FIG. 7.

ICOS^−/− mice show delayed clearance of Salmonella-OVA. Mice were infected with Salmonella-OVA as described in the legend to Fig. 1. At different times, three to five mice per group were sacrificed, and the bacterial loads in the spleens and livers were determined and expressed as the number of CFU/organ. The data are means ± standard errors of the means. The data are representative of two similar experiments with additional experiments on day 21. An asterisk indicates that the P value is <0.05. At day 36, there were few or no bacteria in WT spleens or livers (10 ± 15 CFU/liver and 20 ± 17 CFU/spleen), whereas in ICOS^−/− mice there were 1,200 ± 260 CFU/spleen and 80 ± 15 CFU/liver.