Figure 5. IκBδ Limits the Proliferative Capacity of BCR-Stimulated B Cells.

(A) Model simulation of fold p100 protein levels (log2) in wild-type (black) and Nfkb2 heterozygous (green) B cells stimulated with anti-IgM alone.

(B) Immunoblot of p100 protein expression in wild-type and Nfkb2^+/− B cells stimulated with anti-IgM alone. Blots were quantified and plotted (log2, right).

(C) Computational prediction of p100:cRel complex following 24 hr of anti-IgM stimulation in wild-type (black) and Nfkb2^+/− (green) B cells.

(D) Representative immunoblot blot for coimmunoprecipitation of p100:cRel complex from wild-type and Nfkb2^+/− B cells following 24 hr of stimulation with either anti-IgM alone or anti-IgM plus BAFF ligand. Samples normalized to cRel protein levels (bottom). Immunoblots were quantified and graphed (right).

(E) Model simulation of nuclear cRel protein levels in wild-type and Nfkb2 heterozygous B cells stimulated with anti-IgM alone (log2).

(F) cRel DNA-binding activities in wild-type and Nfkb2 heterozygous B cells induced by anti-IgM alone were monitored by EMSA. EMSA was quantified and graphed (log2, right).

(G) Time course of cell proliferation for CD23⁺ wild-type (black) and Nfkb2^+/− (green) B cells labeled with CFSE and 7AAD.

(H) FlowMax analysis of CFSE proliferation assay in (G).

(I) T-dependent Ag responses in Nfkb2^+/− mice immunized with NP-KLH, and serum levels of anti-NP total Ig and specific Ig isotypes at 10 and 28 days postimmunization measured by ELISA (n = 5). Indicated p values are calculated by two-way ANOVA.

Unless stated, all experiments in Figure 5 used total splenic B cells. Immunoblots and FACS plot for (B), (D), (F), and (G) are representative of at least three experiments. Error bars in (D) SD; n = 3. Bar graphs in (H) summarize best-fit cellular parameters with the lognormal SD; *p < 0.05; **p < 0.01.

See also Figure S7.