Induction of IgE-mediated immediate hypersensitivity to group I rye grass pollen allergen and allergoids in non-allergic man.

The major (Group I) allergen of rye grass pollen and two of its allergoids, adsorbed on alumina gel, were injected into three groups of non-allergic humans. In addition to inducing the anticipated blocking antibody (IgG) response, all individuals developed immediate skin hypersensitivity to the allergen and its allergoids characteristic of reaginic antibody-(IgE-)mediated reactions. At some time during the course of the study, virtually every individual's peripheral blood leucocytes were also found to release histamine when challenged with low concentrations of allergen and allergoids. Quantitatively, each person's skin and leucocyte sensitivities were not as well correlated as in naturally allergic people. Leucocyte responsiveness was generally shortlived, but could be restored by antigenic restimulation. Allergoid: allergen sensitivity ratios were greater in allergen-than allergoid-immunized individuals, but less than in naturally allergic individuals. Unexpectedly, allergoid-immunized individuals' leucocytes were more sensitive to allergen than allergoid. Despite the observed skin and leucocyte reactivities, none of the people showed clinical manifestations of hay fever following natural exposure to pollen. The skin sensitivity of the artificially sensitized individuals could be passively transferred to non-allergic humans by intradermal injection of serum (P-K Test), thereby implicating the involvement of IgE antibody. Further proof of the role of IgE was obtained by blocking the P-K test, either by heating the serum or by adsorbing it using an anti-IgE immunosorbent.