FIG. 3.

Mc-cpa^−/− peritoneal mast cells resemble immature BMMC and possess a mast cell progenitor phenotype. Forward (FSC) and side scatter (SSC) were determined by flow cytometry for Mc-cpa^+/+ (+/+) (A, C, and E) and Mc-cpa^−/− (−/−) (B, D, F, and G) peritoneal mast cells (A, B, E, F, and G) and immature BMMC (C and D). Peritoneal mast cells from Mc-cpa^−/− mice were separated by cell sorting into small (F) and large (G) subpopulations. Cytospins from the indicated peritoneal mast cell populations were stained with toluidine blue (H to J) and with alcian blue and safranin (L to N) and compared to BMMC (K and O). The scale bar in panel H (20 μm) applies to panels H to O. wt, +/+; ko, −/−.