The analysis of cytostatic activity of human peripheral blood granulocytes and its augmentation with Nocardia rubra cell wall skeleton (N-CWS).

Granulocytes of normal volunteers showed substantial levels of cytostatic activity against tumor-cell-derived cell lines. Spontaneous cytostatic activity of the granulocytes was observed after 24 h incubation and reached the maximal level within 48 h. Lysates of granulocytes also showed significant cytostatic activity. The cytostatic activity of the granulocytes was significantly augmented by in vitro incubation with Nocardia rubra cell-wall skeleton (N-CWS). Maximal augmentation of granulocyte-mediated cytostasis was achieved with 2.5 micrograms N-CWS per ml after 24 h incubation when the granulocyte-to-tumor-cell ratio was 10:1. The N-CWS itself showed no direct effect on the uptake of 3H-thymidine by tumor cells.