K-cell cytotoxic activity in the spleen and lymph nodes of tumour-bearing mice.

The cytotoxic activity of spleen and lymph node cells from female CBA mice bearing a methylcholanthrene-induced fibrosarcoma on target cells coated with anti-target cell antibody has been investigated. Spleen cells from tumour-bearing mice caused a significantly greater degree of target cell lysis than did spleen cells from control mice. This increase in cytotoxicity was most apparent when a ratio of ten lymphoid cells to one target cell was used. With control mice, the mean cytotoxic index was 13.54 +/- 1.05 (s.e.m.) as compared to 55.00 +/- 6.11 with tumour-bearing mice. An increase in the cytotoxic activity of lymph node cells was also noted. In control mice, the cytotoxic index, using a ratio of 100:1 was 8.55 +/- 2.27. In tumour-bearing mice, the mean cytotoxic activity of the draining lymph node was 21.66 +/- 4.96, and of the contralateral lymph node, 13.00 +/- 3.46.