Morrison RP, Feilzer K, Tumas DB. Gene knockout mice establish a primary protective role for major histocompatibility complex class II-restricted responses in Chlamydia trachomatis genital tract infection.
Infect Immun 1995;
63:4661-8. [PMID:
7591120 PMCID:
PMC173669 DOI:
10.1128/iai.63.12.4661-4668.1995]
[Citation(s) in RCA: 255] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Mice with disrupted beta 2-microglobulin (beta 2m-/-), I-A (class II-/-), or CD4 (CD4-/-) genes were examined for their capacity to resolve Chlamydia trachomatis genital tract infection. C57BL/6 and beta 2m-/- mice resolved infection similarly and were culture negative by 4 to 5 weeks following infection. Conversely, major histocompatibility complex (MHC) class II-/- mice failed to resolve infection, and CD4-/- mice showed a significant delay (2 weeks). Secondary challenge of C57BL/6, beta 2m-/-, and CD4-/- mice established that acquired protective immunity, which was characterized by an infection of shortened duration and reduced shedding of infectious organisms, developed. Serological analysis of C57BL/6 and beta 2m-/- mice by enzyme-linked immunosorbent assays revealed no striking differences in the immunoglobulin subclass specificity of the anti-Chlamydia response, although some differences were observed in the magnitude of the immunoglobulin G2a (IgG2a) and IgG2b responses. Class II-/- mice produced lower-titered serum anti-Chlamydia antibodies of all isotypes. The serum antibody responses of CD4-/- mice were similar to those of C57BL/6 mice, except that the anti-Chlamydia IgA response was delayed by approximately 3 weeks. Analysis of vaginal washes for Chlamydia-reactive antibodies revealed the presence of IgG2a, IgG2b, and IgA in C57BL/6 and beta 2m-/- mice and primarily of IgA in CD4-/- mice. Vaginal washes from class II-/- mice were consistently antibody negative. Interestingly, the Chlamydia-specific IgA response in the vaginal washes of CD4-/- mice was delayed, but its appearance coincided with decreased shedding of infectious organisms and resolution of infection. Our results demonstrate that MHC class II-restricted T-cell responses are necessary for the development of protective immunity to Chlamydia genital tract infection and that local (vaginal) anti-Chlamydia IgA antibody coincides with the resolution of infection. A substantive role for MHC class I-restricted T-cell responses in protective immunity to Chlamydia genital tract infection was not confirmed.
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