Figure 6

Model for the roles of NF-kB members in B cell development Distinct NF-kB members are employed at different stages of B cell development. Previous studies indicate that p50 and p65 are likely involved in the Pre-BCR-mediated differentiation process, including the Ig light chain expression. C-Rel expression becomes detectable following Pre-B to immature B cell differentiation [38]. Meanwhile, p50 and p52 members are critical for the survival and differentiation of Transitional B cells, particularly in response to Blys signals. The final maturation of late-stage T2 B cells into follicular B cells also requires BCR signals that induce p65 and c-Rel activity. In mature B cells, the c-Rel complexes are especially important for BCR-mediated survival and cell cycle progression. All NF-kB members have been shown to participate in Ig class switching.