Loss of IRF-4–binding protein leads to the spontaneous development of systemic autoimmunity
J. Clin. Invest. Jessica C. Fanzo, et al. 116:703 doi:10.1172/JCI24096 [Go to this article.]

Figure 6
Enhanced T cell–dependent humoral responses in IBP^trap/trap mice. (A) Proliferation of B cells. Cells were stimulated with soluble anti-CD40 (5 μg/ml), LPS (10 μg/ml), or anti-IgM (10 μg/ml) with or without IL-4 (20 ng/ml) for 48 hours. The culture was then pulsed with [³H]thymidine for 18 hours. (B) Basal Ig levels in IBP^trap/trap mice. Serum Ig levels from nonimmunized 6-week-old IBP^+/+ (filled circles) and IBP^trap/trap (open circles) mice were determined by isotype-specific ELISA. Each symbol represents 1 mouse. Horizontal bars are drawn through the mean value of each group. *P < 0.005 (IBP^trap/trap versus WT). (C) T cell–dependent immunizations. IBP^+/+ (filled circles) and IBP^trap/trap (open circles) mice were immunized with NP-KLH. Relative amounts of NP-specific IgM, IgG₁, IgG_2a, and IgG₃ antibodies and total IgE levels at the indicated times after primary immunization were determined by ELISA. Each symbol represents 1 mouse. Horizontal bars are drawn through the mean value of each group. The data were analyzed using Student’s t test. A statistical probability of P < 0.05 was considered significant. *P < 0.05; **P < 0.005 (IBP^trap/trap versus WT).