Induced homocytotropic antibody to bovine serum albumin in nonatopic dogs

Abstract

Six dogs with no skin reactivity to bovine serum albumin (BSA) were used to determine the antibody response to that antigen. The animals were divided into 3 equal groups given 5, 10, or 25 mg. BSA in Freund's incomplete adjuvant weekly, until a definite skin reaction could be detected. All sera were studied by passive transfer, double-gel diffusion, tanned sheep red blood cell hemagglutination, co-precipitation, and passive cutaneous anaphylaxis (PCA). Serum from one dog contained passively transferable antibody and was studied further by autoradiography and fractionation on Sephadex G-200. Skin reactivity to BSA could be detected up to 27 weeks in 5 of the 6 dogs. Hemagglutinating antibody was inhibited by the addition of 2-mercaptoethanol, and coprecipitation demonstrated that the antigenbinding capacity could be correlated with hemagglutinating antibody. Serum from the dog with passive transfer activity also contained precipitating antibody, and PCA activity could be demonstrated in guinea pigs. Autoradiography of the serum demonstrated 2 distinct arcs of anti-BSA activity. Homocytotropic antibody activity could be detected on the ascending slope of the second peak by Sephadex G-200 filtration, while hemagglutination antibody was localized to the first peak. These results indicate that antibodies with different activities can be induced in the dog following injection of BSA. The induced homocytotropic antibody has characteristics similar to spontaneous canine homocytotropic antibody.