DOCK5 acts in mast cells and regulates anaphylactic responses in vivo. (A) Cell surface expression of c-kit and FcεRI on WT and Dock5^−/− BMMCs was measured by flow cytometry. Data are representative of 10 independent experiments. (B) mRNA expression of mast cell–specific proteases in WT and Dock5^−/− BMMCs was determined by RT-PCR. Data are representative of two independent experiments. (C) Toluidine blue staining of the stomach and spleen from the Kit^W-sh/W-sh C57BL/6 mice reconstituted with WT and Dock5^−/− BMMCs. The arrowheads indicate mast cells. Data are representative of four mice per group collected from two independent experiments. The data on nontreated Kit^W-sh/W-sh mice are shown as controls (–). Bar, 100 µm. (D) Comparison of the number of mast cells in the stomach (top) and spleen (bottom) from the Kit^W-sh/W-sh C57BL/6 mice reconstituted with WT and Dock5^−/− BMMCs (n = 4 mice per group) was made from histological analysis as in C. Data were collected from two separate experiments and are indicated as mean ± SD. (E) The change of rectal temperature in Kit^W-sh/W-sh C57BL/6 mice receiving WT (n = 6) or Dock5^−/− (n = 7) BMMCs. Nontreated Kit^W-sh/W-sh mice (n = 3) were also analyzed as controls (–). Mice were sensitized with anti-DNP IgE antibody and then challenged 24 h later with DNP-HSA. Data were collected from three separate experiments and are indicated as mean ± SEM; **, P < 0.01.