Humoral immune response of patients receiving specific active immunotherapy for renal cell carcinoma

The object of this study was to characterize the antigens evoking an immune response in renal cell carcinoma (RCC) patients receiving specific active immunotherapy with irradiated autologous tumor cells and Corynebacterium parvum as adjuvant. Seventy serum samples from 11 patients with RCC undergoing specific active immunotherapy were evaluated. Fifty of the 70 serum specimens (71%) had immunoglobulin G antibody directed to autologous tumor cells. Absorption studies were completed on 4 patients (S.E., M.M., R.N., S.V.) with 2 patients (S.V. and M.M.) demonstrating reactivity to a RCC-associated antigen present on their autologous tumor cells. One patient's serum (R.N.) was absorbed not only with autologous tumor cells but also with an allogeneic RCC cell line. The fourth patient's (S. E.) serum reactivity was able to be absorbed only with autologous tumor cells and several, but not all, of the clones of that autologous cell line. Patient S.E. serum binding by clones of RCC cell line RPMI-SE was seen to vary from no ability to bind RPMI-SE in some clones to double the parental binding in others. Consistent with this finding was the demonstration that high serum-binding clones could absorb Patient S.E. serum reactivity to autologous RCC cells, while low binding clones could not. These data suggest a measure of heterogeneity among the parental RCC cell line, as demonstrated by its clones. This study has shown that the autologous tumor vaccine with adjuvant used here was an immunogenic therapeutic agent. The response mounted by these patients was a response to a RCC-associated antigen with the level of reactivity changing with the number of immunizations and disease status. Also suggested by this work is the possible primary tumor heterogeneity, as demonstrated by the differential reactivity seen among clones of a RCC cell line established from such a primary tumor.