8ut7
From Proteopedia
CryoEM structure of A/Perth/16/2009 H3 in complex with polyclonal Fab from mice immunized with H3 stem nanoparticles-28 days post immunization
Structural highlights
FunctionC6KNH7_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).[RuleBase:RU003324][SAAS:SAAS001364_004_327643] Publication Abstract from PubMedBroadly neutralizing antibodies (bnAbs) targeting the hemagglutinin (HA) stem of influenza A viruses (IAVs) tend to be effective against either group 1 or group 2 viral diversity. In rarer cases, intergroup protective bnAbs can be generated by human antibody paratopes that accommodate the conserved glycan differences between the group 1 and group 2 stems. We applied germline-engaging nanoparticle immunogens to elicit a class of cross-group bnAbs from physiological precursor frequency within a humanized mouse model. Cross-group protection depended on the presence of the human bnAb precursors within the B cell repertoire, and the vaccine-expanded antibodies enriched for an N55T substitution in the CDRH2 loop, a hallmark of the bnAb class. Structurally, this single mutation introduced a flexible fulcrum to accommodate glycosylation differences and could alone enable cross-group protection. Thus, broad IAV immunity can be expanded from the germline repertoire via minimal antigenic input and an exceptionally simple antibody development pathway. Eliciting a single amino acid change by vaccination generates antibody protection against group 1 and group 2 influenza A viruses.,Ray R, Nait Mohamed FA, Maurer DP, Huang J, Alpay BA, Ronsard L, Xie Z, Han J, Fernandez-Quintero M, Phan QA, Ursin RL, Vu M, Kirsch KH, Prum T, Rosado VC, Bracamonte-Moreno T, Okonkwo V, Bals J, McCarthy C, Nair U, Kanekiyo M, Ward AB, Schmidt AG, Batista FD, Lingwood D Immunity. 2024 Apr 18:S1074-7613(24)00143-2. doi: 10.1016/j.immuni.2024.03.022. PMID:38670113[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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