Increased autoantibody production from adoptively transferred splenic CD1d^−/− B cells. (A) Schematic illustration of the transfer of purified B cells from WT or CD1d^−/− mice to a CD19^−/− recipient, followed by four injections of apoptotic cells. (B) IgM and IgG3 anti-DNA measured by ELISA in apoptotic cell–injected recipients and control mice. (C) Representative splenic immunofluorescence image from transferred WT B cells and CD1d^−/− B cells at day 26. Transferred cells are visualized by their CD19 and B220 expression in contrast to the recipient B cells (CD19^−/−) only expressing B220. GCs are visualized by GL7 staining and indicated by arrows. (D) Representative splenic GC histology of WT and CD1d^−/− mice injected four times with apoptotic cells. Bars: (C) 150 µm; (D) 300 µm. Results are shown as mean ± SEM in B (n = 6–12 for recipient groups; n = 4 for CD19^−/− without transfer) and D (n = 6). *, P < 0.05. Data are representative of at least two independent experiments.