tNucleotides and nucleosides are secreted into extracellular media at different concentrations as a conse-quence of different physiologic and pathological conditions. Ecto-nucleotidases, enzymes present on thesurface of most cells, hydrolyze these extracellular nucleotides and reduce the concentration of them,thus affecting the activation of different nucleotide and nucleoside receptors. Also, ecto-nucleotidasesare present in a number of microorganisms and play important roles in host–pathogen interactions.Here, we characterized the ecto-ATPase activities present on the surface of HIV-1 particle and humanmacrophages as well. We found that the kinetic properties of HIV-1 and macrophage ecto-ATPases aresimilar, suggesting that the enzyme is the same. This ecto-ATPase activity was increased in macrophagesinfected in vitro with HIV-1. Using three different non-related ecto-ATPase inhibitors—POM-1, ARL67156and BG0—we showed that the inhibition of these macrophage and viral ecto-ATPase activities impairsHIV-1 infection. In addition, we also found that elevated extracellular concentrations of ATP inhibit HIV-1production by infected macrophages.2016-04-30