A RECOMBINANT SIALIDASE FUSION PROTEIN EFFECTIVELY INHIBITS HUMAN PARAINFLUENZA VIRAL INFECTION IN VITRO AND IN VIVO.

Background: The first step in infection by human parainfluenza viruses (HPIVs) is binding to the surface of respiratory epithelial cells via interaction between viral receptor-binding molecules and sialic acid–containing receptors. DAS181, a recombinant sialidase protein containing the catalytic domain of Actinomyces viscosus sialidase, removes cell surface sialic acid, and we proposed that it would inhibit HPIV infection.  Methods:  Depletion of sialic acid receptors by DAS181 was evaluated by lectin-binding assays. Anti-HPIV activity in cultured cell lines and in human airway epithelium was assessed by the reduction in viral genomes and/ or plaque forming units on treatment. In vivo efficacy of intranasally administered DAS181 was assessed using a cotton rat model.  Results:  DAS181-mediated desialylation led to anti-HPIV activity in cell lines and human airway epithelium. Intranasal DAS181 in cotton rats, a model for human disease, significantly curtailed infection.  Conclusions: Enzymatic removal of the sialic acid moiety of HPIV receptors inhibits infection with all tested HPIV strains, both in vitro and in cotton rats. Enzyme-mediated removal of sialic acid receptors represents a novel antiviral strategy for HPIV. The results of this study raise the possibility of a broad spectrum antiviral agent for influenza virus and HPIVs.

Antiviral agent, DAS181-mediated desialylation, EpiAirway AIR-100, EpiAirway AIR-196, Human parainfluenza virus receptor, Human parainfluenza viruses (HPIVs), Influenza virus, Sialic acid receptors, Sialic acid-containing receptors, Viral infection, Viral receptor-binding molecules

Human parainfluenza viruses, Sialidase fusion protein