Hyaluronidases of the gastrointestinal invasive nematodes Ancylostoma caninum and Anisakis simplex: possible functions in the pathogenesis of human zoonoses.

The gastrointestinal invasive stages of two parasitic nematodes, Ancylostoma caninum and Anisakis simplex, were each found to release in vitro a hydrolytic enzyme that degrades the glycosaminoglycan hyaluronic acid. The parasite hyaluronidases were partially purified by ion-exchange chromatography and biochemically characterized. The hyaluronidase from A. caninum adult worms had a molecular weight of 65,000 and a pH optimum of 6 with activity at neutral pH, while the hyaluronidase from A. simplex larvae had a molecular weight of 40,000 and a pH optimum of 4 with no activity at neutral pH. Both parasite hyaluronidases also degraded the glycosaminoglycan chondroitin sulfate A. Cupric sulfate and high concentrations of sodium chloride were inhibitory. The nematode hyaluronidases are postulated to have a role in tissue histolysis and mucosal invasion; their distinct biochemical properties have relevance to the pathogenesis of the zoonoses anisakiasis and eosinophilic enteritis.