Deletion of Stat3 in the B-cell lineage does not disrupt B-cell development. (A) Top row: Genomic DNA from T cells, B cells, and myeloid cells from Stat3^fl/flCD19^+/+ (Wt) and Stat3^fl/flCD19^Cre/+ (KO) mice was subjected to PCR analysis using primers that yield bands corresponding to both the Stat3^fl/fl and Stat3^Δ/Δ alleles. Bottom row: Whole-cell lysates were prepared from the same cell types as in panel A and were subjected to Western blot analysis for total Stat3. (B) B-cell numbers in the bone marrow, spleen, and lymph nodes of Wt (▪) and KO (□) mice were calculated based on percentages of total cells that stained as B220⁺ upon flow cytometric analysis. Error bars represent the SD of at least 3 mice. (C) Flow cytometric analysis was performed on lymph nodes from Wt and KO mice for canonical B-cell markers. Flow cytometric results are representative of at least 3 experiments.