IFN-alpha 4 (IFN-α4 or IFNA4) belongs to the type I interferon family, a group of cytokines primarily produced in response to viral infections. As a key player in the innate immune response, IFN-α4 provides the body's first line of defense against pathogens by inducing an antiviral state in neighboring cells. Produced primarily by macrophages, IFN-α4 exerts its antiviral effects by binding to the interferon alpha receptor (IFNAR) on cell surfaces, thereby activating downstream immune signaling pathways . This binding triggers the expression of antiviral proteins, such as a protein kinase and an oligoadenylate synthetase, which inhibit viral RNA replication and enhance natural killer cell cytotoxicity against viruses.