CD4(+) T-CELLS PLAY A SIGNIFICANT ROLE IN ADOPTIVE IMMUNITY TO CHLAMYDIA-TRACHOMATIS INFECTION OF THE MOUSE GENITAL-TRACT

The ability of CD4(+) and CD8(+) T cells to adoptively immunize mice against Chlamydia trachomatis infection of the mouse genital tract was studied. Adoptive transfer experiments were performed with splenic CD4(+) or CD8(+) T cells obtained from mice following resolution of a primary genital tract infection and after a secondary chlamydial challenge. The results show that donor CD4(+) T cells, but not CD8(+) T cells, obtained from mice following resolution of a primary infection or after secondary challenge were effective in transferring significant antichlamydial immunity to the genital tracts of naive animals, The lymphokine profiles in the culture supernatants of proliferating Chlamydia-specific CD4(+) T cells obtained from mice following resolution of a primary infection and after secondary challenge were assayed by an enzyme-linked immunoadsorbent assay, Protective CD4(+) T cells restimulated in vitro secreted interleukin 2, gamma interferon, and interleukin 6, lymphokine profiles characteristic of both Th1- and Th2-like responses, Resting CD4(+) T cells obtained from mice 4 months following resolution of a primary infection were also capable of conferring significant levels of adoptive protective immunity to naive mice. These findings support an important role for CD4(+) T cells in acquired immunity to chlamydial infection of the genital tract and indicate that protective CD4(+) immune responses in this model are relatively long lived.