Figure 7

Impaired T-cell independent humoral response in AUF1^-/- mice. (a) Total serum immunoglobulin levels in naïve mice. Each point represents the value obtained from an individual mouse, AUF1^-/- (black) or wild-type (white); n = 6. Naïve spleens were stained for B cells (B220) and germinal centers (PNA). (b) B cell follicles were visualized by antibody to B220 and arrows indicate splenic arterioles. Follicular dendritic cells were visualized by antibody to CR1. Scale bar = 0.1 mm. (c) Serum immunoglobulin (Ig) levels in naïve mice (preimmune, PI), and in mice post immunization with TNP-Ficoll (TI-II) or TNP-KLH (TD). Each point represents the value obtained from an individual mouse, AUF1^-/- (black) or wild-type (white); n = 5, * p < 0.05. (d) Spleen sections from immunized wild-type and AUF1^-/- mice were stained for B cells with anti-B220 (brown) and peanut agglutinin (PNA; blue) to visualize germinal centers (GCs, arrows). Scale bar = 0.5 mm. Numbers of GCs per lower power field (LPF, 10×) were quantified. Values represent means from 5 mice (5 fields per mouse) ± SD. (e) Median cell size and (f) proliferation response to anti-IgM (10 μg/ml) or LPS (10 μg/ml) in sorted MZ B cells. Plots represent mean ± SD, n = 3; * p < 0.05. (g) Calcium flux analysis in response to BCR cross-linking. Arrow indicates time at which anti-IgM (10 μg/ml) was added to cells. Data is representative of three independent experiments. (h) RT-PCR directed at amplifying post-switch targets composed of Iμ exon spliced onto the 5' exon of Cγ₁ and Cγ_2b gene or β-actin gene control performed on B cells stimulated with LPS + IL-4 for 4 days. (i) Total secreted immunoglobulin (Ig) levels or indicated isotypes in culture supernatants from B cells stimulated with LPS + IL-4 or anti-CD40 + IL-4 for 4 days as determined by ELISA.