Interferon lambda 2 （IFN-λ2）, also known as interleukin-28A （IL-28A）, is a type III interferon that belongs to the interferon lambda family. IFN-λ2 is produced in response to viral infections and plays a crucial role in the innate immune response against viruses. It exerts antiviral effects by inducing the expression of interferon-stimulated genes （ISGs） that inhibit viral replication and spread. IFN-λ2 signals through the IFN-λ receptor complex, which consists of IL-10R2 and IL-28Rα subunits, leading to the activation of downstream signaling pathways involved in antiviral defense. IFN-λ2 is considered a promising therapeutic agent for the treatment of viral infections due to its potent antiviral properties and reduced potential for side effects compared to type I interferons.