Modulation of human neutrophil function in vitro by gastrin.

We have studied the effects in vitro of gastrin-17 and gastrin-34, at concentrations from 10(-14) M to 10(-6) M, on several of the functions of peripheral blood human neutrophils, i.e. adherence to substrate, mobility (spontaneous and directed by a chemical gradient or chemotaxis), ingestion of inert particles (latex beads) and cells (Candida albicans) and superoxide anion production. Both gastrins inhibited several steps of the phagocytic process of human neutrophils, such as mobility and ingestion. By contrast, these peptides increased adherence and had no effect on superoxide anion production. In general, these effects were significant at peptide concentrations between 10(-12) M and 10(-8) M with a maximal effect at 10(-10) M. In addition, gastrin peptides induced a significant increase in intracellular cAMP levels at 30, 60 and 120 s. Moreover, the inhibitory effect of gastrin-17 on the ingestion capacity of neutrophils (latex bead phagocytosis) was similar to that obtained with EGTA, a well-known extracellular calcium chelating compound. Gastrin-17 was found to inhibit completely the stimulation of latex bead phagocytosis in neutrophils caused by the calcium ionophore A23187. These results suggest that gastrin is a negative modulator of the phagocytic process of human neutrophils, and that this effect might involve an increase in intracellular cAMP levels and a decrease in calcium entry into the cells.