CpG treatment preferentially depletes late-stage B lymphoid precursors in BM and simulates production of some inflammatory cytokines. (A,B) Mice were given single intraperitoneal injections of CpG, and 48 hours later lymphoid progenitors in BM were evaluated with respect to IL-7Rα expression by flow cytometry and RT-PCR. (C) Using stringent flow cytometry gating criteria, numbers of pro-B/large pre-B, small pre-B, and B cells in BM were evaluated. Data are mean plus or minus SEM (*significant difference, P < .05). (D) Levels of proinflammatory cytokines and Flt3-L (FL) in sera were tested by ELISA. Data are representative of more than 3 experiments with each having N = 3.