Rabbit Antibodies to Histone Fractions As Specific Reagents for Preparative and Comparative Studies

Abstract

Antibodies specific for each of the F1, F2a1, F2a2, and F2b calf thymus histone fractions were induced by immunization of rabbits with varying histone-nucleic acid complexes. At appropriate dilution, each serum reacted in quantitative complement fixation with only one homologous fraction. With very much higher serum concentrations, cross-reactions with other fractions occurred and were estimated to be approximately 5% in all but one case, in which 20% cross-reactivity was observed. Antibodies induced by F3 histone-RNA complexes were less specific than the other four types of sera. The more specific sera were effective as reagents for the identification of individual histone fractions obtained by preparative electrophoresis, column chromatography, and dissociation of histones from nucleoprotein by increasing salt concentrations. With each of the anti-F2a1, anti-F2a2, and anti-F2b sera, comparisons were made of the corresponding fractions from human, calf, chicken, frog, and lobster tissues. With any one fraction and the corresponding antiserum, little or no difference was seen in the reactivity of the protein isolated from any of these species.