[Expression of C-type oncornavirus proteins in tumors of CC57BR mice].

Murine endogenous oncornavirus (C-type) genome expression was investigated in methylcholanthrene-induced (MC-induced) tumours of low-leukemic CC57BR mice by means of the radioimmunodiffusion method, using the precipitating test-systems. The gs-1 antigen of murine C-type viral p30 protein and Gross leukemia virus type-specific antigen (AGLV) served as viral genome markers. The gs-1 antigen was found in the primary and continuous MC-induced sarcomas, whereas AGLV appeared only during the tumour passage. A distinct association was revealed between the quantity of p30 protein (gs-1 antigen titre) and the presence of AGLV. Simultaneously with the appearance of AGLV the gs-1 titre increased markedly and the AGLV disappearance was always accompanied by a decrease of the gs-1 titre. The data presented suggest a coordinated expression of the two investigated proteins of murine C-type endogenous oncornaviruses in the chemically-induced tumours of CC57BR mice.