Immunity against Sarcoma Cells*

Mouse sarcoma cells derived from recent methyicholanthrene-induced tumors of known genotypes were inoculated into isologous or homologous hosts after incubation with serum or lymph node cells from different sources. Isoantiserum enhanced the out growth of the tumors in genetically incompatible, homologous systems, whereas in isologous systems it had no effect. Lymph node cells of preimmunized homologous hosts were inhibitory in both homologous and isologous systems. Homologous lymph node cells, taken from untreated mice, showed variable effects, depending on the system used. Based on this experience, obtained with various experimental designs, all of which were concerned with some aspect of the homograft reaction, similar studies were carried out with completely isologous systems. Primary or first or second passage sarcomas were exposed to lymph node cells of isologous mice, pretreated with heavily irradiated cells of the same tumor, or of the primary autologous host. Lymph node cells derived from autologous, or untreated or pretreated isologous, hosts were inhibitory in a num ber of cases.