The effect of Faslpr on PtC-specific B cells. (A) Comparison of 6-1 and 6-1/Faslpr peritoneal B cells for liposome binding and CD43 and CD5 expression. Histograms are gated on CD19+ B cells. PtC-specific B-1 cells (CD43+ and CD5+) are boxed, and the percent of total CD19+ B cells is indicated. (B) The number, ± SEM, of PtC-specific B-1 cells present in the peritoneal cavity of 6-1 and 6-1/Faslpr between 1 and 6 months is graphed. PtC-specific B-1 cells were gated as shown in panel A. (C) Number, ± SEM, of IgMa ASCs in wt and Faslpr recipient mice 2 weeks after transfer of 6-1 peritoneal cells.