Systemic Anaphylaxis Produced in Guinea Pigs by Soluble Bovine Serum Albumin-Antibody Complexes

Abstract

Summary Systemic anaphylaxis was induced in normal unsensitized guinea pigs by intravenous injection of soluble bovine serum albumin (BSA)-antibody complexes, prepared with rabbit immune serum under conditions of antigen excess. The importance of using sufficiently large numbers of guinea pigs, when studying anaphylaxis, is emphasized. The severity of the anaphylactic response showed a linear dependence on the log dose of antibody in the complex. No effect of the concentration of complex was detected. Doses of antibody N (in complex) as small as 250 µg Ab N caused death, and doses as little as 10 µg Ab N caused definite signs of respiratory embarrassment. Effective doses could be administered in minute volumes, e.g., 0.005 ml. Optimum effects were produced by complexes which were prepared at five times antigen excess. A prior injection of antigen had no influence on the severity of the reaction caused by a subsequent injection of soluble antigen-antibody complexes. The results suggest that certain soluble antigen-antibody complexes per se are effective mediators of systemic anaphylaxis in guinea pigs. Parallel studies of passive systemic anaphylaxis, using the same pool of antiserum, confirmed earlier findings that the severity of anaphylaxis is proportional to the dose of antibody employed for sensitization and to the duration of the latent period before the antigen is administered. The degree of response was similar whether the reagents were administered simultaneously and complex formation occurred in vivo, or whether similar amounts of reagents were equilibrated in vitro prior to injection. However, substantially augmented responses occurred when a period of only 5 min elapsed between the injection of antibody and antigen.