Detection of PtC-specific peritoneal B-1a cells derived from the BM of induced B-Indu-Rag1^fl/fl mice. (A) Flow cytometry of splenic and peritoneal cells from wild-type and tamoxifen-induced B-Indu-Rag1^fl/fl mice using PtC liposomes. Such PtC binders were also found to express CD5 (S.D., unpublished data, August 2006). Mice were induced twice at an age of 8 weeks and analyzed 5 weeks after initiation of the experiment. (B) PtC specificity of B cells from induced B-Indu-Rag1^fl/fl mice is mediated by V genes characteristic for this specificity. CD19⁺ PtC-specific cells were bulk sorted from wild-type and tamoxifen-induced B-Indu-Rag1^fl/fl mice, and V gene usage was determined by cloning and subsequent sequencing of RT-PCR products.