Topographical distribution and association of tumor--associated antigens and their role in antigenicity in rat tumor cells.

The antigenicity of tumor-associated antigen (TAA) was compared between 3-methylcholanthrene-induced rat fibrosarcoma KMT-17 and Friend murine leukemia virus-infected KMT-17 (FV-KMT-17) cells. The antigenicity was classified into immunosensitivity and immunogenicity, and studied from the viewpoint of humoral immunity. The immunosensitivity to anti TAA antibodies increased by artificial infection of KMT-17 cells with Friend virus. The results suggested that an increase of lateral mobility of TAA on the cell surface contributes to the increase of immunosensitivity. Concerning the immunogenicity of TAA, an augmentation of anti-TAA antibody formation was demonstrated when FV-KMT-17 cells were used as the immunogen. In this case, a physical association between TAA and virus-associated antigen (VAA) was suggested to be very important to increase the immunogenicity of TAA.