Antitumor factor of regional lymph node cells in the transplantation of Ehrlich tumor cells. 3. Passive transfer of the antitumor factor

In vitro and in vivo experiments were conducted for the purpose to determine whether or not the antitumor factor found in the regional lymph node cells of the mouse sensitized with Ehrlich tumor cells would transfer its antitumor activity to normal lymph node cells. In in vivo experiments normal lymph node cells incubated at 5°C for 60 minutes in the supernatant containing the antitumor activity have shown the antitumor activity against JTC-11 cells in mixed culture. Namely, it hs been demonstrated that the antitumor activity in the supernatant can be transferred directly to normal lymph node cells in vitro. In the in vitro experiments, the same results as in in vivo experiments were obtained. The antitumor activity against JTC-11 cells has been detected in the lymph node cells obtained on 4, 7 and 9 days after subcutaneous and intraperitoneal injections of the supernatant having antitumor activity. Next, we tried DNase and RNase treatments of the sensitized supernant to observe the transfer factor-like snbstance. The results indicate that, while the passive transfer is possible with the supernatant treated with DNase, it is not with the RNase-treated supernatant. From these findings it is assumed that the factor (in the sensitized supernatant) capable of conferring the antitumor activity is an RNA-dependent substance (or a substance closely associated with RNA) and is probably different from the antitumor factor reported in Parts 1 and 2.