FIG. 5.

Cytokine production in CD28^−/− and wt mice. Splenocytes (A) and peritoneal macrophages (B and C) from wt and CD28^−/− mice were isolated from uninfected (day 0) and C. burnetii-infected mice. Cells were incubated with inactivated C. burnetii (10:1 bacterium-to-cell ratio) for 24 h. The amounts of IFN-γ (A), TNF (B), and IL-10 (C) contained in cell supernatants were determined by immunoassays. Results are expressed as pg/ml and represent the means ± SD from three experiments.