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Inhibition of CD23 processing and regulation of IgE production
POSTER ABSTRACT
269
bronchial hyperreactivity (BHR) to inhaled methacholine, a rise in the levels of OVA-specific IgE and IgG1 in the serum, interleukin (IL)5, but not interferon-T release in the bronchoalveolar lavage (BAL) fluid and a massive eosinophil, CD4 + and CD8 + T-cell accumulation in the BAL fluid and bronchial tissue. In contrast, '~5 T cell -/OVA-challenged mice showed very low numbers of CD4 + and CD8 ÷ T cells and of eosinophils in BAL fluid and tissue, practically no IL5 release and diminished levels of circulating OVA-specific IgE and IgG1. BHR, however, was only minimally affected, indicating that mechanisms unrelated to eosinophilia and IL5 release may account for the development of BHR in this model. We then hypothesized that impaired immune response and allergic airway inflammation in ~/~ T cell -/- mice could result from a lack of' early IIA production. In confirmation, the intravenous administration of IL4 (5 p.g/mouse mixed with 50 ~tg of the anti-IL4 mAb, 11B11) 3 times during the immunization period restored Th2 response both in the periphery and in the lung, Finally, peritoneal "~5 T cells from +/+ mice produce IL4 during the immunization, as shown by flow cytometry after the intracellular and surface staining for IL4 and the ~5 TCR, respectively. We conclude that ~5 T cells play a key role in IL4dependent Th2 responses to OVA in mice.
Bronchopulmonary hyperreactivity, inflammation and mucosal metaplasia in a murine model of asthma S. Hail6 <~), J. Lefort (1), M. H u e r r e ~29 and B.B. Vargaftig ~ ~) Unit~ de Pharmacologie Cellulaire and ~2) Unit~ d'Histopathologie, Institut Pasteur, 75724 Paris cedex 15 Eosinophil infiltration into the airways and bronchopulmonary hyperresponsiveness (BHR) characterize asthma. Eosinophilia and BHR were induced in hyper-IgE BP2 mice immunized with ovalbumin (OA) in AL(OH)3 and challenged on day 14 with a single intranasal (i.n.) instillation of OA. BHR started 1 h after challenge, returned to basal values at around 3 h, to rebound at 6-24 h and persisted up to 6-11 days. BHR was accompanied by eosinophilia in the airways, BALF, blood and bone marrow, elevated TNFct (early) and IL4 and IL5 titres in serum and BALF; 48 h and later after provocation, >50% of the epithelial cells were transformed into mucus-producing cells (AB-PAS). Two major differences were noted between BALB/c and BP2 mice: eosinophils in hyperresponsive BP2 mice were frequently in the bronchial submucosa and in the respiratory epithelium, but tended to remain in the submucosa in BALB/c as if their washout via the BALF was accelerated in the absence of a signal from the epithelium, and BP2 mice contained elevated titres of IgE, identified immunohistochemically on granulocytes (basophils ?). Enhanced availability of IgE in the microenvironment, where the recruited eosinophils localize, may support enhanced cell activation. Eosinophilia, BHR, IL4 and mucus-producing cells were reduced by dexamethasone and by anti-IgE antibody 1-5 (courtesy of Dr C. Heusser, Novartis), supporting a coordinated role of T lymphocytes and IgE in airway inflammation and disease chronicity. Our model associating subacute and chronic inflammation enables the study of the mechanisms of passage from one to the other.
Inhibition of CD23 processing and regulation of IgE production R.J. M a y e r Smith Kline Beecham Pharmaceuticals, P.O. Box 1539, Kings of Prussia, PA 19406 (USA) CD23, the low-affinity IgE receptor, is upregulated on IL4-stimulated B ceils and monocytes, with a concomitant increase in the release of soluble fragments of CD23 (sCD23), generated by proteolytic processing of the membrane CD23. Both membrane and soluble forms of human CD23 are involved in a number of immune or inflammatory functions, including the regulation of IgE secretion following IL4 stimulation. The enzymatic process leading to the formation of sCD23 has been characterized and inhibitors of CD23 processing have been
270
N E W T H E R A P Y IN A L L E R G I C DISEASES
identified and characterized in cellular and animal models of CD23 release and IgE production. Batimastat, a non-selective metalloprotease inhibitor that blocks CD23 release, or related, selective inhibitors of CD23 release, have been shown to inhibit IgE production in IL4-challenged human peripheral blood leukocytes (PBL) as well as in ILA-challenged hu-PBL-SCID mice.
