Fig. 1. Impaired survival and proliferation of B cells from ζPKC–/– mice. B cells from either wild-type (empty bars) or ζPKC-deficient (black bars) mice were incubated for different times in culture medium, after which the percentage of apoptotic cells was determined by flow cytometry analysis (A). In other experiments, cells were stimulated for 72 h with either an anti-CD40 antibody or different concentrations of IgM (B), and the amount of [³H]thymidine incorporated was determined as described in Materials and methods. In a parallel experiment (C), cells were stimulated with 2 µg/ml IgM in the absence or presence of different concentrations of BAFF. This is a representative experiment of at least another two with incubations in duplicate.