RELEASE OF PLATELET-ACTIVATING FACTOR (PAF) AND HISTAMINE .2. THE CELLULAR-ORIGIN OF HUMAN-PAF - MONOCYTES, POLYMORPHONUCLEAR NEUTROPHILS AND BASOPHILS

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  • 1 January 1981
    • journal article
    • research article
    • Vol. 42  (2) , 191-199
Abstract
The origin of platelet activating factor (PAF) from human leukocytes was investigated. Purified monocytes release PAF passively at pH 10.6 when challenged with ionophore A23187 [calcimycin] or under phagocytic stimuli. Pure preparations of polymorphonuclear neutrophils liberate PAF passively, when challenged with C5a, neutrophil cationic proteins (CP), their carboxypeptidase B derived products (C5a des Arg, CP des Arg) or under phagocytic stimuli. Basophil rich buffy coat cells release PAF when challenged with C5a, CP, anti-IgE (in low amount) or Synacthen concomitantly with basophil degranulation and histamine release. EM studies, carried out on Synacthen-stimulated basophil rich buffy coat, provide morphological evidence for platelet-basophil interaction. Evidently PAF can be released from different leukocyte populations. However, the stimuli able to trigger such release appear to have some specificity for the cell target.