For the aim of adoptive immunotherapy in mice bearing transplanted sarcoma and in cancer patients, we performed secondary in vitro sensitization to obtain functionally active T cells. Specific tumor antigens, cytokines, viable irradiated tumor cells, an anti-CD3 monoclonal antibody and others were used. We preferred the method of complex stimulation with PHA, T-cell growth factor or IL-2, in small doses, and 3 M KCl tumor extract. In patients with cancer, many authors reported for an activity of cells with suppressor function. CD4⁺CD25⁺ regulatory T cells increased in number in peripheral blood and lymph node lymphocytes, and among tumor-infiltrating cells. In our investigations, production both of factor, inhibiting Ehrlich-cell migration and suppressor factor was revealed from T cells, in vitro sensitized with 3 M KCl cancer extract containing solubilized cancer antigens. The suppressor factor decreased or abrogated the effect of the inhibitory Ehrlich-cell migration factor. It is important to further scrutinize the spread and clonal proliferation of in vitro sensitized, transferred T cells, thus, their subsequent invasion in cancer node, in the host.