Neuraminidase inhibitors are the only licensed antiviral medications available to treat avian influenza A(H7N9) virus infections in humans. According to a neuraminidase inhibition assay, an R292K substitution reduced antiviral efficacy of inhibitors, especially oseltamivir, and decreased viral fitness in cell culture. Monitoring emergence of R292K-carrying viruses using a pH-modified neuraminid...

A deletion of ∼20 amino acids in the stalk of neuraminidase is frequently observed upon transmission of influenza A viruses from waterfowl to domestic poultry. A pair of recombinant H7N1 viruses bearing either a short- or long-stalk neuraminidase was genetically engineered. Inoculation of the long-stalk-neuraminidase virus resulted in a higher cloacal excretion in ducks and led conversely to lo...

Neuraminidase-treatment greatly increased 3H-thymidine incorporation by human lymphocytes at lower concentrations of Con A. An irreversible sequence after 24 hr of incubation in the presence of the optimal concentration of Con A was found. However, at a suboptimal concantraiton of Con A, neuraminidase-treated lymphocytes exposed to Con A for 72 hr exhibited a greater magnitude of 3H-thymidine i...

The mechanism of association of the human platelet membrane GPIIb-GPIIIa-Ca2+ complex was studied by treating solubilized membranes with various enzymes and cationic peptides and by studying the binding of “Ca2+ and 1261-fibrinogen before and after dissociation with EGTA and association with Ca2+. Neuraminidase shifted the complex cathodally (presumably due to cleavage of negatively charged dom...

Abstract There is limited knowledge of influenza‐specific immune responses and their kinetics in critically ill patients. We investigated humoral cellular after critical influenza A/H1N1 infection hypothesized that dysfunctionality or absence could contribute to more severe illness. followed 12 patients hospitalized with infection; the majority admitted intensive care unit (ICU). Blood samples ...

Xyloside-initiated 35SO4(2-)-labelled glycosaminoglycans were isolated from the medium of cultured bovine glomeruli and covalently coupled to Sepharose 4B to construct a solid-phase substrate suitable for the detection of endoglycosidases. The substrate is rendered specific for heparitinase by prior digestion with chondroitin sulphate ABC lyase and is insensitive to proteinase, neuraminidase an...

I-cell disease (mucolipidosis II) is presented as a model for endoand exo-cytosis phenomena in man. A hypothesis is presented for the structure of the carbohydrate recognition site on fibroblast-derived fJ-D-N-acetylhexosaminidase that may extend to the other affected hydrolases and that is responsible for specific uptake of the enzyme by fibroblasts. The proposed neuraminidase deficiency in I-...

The His274→Tyr (H274Y) oseltamivir (Tamiflu) resistance mutation causes a substantial decrease in the total levels of surface-expressed neuraminidase protein and activity in early isolates of human seasonal H1N1 influenza, and in the swine-origin pandemic H1N1. In seasonal H1N1, H274Y only became widespread after the occurrence of secondary mutations that counteracted this decrease. H274Y is cu...

We have used a neuraminidase-deficient influenza virus, NWS-Mvi, which was selected by supplying bacterial neuraminidase in the medium (C. Liu and G. M. Air, Virology 194:403-407, 1993), to define the role of neuraminidase in influenza virus replication. Electron microscopy showed that virions of the NWS-Mvi mutant assembled normally and formed large aggregates associated with cell surfaces. Th...