| Structural highlights
Function
Q6WG00_9INFA Binds to sialic acid-containing receptors on the cell surface, bringing about the attachment of the virus particle to the cell. This attachment induces virion internalization of about two third of the virus particles through clathrin-dependent endocytosis and about one third through a clathrin- and caveolin-independent pathway. Plays a major role in the determination of host range restriction and virulence. Class I viral fusion protein. Responsible for penetration of the virus into the cell cytoplasm by mediating the fusion of the membrane of the endocytosed virus particle with the endosomal membrane. Low pH in endosomes induces an irreversible conformational change in HA2, releasing the fusion hydrophobic peptide. Several trimers are required to form a competent fusion pore (By similarity).[SAAS:SAAS00204388]
Publication Abstract from PubMed
Conserved epitopes on the influenza hemagglutinin (HA) stem are an attractive target for universal vaccine strategies as they elicit broadly neutralizing antibodies. Such antibody responses to stem-specific epitopes have been extensively characterized for HA subtypes H1 and H5 in humans. H2N2 influenza virus circulated 50 years ago and represents a pandemic threat due to the lack of widespread immunity, but, unlike H1 and H5, the H2 HA stem contains Phe45(HA2) predicted to sterically clash with HA stem-binding antibodies characterized to date. To understand the effect of Phe45(HA2), we compared the HA stem-specific B cell response in post hoc analyses of two phase 1 clinical trials, one testing vaccination with an H2 ferritin nanoparticle immunogen ( NCT03186781 ) and one with an inactivated H5N1 vaccine ( NCT01086657 ). In H2-naive individuals, the magnitude of the B cell response was equivalent, but H2-elicited HA stem-binding B cells displayed greater cross-reactivity than those elicited by H5. However, in individuals with childhood H2 exposure, H5-elicited HA stem-binding B cells also displayed high cross-reactivity, suggesting recall of memory B cells formed 50 years ago. Overall, we propose that a one-residue difference on an HA immunogen can alter establishment and expansion of broadly neutralizing memory B cells. These data have implications for stem-based universal influenza vaccination strategies.
A single residue in influenza virus H2 hemagglutinin enhances the breadth of the B cell response elicited by H2 vaccination.,Andrews SF, Raab JE, Gorman J, Gillespie RA, Cheung CSF, Rawi R, Cominsky LY, Boyington JC, Creanga A, Shen CH, Harris DR, Olia AS, Nazzari AF, Zhou T, Houser KV, Chen GL, Mascola JR, Graham BS, Kanekiyo M, Ledgerwood JE, Kwong PD, McDermott AB Nat Med. 2022 Feb;28(2):373-382. doi: 10.1038/s41591-021-01636-8. Epub 2022 Feb , 3. PMID:35115707[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Andrews SF, Raab JE, Gorman J, Gillespie RA, Cheung CSF, Rawi R, Cominsky LY, Boyington JC, Creanga A, Shen CH, Harris DR, Olia AS, Nazzari AF, Zhou T, Houser KV, Chen GL, Mascola JR, Graham BS, Kanekiyo M, Ledgerwood JE, Kwong PD, McDermott AB. A single residue in influenza virus H2 hemagglutinin enhances the breadth of the B cell response elicited by H2 vaccination. Nat Med. 2022 Feb;28(2):373-382. PMID:35115707 doi:10.1038/s41591-021-01636-8
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