OAS1, OAS2, and OAS3 homologous are members of the 2′-5′-oligoadenylate synthetase (OAS) family, which inhibits cellular protein synthesis and confers resistance to viral infection (86). Polymorphisms in the interferon-stimulated gene, OAS1, have been linked to host immune responses against several classes of viral infections (86, 87), and extracellular OAS1 may play a role in antiviral immune responses (88). This evidence concerns the gene OAS2 and viral infectious disease.