Abstract: | In guinea-pigs a delayed type allergy against sheep erythrocytes (SE) or ovalbumin without detectable circulating and macrophage-cytophilic antibodies was produced by immunization with antigen—antibody complexes. In these animals skin reactions to SE were not enhanced by admixture of macrophages, neither when the macrophages had been sensitized with cytophilic antibodies in vitro, nor when the SE had been (partially) ingested within the macrophages after incubation with opsonizing antibody in vitro. Also in these animals no enhanced delayed skin reactions to SE were obtained if before the injection of the antigen the skin had been infiltrated with cytophilic antibody or passive cutaneous anaphylaxis (PCA) antibody. Thus, no enhancing effect of cytophilic antibody on delayed cutaneous hypersensitivity reactions could be obtained. Furthermore, in guinea-pigs with delayed type allergy to ovalbumin, no enhancing effect of delayed allergy on passive cutaneous anaphylaxis was observed. |