Correlation between tumour antigens and malignancy in BKV-transformed hamster cells

Hamster kidney cells transformed by BK virus (HKBK cells) were studied in order to correlate the membrane tumour antigens to the metastatic capability. The presence of the tumour associated surface antigen (TASA) on the surface of HKBK cells was detected by the immunofluorescence test on live cell suspensions. The metastatic ability was investigated by inoculating HKBK cells subcutaneously (s.c.) into newborn hamsters, s.c., intraperitoneally (i.p.) and in the foot pads into adult hamsters, and s.c. into adult hamsters previously immunized with surface antigens extracted from HKBK cells. The results indicate that there is a correlation between the appearance of tumour antigens on the cell surface and the metastatic ability: HKBK cells at low passage (about 30 subcultures after transformation) showed the capping of TASA in the cell membrane and low metastatic ability, whereas HKBK cells at high passage (about 130 subcultures after transformation) exhibited a diffuse appearance of TASA in the cell surface and were highly metastatic.