Abdulla Shuhait, Dalhousie University

Abdulla Shuhait1, Eric S. Pringle1, Ishraq Rahman2, Susantha Gomis3, JT McClure4, Lisanework Ayalew5, Lisa Barret1, Andrew Lang2, Craig McCormick1, Denys A. Khaperskyy1 1Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, NS; 2Department of Biology, Faculty of Science, Memorial University of Newfoundland, St. John's, NL; 3Department of Veterinary Pathology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK; 4Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE; 5Department of Pathology & Microbiology, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE.

Discovering & Evolving

Highly pathogenic avian influenza (HPAI) H5N1 are zoonotic viruses circulating in birds that pose serious threat to mammals, including humans, due to sporadic cross-species transmission that is associated with severe disease. Influenza virus envelope has two major glycoproteins: hemagglutinin (HA) and neuraminidase (NA). HA mediates attachment to sialic acid on host cells and NA cleaves sialic acid during viral egress, making both glycoproteins key targets for vaccines and antiviral drugs. While seasonal H1N1 and HPAI H5N1 viruses share the N1 subtype of NA, HA remains immunodominant, and the lack of pre-existing H5-specific immunity in humans highlights the pandemic threat of H5N1. Developing serologic surveillance tools to monitor infection of animals and humans is essential for early detection and preparing for potential spread of this pathogen. Virus neutralization assays are the gold standard in assessing antibody-mediated protection. However, conducting these assays using the H5N1 HPAI virus requires high containment level 3 (CL3) facilities, which significantly raises the cost and limits throughput. Using H5N1 pseudotyped lentivirus particles combined with enzyme-linked lectin assays we established a robust CL2 system for surveying and functionally assessing antibody-mediated immunity to H5 and N1 in a wide range of species and sample types (e.g. milk) acquired through immunization or prior infections. Using our assays, we characterized significant levels of cross-reactive anti-N1 antibodies in serum samples from wild waterfowl and mammals infected with different influenza virus subtypes and confirmed that measurable anti-H5 neutralizing antibodies are elicited only through prior exposure to H5 subtype virus infection or vaccination.