Cell Surface Antigens of Human Renal Cancer

The two key questions of h u m a n cancer immunology remain unresolved. These relate to whether tumor-specific antigens exist in h u m a n cancer and, if so, whether there is immunological recognition of these antigens in humans. To date, candidate h u m a n tumor-specific antigens defined by heterologous sera have, on further analysis, turned out to belong to the category of differentiation antigens, antigens characterizing normal cells at some phase of differentiation, rather than antigens that are restricted to neoplastic cells. The tumor antigens that are detected by reactions with h u m a n sera fall into several categories, with alloantigens (particularly products of the HLA complex and ABO locus), antigens related to Epstein-Barr virus, and antigens related to the heterologous sera used in cul tur ing h u m a n cancer cells representing the best studied examples. In general, however, most surveys of h u m a n populat ions for humoral or cell-mediated immuni ty to cell surface or intracellular antigens of h u m a n cancer cells have not provided the sort of evidence that would permit the distinction of tumor-specific reactions from reactions directed to other categories of antigens. To develop as direct an approach as possible to the question of whether patients with cancer recognize tumor-specific antigens on the surface of their cancer cells, we have developed a serological approach, referred to as autologous typing, that has been applied to the study of cell surface antigens of mal ignant melanoma (1-3), acute leukemia (4), and astrocytoma (5). Autologous typing has several features: (a) direct tests are restricted to reactions between sera and tumor cells from the same patient, el iminating the need to consider reactions that are a result of conventional alloantibodies and assuring the detection of antigens restricted to autologous tumor cells, i.e., class 1 antigens, see below; (b) several serological tests are used in parallel, reducing the possibility that ant ibody belonging to a part icular class might be missed; (c) target cells from solid tumors are provided by serially passaged tissue culture lines, permit t ing