]64 De Fougerolles AR, Springer TA Ž1992. Intercellular adhesion molecule 3, a third adhesion counter-receptor for lymphocyte function-associated molecule 1 on resting lymphocytes. J Exp Med 175:185]190 Pober JS, Gimbrone MAJ, Lapierre LA, Mendrick DL, Fiers W, Rothlien R, Springer TA Ž1986. Overlapping patterns of activation of human endothelial cell by interleukin-1, tumor necrosis factor and immune interferon. J Immunol 137: 1893]1896 Dustin ML, Rothlein R, Bhan AK, Dinarello CA, Springer TA Ž1986. Induction by IL-1 and interferon-g: Tissue distribution, biochemistry, and function of a natural adherence molecule ŽICAM-1 .. J Immunol 137:245]254
61. Haskard DO, Cavender DE, Beatty PG, Springer TA, Ziff M Ž1986. T lymphocyte adhesion to endothelial cells: mechanisms demonstrated by anti-LFA-1 monoclonal antibodies. J Immunol 137:2901]2906 62. Hamann A, Jablonski -WD, Duijvestijn A, Butcher EC, Baisch H, Harder R, Thiele HG Ž1988. Evidence for an accessory role of LFA-1 in lymphocyte-high endothelium interaction during homing. J Immunol 140:693]699 63. Issekutz TB Ž1993. Dual inhibition of VLA-4 and LFA-1 maximally inhibits cutaneous delayed-type hypersensitivity-induced inflammation. Am J Pathol 143:1286]1293 64. Issekutz TB Ž1995. In vivo blood monocyte migration to acute inflammatory reactions, IL-1 a , TNFa , IFN-t , and C5a utilizes LFA-1, Mac-1 and VLA-4: The relative importance of each integrin. J Immunol 154:6533]6540 65. Issekutz TB Ž1992. Inhibition of lymphocyte endothelial adhesion and in vivo lymphocyte migration to cutaneous inflammation by TA-3, a new monoclonal antibody to rat LFA-1. J Immunol 149:3394]3402 66. Sligh JD, Ballantyne CM, Rich SS, Hawkins HK, Smith CW, Bradley A, Beaudet AL Ž1993. Inflammatory and immune responses are impaired in mice deficient in intercellar adhesion molecule 1. Proc Natl Acad Sci USA 90:8529]8533 67. Xu H, Gonzalo JA, St. Pierre Y, Williams IR, Kupper TS, Cotran RS, Springer TA, Gutierrez-Ramos J-C Ž1994. Leukocytosis and resistance to septic shock in intercellular adhesion molecule 1-deficient mice. J Exp Med 180:95]109 68. Bell RG, Issekutz TB Ž1993. Expression of a protective intestinal immune response can be inhibited at three distinct sites by treatment with anti-a 4 integrin. J Immunol 151:4790]4802 69. Jasin HE, Lightfoot E, Davis LS, Rothlein R, Faanes RB, Lipsky PE Ž1992. Amelioration of antigen-induced arthritis in rabbits treated with monoclonal antibodies to leukocyte adhesion molecules. Arthritis Rheum 35:541]549 70. Hemler ME, Elices MJ, Parker C, Takada Y Ž1990. Structure of the integrin VLA-4 and its cell]cell and cell]matrix adhesion functions. Immunol Rev 114:45 71. Kubes P, Niu X, Smith CW, Kehrli Jr ME, Reinhardt PH, Woodman RC Ž1995. A novel b 1-dependent adhesion pathway on neutrophils: a mechanism invoked by dihydrocytochalasin B or endothelial transmigration. FASEB J 9:1103]1111 72. Issekutz TB, Miyasaka M, Issekutz AC Ž1996. Rat blood neutrophils express very late antigen 4 and it mediates migration to arthritic joint and dermal inflammation. J Exp Med 183:2175]2184 73. Elices MJ, Osborn L, Takada Y, Crouse C, Luhowskyj S, Hemler ME, Lobb RR Ž1990. VCAM-1 on activated endothelium interacts with the leukocyte integrin VLA-4 at a site distinct from the VLA-4rfibronectin binding site. Cell 60:577]584 74. Issekutz TB, Wykretowicz A Ž1991. Effect of a new monoclonal antibody, TA-2, that inhibits lymphocyte adherence to cytokine stimulated endothelium in the rat. J Immunol 147:109]116 75. Elices MJ, Tsai V, Strahl D, Goel AS, Tollefson V, Arrhenius T, Wayner EA, Gaeta FC, Fikes JD, Firestein GS Ž1994. Expression and functional significance of alternatively spliced CS1 fibronectin in rheumatoid arthritis microvasculature. J Clin Invest 93:405]416 76. Rice GE, Munro JM, Bevilacqua MP Ž1990. Inducible cell adhesion molecule 110 ŽINCAM-110 . is an endothelial receptor for lymphocytes. A CD11rCD18-independent adhesion mechanism. J Exp Med 171:1369]1374 77. Gurtner GC, Davis V, Li H, McCoy MJ, Sharpe A, Cybulski MI Ž1995. Targeted disruption of the murine VCAM1 gene: essential role of VCAM-1 in chorioallantoic fusion and placentation. Genes Dev 9:1]14 78. Issekutz TB Ž1991. Inhibition of in vivo lymphocyte migration to inflammation and homing to lymphoid tissues by the TA-2
92
Rodent models of lymphocyte migration
monoclonal antibody: A likely role for VLA-4 in vivo. J Immunol 147:4178]4184 79. Yednock TA, Cannon C, Fritz LC, Sanchez-Madrid F, Steinman L, Karin N Ž1992. Prevention of experimental autoimmune encephalomyelitis by antibodies against a 4b 1 integrin. Nature 356:63]66 80. Issekutz TB Ž1992. Effect of anti-LFA-1 and anti-VLA-4 on T lymphocyte migration to skin, joint, and CNS inflammation and lymph nodes. Int Cong Immunol 8:288 81. Nakajima H, Sano H, Nashimura T, Yoshida S, lwamoto T
Ž1994. Role of VCAM-1rVLA-4 and ICAM-1rLFA-1 interactions in antigen induced eosinophil and T cell recruitment into the tissue. J Exp Med 179:1145]1154 82. Pretolani M, Ruffie C, Lapa e Silva JR, Joseph D, Lobb RR, Vargaftig B Ž1994. Antibody to very late activation antigen 4 prevents antigen-induced bronchial hyperactivity and cellular infiltration in the guinea pig. J Exp Med 180:795]805 83. Paul LC, Davidoff A, Issekutz TB Ž1993. The efficacy of LFA-1 and VLA-4 antibody treatment in rat vascularized cardiac allograft rejection. Transplantation 55:1196]1199
93