The effects of the anaphylatoxins C3a and C5a on isolated mast cells from rat and man.

Of the complement peptides comprising anaphylatoxin activity, only C5a caused a very small (less than 1.5%) but statistically significant histamine release from isolated human adenoidal mast cells. C3a and the respective des-Arg-derivatives were found to be ineffective. In rat peritoneal mast cells, neither peptide caused histamine release.