[Antisera to individual histone fractions of the calf thymus. II. A study of the immunochemical specificity of the histones by an indirect immunofluorescence method].

Immune antisera to 5 fractions (H1, H2a, H2b, H3, H4) of calf thymus histone were assayed using indirect immunofluorescence (IIF). The analysis of such sera by this technique, as well as the data on complement fixation obtained previously, show that these antisera are highly active and specific for various test-objects: thymys, liver nuclei of rat, chicken, and calf, chicken erythrocytes, metaphase chromosomes of mouse fibroblasts. These antisera are of importance for the evaluation of species- and tissue-specificity of different histone fractions. Using the IIF reaction, a comparison was made between the nucleosome fraction H3, which is evolutionary stable, and fraction HI from calf thymus, rat and chicken liver, and chicken erythrocytes.