Heterogeneity and Average Combining Constants of Antibodies from Individual Rabbits

Abstract

Specifically purified anti-p-azobenzoate antibody from individual rabbits exhibits a large degree of heterogeneity with respect to free energy of combination with p-iodobenzoate, as measured by equilibrium dialysis. Antibody prepared from a pool of 5 sera was intermediate in heterogeneity among preparations from the individual sera comprising the pool. Quantitative indexes of heterogeneity and average equilibrium constants were obtained by application of the equations of Sips to the experimental data. Average free energies of combination with hapten of purified antibody from the individual sera, a pool of these sera, and 3 other serum pools varied over a narrow range, indicating only small differences in the effectiveness of precipitating antibodies produced in the different rabbits. The results are discussed in terms of the mechanism of antibody formation. A method for specifically purifying antihapten antibody in good yield is described. The procedure was shown to have no appreciable effect on the average combining constant or index of heterogeneity.