Studies of virus-specific antigenicity of tumour cells transformed by bovine adenovirus type 3.

The present paper deals with the study of immunologic relationship between tumours induced by bovine adenovirus type 3 and the organism of the tumour-bearing hamster. The experiments showed that primarily induced tumours were not virus-specifically antigenic as a result of non-expression of weak TSTA presumably due to the presence of more potent antigens of cellular origin. It was only after repeated passages of tumour cells in vivo or in vitro, as a result of tumour progression, that the loss of potent antigens of cellular origin occurs which contributes to expression of weak virus-specific antigens. The findings obtained can explain unsuccessful attempts at detecting virus-specific antigens in spontaneous tumours. Antigenicity of spontaneous tumour and its immunologic relationship with the organism are probably associated with antigens of cellular origin occurring on cell membrane as a result of malignization rather than with antigens induced by an etiological agent. Consequently, the more profound development of immunological methods for diagnosis, therapy and prophylaxis of oncogenic processes irrespective of their etiology seems to be expedient.