Gene knockout B cell-deficient mice demonstrate that B cells play an important role in the initiation of T cell responses to Chlamydia trachomatis (mouse pneumonitis) lung infection.
T cell-mediated immunity as measured by delayed-type hypersensitivity, and IFN-gamma production has been shown to be critical for host defense against Chlamydia trachomatis infection in both human and animal studies. Using gene-targeted B cell-deficient mice, we examined the role of B cells in protective immunity to C. trachomatis (mouse pneumonitis) (MoPn) lung infection. B cell-deficient mice were observed to have a significantly higher mortality rate and in vivo chlamydial growth than did wild-type mice following MoPn lung infection. Interestingly, B cell-deficient mice not only lacked Ab responses but also failed to mount an efficient delayed-type hypersensitivity response following chlamydial lung infection. In contrast to results obtained from MoPn-infected wild-type C57BL/6 mice, spleen cells from infected B cell-deficient mice failed to produce Th1-related (IFN-gamma) or Th2-related (IL-6 and IL-10) cytokines after Chlamydia-specific in vitro restimulation. Moreover, unlike wild-type mice, B cell-deficient mice were not immune to rechallenge infection following recovery from primary chlamydial infection. The data indicate that B cells play an important role in host defense to primary and secondary chlamydial infection and suggest that B cells are crucial for the initiation of early T cell responses to chlamydial infection. This study provides evidence for the role of B cells in the in vivo priming of T cells during infection with the intracellular bacterial pathogen, C. trachomatis.
Department of Medical Microbiology, University of Manitoba, Winnipeg, Canada. yangxi@cc.umanitoba.ca
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D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D002690:Chlamydia Infections / Q000235:genetics* / Q000276:immunology* / Q000503:physiopathology; D002692:Chlamydia trachomatis / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis; D004198:Disease Susceptibility; D006968:Hypersensitivity, Delayed; D007113:Immunity, Innate; D007153:Immunologic Deficiency Syndromes / Q000235:genetics*; D008168:Lung / Q000382:microbiology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018410:Pneumonia, Bacterial / Q000235:genetics* / Q000276:immunology* / Q000503:physiopathology; D016019:Survival Analysis
D000907:Antibodies, Bacterial; D016207:Cytokines