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Regulation of endothelial-lymphocyte interactions at the blood-brain barrier
4
Speaker Abstracts / Journal of Neuroimmunology 90 (1998) 1-11
Experimental "Autoimmune" versus "Allergic" Encephalomyelitis IL Dal Canto, G. Costa, L. Steinman, Stanford University,Stanford, USA, M. Dal Canto, Northwestern University,USA,C.G. Fathman. Stanford University, Stanford, USA
Adoptive transfer of encephalitogenie T-cells, transduced for the expression of ILl0, suggested that autoimmune and allergic encephalomyelitis might be different entities. Using rctroviral transduction of encephalitogenie T-cell hybridomas to allow site directed delivery of ILl0, we asked whether excess ILl0 would create "allergic" EAE whereas less ILl0 might ameliorate "autoimmune" EAE. Histochemical analysis demonstrated localization of transduced T cells in sites of inflammation. Data to be presented demonstrate that graded amounts of T-cells transduced for the expression of ILl 0 allowed different phenotypic expressions of disease, depending upon the amount of cytokine secreted in the lesion. Excess ILl0 gave a PMN and eosinophil mediated "allergic" EAE while limited amounts of ILl0 secreted into lesions of EAE allowed amelioration of the lymphocyte mediated "autoimmune" form of EAE.
Visualizing T Cell Recognition M.M. Davis. Stanford University,Stanford, USA
Precursor Cells of Oligndendroeytes and their Mydlnating Potential M. Dubois-Dalcq. Tamir Ben-Hur, Bernard Rogister, Murray Kerren, lns~,t Pasteur,France,Oliver Brustle, Dept. of Neuropathology,Germany,Ran MeKay, NINDS-NIH, USA
The generation of oligodmadrocytes from multipotential precursors is characterized by a progressive restriction in fate. Neural stem tells expressing nestin can ge~aerato neurons, astrocytes and oligodendrocytes. In the neonatal rat brain, such multipotential precursors are distinct from tells expressing the polysialylated (PSA) form of NCAM which give rise to astrocytes and oligodendrocyte progenitorS (OP).When grafted into a focal demyelinating lesions in adult rats, PSA-NCAM+ neural precursors repair myelin very efficiently (Keirstead et al, in prep). By injecting multipotential neural precursors into the embryonic rat brain ventrienies, we have geneaated human/rat neursl chimeras_ Human embryonic neural precursors migram and integrate extensively in the developping rat brain during the first two months, generating all CNS lineages but most effaeiently oligodendrocytes. These models caa be used to study the myelinating potential of neural precursor tells in rodent and man.
MHC Expression in CNS Cells in Vivo and the Biologic Consequences C.F. Evans, M.B.A. Oldstonc. TheScrippsReseamhlnstitute, CA, USA
W e are interested in h o w T cell r e c e p t o r s a n d other molecules on the cell surface 'collaborate' in the recognition of p a r t i c u l a r antigens p r e s e n t e d b y o t h e r cells. To a c c o m p l i s h this w e h a v e m a d e Green H u o r e s t e n c e Protein fusions of m a n y of these molecules a n d expressed t h e m in either antigen presenting cells or T cells a n d followed their m o v e m e n t s during T cell recognition using multi-color v i d e o m i c r o s c o p y . Uniformly, w e see a r a p i d clustering of these molecules at the T:B interface within s e c o n d s of the first calcium flux in the T cell. This p h e n o m e n o n a p p e a r s to be T cell d r i v e n a n d d e p e n d e n t on co-stimulation through CD28 a n d / o r LFA-I. T h e resulting concentration of receptors a t the cell:cell interface m a y thus account for the increased efficiency a n d sensitivity of antigen p r e s e n t a t i o n b y " p r o f e s s i o n a l " antigen presenting cells.
Regulation of Endotheiial-lymphoeyte Interactions at the Blood-brain Barrier _K.Dorovini-Zi~,UniversityofBritish Columbia,Canada
Specific interactions of circulating lymphocytes with cerebral endothelial cells (EC) and increased permeability of the blood-brain barrier (BBB) are early critical events during the development of central nervous system (CNS) inflammation. These interactions are largely dependent upon the activation status of brain EC and lymphocytes which, in turn, are governed by a host of inflammatory mediators. Exposure of human brain EC (HBEC) to eytokines (TNF-ct, IFN-7, IL-II3) or LPS in vitro induces de nova expression or upregutation of the adhesion molecules [CAM-I, VCAM-I and E-selectin which act singly or in combination to mediate adhesion and migration of resting T lymphocytes across activated HBEC monolayers. IFN-y induces expression of Class II MHC on HBEC leading to enhanced lymphocyte adhesion and transendothelial migration. Adhesion of resting, activated, and memory CD4" T cells to activated endothelium is tightly regulated by the chemokines RANTES and MIP-113 expressed and released by HBEC following cytokine stimulation. The constitutive expression of the costimutatory molecules B7-2 and LFA-3 and induced expression of B7-1 by HBEC promotes antigen independent proliferation of CD4 ~ T cells. During lymphocyte-endothelial interactions the permeability of the endothelial barrier increases as a result of both lymphocyte transendothelial migration and the direct effect of cytokines on the endothelial cytoske'leton. The evidence so far indicates that human cerebral endothelial cells play an active role in the recruitment of lymphocytas across the BBB.
