Immunological Specificities of Lysine-rich Histones from Tumors

Abstract

The specificity of F₁ histones from tumors was investigated with the following immunological probes: antisera elicited by each of the F₁ subfractions obtained from rat thymus; antisera elicited by purified unfractionated rat hepatoma F₁ histones; and antisera elicited by the COOH-terminal (N₁) fragment of rat hepatoma F₁ histones. The results indicate that F₁ histones derived from tumors retain to a large extent the species and tissue specificity of the normal tissues. The species and tissue specificity was also observed with N₁ fragments derived from the tumor F₁ histones, suggesting that the COOH-terminal portions contain regions which vary from one molecular type to another.

Comparison of the chromatographic elution profiles of F₁ histone from rat liver and rat hepatoma revealed that one of the peaks in rat liver (Peak 4a) was either absent or present in very low amounts in rat hepatoma. With the exception of Peak 2, the respective peaks of rat liver and rat hepatoma were immunologically closely related.