FIG. 1.

Increased numbers of macrophages and T cells in the spleens of ICOS^−/− mice. ICOS^−/− and (C57BL/6 × Sv129) F1 mice were infected i.p. with 10⁵ S. enterica serovar Typhimurium x4550(pYA3149-OVA) cells and sacrificed on days 7, 14, 21, and 36 postinfection. Cells were isolated from the spleen, counted, stained with mAb to CD8, CD4, and Mac-1 (Cd11b), and analyzed by flow cytometry. The graphs show the total numbers of CD4 T cells, CD8 T cells, and macrophages as a function of time postinfection. Each symbol indicates the average for three mice, and the error bars indicate standard errors of the means. The data are representative of two complete experiments at all times, with additional experiments at day 21. An asterisk indicates that the P value is <0.05.