The influence of IgE-mediated reactions on the expression of delayed hypersensitivity in the rat.

The effect of IgE-mediated reactions on the expression of delayed hypersensitivity skin reactions was examined in the rat. It was found that the elicitation of an IgE-mediated reaction at the time of skin test could either potentiate or inhibit the development of delayed reactions. At a fixed level of IgE sensitivity, large delayed reactions were potentiated and small delayed reactions suppressed. These interactions were not dependent on the two types of sensitivity being direct against the same antigen but were dependent on the reaction of IgE with its appropriate antigen.