Interleukin-28A （IL-28A）, also known as interferon lambda-2 （IFN-λ2）, is a member of the type III interferon family. It is produced in response to viral infections and plays a critical role in the innate immune response. IL-28A exhibits antiviral activity by inducing the expression of interferon-stimulated genes （ISGs） and activating immune cells to inhibit viral replication and spread. IL-28A is primarily expressed by immune cells, such as dendritic cells and macrophages, and acts through the IFN-λ receptor complex to exert its antiviral effects. Due to its role in antiviral defense and immune regulation, IL-28A has garnered significant interest as a potential therapeutic target for viral infections, including hepatitis C and respiratory viruses.