Studies on passive cutaneous anaphylaxis in the rat with disodium cromoglycate. I. Cutaneous reactions induced by an anti-DNP 7S-gamma-2 antibody.

The 4-hour passive cutaneous anaphylaxis reaction (PCA) in rats induced by rat anti-DNP 7Sγ antibody has been investigated and compared with the rat reagin induced PCA reaction. Time course studies revealed that the PCA reaction was made up of at least two parts, an early immediate reaction which involved mast cell degranulation, was inhibited by disodium cromoglycate and by cyproheptadine and a late reaction unaffected by disodium cromoglycate, by cyproheptadine and by an anti-SRS-A agent, diethyl-carbamazine. The early part of the 7Sγ reaction was found to be comparable to the rat reagin PCA reaction whereas the later part of the 7Sγ reaction does not appear to involve similar pathways or mediators.