Receptor-binding specificity and antigenic properties of a genotype D1.1 A(H5N1) influenza virus isolated from a human

Clade 2.3.4.4b A(H5N1) influenza viruses continue to expand their host range and pose increasing public health concerns. A case of severe human infection with genotype D1.1 A(H5N1) with HÀ substitutions was diagnosed in British Columbia. It is important to monitor receptor-binding specificity and antigenicity of emerging variants of circulating influenza A(H5N1) viruses. To evaluate potential human adaptation of this virus, we enriched HA-variant subpopulations and assessed sialic acid receptor usage via glycan microarray, solid-phase assays, and biolayer interferometry. All variants bound exclusively to avian-type sialic acid receptors. The antigenicity of the tested A(H5N1) variants was covered by candidate vaccine viruses.