Studies on passive cutaneous anaphylaxis in the rat with disodium cromoglycate. II. A comparison of the rat anti-dnp 7S 2 and rat reagin induced cutaneous reactions

Abstract

A study of the passive cutaneous anaphylactic reaction induced by anti-DNP 7Sγ₂ antibodies was undertaken in rats to compare this anaphylactic reaction with that induced by rat reagin. This study revealed that disodium cromoglycate was capable of inhibiting the 7Sγ₂ induced PCA reaction immediately following antigen challenge but not the slow developing late reaction. Using various doses of disodium cromoglycate on a series of rat reagin PCA reactions and on a series of early 7Sγ₂ induced PCA reactions, similarities in dose dependence were demonstrated suggesting that certain pathways might be common to both reactions. Studies using 48/80 treatment after sensitization revealed inhibition of both early and late 7Sγ₂ reactions. Concomitant sensitization with rat reagin and 7Sγ₂ at various concentrations demonstrated that either antibody was capable of inhibiting the reaction induced by the other antibody, suggesting similar sensitization sites might be involved. In actively sensitized rats with a high reagin titre we were unable to induce a 7Sγ₂ or rat reagin PCA reaction whereas a cutaneous reaction of the `Arthus' type was readily induced. It is concluded that passive sensitization by anti-DNP 7Sγ₂ antibodies has certain factors in common with sensitization by rat reagin and that the sensitized mast cell plays a vital role in the elicitation of both early and late 7Sγ₂ PCA reactions.