Abnormal development of B cells and B cell progenitors in autoimmune (NZB x NZW)F1 mice

The (NZB x NZW)F1 (BWF1) autoimmune strain displays reduced numbers of both c mu+ pre-B cells and Ly5(220)+ B cell progenitors in the bone marrow. The loss of these B cell precursor populations in the bone marrow increases with age. In contrast, the bone marrow of BWF1 mice possesses sIg+ B cells comparable in both number and surface phenotype to that observed in conventional strains. Analysis of the surface densities of both sIg and Ly5(220) antigens indicates that BWF1 bone marrow B cells comprise a heterogeneous population of both immature and mature B cells. In addition, BWF1 bone marrow still possessed progenitor cells capable of yielding newly generated B cell precursors and B cells in vitro. The diminished levels of intermediate B cell progenitors observed in BWF1 bone marrow may reflect abnormal regulation of B lineage differentiation during the life span of this autoimmune strain.