Immune surveillance is a function of activated T lymphecytes that travel to all body components, including tl~ central nervous system. Their activation requires foreign or altered self proteins complex with the host major histocompafibility (MHC) molecuies presented on the cell surface. MHC molecules are constimilvely presented oa micmglia anti endothefial cells, but not on neurons, asu'ocytes or oligodendrocytns in vivo. To determine what CNS cells MHC molecules could be induced on in vivo we created tmnsgenic mice that express interferon-3, restricted to the CNS by use of a brain-specific promoter. Expression of IFN-y occurred at eight weeks of life at~r myelin was formed. MHC class I and II glyeoproteins were not induced on neurons in viv_.._qby IFN-y. Contrary to in vitro tissue culture studies, asnocytes were not induced to express MHC molecules indicating that at the level of detection (antibodies and confocai microscopy), they are likely unable to present antigens in vivo. Oligndendr~ytes were capable of expressing both MHC class I and II molecules in vivo suggest their ability to present antigen and act as a target for T cell mediated injury.
Experimental Autoimmune Encephafitis in Cytokine Gene Knockout Mice A. Fontana, UniversityHospttal,Switzerland,H.-E Eugster, K. Fret, University of Zarfch, Switzerland, H. Lassmann, Universityof Vienna,Austria, U. Malipiero, U. SahrbaQher, Universityof Zurich, Switzerland
TNF, LT-a and FasL belong to the TNF/NGF ligand superfamily. Together with other Thl cytokines they are expressed in the CNS in EAE.MOG was found to induce EAE in mice deficient for TNF and LT-a but not in LTa single knockouts. Lpr and gld mice with absence of Fas signaling show only a transient but not a chronic course of EAE. Thus, whereas the combined action of TNF and LT-a are not required for EAE, LTa and FasL are involved in the onset and course of the disease.The inactivation of the iNOS gene does not prevent induction of EAE. However, resistance of disease was found in IL-6 knockout mice. Resistance Je not due to lower anhoMOG IgG titers,elnce B-cell deficient mice a r e susceptible to EAE. In IL-6-/- mice the emry of MOG specific T celia into the CNS is hindered because of absence of VCAM-I on CNS vessels. Taken collectively, the use of cytokine gene knockout mice in stu~es on EAE shows on one hand the complexity of the cytoldne net work, on the other it highlights the importance of certain cytoldnes in the onset and course of EAE.
Speaker Abstracts / Journal of Neuroimmunology 90 (1998) 1-11
Experimental "Autoimmune" versus "Allergic" Encephalomyelitis IL Dal Canto, G. Costa, L. Steinman, Stanford University,Stanford, USA, M. Dal Canto, Northwestern University,USA,C.G. Fathman. Stanford University, Stanford, USA
Adoptive transfer of encephalitogenie T-cells, transduced for the expression of ILl0, suggested that autoimmune and allergic encephalomyelitis might be different entities. Using rctroviral transduction of encephalitogenie T-cell hybridomas to allow site directed delivery of ILl0, we asked whether excess ILl0 would create "allergic" EAE whereas less ILl0 might ameliorate "autoimmune" EAE. Histochemical analysis demonstrated localization of transduced T cells in sites of inflammation. Data to be presented demonstrate that graded amounts of T-cells transduced for the expression of ILl 0 allowed different phenotypic expressions of disease, depending upon the amount of cytokine secreted in the lesion. Excess ILl0 gave a PMN and eosinophil mediated "allergic" EAE while limited amounts of ILl0 secreted into lesions of EAE allowed amelioration of the lymphocyte mediated "autoimmune" form of EAE.
Visualizing T Cell Recognition M.M. Davis. Stanford University,Stanford, USA
Precursor Cells of Oligndendroeytes and their Mydlnating Potential M. Dubois-Dalcq. Tamir Ben-Hur, Bernard Rogister, Murray Kerren, lns~,t Pasteur,France,Oliver Brustle, Dept. of Neuropathology,Germany,Ran MeKay, NINDS-NIH, USA
The generation of oligodmadrocytes from multipotential precursors is characterized by a progressive restriction in fate. Neural stem tells expressing nestin can ge~aerato neurons, astrocytes and oligodendrocytes. In the neonatal rat brain, such multipotential precursors are distinct from tells expressing the polysialylated (PSA) form of NCAM which give rise to astrocytes and oligodendrocyte progenitorS (OP).When grafted into a focal demyelinating lesions in adult rats, PSA-NCAM+ neural precursors repair myelin very efficiently (Keirstead et al, in prep). By injecting multipotential neural precursors into the embryonic rat brain ventrienies, we have geneaated human/rat neursl chimeras_ Human embryonic neural precursors migram and integrate extensively in the developping rat brain during the first two months, generating all CNS lineages but most effaeiently oligodendrocytes. These models caa be used to study the myelinating potential of neural precursor tells in rodent and man.
