Platelet activating factor: an inhibitor of neutrophil activation?
Preparations of platelet activating factor (PAF) derived by methanolic extraction of supernatants from antigen-challenged rabbit basophils proved capable of activating platelets while concurrently inhibiting neutrophil aggregation/secretion stimulated by biologically active F-Met peptides, ionophore A23187, or zymosan-treated serum. This inhibition was non-cytotoxic and species-non-specific. When these PAF preparations were analysed using thin-layer chromatography, multiple lipids were detected. Both platelet-stimulating as well as neutrophil-inhibitory activity was present in a lipid component migrating at an RF consistent with native PAF; however, these biological activities were not limited only to PAF and, indeed, could also be detected in lipid with solubility characteristics more closely related to a lysophosphatide than to native PAF. These data are compatible with the belief that native PAF may belong to a family of biologically active lipids differing somewhat in physico-chemical properties. Moreover, these data illustrate that PAF and/or PAF-like molecules may also demonstrate a biological activity distinct from their effects upon the platelet.
D000818:Animals; D001779:Blood Coagulation Factors / Q000494:pharmacology / Q000502:physiology*; D001792:Blood Platelets / Q000378:metabolism; D002449:Cell Aggregation / Q000187:drug effects; D006801:Humans; D008244:Lysophosphatidylcholines / Q000494:pharmacology / Q000502:physiology*; D009504:Neutrophils / Q000502:physiology*; D010972:Platelet Activating Factor; D010974:Platelet Aggregation; D011817:Rabbits; D012701:Serotonin / Q000097:blood
D001779:Blood Coagulation Factors; D008244:Lysophosphatidylcholines; D010972:Platelet Activating Factor; D012701:Serotonin