The Secondary B Cell Lineage for Phosphorylcholine Is Conserved in CBA/CaHN-xid/J Mice

In order to determine the mechanism of generation of immunological memory, we used the splenic focus assay to analyze primary and in vitro generated secondary phosphorylcholine (PC)-specific B cell precursors in CBA/CaHN-xid/J mice (CBA/N) expressing an X-linked immune defect (xid). A quantitative analysis of the kinetics of the appearance of these precursors over the time of the culture period was performed. The precursors were analyzed for TEPC 15 idiotype expression and epitope specificity. We found that there was a significantly reduced total frequency of PC-specific precursors in CBA/N female and (CBA/CaHN-xid/J♀ × BALB/cRos♂)F1 (NBF1) male mice (xid phenotype), relative to BALB/c and NBF1 female mice (normal phenotype). Memory precursors representing a distinct lineage of B cells, however, were present at normal levels in CBA/N female and NBF1 male mice. These results help explain the reported characteristics of the serum antibody responses induced in these mice and also better our understanding of the mechanism of B cell memory generation.