Studies in vascular permeability. ii. comparative extravasation of different immunoglobulin classes in normal guinea pig skin

Abstract

In an attempt to study the tissue accessibility for different immunoglobulin classes (known to be heterogenous according to their immunobiological and physiochemical properties) the extravasation rate of passively injected radiolabeled guinea pig IgG, IgG1, IgG2 and IgM were compared in normal homologous (guinea pig) cutaneous tissues.As a criterion of unaltered globulins, the half‐lives were estimated and their immunobiological properties (complement fixation, passive cutaneous anaphylaxis or bacterial agglutination) were assayed before and after radiolabeling. The average half‐life of IgG1 was 6.8 days, that of IgG2, 4.8 and that of IgM, 1.2.The extravasation rate of IgG was found higher than that of IgM by using a paired radiolabel technique, IgG and IgM mixture being injected intravenously simultaneously in the same animal. It was further found that the extravasation rate of IgG1 is slightly higher than that of IgG2.The immunopathological consequences of these findings are discussed in view of the observed discrepancies between in vitro and in vivo activities of the same immune sera containing mixtures of antibodies of same specificity, but of the different immunoglobulin classes.