The H7N9 virus is a type of avian influenza virus that belongs to the influenza A virus category. Due to its high pathogenicity and potential pandemic risk, it has drawn significant attention from global health organizations and governments worldwide. The HA protein is a glycoprotein on the surface of the H7N9 virus and is primarily responsible for the virus binding to and entering host cells. It facilitates viral attachment and internalization by recognizing and binding to sialic acid receptors on the surface of host cells. The NA protein is another glycoprotein that plays a key role in the release and spread of the virus from host cells. By cleaving sialic acid on the surface of host cells, it enables newly formed viral particles to detach from the host cell and infect other cells. The H7N9 virus first binds to sialic acid receptors on the surface of host cells via the HA protein. The resulting complex enters the host cell through endocytosis, where the virus completes transcription, replication, protein synthesis, assembly, and budding. The NA protein then cleaves sialic acid on the host cell surface, releasing newly formed viral particles to infect other cells.
To address the biosafety risks associated with traditional H7N9 virus neutralization assays that require handling live viruses, Genomeditech has developed a pseudotyped virus based on an HIV lentiviral backbone, with HA and NA proteins embedded on its surface (Strain: A/Shanghai/4664T/2013; GenBank ID: AGI60292.1). This pseudotyped virus can simulate the process of binding to receptors and entering receptor cells, similar to the authentic virus. Additionally, the pseudotyped virus carries GFP fluorescence and luciferase reporter genes, allowing the evaluation of its infectivity in cells by observing fluorescence or measuring luciferase activity. It can also be used to assess the ability of neutralizing antibodies to block pseudovirus infection in cells. This pseudotyped virus lacks autonomous replication capability, ensuring high safety. It serves as an important tool for H7N9-related drug screening, neutralizing antibody activity testing, and vaccine efficacy evaluation.
