B-cell development in p100^−/− bone marrow is rescued by partial inactivation of RelB but not of p50/NF-κB1. (A) Examination of bone marrow CD19⁺B220⁺ pro-B cells (c-Kit⁺CD43⁺ gate) by flow cytometry in wild-type and p100^−/−relB^−/+ mice. (B) B-cell development in bone marrow was analyzed in 3-week-old wild-type, p100^−/−, p100^−/−relB^−/+, p100^−/−relB^−/−, and relB^−/− mice for expression of CD19 and B220 by flow cytometry. (C) CD19 and B220 expression on bone marrow cells was examined in wild-type, p100^−/−, p100^−/−nfkb1^−/+, p100^−/−nfkb1^−/−, and nfkb1^−/− mice. Lymphocytes were gated for flow cytometric analysis. Percentages indicate mean values (± SD) from 3 to 5 mice.