Amino acid investigations of tumor-associated antigen of Mc31 transformed cells.

There are numerous evidences (mainly indirect) for the presence of tumor-associated surface antigens (TASA) in cells transformed by avian oncornaviruses. Hayami, et al. (1977) and Ignjatovic et al. (1978) established that such antigens on avian leukosis virus (ALV) cells have neither virus, nor oncofetal origin. On leukosis virus strain Mc31-transformed turkey cells, Filchev and Ivanov (1986) and Wesselinova (1989, 1991) also describe a TASA. But there are only a few studies on the nature and properties of such antigens (with proven antigenic properties). A TASA, induced by avian tumor viruses with MW of about 42,000 Daltons have been established on hamster cells (Aupoix et al., 1974), but there has been no further examination of it. Bauer et al. (1979) only showed that a TSSA (tumor specific surface antigen) on avian virus-transformed 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) possessing antigenic properties and that it is the specific for the tumor cells, we decided to investigate its amino acid content.