FIG 6.

Both IL-7 signaling and IL-15 signaling are required to clear the intracellular bacterial mutant from the colon. Wild-type C57BL/6J mice (a), IL-7 receptor knockout mice (IL-7R^−/− [b]), and IL-15 receptor knockout mice (IL-15R^−/− [c]) were infected with 1 × 10⁷ IFU of the mutant intracellular bacterial clone G28.51.1 via intracolonic inoculation. On days 3 and 7 and weekly thereafter, rectal swabs were taken (a, c, and e), or on day 28, mouse tissues were harvested (b, d, and f), as indicated along the x axis, for monitoring live chlamydial organisms as shown along the y axis. Mouse tissues include different segments of gastrointestinal tract and extra-GI tract tissues as described in the Fig. 1 legend. Note that both IL-7R^−/− mice (b) and IL-15R^−/− knockout mice (c) rescued the ability of the mutant to colonize the GI tract. P < 0.01, Wilcoxon rank sum (area-under curves for IFU comparison [n = 3 to 5 from 2 independent experiments]).