Enhancement of reaginic antibody formation in the mouse by concanavalin a1

SWR mice injected with Concanavalin A (Con A) and Ovalbumin (Ov) one immediately after the other or with mixtures of Con A and Ov produced reaginic antibodies to Ov (titer 1:80) after primary immunization and reaginic antibody levels of 1:640 after secondary immunization. Mixtures of Con A and Ov were shown to contain soluble complexes which could be precipitated by 20°/o polyethylene glycol (PEG). Mixtures of Con A and human serum albumin or Con A and bovine serum albumin did not form soluble complexes and did not induce detectable reagin formation. The possible role of soluble Con A-Ov complexes in stimulating reaginic antibody is discussed.