In vitro studies on tumor-specific immunity by using C3H mammary cancer-A cells. I. Inhibitory effect of lymph-node cells from the tumor bearing isologous C3H mouse on the proliferation of the tumor cells

As a link in the series of studies on tumor-specific immunity, in vitro inhibitory effect of sensitized isologous lymph-node cells on the proliferation of C3H mammary cancer was studied. For this purpose tissue culture was conducted with regional lymph-node cells obtained from truly isologous C3H mouse inoculated with A strain cells derived from C3H mouse mammary cancer along with A cells, and the following results were obtained. In the case of tissue culture with those lymph-node cells obtained from the groups of mice 10 days after the inoculation of 5 X 106 A cells, the inhibitory effect on the proliferation of A cells was most marked, followed by that of those taken on day 14, 7, and 5 decreasing in the order mentioned. In the case with those regional lymph-node cells obtained from mice which did not have recurrence of tumor 1 week after extirpation of 2-week old tumor, the inhibitory effect on proliferation of A cells was marked, with the regional lymph-node cells obtained two weeks after transplantation of 1 × 108 A cells there could be observed no inhibitory effect at all. This suggests that at a certain stage after implantation of such regional lymph- node cells there develops a specific anti-tumor activity in the host.