MHC Expression in CNS Cells in Vivo and the Biologic Consequences C.F. Evans, M.B.A. Oldstonc. TheScrippsReseamhlnstitute, CA, USA
W e are interested in h o w T cell r e c e p t o r s a n d other molecules on the cell surface 'collaborate' in the recognition of p a r t i c u l a r antigens p r e s e n t e d b y o t h e r cells. To a c c o m p l i s h this w e h a v e m a d e Green H u o r e s t e n c e Protein fusions of m a n y of these molecules a n d expressed t h e m in either antigen presenting cells or T cells a n d followed their m o v e m e n t s during T cell recognition using multi-color v i d e o m i c r o s c o p y . Uniformly, w e see a r a p i d clustering of these molecules at the T:B interface within s e c o n d s of the first calcium flux in the T cell. This p h e n o m e n o n a p p e a r s to be T cell d r i v e n a n d d e p e n d e n t on co-stimulation through CD28 a n d / o r LFA-I. T h e resulting concentration of receptors a t the cell:cell interface m a y thus account for the increased efficiency a n d sensitivity of antigen p r e s e n t a t i o n b y " p r o f e s s i o n a l " antigen presenting cells.
Regulation of Endotheiial-lymphoeyte Interactions at the Blood-brain Barrier _K.Dorovini-Zi~,UniversityofBritish Columbia,Canada
Specific interactions of circulating lymphocytes with cerebral endothelial cells (EC) and increased permeability of the blood-brain barrier (BBB) are early critical events during the development of central nervous system (CNS) inflammation. These interactions are largely dependent upon the activation status of brain EC and lymphocytes which, in turn, are governed by a host of inflammatory mediators. Exposure of human brain EC (HBEC) to eytokines (TNF-ct, IFN-7, IL-II3) or LPS in vitro induces de nova expression or upregutation of the adhesion molecules [CAM-I, VCAM-I and E-selectin which act singly or in combination to mediate adhesion and migration of resting T lymphocytes across activated HBEC monolayers. IFN-y induces expression of Class II MHC on HBEC leading to enhanced lymphocyte adhesion and transendothelial migration. Adhesion of resting, activated, and memory CD4" T cells to activated endothelium is tightly regulated by the chemokines RANTES and MIP-113 expressed and released by HBEC following cytokine stimulation. The constitutive expression of the costimutatory molecules B7-2 and LFA-3 and induced expression of B7-1 by HBEC promotes antigen independent proliferation of CD4 ~ T cells. During lymphocyte-endothelial interactions the permeability of the endothelial barrier increases as a result of both lymphocyte transendothelial migration and the direct effect of cytokines on the endothelial cytoske'leton. The evidence so far indicates that human cerebral endothelial cells play an active role in the recruitment of lymphocytas across the BBB.
Immune surveillance is a function of activated T lymphecytes that travel to all body components, including tl~ central nervous system. Their activation requires foreign or altered self proteins complex with the host major histocompafibility (MHC) molecuies presented on the cell surface. MHC molecules are constimilvely presented oa micmglia anti endothefial cells, but not on neurons, asu'ocytes or oligodendrocytns in vivo. To determine what CNS cells MHC molecules could be induced on in vivo we created tmnsgenic mice that express interferon-3, restricted to the CNS by use of a brain-specific promoter. Expression of IFN-y occurred at eight weeks of life at~r myelin was formed. MHC class I and II glyeoproteins were not induced on neurons in viv_.._qby IFN-y. Contrary to in vitro tissue culture studies, asnocytes were not induced to express MHC molecules indicating that at the level of detection (antibodies and confocai microscopy), they are likely unable to present antigens in vivo. Oligndendr~ytes were capable of expressing both MHC class I and II molecules in vivo suggest their ability to present antigen and act as a target for T cell mediated injury.
Experimental Autoimmune Encephafitis in Cytokine Gene Knockout Mice A. Fontana, UniversityHospttal,Switzerland,H.-E Eugster, K. Fret, University of Zarfch, Switzerland, H. Lassmann, Universityof Vienna,Austria, U. Malipiero, U. SahrbaQher, Universityof Zurich, Switzerland
TNF, LT-a and FasL belong to the TNF/NGF ligand superfamily. Together with other Thl cytokines they are expressed in the CNS in EAE.MOG was found to induce EAE in mice deficient for TNF and LT-a but not in LTa single knockouts. Lpr and gld mice with absence of Fas signaling show only a transient but not a chronic course of EAE. Thus, whereas the combined action of TNF and LT-a are not required for EAE, LTa and FasL are involved in the onset and course of the disease.The inactivation of the iNOS gene does not prevent induction of EAE. However, resistance of disease was found in IL-6 knockout mice. Resistance Je not due to lower anhoMOG IgG titers,elnce B-cell deficient mice a r e susceptible to EAE. In IL-6-/- mice the emry of MOG specific T celia into the CNS is hindered because of absence of VCAM-I on CNS vessels. Taken collectively, the use of cytokine gene knockout mice in stu~es on EAE shows on one hand the complexity of the cytoldne net work, on the other it highlights the importance of certain cytoldnes in the onset and course of EAE.