The difference in immunological properties between lymph node metastatic and non-metastatic cell lines of MCA-induced fibrosarcoma of C4W mice.

To pursue the process of lymph node metastasis, i.e, the preferential tumor growth in lymph node, we have established the non-metastatic M2B cell line which was derived from 3-methylcholanthrene-induced fibrosarcoma of C4W mouse and a metastatic cell line, M2BLN-M+ which was obtained from metastatic lymph nodes of irradiated C4W mouse which was subcutaneously implanted with cultured tumor cells, because implanted tumor cells were derived from the spontaneous metastatic lymph node of the parental M2B tumor, but regressed in naive C4W mouse. We examined the characteristics of both tumor cell lines in terms of the immunological cellular interactions. M2BLN-M+ showed unexpectedly to be more susceptible to cytotoxicity of immune effectors (NK cell, macrophage and cytotoxic T lymphocyte) than M2B did. When cultured both tumor cells with these effector cells, the growth inhibition of M2BLN-M+ was greater than that of M2B. The regional lymph node of tumor-bearer, however, showed no effective cytotoxic activity as reported by others. On the contrary, when cultured both tumor cells with non-immune lymph node cells, to be surprised, the proliferation of M2B was markedly suppressed, while that of M2BLN-M+ was slightly inhibited. The lymph node cells of M2B-bearing mice showed stronger cytostatic activity to M2B. The results suggest that the cytostatic activity of lymph node cells will be a pivotal factor, concerning the establishment of lymph node metastasis.