FIG. 1.

Characterization of a C. trachomatis-specific CD8⁺-T-cell clone. (A) IFN-γ production by the clone in response to C. trachomatis-infected autologous PBMC. (B) IFN-γ production in response to U937-A2 infected with live or heat-killed C. trachomatis, live S. enterica and live Y. enterocolitica. (C) Surface expression of CD8, CD4, and TCR-α/β and intracellular expression of perforin and granzyme A by a C. trachomatis-specific CD8⁺-T-cell clone, analyzed by using two-color flow cytometric analysis (a and b) and a single-color flow cytometric analysis (c and d). These data are representative of 31 C. trachomatis-specific T-cell clones studied. Each experiment was carried out at least three times. CT, C. trachomatis.