Receptor Binding Specificity of Feline H5N1 Isolates in South Korea
A recent study published in the journal Virulence has investigated the zoonotic potential of highly pathogenic avian influenza (HPAI) H5N1 viruses following fatal cluster infections in felines in South Korea during July 2023. The research aimed to determine if these viruses had acquired the ability to infect humans more efficiently after jumping from birds to mammals. The research team compared two feline-derived H5N1 strains (Feline/GA/2023 and Feline/YS/2023) with a genetically related avian strain (Duck/YC/2022) and a human pandemic H1N1 (pdm09) reference control. The investigation focused on the virus's preference for two types of sialic acid (SA) receptors: α2,3-linked (avian-type) and α2,6-linked (human-type). Both the feline and avian H5N1 isolates exhibited strong binding affinity for avian-type α2,3 receptors. Critically, none of the H5N1 viruses showed detectable binding to human-type α2,6 receptors. In contrast, the pdm09 control bound strongly to human-type receptors as expected.
The study provides experimental and computational evidence that despite their high pathogenicity and successful transmission among felines, these H5N1 viruses have not yet adapted to human-type receptors.
