FIGURE 6.

Vav1 deficiency impairs efficient GC formation and immunoglobulin production. Mice were immunized with SRBCs and GC formation was assessed by flow cytometry and immunohistochemistry and immunoglobulin serum titers were determined by ELISA. (A) Statistics of flow cytometric analyses of GC B (GL7⁺ CD95⁺) cell numbers in the spleen are shown. (B) Representative immunohistochemical staining of PNA⁺ GCs for each genotype and are shown. Scale bars indicate 200 µm (C) Statistical analyses showing ratio of PNA⁺ GCs/total follicles stained by immunohistochemistry. (D) Statistical analysis showing GC size of WT (n = 10) and Vav3-single knockouts (n = 5). Size of GCs of three image sections for each animal was measured. The mean of all three analyzed image sections for each mouse is depicted. (E) Statistical representation of IgM serum concentrations (µg/ml) determined relative to a standard IgM. (F) Statistical representation of IgG1, IgG2b and IgG3 serum concentrations (µg/ml) determined relative to corresponding standard antibodies. (G,H) Mice were immunized with NP-KLH to determine levels of antigen-specific IgM (G) as well as IgG1 and IgG3 (H). Each point represents data from a single mouse. Data in the graphs are shown as means ± SD (n = at least 5 mice per group). Data are merged from two independent experiments. *p < 0.05, **p < 0.01, and ***p < 0.001. p-values were determined using a two-tailed Student’s t test or Mann-Whitney-U test. Mice were analyzed in an age range from 7–13 weeks. Gating strategy is shown in Supplementary Figure S7.