IgE receptor crosslinking induces mast cell survival and A1 expression. (A) Murine BMMCs, cultured under IL-3 deprivation, show enhanced survival when activated by IgE receptor crosslinking (IgER CL). (B) RNase protection assay (RPA) shows an increased expression of A1 in both BMMC and the mouse mast cell line C57 on IgER CL. Data are presented as mean plus or minus SEM of 3 independent experiments.