Figure 6.

B-1 cells from female Apoe^−/− mice are more susceptible to apoptosis. A, Spleen B-1 cell levels in male and female Apoe^−/− mice (CD19⁺ B220^+/lo IgM⁺ CD43⁺ CD23⁻; pooled data from 4 experiments). B, Proportion of spleen B-1 cells staining positive for Ki67 (relative to males, 4 experiments pooled). C, IgM production by purified B-1 cells from male or female Apoe^−/− mice after 72 h with IL-5 and BAFF (B cell–activating factor; relative to males, 4 pooled experiments in at least duplicate). D, B-1 cells purified from peritoneum of male or female Apoe^−/− mice were cultured with or without anti-FcγRIIB (2.4G2 antibody) and then stained with annexin V and propidium iodide. Absolute numbers of remaining live cells (AnnV⁻ PI⁻) was quantified by flow cytometry using beads for normalization. *P<0.05, **P<0.01, ***P<0.005.