Many of the studies described below utilize a number of approaches to test the antiviral activity of host restriction factors against viruses, with the two most common techniques being: a) overexpression of the protein of interest to test for inhibition of virus infection and/or replication or b) knockdown of the endogenous protein, sometimes following IFN treatment, to test for an enhancement of viral replication. The gene discussed is IFNA1; the disease is viral infectious disease.