Characterisation of the secreted apyrase family of Heligmosomoides polygyrus

Apyrases are a recurrent feature of secretomes from numerous species parasitic nematodes. Here we characterise the five apyrases secreted by Heligmosomoides polygyrus, natural parasite mice and widely used laboratory model for intestinal nematode infection. All enzymes closely related to soluble calcium-activated nucleotidases described in variety organisms, distinct CD39 family ecto-nucleotidases. Expression is maximal adult worms restricted adults L4s. Recombinant were produced purified Pichia pastoris. The showed very similar biochemical properties, with strict calcium dependence broad substrate specificity, catalysing hydrolysis all nucleoside tri- diphosphates, no activity against monophosphates. Natural infection provoked low antibodies any enzyme, but immunisation an apyrase cocktail partial protection reinfection, reduced egg output recovery. most likely role extracellular ATP, which acts as alarmin cellular release IL-33 initiation type 2 immunity.