Heparan Sulphate Binding Increases the Half-Life and Activity of the Suppressive HpARI Proteins, HpARI1 and HpARI2
The parasitic nematode Heligmosomoides polygyrus bakeri secretes a family of proteins (HpARI) that modulate the host immune response by binding to the cytokine IL-33, with HpARI1 and HpARI2 suppressing and HpARI3 enhancing IL-33 activity; the differential activity is determined by the ability of HpARI1 and HpARI2, but not HpARI3, to bind to heparan sulphate, which increases their half-life and retains them at the site of infection.