Further Evidence of the Role of γl Guinea Pig Antibodies in Mediating Passive Cutaneous Anaphylaxis (PCA)¹

It has been previously shown that passive anaphylactic reactions can be produced in the guinea pig and the mouse by an electrophoretically fast moving homologous immunoglobulin which is usually designated as γ1 globulin (1–4). In some other species (man, rabbit, dog, monkey and rat) anaphylactic reactions are mediated by homologous reaginic antibodies which have physicochemical properties clearly different from those of γ1 globulin (5). In man, these antibodies have been identified as belonging to the γE class of immunoglobulins (6). In mice both γ1 and reaginic antibodies have been shown to mediate passive cutaneous anaphylaxis (PCA) (7–9). It has recently been suggested that PCA in the guinea pig is not mediated by γ1 globulin but by a contaminant of the γ1 fraction (10). The object of this study was to investigate this possibility.