Involvement of platelet-activating factor in endotoxin-induced priming of rabbit polymorphonuclear leukocytes

Abstract

Endotoxin primes polymorphonuclear leukocytes (PMNs) for increased superoxide anion (O2-) generation in response to the chemotactic peptide, formyl-methionyl-leucyl-phenylalanine (fMLP). We have investigated the role of platelet-activating factor (PAF) in the priming of rabbit PMNs by endotoxin. In non-primed PMNs, fMLP stimulated PAF generation, but none was detected in the supernatant, whereas in primed PMNs PAF generation increased 17-fold and a large proportion of the total PAF formed was released. There was a close relationship between the concentration-response curve for increases in PAF synthesis and that for enhanced O2- generation. The possibility that PAF was causally linked to enh..