Mast cell numbers and passive cutaneous anaphylaxis in irradiated mice.

IgE antibody levels in irradiated mice immunized with primed spleen cells are significantly higher than those measured in actively immunized intact mice. The possible role of mast cells in this elevated IgE response was assessed by the enumeration of mast cells and by determining their capacity to give rise to passive cutaneous anaphylactic (PCA) reactions in the skin of irradiated mice. The number of mast cells was found to be not significantly depleted over a period of 11 days by the irradiation doses used. Furthermore, the capacity of these mast cells to give PCA reactions was unimpaired. Radiation effects on mast cells in adoptively immunized mice therefore do not contribute to the high IgE levels observed in such animals.