Peritoneal cavity B1 cells from engrafted mice. Cells were stained for CD45.1, IgM, and CD5. (A) Profiles of CD5 and IgM expression on gated CD45.1⁺IgM⁺PI^– cells are presented. One representative analysis of at least 3 experiments is shown. Absolute cell numbers are given in panel B. (B) The absolute cell numbers of the indicated cells found in the respective recipient mice are presented. The dotted line separates flow cytometric results from unmanipulated C57Bl/6 Ly5.1 mice and those from reconstituted recipient mice.