Engraftment of BMCMCs into C57BL/6-Kit^W-sh/Wshrecipients. (A) Engraftment of BMCMCs derived from luc⁺C57BL/6J mice was assessed 8 weeks after intraperitoneal injection. Ex vivo imaging of internal organs indicates that mast cell engraftment was primarily in the gut and stomach tissue and not in mesenteric lymph nodes or (from top left to right) kidney, cervical lymph nodes, liver, or spleen. (B) Toluidine blue staining confirmed the presence of mast cells in mesenteric windows, peritoneal cavity (by lavage), and forestomach of mice, whether mast cells were derived from WT C57BL/6 mice or IL-10^−/− C57BL/6 mice.