This result suggests that differences in Mtb recovery are due primarily to H2S. Lastly, we observed no impact on bacterial recovery from infected peritoneal macrophages treated with homocysteine (10, 25 or 50 μM), ruling out mild hyperhomocysteinemia observed in Cbs+/− mice (<15 μM)22,25 as a contributor to reduced bacterial burden (Supplementary Fig. 1). The gene discussed is CBS; the disease is hyperhomocysteinemia.