Allogeneic inhibitory activity of regional lymph node cells in the mouse isografted with methylcholanthrene-induced tumor

In mouse bearing progressive cancer a decrease was present in the allogeneic inhibitory activity of T-lymphocytes, which constitutes the core of immunological surveillance system in mammalians. For tests, methylcholanthrene-induced tumor (MC-tumor) was isografted subcutaneously on the back between scapulae of C3H mice, and the lymphocytes were prepared from the regional axillary lymph nodes removed from these mice at 1, 2, 3, or 4 weeks after grafting. These lymph nodes cells were cultured together with 40-fold numbers of allogeneic JTC-11 cells derived from Ehrlich cancer cells in a culture medium containing 2.0% (v/v) PHA for 24 or 48 hours. The proliferation rate of JTC-11 cells (increased numbers) at weekly interval was considered the allogeneic inhibitory activity of lymph node cells. As a result it was demonstrated that in the early stage after tumor transplantation, i.e., in the first or second week, regional lymph node cells showed a strong allogeneic inhibitory activity, as in the case with lymph-node cells from normal mice, but at progressive stage of cancer, i.e., the third or fourth week when tumors were larger, such activity was completely lost. It seems that mice with progressive cancer showed a decrease of allogeneic inhibitory activity, i.e., a disruption of homeostasis was present.