AMINO-ACID INVESTIGATIONS OF TUMOR-ASSOCIATED ANTIGEN OF MC31 TRANSFORMED-CELLS

There are numerous evidences (mainly indirect) for the presence of tum or-associated surface antigens (TASA) in cells transformed by avian on cornaviruses. Hayami, ei al. (1977) and Ignjatovic et al. (1978) estab lished that such antigens on avian leukosis virus (ALV) cells have nei ther virus, nor oncofetal origin. On leukosis virus strain Mc31-transf ormed turkey cells, Filchev and Ivanov (1986) and Wesselinova (1989, 1 991) also describe a TASA. But there are only a few studies on the nat ure and properties of such antigens (with proven antigenic properties) . A TASA, induced by avian tumor viruses with MW of about 42,000 Dalto ns have been established on hamster cells (Aupoix et al., 1974), but t here has been no further examination of it. Bauer et al. (1979) only s howed that a TSSA (tumor specific surface antigen) on avian virus-tran sformed cells is a glycoprotein. The protein fraction we isolated from Mc31-transformed turkey tumor cells (Wesselinova, 1994) is the first attempt to characterize such purified TASA on chicken cells. After we demonstrated that it is a protein with low MW (about 14,000 Daltons) p ossessing antigenic properties and that it is be specific for the tumo r cells, we decided to investigate its amino acid content.