Reversibility of IgE-mediated rat mast cell desensitization

Desensitization in normal rat peritoneal mast cells was induced by subthreshold and suboptimal levels of antirat IgE under normal calcium buffer conditions. Low doses of anti-IgE which triggered 0-10% net histamine release, initiated up to 100% desensitization. The rate of desensitization was highly variable in different rats, resulting in an irregular decay of releasability over the first 30 min. After 120-150 min of desensitization, rat mast cells in 3 of 5 experiments spontaneously regained releasability. We hypothesize that IgE-mediated desensitization in rat mast cells may represent a potentially reversible physiologic blockade in the degranulation process.