K430R-Btk partially corrects the defects in B-cell development in Btk/SLP-65 double-mutant mice. Flow cytometric analysis of (A) spleen and (B) bone marrow of Btk⁺, Btk^-, and K430R-Btk mice on either the SLP-65⁺ or the SLP-65^- background. (A) IgM/IgD profiles of total splenic lymphoid cells, (B) IgM/B220, and (C) IgM/IgD profiles of total bone marrow lymphoid cells. Lymphoid cells were electronically gated on the basis of forward and side scatter characteristics. Data are presented as dot plots and the percentages within the indicated quadrants or gates are given. The plots are representative for 5 to 14 mice of each genotype.