Camp-deficient B cells produce less IgG1 and IgE antibody in vitro. Resting CD43− WT and Camp−/− (KO) B cells were purified and cultured in the presence of LPS for the indicated number of days and cell culture supernatants were collected and analyzed by ELISA for the level of (A) IgM and (B) IgG3 antibody. B cells were also cultured with CD40L/IFN-γ or CD40L/IL-4, in the presence or absence of 100 ng/mL mCRAMP, and cell culture supernatant was collected and analyzed on days 4–6 for (C) IgG2c, (D) IgG1, and (E) IgE antibody, respectively. (F) CD40L/IL-4-activated Camp KO B cells were cultured in the presence of increasing concentrations of mCRAMP and total IgG1 was measured in culture supernatant on day 6. Data represent the mean+SEM from three independent experiments. Data with three or more groups were analyzed by a one-way ANOVA followed by post hoc analysis, while data with two groups were analyzed by a two-tailed unpaired t test. *p<0.05.