Physical Properties of Antibody to Bovine Serum Albumin as Demonstrated by Hemagglutination

Rabbit antibovine serum albumin antisera were fractionated by zone electrophoresis on starch, zone ultracentrifugation in sucrose density gradients, and diethylaminoethyl-cellulose chromatography, and were assayed by the passive HA technique. Antisera had at least two antibodies: one associated with a fraction characterized as a gamma-2 globulin with a sedimentation rate of 7.3S and low anionic binding (fraction I), and one associated with a fraction characterized as a gamma-1 globulin (or beta-globulin) with a sedimentation rate of 20.4S and high anionic binding (fraction IV). The HA titers of fractions I and IV of early sera were approximately equal. On prolonged antigenic stimulation fraction IV agglutinin decreased in concentration and the relative concentration of fraction I agglutinin increased. Chromatographic analysis of hyper-immune sera yielded 2 additional HA fractions with intermediate anionic binding. These results indicated that rabbits synthesize anti-BSA antibodies similar to rabbit anti-cellular antibodies. Rabbit anti-BSA precipitin migrated mainly as a gamma-2 globulin and the agglutinin migrated with gamma- and beta-globulins. The evidence suggested that the HA method might measure antibody not measured by the quantitative precipitin technique.