SR-A and MARCO enhance bacterial clearance in vivo and limit NM-TLR4–mediated inflammatory cytokine responses. (A) SR-A^−/−, MARCO^−/−, and DKO mice show defective bacterial clearance in vivo. 10⁶ CFU of RdGNX-labeled NM was injected into the peritoneal cavity of WT, SR-A^−/−, MARCO^−/−, and DKO mice. After 45 minutes, peritoneal exudate cells were harvested by lavage and bacterial uptake was analyzed by flow cytometry. (B) SR-A^−/−, MARCO^−/−, and DKO mice showed enhanced cytokine production following intraperitoneal injection of 10⁵ CFU of inactivated NM. Secretion of TNF-α (top panel) and IL6 (bottom panel) was measured by ELISA in peritoneal lavage fluid 2 hours after NM injection. Data presented are representative of 3 independent experiments. One-way ANOVA with Dunnett multiple comparison test was used to assess statistical significance. *P ≤ .05; ***P < .001