Inflammatory but not patrolling monocytes contribute to plasma proinflammatory mediator production involved in S. suis-induced systemic inflammation. Plasma levels of IL-6 (A), IL-12p70 (B), IFN-γ (C), CCL3 (D), CCL4 (E), CCL5 (F), CXCL2 (G), and CXCL9 (H) in wild-type, CCR2−/−, and Nr4a1−/− mice 12 h following infection with S. suis by intraperitoneal inoculation. The data represent the mean ± SEM (n = 8). * (P < 0.05) indicates a significant difference in plasma levels between wild-type and CCR2−/− mice as determined using the unpaired t test.