Ovarian sex hormones contribute to sex differences in resident immune cell population. OVX or sham operation was performed on female mice at 4 weeks of age and they were allowed to recover for 4-5 weeks. (A) Total number of resident F4/80⁺ macrophages, CD3⁺ or CD8⁺ T lymphocytes, and CD19⁺ B lymphocytes in peritoneal cavity (n = 5 mice). Basal mRNA expression of (B) mesenteric tissue chemokines (n = 6-7 mice), (C) chemokine receptors on resident peritoneal leukocytes (n = 6 mice), and (D) peritoneal leukocyte TLR expression (n = 6 mice). (E) Surface expression of TLR2 or TLR4 on F4/80⁺ resident peritoneal macrophages (n = 3-5 mice). (F) Phagocytosis of zymosan A (5 × 10⁶ particles/10⁵ cells, 30 minutes, n = 4 mice) by resident peritoneal cells in vitro. (G) GBS-induced (30 × 10⁶ bacteria/mouse IP for 3 hours, n = 7 mice) accumulation of leukocytes in peritoneal cavity. All values (A-G) are expressed as means ± SEM. Expression of mRNA for each sample is normalized to corresponding levels of the housekeeping gene for small 18S and is calculated as the -fold expression relative to OVX females. All comparisons are relative to Sham females. *P < .05; **P < .01; and ***P < .001 by Student t test; NS denotes P > .05.