Elevated pathogen-sensing and phagocytosis by female macrophages. (A) Basal mRNA expression of TLRs and Myd88 in naive peritoneal cells (n = 5-6 mice) and (B) Flow cytometric analysis of surface TLR2 and TLR4 protein expression on resident F4/80⁺ peritoneal macrophages (n = 6-8; 2 independent experiments). (C) Phagocytosis of zymosan A (5 × 10⁶ particles/10⁵ cells, 30 minutes) by equivalent numbers of resident peritoneal leukocytes (macrophage and lymphocytes), measured in vitro by a colorimetric assay (n = 5 mice). Basal levels of TLR mRNA in (D) mesenteric tissue and (E) aortae of male and female mice (n = 6 mice). Levels of mRNA for each sample are normalized to corresponding mRNA levels of housekeeping gene for small 18S and calculated as the -fold expression relative to the mean value in females. All results are shown as means ± SEM. *P < .05; **P < .01; and ***P < .001 compared with male by Student t test.