OAS2 and viral infectious disease: Antiviral genes specifically induced by Neospora infection included interferon-β1 (Ifnb1) as well as several key regulators of type I interferon responses (Fig. 1b, arrows) [25]–[27], including the transcription factor Irf7 (a master regulator of the antiviral program), Oas1 and Oas2 (members of the 2′-5′-oligoadenylate synthetase family that activate RNase L to initiate degradation of cellular RNA as an innate defense mechanism during viral infection), and Mx1 (a GTP-binding protein that is essential for antiviral responses to influenza infection).