Antigenic Characterization and Pandemic Risk Assessment of North American H1 Influenza A Viruses Circulating in Swine

Journal Article · Tue Nov 01 00:00:00 EDT 2022 · Microbiology Spectrum

DOI:https://doi.org/10.1128/spectrum.01781-22· OSTI ID:2424086

Venkatesh, Divya ^[1]; Anderson, Tavis K. ^[2]; Kimble, J. Brian ^[2]; Chang, Jennifer ^[2]; Lopes, Sara ^[1]; Souza, Carine K. ^[2]; Pekosz, Andrew ^[3]; Shaw-Saliba, Kathryn ^[4]; Rothman, Richard E. ^[4]; Chen, Kuan-Fu ^[5]; Lewis, Nicola S. ^[6]; Vincent Baker, Amy L. ^[2]

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1. Univ. of London, London, Hertfordshire (United Kingdom). The Royal Veterinary College
2. US Dept. of Agriculture (USDA), Ames, IA (United States). Agricultural Research Service (ARS)
3. Johns Hopkins Univ., Baltimore, MD (United States). Bloomberg School of Public Health
4. Johns Hopkins Univ., Baltimore, MD (United States). School of Medicine
5. Chang Gung Memorial Hospital, Keelung City (Taiwan)
6. Univ. of London, London, Hertfordshire (United Kingdom). The Royal Veterinary College; Animal and Plant Health Agency (APHA), Surrey (United Kingdom)

The first pandemic of the 21st century was caused by an H1N1 influenza A virus (IAV) introduced from pigs into humans, highlighting the importance of swine as reservoirs for pandemic viruses. Two major lineages of swine H1 circulate in North America: the 1A classical swine lineage (including that of the 2009 H1N1 pandemic) and the 1B human seasonal-like lineage. Here, we investigated the evolution of these H1 IAV lineages in North American swine and their potential pandemic risk. We assessed the antigenic distance between the HA of representative swine H1 and human seasonal vaccine strains (1978 to 2015) in hemagglutination inhibition (HI) assays using a panel of monovalent antisera raised in pigs. Antigenic cross-reactivity varied by strain but was associated with genetic distance. Generally, the swine 1A lineage viruses that seeded the 2009 H1 pandemic were antigenically most similar to the H1 pandemic vaccine strains, with the exception of viruses in the genetic clade 1A.1.1.3, which had a two-amino acid deletion mutation near the receptor-binding site, which dramatically reduced antibody recognition. The swine 1B lineage strains, which arose from previously circulating (pre-2009 pandemic) human seasonal viruses, were more antigenically similar to pre-2009 human seasonal H1 vaccine viruses than post-2009 strains. Human population immunity was measured by cross-reactivity in HI assays to representative swine H1 strains. There was a broad range of titers against each swine strain that was not associated with age, sex, or location. However, there was almost no cross-reactivity in human sera to the 1A.1.1.3 and 1B.2.1 genetic clades of swine viruses, and the 1A.1.1.3 and 1B.2.1 clades were also the most antigenically distant to the human vaccine strains. Our data demonstrate that the antigenic distances of representative swine strains from human vaccine strains represent an important part of the rational assessment of swine IAV for zoonotic risk research and pandemic preparedness prioritization.

• Research Organization: Oak Ridge Associated Universities (ORAU), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-06OR23100
• OSTI ID: 2424086
• Journal Information: Microbiology Spectrum, Journal Name: Microbiology Spectrum Journal Issue: 6 Vol. 10; ISSN 2165-0497
• Publisher: American Society for Microbiology
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
H1N1
antigenic cartography
influenza A virus
pandemic risk assessment
swine