Name: neuraminidase inhibitors and flu spread
Uploaded: 2026-05-20T14:34:12.962Z
Duration: 1 min 25 s
Channel: JoVE

Viral release from an infected cell is crucial for the spread of infection.Neuraminidase inhibitors are a class of antiviral drugs that can prevent the release of viruses, such as influenza A.The influenza A viral surface contains two essential glycoproteins &#x2014; hemagglutinin and neuraminidase.Hemagglutinin binds to sialic acid receptors on the host cell surface, helping in viral entry.Once inside, the viral RNA uses the host cell&#x27;s machinery to produce viral proteins.These proteins, including hemagglutinin and neuraminidase, are assembled into new viral particles at the host cell membrane.As the virus matures, new virions bud from the host cell surface. But they initially remain attached because hemagglutinin binds to sialic acid residues on the host cell membrane.Neuraminidase cleaves these residues, allowing the virion to detach from the host cell.Neuraminidase inhibitors are structural analogs of sialic acid that block neuraminidase activity.As a result, the virus remains bound to the host cell, preventing further spread of infection.

inhibitors of virion release

Inhibitors Of Virion Release

Viral replication and dissemination rely on efficient mechanisms for host cell entry, genome replication, assembly, and release. Influenza viruses, such as types A and B, are negative-sense single-stranded RNA viruses with a segmented genome, that depend on two critical surface glycoproteins to carry out these processes: hemagglutinin (HA) and neuraminidase (NA). HA initiates infection by binding to sialic acid residues on the surface of host epithelial cells, facilitating receptor-mediated endocytosis of the viral particle. Once inside the cell, the virus is uncoated, and its viral ribonucleoprotein (vRNP) complexes are transported to the nucleus. Because the viral RNA cannot be directly translated, it must first be transcribed into positive-sense mRNA by the viral RNA-dependent RNA polymerase. These viral mRNAs then hijack the host&#x27;s translational machinery to produce viral proteins needed for replication and assembly.Assembly and Budding of New Virions: Newly synthesized viral proteins, including HA and NA, are transported to the host cell membrane, where they coalesce to form progeny virions. These viral particles bud from the plasma membrane, acquiring a lipid envelope embedded with HA and NA. However, the newly formed virions initially remain tethered to the cell surface due to persistent interactions between HA and sialic acid residues on the host membrane.Role of Neuraminidase in Viral Release: To complete the viral life cycle, NA cleaves terminal sialic acid residues from glycoproteins and glycolipids on the host cell surface. This enzymatic activity liberates the budding virions, facilitating their release and enabling infection of neighboring cells. Without this step, the virus cannot efficiently spread, significantly impairing pathogenicity.Mechanism of Neuraminidase Inhibitors: Neuraminidase inhibitors, such as oseltamivir, function as competitive inhibitors by mimicking the natural substrate, sialic acid. These drugs bind to the active site of NA, obstructing its enzymatic function. As a result, the virions remain anchored to the host cell surface, curtailing further propagation of the virus. This mode of action makes neuraminidase inhibitors an essential class of antiviral agents in the treatment and control of influenza infections.

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JoVE Core

Microbiology

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Antimicrobial Agents

KEY TERMS AND CONCEPTS

neuraminidase inhibitors and flu spread

Influenza viruses spread when new virions leave an infected cell and reach nearby cells. Influenza A and B are negative-sense, single-stranded RNA viruses with segmented genomes. They depend on two surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA), to infect cells, make new viral particles, and release them.

HA starts infection by binding to sialic acid on the surface of host epithelial cells. This binding helps the virus enter the cell by receptor-mediated endocytosis. After entry, the virus is uncoated, and its viral ribonucleoprotein complexes move to the nucleus. The viral RNA cannot be used directly, so the viral RNA-dependent RNA polymerase first makes positive-sense mRNA. The host cell then uses its own translation machinery to produce viral proteins needed for replication and assembly.

Newly made viral proteins, including HA and NA, move to the host cell membrane. There they gather to form new virions, or progeny viruses. These particles bud from the plasma membrane and take on a lipid envelope that contains HA and NA. At first, the new virions stay attached to the cell surface because HA still binds to sialic acid on the host membrane.

NA completes the release step by cutting terminal sialic acid residues from glycoproteins and glycolipids on the host cell surface. This action frees the budding virions so they can spread to neighboring cells. Without this step, the virus cannot spread efficiently, and its ability to cause disease is reduced. Neuraminidase inhibitors, such as oseltamivir, act as competitive inhibitors. They mimic sialic acid and bind to the active site of NA, blocking its function and keeping virions anchored to the host cell surface.

Neuraminidase Inhibitors and Flu Spread

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Influenza viruses spread when new virions leave an infected cell and reach nearby cells. Influenza A and B are negative-sense, single-stranded RNA viruses with segmented genomes. They depend on two surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA), to infect cells, make new viral particles, and release them. HA starts infection by binding to sialic acid on the surface of host epithelial cells. This binding helps the virus enter the cell by receptor-mediated endocytosis. After...

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key terms and concepts

Learn how influenza neuraminidase helps new virions leave infected cells and how drugs like oseltamivir block this step to slow flu spread.

Neuraminidase Inhibitors and Flu Spread | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

Neuraminidase Inhibitors and Flu Spread

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