Human monocyte derived dendritic cells express functional P2X and P2Y receptors as well as ecto-nucleotidases

We investigated the expression and function of P2 receptors and ecto-nucleotidases on human monocyte derived dendritic cells (DC), In addition we analyzed the effect of extracellular ATP on the maturation of DC. By RT-PCR, DC Here found to express mRNA for several P2X (P2X1, P2X4, P2X5, P2X7) and P2Y (P2Y1, P2Y2, P2Y4, P2Y5, P2Y6, P2Y10, P2Y11) receptors, AS shown by FURA-2 measurement, triggering of P2 receptors resulted in an increase in free intracellular Ca2+. In combination with Tumor necrosis factor-alpha ATP increased the expression of the DC surface markers CD80, CD83 and CD86 indicating a maturation promoting effect. DC expressed the ecto-apyrase CD39 and the ecto-5'-nucleotidase CD73 as demonstrated by RT-PCR, Extracellular ATP was rapidly hydrolyzed by these ecto-enzymes as shown by separation of H-3-labeled ATP metabolites using a thin layer technique. These data suggest that ATP acts as a costimulatory factor on DC maturation. (C) 1999 Federation of European Biochemical Societies.