FcR+ lymphocytes and ADCC in tumor-bearing adult and aging rats.

It was shown that in the normal, aging rats as compared with adults a decrease of cytotoxic activity of spleen lymphocytes in syngeneic ADCC test appeared which was followed by the parallel decrease of percentage of EA rosetting lymphocytes. In adult rats with the syngeneic transplants of immunogenic, methylcholanthrene-induced sarcoma (MC-Sa) a dramatic decrease of ADCC and much smaller decrease of EA rosettes were observed in comparison with the normal animals. On the contrary, in aging tumor-bearing rats an increase of ADCC activity was found, however, it was not followed by the changes of EA rosettes. Moreover, it was found that the non-forming EA rosette lymphocytes demonstrated a slight ADCC activity mostly expressed in aging rats with MC-Sa.