Receptors for immune complexes on cells within a polyoma virus-induced murine sarcoma

Cells present in the polyoma virus-induced murine ascites tumor SEYF-a showed the capacity to fix soluble immune complexes of ovalbumin anti-ovalbumin. The fixation could be inhibited by preincubating the cells with antisera directed against H-2 antigens and with syngeneic anti-tumor antibodies. The latter did not react with normal cells. Depletion of phagocytes from the ascites cell population, thus enriching for tumor cells, increased the inhibition of complex fixation by the syngeneic anti-tumor antiserum. The inhibition of complex fixation by the anti-tumor antibodies was not mediated by "third-party" complexes. Pepsin-treated globulin derived from the syngeneic anti-tumor antiserum could still inhibit complex fixation by SEYF-a cells. These results raise the possibility that tumor cells, per se, expressed receptors for immune complexes. Macrophages, apparently of host origin, residing in the SEYF-a tumor, also expressed such receptors.