In vitro effects of synthetic chemotactic peptides on neutrophil function.

The effects of the three synthetic chemotactic N-formyl-L-methionyl peptides, namely f-met-phe, f-met-val and f-met-ala, on neutrophil chemotaxis, adhesiveness, oxidative metabolism, phagocytosis and killing were evaluated in vitro. The three peptides displayed different stimulating properties, with relative activity f-met-phe greater than f-met-val greater than f-met-alal for all functions tested. Experiments performed with chemotactically deactivated neutrophils showed that deactivation does not interfere with neutrophil functions other than chemotaxis and does not prevent further stimulation by the same chemo-attractant. The results demonstrate that the interaction of a single chemotactic agent with neutrophil membrane can trigger different cellular responses, dependent in their type and intensity on the concentrations of the chemotactic factor and on the functional state of the cell.