system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, METHODS, RESULTS. Meshes: Amphiregulin, Animals, Cell Line, Disease Models, Animal, EGF Family of Proteins, Enzyme-Linked Immunosorbent Assay, Glycoproteins, Humans, Intercellular Signaling Peptides and Proteins, Lymphocyte Depletion, Neuraminidase, Paramyxoviridae Infections, Phosphoproteins, Rats, Receptors, Cell Surface, Recombinant Fusion Proteins, Sigmodontinae, Trachea, Viral Plaque Assay, Viral Proteins.
user
Does a recombinant sialidase fusion protein effectively inhibit human parainfluenza viral infection in vitro and in vivo? Context: 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. 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. 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.
assistant
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. Final Decision: yes