Human tumor — Lymphocyte interaction in vitro

Summary Biopsy derived tumor cells have been tested for capacity to induce DNA synthesis in autologous blood lymphocytes in vitro (ATS test). In the present series 5/20 biopsies were ATS positive when mechanically separated cells were used. Preincubation of the tumor cells at 37° C, but not at 0° C, markedly increased the stimulating capacity. Parallel experiments gave 7/9 positive tests with preincubated and 3/9 positive tests with cells used directly. When the biopsy cells were brought into suspension by enzyme treatment they did not stimulate unless incubated at 37° C before confronting the lymphocytes. In accordance with previous results, the presence of autologous serum during ATS inhibited the reaction.