Transgenic Bcl-2 expression does not rescue the morphologic or phenotypic activation defects seen in Nfkb1^–/– C-Rel^–/– pDC. Purified splenic pDCs isolated from bcl-2^T and Nfkb1^–/–C-Rel^–/–.bcl-2^T mice were incubated in culture for approximately 16 hours in the absence or presence of CpG1668-ODN. (A) Cell morphology in response to CpG-mediated activation. (B) Histograms of MHCII expression on CpG-stimulated wt.bcl-2^T (heavy dark line) and Nfkb1^–/–C-Rel^–/–.bcl-2^T (gray shaded) pDCs. The unstained control is depicted as the dotted histogram. Data are representative of 3 independent experiments. (C) Western blot analysis of endogenous BH3 prosurvival protein expression in pDCs. Cellular extracts isolated from equivalent numbers (10⁶) of wild-type (lanes 1 and 2) and Nfkb1^–/–C-Rel^–/– (lanes 3 and 4) pDCs prior to (lanes 1 and 3) and following CpG activation for 6 hours (lanes 2 and 4) were subjected to Western blot analysis. Filters were sequentially probed with antibodies specific for Bcl-X_L, A1, Bcl-2, and HSP70. These data are representative of 3 independent experiments.