FIG. 1.

Flow cytometry analysis of viable T cells cocultivated with C. trachomatis-infected macrophages and stained with PI and anti-CD3 antibody (FITC labeled). Staining was performed after 6 days of coculture. PHA-preactivated T cells were incubated with noninfected macrophages (A, B, and C) or with macrophages infected with C. trachomatis at an MOI of 5 (D, E, and F) at a ratio of 1:1. (A and D) Dot blot analysis of double-stained cells was used to gate CD3⁺ and CD3⁻ cells. The PI contents of gated cells were subsequently determined by histogram analysis. (B and E) PI fluorescence of CD3⁺ T cells (gate R1 [B] or gate R3 [E]). (C and F) PI fluorescence of CD3⁻ cells (gate R2 [C] or gate R4 [F]). M1 markers indicate viable cells with at least a diploid DNA content. Percentages in panels E and F indicate the reduction in numbers of viable cells in comparison to the cultures of T cells with noninfected macrophages in the depicted experiment. In total, five experiments were performed; the mean viability ± standard deviation of CD3⁻ cells in C. trachomatis-infected cultures (MOI = 5) compared to that of noninfected cultures was 103% ± 12%, while that of CD3⁺ cells in C. trachomatis-infected cultures (MOI = 5) compared to noninfected cultures was 62% ± 6%, P = 0.004, as determined by one-way ANOVA (accounting for multiple comparisons by using the Bonferroni test).