Relation between bronchial reactivity to antigen in vivo and serum IgE and IgG2a antibody levels in rats.

Sprague Dawley rats were immunized with graded doses of ovalbumin (OA) together with alum. The capacity of the animals to produce a bronchial anaphylactic response to intravenous antigen challenge was related to serum OA-IgE and OA-IgG2a antibody levels estimated by radioimmunoassay. A significant correlation between bronchial anaphylactic response capacity and OA-IgE antibody levels was found under a few, but not all, of several carefully chosen experimental conditions. No correlation was demonstrable between the in vivo reactivity of the animals and their serum levels of OA-specific IgG2a antibodies.