Synergism between the responses to LPS and to allergen of the murine airways: role and limitations of TNFt M.D. P o s s e b o n da Silva ~2), J. L e f o r t 0), M. N a h o r i (I~, C. D u m a r e y (1), C. Ruffi6 ~1), C. N a s p i t z ~2~ and B.B. Vargaftig ~1) (1)
Unit~ de Pharmacologie cellulaire, Unit~ Associ~e Institut Pasteur-INSERM U485, 75724 Paris cedex 15, and (2) Dept. Paediatrics, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, S. Paulo
Michel et al. (Am. J. Respir. Crit. Care Med., 154, 1641, 1996) showed that the concentration of LPS in house dust is an important determinant of asthma severity. We demonstrated that hyper-IgE BP2 Biozzi mice develop bronchopulmonary hyperresponsiveness (BHR) when challenged with ovalbumin (OVA), a standard allergen, 3-4 times (Eum et al., PNAS, 92, 12290, 1995) or once only (Hail6 et al., in preparation). In unpublished results we showed that the intranasal (i.n.) instillation of LPS also induces BHR, in which a role for TNFtx is likely. The present study was performed with BP2 mice immunized with s.c. 100 pg OVA in AI(OH)3 twice at a 7-day interval and challenged at day 14 with OVA (1-10 p.g) and/or with E. coli 055:B5 LPS (Sigma, 0.01-0.1 Ixg). The association of OVA to LPS, at 10 ~tg and 0.1 pg, respectively, failed to increase BHR. These doses of OVA and LPS induce, at the most, a submaximal BHR, and recruit eosinophils (24 h) and neutrophils (from 3 h on) respectively, to the bronchoalveolar lavage fluid (BALF). OVA (1 p~g) and LPS (0.01 pg) had effects similar to those of saline on BHR, but their association was followed by marked BHR 3 and 24 h later. At 3 and 6 h, the titres of TNFtx in the BALF were markedly augmented, whereas the those of IL5 and IL4 were unaffected. Neutrophil and eosinophil counts in the BALF showed a tendency to increase. To verify if OVA primes for LPS or LPS primes for OVA, they were given sequentially, at a 3-h interval, readings being 6 or 24 h after the first instillation. The production of TNFt~ at 6 h was markedly enhanced for the sequence OVA-LPS, but remained practically similar to the saline controls for the sequence LPS-OVA. When the reading was at 24 h, a tendency was observed for increased amounts of IL4 in the BALF for the sequence OVALPS. mrTNFct, one of the potential mediators of LPS, did not induce BHR when instilled i.n. at 10 ng, but did so when associated with 1 pg OVA. Anti-TNFc~ antibodies were given i.n. and s.c. and suppressed the enhanced effects of OVA by TNFt~. Nevertheless, the synergism between OVA and LPS was not modified by anti-TNF treatment, suggesting the participation of other mediators. A model was thus developed in which synergism between antigen and LPS for BHR and TNFc~ was shown, the latter replacing LPS as a costimulator with OVA, but not fully accounting for the synergized effect of antigen and LPS. MDPS was supported by the Conselho Nacional de Pesquisas (CNPq), Brazil.
269
bronchial hyperreactivity (BHR) to inhaled methacholine, a rise in the levels of OVA-specific IgE and IgG1 in the serum, interleukin (IL)5, but not interferon-T release in the bronchoalveolar lavage (BAL) fluid and a massive eosinophil, CD4 + and CD8 + T-cell accumulation in the BAL fluid and bronchial tissue. In contrast, '~5 T cell -/OVA-challenged mice showed very low numbers of CD4 + and CD8 ÷ T cells and of eosinophils in BAL fluid and tissue, practically no IL5 release and diminished levels of circulating OVA-specific IgE and IgG1. BHR, however, was only minimally affected, indicating that mechanisms unrelated to eosinophilia and IL5 release may account for the development of BHR in this model. We then hypothesized that impaired immune response and allergic airway inflammation in ~/~ T cell -/- mice could result from a lack of' early IIA production. In confirmation, the intravenous administration of IL4 (5 p.g/mouse mixed with 50 ~tg of the anti-IL4 mAb, 11B11) 3 times during the immunization period restored Th2 response both in the periphery and in the lung, Finally, peritoneal "~5 T cells from +/+ mice produce IL4 during the immunization, as shown by flow cytometry after the intracellular and surface staining for IL4 and the ~5 TCR, respectively. We conclude that ~5 T cells play a key role in IL4dependent Th2 responses to OVA in mice.
Bronchopulmonary hyperreactivity, inflammation and mucosal metaplasia in a murine model of asthma S. Hail6 <~), J. Lefort (1), M. H u e r r e ~29 and B.B. Vargaftig ~ ~) Unit~ de Pharmacologie Cellulaire and ~2) Unit~ d'Histopathologie, Institut Pasteur, 75724 Paris cedex 15 Eosinophil infiltration into the airways and bronchopulmonary hyperresponsiveness (BHR) characterize asthma. Eosinophilia and BHR were induced in hyper-IgE BP2 mice immunized with ovalbumin (OA) in AL(OH)3 and challenged on day 14 with a single intranasal (i.n.) instillation of OA. BHR started 1 h after challenge, returned to basal values at around 3 h, to rebound at 6-24 h and persisted up to 6-11 days. BHR was accompanied by eosinophilia in the airways, BALF, blood and bone marrow, elevated TNFct (early) and IL4 and IL5 titres in serum and BALF; 48 h and later after provocation, >50% of the epithelial cells were transformed into mucus-producing cells (AB-PAS). Two major differences were noted between BALB/c and BP2 mice: eosinophils in hyperresponsive BP2 mice were frequently in the bronchial submucosa and in the respiratory epithelium, but tended to remain in the submucosa in BALB/c as if their washout via the BALF was accelerated in the absence of a signal from the epithelium, and BP2 mice contained elevated titres of IgE, identified immunohistochemically on granulocytes (basophils ?). Enhanced availability of IgE in the microenvironment, where the recruited eosinophils localize, may support enhanced cell activation. Eosinophilia, BHR, IL4 and mucus-producing cells were reduced by dexamethasone and by anti-IgE antibody 1-5 (courtesy of Dr C. Heusser, Novartis), supporting a coordinated role of T lymphocytes and IgE in airway inflammation and disease chronicity. Our model associating subacute and chronic inflammation enables the study of the mechanisms of passage from one to the other.
