Immunological specificities of lysine-rich histones from tumors.

The specificity of Fr histones from tumors was investigated with the following immunological probes: antisera elicited by each of the Fr subfractions obtained from rat thymus; antisera elicited by purified unfractionated rat hepatoma FI histones; and antisera elicited by the COOH-terminal (N1) fragment of rat hepatoma F1 histones. The results indicate that Fr histones derived from tumors retain to a large extent the species and tissue specificity of the normal tissues. The species and tissue speciticity 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 proiiles 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.