ISOLATION OF A LIPID-SOLUBLE HISTAMINE-RELEASE FACTOR FROM HUMAN PLATELETS

We have isolated a histamine release factor from human platelet supern atants by heparin column chromatography, gel filtration and reversed p hase HPLC. Fractions from each chromatographic step were assayed for h istamine release factor activity (HRF). A peak of HRF activity was det ected at a molecular mass of 60 kDa. Subsequent HPLC purification show ed that the factor co-eluted with human serum albumin, but was totally extractable into the lipid phase. Comparison of biological activity w ith known basophil and eosinophil-activating hydroxyeicoasnoids demons trated similar activity with 5(S)-hydroperoxy-6E,8Z,11Z,14Z-eicosatetr aenoic acid (5(S)-HPETE). The identification of this lipid soluble HRF demonstrates the novel potential role of an as yet unidentified lipid as an HRF, in the absence of priming stimuli. (C) 1994 Academic Press , Inc.