Adenosine inhibits platelet-activating factor, but not tumour necrosis factor-α-induced priming of human neutrophils

Abstract

Regulation of the respiratory burst and its priming by recombinant human tumour necrosis factor-α (rhTNF-α) and platelet-activating factor (PAF) were investigated in human polymorphonuclear leucocytes (PMN). Adenosine (0.1-10 μM) pretreatment of PMN concentration-dependently inhibited the superoxide anion generation (O2-) in response to formyl-methionyl-leucyl-phenylalanine (EMLP). The priming by PAE (1 μM) for an increased O2- generation by FMLP-stimulated PMN was completely blocked by adenosine pretreatment. In contrast, rhTNF-α-induced priming was unaffected by adenosine. In addition, the direct stimulation of PMN O2- by rhTNF-α was also unaffected by adenosine as was rhTNF-α-induced PAF ..