SYNTHETIC PEPTIDE CHEMOTACTIC FACTORS FOR NEUTROPHILS - RANGE OF ACTIVE PEPTIDES, THEIR EFFICACY AND INHIBITORY ACTIVITY, AND SUSCEPTIBILITY OF THE CELLULAR-RESPONSE TO ENZYMES AND BACTERIAL TOXINS

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  • 1 January 1979
    • journal article
    • research article
    • Vol. 36  (3) , 579-588
Abstract
The chemotactic activity for [human] neutrophil leukocytes of 26 peptides of varied sequence, of which the majority were N-formylated, was assessed by determining the concentration at which each was maximally active and the efficacy of each peptide at that concentration. These 2 measures of activity did not correlate with one another. Many formylated peptides with a wide variety of sequences were active. Of these the formyl-methionyl peptides had highest efficacy, but many other peptides were active at concentrations as low as the formyl-methionyl tripeptides. Unrelated peptides, i.e., formyl-methionyl-leucyl-phenylalanine, acetyl-tri-alanine, formyl-tri-phenylalanine, cross-inhibited the cells'' response to one another, and this inhibition was reversible. Inhibition was prevented if the cells were incubated throughout the experiment in levamisole or A23187. The leukocyte peptide receptor is apparently capable of binding many ligands, and activation of a response is not solely a function of binding affinity. A strict steric specificity for binding was excluded. Chemotactic responses to formylated peptides were reduced in cells pretreated with perfringolysin, a bacterial cholesterol-binding toxin, and with phospholipase C. Trypsin and pronase also reduced these responses when used at 500 .mu.g/106 cells but not at lower doses.