Immunomodulatory drugs and endogenous spleen colonies (CFC-s)

The influence of the immunomodulators--thymus factor X (TFX), levamisole and isoprinosine--on the multipotential hemopoietic stem cells (CFC-s) was studied. They were shown to influence actively the formation of endogenous spleen colonies. The intensity of effect appeared to be related to a strategy of the drugs administration. If administered prior to irradiation (500Ra) they were more efficacious than after irradiation. Their activity consists in an increment of the number of endogenous spleen colonies. Only the effect of levamisole appeared to be differentiated: at a small dose it stimulated the appearance of endogenous spleen colonies and at a large dose it reduced their number. It was assumed that the immunomodulatory drugs applied in therapy in combination with cytostatics may prevent the cytostatic effect of the latter as concerns the granulocyto--erythrocytic system.