"Activated" monocytes in gastric cancer patients. II. Suppressor and cytostatic activity in vitro

The spontaneous nitro-blue tetrazolium (NBT) reduction of monocytes from patients with gastric cancer was assessed and compared with an in vitro monocyte-mediated cytostasis of tumor cell lines and their suppressor activity. The increased NBT reduction correlated with the ability of monocytes to inhibit mitogen-induced normal lymphocyte response and cytostatic activity against L-1210 murine lymphoma cell line. These observations suggest that "activated" monocytes of some cancer patients may play the role of suppressor cells and exert an anti-tumor effect in vitro.