IL-4 enhances the survival of peritoneal mast cells through γ_c- and Jak3-dependent signaling.

Peritoneal cells from WT, γ_c⁻, and Jak3⁻ mice were cultured in the presence of IL-4 or IL-9 for 24 hours, and cell viability of c-kit⁺ cells was determined by FACS as described in “Materials and methods.” Data are means ± SD for 4 mice in each group. The mean value of IL-4–stimulated peritoneal mast cells is significantly different from the mean value of control peritoneal mast cells in WT mice. *P < .01.