ETIDIoHNov 20, 2024

Dual #receptor-binding, #infectivity, and #transmissibility of an emerging #H2N2 low pathogenicity avian #influenza virus

Source: Nature Communications, https://www.nature.com/articles/s41467-024-54374-z

Abstract
The 1957 H2N2 influenza pandemic virus [A(H2N2)pdm1957] has disappeared from humans since 1968, while H2N2 avian influenza viruses (AIVs) are still circulating in birds. It is necessary to reveal the recurrence risk and potential cross-species infection of these AIVs from avian to mammals. We find that H2 AIVs circulating in domestic poultry in China have genetic and antigenic differences compared to the A(H2N2)pdm1957. One H2N2 AIV has a dual receptor-binding property similar to that of the A(H2N2)pdm1957. Molecular and structural studies reveal that the N144S, and N144E or R137M substitutions in hemagglutinin (HA) enable H2N2 avian or human viruses to bind or preferentially bind human-type receptor. The H2N2 AIV rapidly adapts to mice (female) and acquires mammalian-adapted mutations that facilitated transmission in guinea pigs and ferrets (female). These findings on the receptor-binding, infectivity, transmission, and mammalian-adaptation characteristics of H2N2 AIVs provide a reference for early-warning and prevention for this subtype.

_____

#aH2n2 #abstract #avianInfluenza #AVIANINFLUENZA #birdFlu #china #health #news #poultry #research

Dual receptor-binding, infectivity, and transmissibility of an emerging H2N2 low pathogenicity avian influenza virus - Nature Communications

The authors identify one emerging H2N2 AIV, reveal the molecular basis of human-type receptor binding of the H2N2 AIV and pandemic strains, and evaluate the public risk of H2N2 AIV by its infection, transmission and mammalian-adaptation features.

Nature
ETIDIoHNov 3, 2024

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2024.10.31.24316514v1

Abstract
Avian H5N1 influenza viruses are circulating widely in cattle and other mammals and pose a risk for a human pandemic. Previous studies suggest that older humans are more resistant to H5N1 infections due to childhood imprinting with other group 1 viruses (H1N1 and H2N2); however, the immunological basis for this is incompletely understood. Here we show that antibody titers to historical and recent H5N1 strains are highest in older individuals and correlate more strongly with year of birth than with age, consistent with immune imprinting. After vaccination with an A/Vietnam/1203/2004 H5N1 vaccine, both younger and older humans produced H5-reactive antibodies to the vaccine strain and to a clade 2.3.4.4b isolate currently circulating in cattle, with higher seroconversion rates in young children who had lower levels of antibodies before vaccination. These studies suggest that younger individuals might benefit more from vaccination than older individuals in the event of an H5N1 pandemic.

____

https://etidioh.wordpress.com/2024/11/03/immune-history-shapes-human-antibody-responses-to-h5n1-influenza-viruses-repost/

#aH1n1 #aH2n2 #aH5n1 #abstract #avianInfluenza #AVIANINFLUENZA #birdFlu #h5n1 #health #immunology #news #pandemicInfluenza #research #vaccination

Immune history shapes human antibody responses to H5N1 influenza viruses

Avian H5N1 influenza viruses are circulating widely in cattle and other mammals and pose a risk for a human pandemic. Previous studies suggest that older humans are more resistant to H5N1 infections due to childhood imprinting with other group 1 viruses (H1N1 and H2N2); however, the immunological basis for this is incompletely understood. Here we show that antibody titers to historical and recent H5N1 strains are highest in older individuals and correlate more strongly with year of birth than with age, consistent with immune imprinting. After vaccination with an A/Vietnam/1203/2004 H5N1 vaccine, both younger and older humans produced H5-reactive antibodies to the vaccine strain and to a clade 2.3.4.4b isolate currently circulating in cattle, with higher seroconversion rates in young children who had lower levels of antibodies before vaccination. These studies suggest that younger individuals might benefit more from vaccination than older individuals in the event of an H5N1 pandemic. ### Competing Interest Statement S.E.H. is a co-inventor on patents that describe the use of nucleoside-modified mRNA as a vaccine platform. S.E.H reports receiving consulting fees from Sanofi, Pfizer, Lumen, Novavax, and Merck. T.A.G. was an employee of the University of Pennsylvania when the work was completed and is now an employee of GSK. The authors declare no other competing interests. ### Funding Statement This project was funded in part with Federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Department of Health and Human Services, under Contract Nos. 75N93021C00015 (S.E.H. and S.C.) and grant numbers R01AI08686 (S.E.H.). S.E.H. holds an Investigators in the Pathogenesis of Infectious Disease Awards from the Burroughs Wellcome Fund. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Experiments using human sera were conducted with the approval of the University of Pennsylvania Institutional Review Board. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data are included in the manuscript and there are no restrictions. The code implementing the analyses is available at https://github.com/cobeylab/H5\_titers\_vs_imprinting

medRxiv