[Cytostatic action of the peritoneal cells of Syrian hamsters on transformed cells]

The cytostatic effect (CSE) of intact Syrian hamster peritoneal cells (PC) was determined by their capability to inhibit 3H-thymidine incorporation in target cells of HETR, which were placed in 1 X 10(4) or 4 X 10(4) cells per well together with 4 tenfold differing concentrations of PC (10(2)-10(5]. The optimum of CSE was seen with the use of maximal doses of PC and HETR in reaction. Maximal level of CSE with all effector-target cell rations was observed between 23-28 hours of contact. These data permit to suggest the role of HETR cells in activation of PC, as well as the transfer of cytostatic state in dense cell shift mediated by cell-cell contacts. The role of humoral cytostatic factor is also not excluded.