Unique amino acid substitution within the spike glycoprotein S1 subunit promotes infectious bronchitis virus infection via enhancing viral attachment.

A histidine substitution at position 413 in the S1 subunit of IBV enhances viral attachment to DF-1 cells by promoting binding to α-2,3-linked sialic acids on gangliosides.

• Why it matters: Understanding the factors that determine IBV cell tropism is crucial for developing effective vaccines and controlling infection, but current knowledge of viral entry mechanisms is limited.
• What they did: The study established a reverse genetics platform based on circular polymerase extension reaction (CPER) and created chimeric viruses with targeted S gene modifications, identifying the key amino acid at position 413.
• The result: The His413 residue facilitates viral binding to gangliosides, activates caveolae-mediated endocytosis via Src kinase, and promotes infection in DF-1 cells, offering new insights into IBV cell adaptation and entry pathways.