Release of platelet-activating factor from HL-60 human leukemic cells following macrophage-like differentiation

G. Camussi, F. Bussolino, F. Ghezzo, L. Pegoraro

Research output: Contribution to journalArticle

Abstract

Platelet-activating factor (PAF), a phospholipid mediator of anaphylaxis, is also known to be released in vitro from both phagocytic polymorphonuclear neutrophils (PMN) and monocytes in response to a variety of stimuli. The fact that human myeloid cells of the HL-60 line can be made to differentiate in vitro into macrophage-like cells by 12-O-tetradodecanoylphorbol-13-acetate (TPA) prompted us to investigate the generation and release of PAF during this transformation. Both passive release of PAF at pH 9.5, and active release, following phagocytosis of C3b- and C3d-opsonized yeast spores, and stimulation with C5a anaphylatoxin from untreated and TPA-treated HL-60 cells, PMN, and plastic-adherent normal human monocytes were studied. It was found that after 3 days of TPA treatment, HL-60 cells released PAF following phagocytosis of C3b- and C3d-opsonized yeast spores. Inhibition of PAF release by a selective inhibitor of phospholipase A2 and labeling of PAF with sodium 14C-acetate indicated that PAF generation is a two-step process: (1) release of PAF precursor from cell membranes and (2) its acetylation. A model for the in vitro study of mechanisms and metabolic events involved in PAF generation and release could perhaps be built on these findings.

Original languageEnglish
Pages (from-to)16-22
Number of pages7
JournalBlood
Volume59
Issue number1
Publication statusPublished - 1982

ASJC Scopus subject areas

  • Hematology

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