Cytostatic activity of in vitro activated human adherent cells against human tumor cell lines

Human adherent cells from peripheral blood were cultured with immunostimulant, BCG, yeast wall, or streptococcal preparation (OK-432), for 3 days, and the cytostatic activity of the adherent cells on human tumor cells was examined. The cells cultured in the presence of an immunostimulant exhibited increased phagocytic activity and the number of phagocytosed sheep red blood cells (sRBC) per cell increased. Adherent cells cultured without the immunostimulant showed slight cytostatic activity of 8 approximately 20%. HD-10 cells, derived from Hodgkin's disease, and QG-K and QG-U cells derived from uterine cervical cancer were more susceptible than HeLa cells to the adherent cells activated by OK-432 or yeast cell wall. Relationship between population doubling time and susceptibility to the cytostatic effect mediated by the activated adherent cells was not observed. The supernatant from the activated adherent cells was also effective in inhibiting DNA synthesis of the rapidly proliferating target cells, HD-10 cells and HeLa cells. However, the proliferation of the other two cell lines was enhanced. The effect of activated adherent cells on tumor cell proliferation and its relation to cytostasis were examined and discussed.