Response of human neutrophils to formyl-peptide modified at the terminal amino and carboxyl groups

Abstract

Two analogs of chemotactic peptideN-formyl-l-methionyl-l-leucyl-l-phenylalanine were examined for their capacity to activate several functions of human neutrophils. The C-terminus methyl ester derivative of the chemotactic peptide was found to possess strong biological activity and was able to induce levels of chemotaxis, enzyme secretion, and Superoxide generation comparable to those observed with the same concentrations ofN-formyl-l-methionyl-l-leucyl-l-phenylalanine. The analog containing atert-butyloxycarbonyl group at the N-terminus, as well as the C-terrninal methyl ester, was completely devoid of activity towards neutrophils. From these results, it appears that the free carboxyl group is not necessary for biological function. In contrast, the substituent at the N-terminus may play a critical role in the induction of the cellular response.