IN VITRO STUDIES OF IMMUNE REACTIONS AGAINST AUTOCHTHONOUS AND SYNGENEIC MOUSE TUMORS INDUCED BY METHYLCHOLANTHRENE AND PLASTIC DISCS

A colony inhibition (CI) technique was used to demonstrate lymph node cell (LNC) and serum‐mediated immune reactions against specific transplantation antigens of mouse sarcomas which were induced by methylcholanthrene (MCA) or by plastic disc implantation. Lymph node cells from mice whose primary MCA sarcomas had been removed 3–8 days before the test strongly reduced the plating efficiency of autochthonous target tumor cells. An approximately equal reduction was also obtained with LNC from mice with progressively growing MCA sarcomas or from those which had been inoculated once with untreated or heavily X‐irradiated (15,000 R) sarcoma cells. Cytotoxic antibodies were infrequently detected in serum from these mice. Repeated immunization with heavily irradiated tumor cells appeared to increase the level of cytotoxic humoral antibodies but did not augment the LNC‐mediated immune reactions. Copyright © 1968 Wiley‐Liss, Inc., A Wiley Company