Figure 7.

T cell-mediated cross-mucosal protection against C. trachomatis is dependent on IFNγ. (A) Groups of 6–10 C57BL/6 and IFNγ^−/− mice were intranasally immunized with 100 IFU of C. trachomatis. A month later, these mice and naïve mice were challenged in the genital tract. Bacterial burden was determined 3 days post-challenge by quantitative PCR. (B) Groups of 9–10 C57BL/6 mice were intranasally immunized with C. trachomatis. A month later, these mice and naïve mice were treated with IFNγ-neutralizing or isotype control antibodies, and then challenged in the genital tract. Bacterial burden was determined by quantitative PCR 5 days after challenge. (C-F) Groups of 19–20 CD90.1⁺ mice were intranasally immunized with C. trachomatis. A month later, CD4⁺ or CD8⁺ T cells were purified from their SLOs, labeled with CFSE, and transferred into CD90.2⁺ wt or IFNγR^−/− mice. These mice and control mice that did not receive any T cells were then challenged in the genital tract. Five days later, (C) bacterial burden was determined by quantitative PCR. (D) Absolute number of donor cells, identified as CD90.1⁺CD4⁺ or CD90.1⁺CD8⁺, (E) percent of donor cells that were CFSE^dim, and (F) IFNγ MFI of donor cells in the uterine tissues were determined by intracellular staining and flow cytometry. These data are representative of 2 independent experiments. *: p ≤ 0.05. **: p ≤ 0.01