Neuraminidase Measurement
Neuraminidase Measurement - Related Videos
03:19
An Assay to Measure Influenza Neuraminidase Inhibition Antibody Titers
0 Views •
2025
This video demonstrates an assay measuring influenza neuraminidase (NA) inhibiting antibody titers in a serum sample. A serum sample containing antibodies against NA is added to a fetuin-coated microwell plate. Upon adding the virus, the antibodies prevent viral NA from cleaving fetuin and exposing its galactose moiety. A peroxidase-conjugated lectin is then added, which binds to the exposed galactose. The NA-inhibiting antibody titer is determined using a colorimetric test, where a peroxidase...
08:11
Measuring Influenza Neuraminidase Inhibition Antibody Titers by Enzyme-linked Lectin Assay
0 Views •
Cited by 54 •
2016
We describe the enzyme-linked lectin assay (ELLA) for measuring influenza neuraminidase (NA)-inhibition antibody titers in sera. The assay uses peanut agglutinin to quantify galactose residues that become accessible when NA removes sialic acid from fetuin-coated, 96-well plates.
09:31
Fluorescence-based Neuraminidase Inhibition Assay to Assess the Susceptibility of Influenza Viruses to The Neuraminidase Inhibitor Class of Antivirals
0 Views •
Cited by 56 •
2017
We describe the use of a phenotypic fluorescence-based neuraminidase inhibition assay to assess the susceptibility of influenza A and B viruses to the neuraminidase inhibitor class of antivirals.
12:18
Expression of Functional Recombinant Hemagglutinin and Neuraminidase Proteins from the Novel H7N9 Influenza Virus Using the Baculovirus Expression System
0 Views •
Cited by 182 •
2013
Here we describe a way to express correctly folded and functional influenza virus surface antigens derived from the novel Chinese H7N9 virus in insect cells. The technique can be adapted to express ectodomains of any viral or cellular surface proteins.
13:12
Quantitative Analyses of all Influenza Type A Viral Hemagglutinins and Neuraminidases using Universal Antibodies in Simple Slot Blot Assays
0 Views •
Cited by 19 •
2011
A simple slot blot method was developed for the quantification of influenza viral hemagglutinin and neuraminidase using universal antibodies targeting their most conserved sequences identified through bioinformatics analyses. This innovative approach may provide a useful alternative to quantitative determination of all viral hemagglutinin and neuraminidase.
FAQs
The assay links enzymatic cleavage to a detectable change in the substrate. When neuraminidase removes terminal sialic acid residues from a labeled or chromogenic sialylated substrate, the reaction generates fluorescence or color. Under defined conditions, the resulting signal is proportional to enzyme activity, allowing researchers to compare activity levels rather than merely detect the enzyme’s presence.
pH, temperature, and incubation time directly affect the measured activity and must be defined consistently. Changing any of these variables can alter how much substrate is cleaved during the assay, even when samples contain comparable enzyme activity. Standardized conditions therefore make comparisons among pathogen samples, strains, inhibitor treatments, or vaccine-related experiments more meaningful.
Both formats report substrate cleavage, but they use different detectable outputs. Fluorescent assays measure emitted fluorescence from a labeled substrate, whereas colorimetric assays measure a visible color change from a chromogenic substrate. The choice determines how activity is read, while the underlying interpretation remains the same: signal generated under matched conditions reflects neuraminidase activity.
Neuraminidase activity provides a functional view of how microbial enzymes can alter glycoconjugates at the host–pathogen interface. Because the enzyme removes terminal sialic acid residues, its activity can be related to changes in cell-surface glycosylation. This connects an assay result with broader questions about microbial pathogenesis and the consequences of infection-related glycan modification.
A typical workflow uses a labeled or chromogenic sialylated substrate, exposes it to the sample, and allows cleavage under specified pH, temperature, and incubation-time conditions. The resulting fluorescence or color is then measured and interpreted as enzyme activity. Keeping the reaction conditions consistent is essential when comparing samples or evaluating experimental treatments.
Researchers can apply this measurement to influenza and other pathogens when they need to characterize enzyme function, compare strains, or examine microbial pathogenesis. The assay also supports studies of host–pathogen interactions by providing an activity-based readout rather than relying only on pathogen identity or presence. Its value comes from connecting enzymatic function with infection-related biological questions.
An inhibitor study compares neuraminidase activity in the presence and absence of the treatment using matched assay conditions. Reduced fluorescence or color relative to an appropriate comparison indicates less substrate cleavage during the measurement. This makes the assay useful for assessing antiviral strategies, provided that differences in signal are interpreted alongside the standardized reaction conditions.
Standardized measurements allow activity levels to be compared across pathogen strains and experimental samples using the same assay framework. They can help characterize differences in enzyme function, examine responses associated with vaccine studies, and relate those findings to host–pathogen biology. The resulting data are most informative when signal differences are distinguished from changes caused by assay conditions.