A colony inhibition (CI) technique for demonstration of tumor cell destruction by lymphoid cells in vitro

A colony inhibition technique is described which was used to demonstrate that immune lymphocytes have a destructive effect on cultivated tumor target cells, if the target cells contain H‐2 isoantigens or tumor‐specific antigens foreign to the lymphocytes. Untreated allogeneic lymphocytes and lymphoma cells, added to the target cells together with phytohemagglutinin, were also effective in reducing the number of colonies formed.