Inhibition of CD23 processing and regulation of IgE production R.J. M a y e r Smith Kline Beecham Pharmaceuticals, P.O. Box 1539, Kings of Prussia, PA 19406 (USA) CD23, the low-affinity IgE receptor, is upregulated on IL4-stimulated B ceils and monocytes, with a concomitant increase in the release of soluble fragments of CD23 (sCD23), generated by proteolytic processing of the membrane CD23. Both membrane and soluble forms of human CD23 are involved in a number of immune or inflammatory functions, including the regulation of IgE secretion following IL4 stimulation. The enzymatic process leading to the formation of sCD23 has been characterized and inhibitors of CD23 processing have been
270
N E W T H E R A P Y IN A L L E R G I C DISEASES
identified and characterized in cellular and animal models of CD23 release and IgE production. Batimastat, a non-selective metalloprotease inhibitor that blocks CD23 release, or related, selective inhibitors of CD23 release, have been shown to inhibit IgE production in IL4-challenged human peripheral blood leukocytes (PBL) as well as in ILA-challenged hu-PBL-SCID mice.
Synergism between the responses to LPS and to allergen of the murine airways: role and limitations of TNFt M.D. P o s s e b o n da Silva ~2), J. L e f o r t 0), M. N a h o r i (I~, C. D u m a r e y (1), C. Ruffi6 ~1), C. N a s p i t z ~2~ and B.B. Vargaftig ~1) (1)
Unit~ de Pharmacologie cellulaire, Unit~ Associ~e Institut Pasteur-INSERM U485, 75724 Paris cedex 15, and (2) Dept. Paediatrics, Escola Paulista de Medicina, Universidade Federal de Sao Paulo, S. Paulo
Michel et al. (Am. J. Respir. Crit. Care Med., 154, 1641, 1996) showed that the concentration of LPS in house dust is an important determinant of asthma severity. We demonstrated that hyper-IgE BP2 Biozzi mice develop bronchopulmonary hyperresponsiveness (BHR) when challenged with ovalbumin (OVA), a standard allergen, 3-4 times (Eum et al., PNAS, 92, 12290, 1995) or once only (Hail6 et al., in preparation). In unpublished results we showed that the intranasal (i.n.) instillation of LPS also induces BHR, in which a role for TNFtx is likely. The present study was performed with BP2 mice immunized with s.c. 100 pg OVA in AI(OH)3 twice at a 7-day interval and challenged at day 14 with OVA (1-10 p.g) and/or with E. coli 055:B5 LPS (Sigma, 0.01-0.1 Ixg). The association of OVA to LPS, at 10 ~tg and 0.1 pg, respectively, failed to increase BHR. These doses of OVA and LPS induce, at the most, a submaximal BHR, and recruit eosinophils (24 h) and neutrophils (from 3 h on) respectively, to the bronchoalveolar lavage fluid (BALF). OVA (1 p~g) and LPS (0.01 pg) had effects similar to those of saline on BHR, but their association was followed by marked BHR 3 and 24 h later. At 3 and 6 h, the titres of TNFtx in the BALF were markedly augmented, whereas the those of IL5 and IL4 were unaffected. Neutrophil and eosinophil counts in the BALF showed a tendency to increase. To verify if OVA primes for LPS or LPS primes for OVA, they were given sequentially, at a 3-h interval, readings being 6 or 24 h after the first instillation. The production of TNFt~ at 6 h was markedly enhanced for the sequence OVA-LPS, but remained practically similar to the saline controls for the sequence LPS-OVA. When the reading was at 24 h, a tendency was observed for increased amounts of IL4 in the BALF for the sequence OVALPS. mrTNFct, one of the potential mediators of LPS, did not induce BHR when instilled i.n. at 10 ng, but did so when associated with 1 pg OVA. Anti-TNFc~ antibodies were given i.n. and s.c. and suppressed the enhanced effects of OVA by TNFt~. Nevertheless, the synergism between OVA and LPS was not modified by anti-TNF treatment, suggesting the participation of other mediators. A model was thus developed in which synergism between antigen and LPS for BHR and TNFc~ was shown, the latter replacing LPS as a costimulator with OVA, but not fully accounting for the synergized effect of antigen and LPS. MDPS was supported by the Conselho Nacional de Pesquisas (CNPq), Brazil.