Mediation of cytotoxic immune responses against human tumor-associated antigens by allogeneic immune RNA.

Allogeneic immune RNA (I-RNA), extracted from the peripheral blood lymphocytes of patients putatively cured of cancer, mediated cytotoxic immune reactions that apparently were directed specifically against human tumor-associated antigens. I-RNA was extracted from the peripheral blood lymphocytes of patients with various types of cancer. Patients selected had not been previously sensitized to HL-A or other normal transplantation antigens or to blood group antigens. Normal human peripheral blood lymphocytes were incubated with these allogeneic I-RNA preparations and tested for cytotoxicity against human target cells in vitro. Allogeneic I-RNA mediated cytotoxic immune reactions only against tumor target cells of the same histologic type as the I-RNA donor. I-RNA's extracted from peripheral blood lymphocytes of melanoma patients mediated cytotoxic immune reactions only against melanoma cells. Similarly, only I-RNA's extracted from the lymphocytes of patients with colon cancer mediated cytotoxic immune reactions against colon carcinoma cells, and only I-RNA's from the lymphocytes of breast cancer patients mediated immune reactions against breast cancer target cells. Allogeneic I-RNA extracted from peripheral blood lymphocytes of cancer patients possibly mediated specific cytotoxic immune reactions that were directed against common tumor-associated antigens shared by human tumors of similar histologic type.