Identification of functional platelet-activating factor receptors in Raji lymphoblasts

J. B. Travers, Q. Li, D. A. Kniss, R. H. Fertel

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

The binding and metabolism of platelet-activating factor (PAF) were characterized in Raji, a human Burkitt's lymphoma-derived cell line. Raji lymphoblasts readily metabolized PAF by deacetylation-reacylation at 37°C, but not at 4°C. Binding studies conducted at 4°C demonstrated specific binding that reacted saturation within 80 min. This binding was only partially reversible. Scatchard analysis of PAF binding data revealed a single class of PAF binding sites (17,800 ± 3,600/cell) with a K of 2.3 ± 0.3 nM. These high-affinity PAF binding sites were shown to be functional receptors, as 100 pm to 1 μM PAF increased free intracellular calcium in a dose-dependent manner. The dose of PAF necessary to achieve half maximal calcium mobilization response was 6.3 nM, which was in the range of the K for the receptor calculated from the binding studies. The structurally dissimilar PAF receptor antagonists CV-3988 and BN52021 inhibited the PAF-induced calcium changes at doses that competed with PAF binding. These studies provide the first evidence for a functional PAF receptor expressed on a lymphocyte cell line.

Original languageEnglish (US)
Pages (from-to)3708-3713
Number of pages6
JournalJournal of Immunology
Volume143
Issue number11
StatePublished - Jan 1 1989
Externally publishedYes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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