The Latency Requirements and Rate of Evolution of Passive Cutaneous Anaphylactic Reactions Produced by Untreated and Carbamylated Rabbit γG Antibody

Abstract

Abstract The amounts of antibody necessary to produce passive cutaneous anaphylaxis (PCA) with and without a latent period were compared, and the rate of evolution of the reaction was studied in both cases as a function of antibody dose. Differences in the morphologic appearance of the reaction in these two cases were defined. It was demonstrated that there is no absolute requirement for a latent period in the production of PCA in guinea pig skin. Rather, latency in this system must be defined in terms of enhanced anaphylactic sensitization as a function of time between the administration of antibody and challenge with antigen. Quantitative comparisons between the amount of antibody needed to produce these two types of PCA reactions and the amount of antibody needed to produce anaphylaxis with soluble immune complexes suggest that the underlying mechanism of all three may be similar. Studies using carbamylated antibody with marked reduction in antigen-aggregating ability suggest that small immune complexes are involved in the production of PCA when antibody and antigen are injected separately. Therefore in analogy with the situation in which soluble complexes are used, where the active complex has been shown to contain two molecules of antibody, it is argued that PCA reactions involve the binding of antigen to at least two molecules of antibody present at adjacent sites on an effector cell. If this is so, then latency, as defined above, may be determined by a time-dependent reassociation of antibody and antigen on the cell surface until optimal configurations are attained.