Influence of serum derived chemotactic factors and bacterial products on human neutrophil chemotaxis

The chemotaxis of granulocytes has been shown to be modulated by serum factors, tissue factors, bacterial products, and a host of other substances. In vivo, these factors may act in concert with each other to modify the motions of these cells. The effect was examined of aggregated gamma globulin activated serum (AS), bacterial factors, and endotoxin either alone or in combination with each other, on human granulocyte chemotaxis. Exposure of granulocytes to AS resulted in deactivation to AS but not to E. coli or S. epidermis culture filtrate. Exposure of neutrophils to S. epidermis or E. coli CF or E. coli endotoxin resulted in deactivation to AS or C5a but not to E. coli or S. epidermis culture filtrate. Addition of endotoxin to AS or C5a resulted in inhibition of chemotaxis but untreated granulocytes toward this combination as compared with AS alone. These results suggest that separate mechanisms may be involved when serum or bacterial chemotactic factors initiate human granulocytc chemotaxis. Furthermore, the potent but specific inhibitory effect of endotoxin on chemotaxis toward AS may be of clinical significance.