title: Chemotaxis of horse polymorphonuclear leukocytes to N-formyl-L-methionyl-L-leucyl-L-phenylalanine.
abstract: Horse polymorphonuclear leukocytes (PMN) isolated from horse blood by sedimentation and isotonic lysis and having about 25% accompanying lymphocytes were as effective at chemotaxis as nearly pure PMN isolated by density gradient techniques. N-Formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP), used as a representative of the formylmethionyl peptides (produced by prokaryocytic organisms), was effective as a chemoattractant only at the high concentration of 10(-4) M. When serum was preincubated with FMLP at concentrations as low as 10(-8) M, the serum attracted horse PMN. This activity was not generated when heat-inactivated (56 to 60 C for 30 minutes) serum was used. A combination of FMLP and zymosan was no more effective than zymosan alone in generating serum chemoattractants. The results of this study indicate that the FMLP is a weak chemoattractant for horse PMN, but that FMLP has the capability similar to that of zymosan to activate complement to produce PMN chemoattractants.
mesh_terms: D000818:Animals; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D006736:Horses / Q000097:blood*; D008715:Methionine / Q000031:analogs & derivatives*; D009239:N-Formylmethionine / Q000031:analogs & derivatives* / Q000494:pharmacology; D009240:N-Formylmethionine Leucyl-Phenylalanine; D009504:Neutrophils / Q000187:drug effects; D009842:Oligopeptides / Q000494:pharmacology*; D015054:Zymosan / Q000494:pharmacology
chemical_list: D009842:Oligopeptides; D009239:N-Formylmethionine; D009240:N-Formylmethionine Leucyl-Phenylalanine; D015054:Zymosan; D008715:Methionine