SIRT1 and infection: Further, we examined the transcript-level profile of Sirt1 and Sirt3 in M1 or M2 polarized RAW 264.7 macrophages at 16 hr post-infection and observed 20-fold and 5-fold increase in Sirt1 and Sirt3 expression in M2-polarized-infected macrophages as opposed to 0.5-fold and 0.4-fold downregulation in M1-polarized-infected macrophages (Figure 1—figure supplement 1C and D).