While the expression of HO-1 and GPx-3 increased significantly in the control macrophages following infection with S. mitis or S. oralis (Fig. 6a, Supplementary Fig. 7), this change was not observed in Nrf2-/- macrophages, providing evidence that these antioxidant genes were under the regulation of Nrf2. The gene discussed is GPX3; the disease is infection.