Genetic analyses of NFKB1 and OCA-B function: defects in B cells, serum IgM level, and antibody responses in Nfkb1-/-Oca-b-/- mice.

Defined patterns of gene expression during cell differentiation are likely to be ensured by multiple factors playing redundant roles. By generating mice deficient in both NFKB1 and OCA-B, we show here that the two transcription factors are required for B-1 cell differentiation and serum IgM production. In addition, relative to Nfkb1(-/-) or Oca-b(-/-) mice, the Nfkb1(-/-)Oca-b(-/-) mice show a decrease in conventional B cell frequencies in the spleen and augmented reductions in T-independent and T-dependent Ab responses. These results suggest that NFKB1 and OCA-B play compensatory roles in multiple aspects of B cell differentiation.