STUDY OF THE CROSS-REACTION BETWEEN RABBIT ANTI-BOVINE SERUM ALBUMIN ANTIBODIES AND EQUINE SERUM ALBUMIN.

Cross-reactions between bovine serum albumin and equine serum albumin were studied using heterologous soluble complexes and specifically purified cross-reacting antibody. Experiments with soluble complexes showed that homologous antigen can displace heterologous antigen specifically bound to antibody but heterologous antigen cannot displace homologous antigen. On gel precipitation tests a specific precipitation resulted when heterologous soluble complex reacted with homologous antigen. By using equine serum albumin conjugated to polyaminopolystyrene the cross-reacting antibodies from anti-bovine serum albumin imune sera could be isolated. These are divalent 7S, γ-globulin antibodies. A figure of cross-reaction was obtained when these purified antibodies were tested by double diffusion in agar with bovine and equine serum albumins. The results obtained both with soluble complexes and with purified antibody support the view that cross-reacting antibody is more avid for the homologous than for the heterologous antigen.