Potentiation of Anaphylactic Histamine Release from Isolated Rat Pleural Mast Cells by Rat Serum Phospholipids

Abstract

Isolation of sensitized rat mast cells by density gradient centrifugation in Ficoll decreases the histamine release obtained when they are subsequently exposed to antigen [egg albumin]. The histamine release from such isolated cells is potentiated by the addition of 2% boiled rat serum. This potentiation is dose-dependent and has a temperature optimum of about 25.degree. C. The potentiating activity was localized to the serum phospholipid fraction. Of the pure phospholipids studied (LPC [lysophosphatidylcholine], PC [phosphatidylcholine], PE [phosphatidylethanolamine], PI [phosphatidylinositol], PS [phosphatidylserine] and SM [sphingomyelin]) only PS and LPC potentiated the histamine release. The mechanism of this potentiation is discussed; it is probably due to a requirement of these phospholipids for the ion exchange (Na+, K+ and Ca2+) or the adenylate cyclase activity essential for the histamine release process.