Immunochemical relationship between natural haemagglutinins and immune antibodies in the toad (Bufo paracnemis).

Natural and induced antibodies from serum of Bufo paracnemis were isolated by specific immunoadsorption (natural antibodies and specific induced antibodies, respectively). Natural agglutinins specific to rabbit red blood cells (RRBC) showed, by immunodiffusion (ID) and by immunoelectrophoresis (IEP) against rabbit anti-B, paracnemis serum, at least three precipitation lines. Similar patterns were obtained with the specific induced antibodies. Immunochemical identity between natural and induced antibodies was observed by ID test. These results were assessed by repeatedly absorbing rabbit anti-Bufo serum with natural antibodies: these natural antibodies totally exhausted the activity of rabbit immune serum against specific anti-bovine serumalbumine and vice-versa. These reactions were studied using a very sensitive radioimmunodiffusion test. The heterogeneity of natural haemagglutinins and their identity with induced antibodies are discussed in relation with these experimental data.