Resolution of Secondary Chlamydia trachomatis Genital Tract Infection in Immune Mice with Depletion of Both CD4(+) and CD8(+) T cells

The essential role of T cells in the resolution of primary murine Chlamydia trachomatis genital tract infection is inarguable; however, much less is known about the mechanisms that confer resistance to reinfection. We previously established that CD4(+) T cells and B cells contribute importantly to resistance to reinfection. In our current studies, we demonstrate that immune mice concurrently depleted of both CD4(+) T cells and CD8(+) T cells resisted reinfection as well as immunocompetent wild-type mice. The in vivo depletion of CD4(+) and CD8(+) T cells resulted in diminished chlamydia-specific delayed-type hypersensitivity responses, but antichlamydial antibody responses were unaffected. Our data indicate that immunity to chlamydial genital tract reinfection does not rely solely upon immune CD4(+) or CD8(+) T cells and further substantiate a predominant role for additional effector immune responses, such as B cells, in resistance to chlamydial genital tract reinfection.