FIG. 5.

Striking Th1 skewing of protective immunity in ICOS^−/− mice. Uterine tissues were collected from WT, CD28^−/−, and ICOS^−/− mice at different time points after reinfection for mRNA extraction. Quantitative analyses using real-time RT-PCR were undertaken to determine the relative levels of (A) IFN-γ or (B) IL-10 mRNA in the effector tissues of reinfected mice at peak expression, on day 2 postreinfection. Values represent the means (WT, CD28^−/−, or ICOS^−/− mice) or means naive (WT, CD28^−/−, or ICOS^−/− mice) from three independent experiments with two to three mice per group in each experiment. Values were normalized against mRNA expression levels for the HRPT gene, the housekeeping gene.