title: Chlamydia trachomatis genital tract infection of antibody-deficient gene knockout mice.
abstract: The importance of antibody-mediated immunity in primary and secondary Chlamydia trachomatis genital tract infections was examined by using a definitive model of B-cell deficiency, the microMT/microMT gene knockout mouse. Vaginally infected B-cell-deficient microMT/microMT mice developed a self-limiting primary infection that was indistinguishable from infection of control C57BL/6 mice. Sera and vaginal secretions from infected mice were analyzed for anti-Chlamydia antibodies. C57BL/6 mice produced high-titered serum anti-Chlamydia immunoglobulin G2a (IgG2a), IgG2b, and IgA antibodies, and vaginal washes contained predominately anti-Chlamydia IgA. Serum and vaginal washes from infected B-cell-deficient mice were negative for anti-Chlamydia antibody. T-cell proliferation and delayed-type hypersensitivity assays were used as measures of Chlamydia-specific cell-mediated immunity and were found to be comparable for C57BL/6 and B-cell-deficient mice. Seventy days following primary infection, mice were rechallenged to assess acquired immunity. B-cell-deficient mice which lack anti-Chlamydia antibodies were more susceptible to reinfection than immunocompetent C57BL/6 mice. However, acquired immune resistance was evident in both strains of mice and characterized by decreased shedding of chlamydiae and an infection of shorter duration. Thus, this study demonstrates that cell-mediated immune responses alone were capable of resolving chlamydial infection; however, in the absence of specific antibody, mice were more susceptible to reinfection. Therefore, these data suggest that both humoral and cell-mediated immune responses were important mediators of immune protection in this model, though cell-mediated immune responses appear to play a more dominant role.
authors.affiliation: Laboratory of Intracellular Parasites, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, USA.
authors.forename: H
authors.initials: H
authors.lastname: Su
authors.forename: K
authors.initials: K
authors.lastname: Feilzer
authors.forename: H D
authors.initials: HD
authors.lastname: Caldwell
authors.forename: R P
authors.initials: RP
authors.lastname: Morrison
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000502:physiology*; D001402:B-Lymphocytes / Q000502:physiology; D001428:Bacterial Vaccines / Q000627:therapeutic use; D002690:Chlamydia Infections / Q000276:immunology*; D002692:Chlamydia trachomatis / Q000276:immunology*; D005260:Female; D005831:Genital Diseases, Female / Q000276:immunology*; D006367:HeLa Cells; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout
chemical_list: D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines