Influenza Virus Research
Influenza Virus Research Tools
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Influenza viruses are enveloped, segmented, negative-sense single-stranded RNA viruses in the family Orthomyxoviridae. Four influenza virus types are recognized: A, B, C, and D. Influenza A and B viruses are responsible for seasonal influenza epidemics in humans, while influenza A viruses are also the only influenza viruses known to cause pandemics.
Influenza A viruses are classified into subtypes according to their surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA). Eighteen HA subtypes and eleven NA subtypes have been identified. Influenza B viruses are not divided into HA/NA subtypes, although genetically and antigenically distinct lineages have circulated in humans.
Influenza A and B viruses contain eight genome segments. Each segment is assembled with nucleoprotein and the viral polymerase complex to form a viral ribonucleoprotein. The segmented genome permits reassortment when two compatible influenza viruses infect the same cell, contributing to viral diversity and, in influenza A viruses, the emergence of novel pandemic strains.
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Influenza virion and segmented genome organization.
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Influenza A Genome Segments and Encoded Proteins
| Segment |
Encoded Protein(s) |
Principal Function |
| 1 |
PB2 |
Polymerase subunit involved in recognition and binding of capped host RNA. |
| 2 |
PB1, PB1-F2 and other strain-dependent products |
PB1 is the catalytic RNA polymerase subunit; accessory products may influence host responses and pathogenesis. |
| 3 |
PA and PA-X |
PA provides endonuclease activity for cap snatching; PA-X contributes to host-gene shutoff. |
| 4 |
Hemagglutinin (HA) |
Mediates receptor binding and membrane fusion; the major target of neutralizing antibodies. |
| 5 |
Nucleoprotein (NP) |
Encapsidates viral RNA and supports transcription, replication, nuclear transport, and genome packaging. |
| 6 |
Neuraminidase (NA) |
Cleaves sialic acids to facilitate virion release and movement through respiratory mucus. |
| 7 |
M1 and M2 |
M1 forms the matrix layer and coordinates assembly; M2 is a proton-selective ion channel involved in uncoating. |
| 8 |
NS1 and NEP/NS2 |
NS1 modulates innate immune responses; NEP supports nuclear export of viral ribonucleoproteins. |
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Influenza A Virus
Infects humans and numerous animal species. Influenza A viruses are classified by HA and NA subtype, undergo antigenic drift, and can undergo antigenic shift through reassortment.
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Influenza B Virus
Primarily circulates in humans and contributes substantially to seasonal influenza. Influenza B viruses undergo antigenic drift but are not classified into HA/NA subtypes.
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Browse Influenza Research Tools
Explore influenza products by reagent type or virus subtype.
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Recombinant Proteins
Hemagglutinin, neuraminidase, nucleoprotein, matrix, and other proteins from Influenza A and B strains.
Influenza A Proteins »
Influenza B Proteins »
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Antibodies
Monoclonal and polyclonal antibodies against influenza HA, NA, NP, M1, M2, and other viral antigens.
Influenza A Monoclonal Antibodies »
Influenza B Monoclonal Antibodies »
Polyclonal Antibodies »
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Pseudoviruses
Influenza pseudoviruses for viral-entry, neutralizing-antibody, vaccine, and antiviral research.
Browse Influenza Pseudoviruses » |
Influenza Research Products by Subtype
| H1N1 |
H2N2 & H4N6 |
H3N2 |
H5N1 |
| H5N2, H5N3, H5N8, H6N1 & H6N2 |
H7N1, H7N2, H7N7 & H7N9 |
H8, H9, H11, H12, H13, H15 & H16 |
Influenza B Strains |
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Research Applications
• Hemagglutinin receptor-binding studies
• Neuraminidase activity and inhibition
• Neutralizing-antibody assays
• Vaccine-antigen evaluation |
• Antigenic drift and subtype comparison
• ELISA and immunoassay development
• Viral entry and membrane-fusion studies
• Antiviral drug discovery |
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Scientific Resources & Further Reading
The following trusted resources provide current information on influenza virus taxonomy, genome sequences, surveillance, vaccines, structural biology, and emerging influenza viruses.
CDC Influenza: Influenza virus types, surveillance, vaccines, and public-health information
WHO Global Influenza Programme: Global influenza surveillance and vaccine strain recommendations
NCBI Virus: Influenza genome sequences, proteins, metadata, and comparative analysis
International Committee on Taxonomy of Viruses: Official influenza virus taxonomy and nomenclature
RCSB Protein Data Bank: Three-dimensional structures of influenza proteins and antibody complexes
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