A Role for IFITM Proteins in Restriction of Mycobacterium tuberculosis Infection

Ranjbar, Shahin; Haridas, Viraga; Jasenosky, Luke D.; Falvo, James V.; Goldfeld, Anne E.

To quantitatively measure the impact of IFITM3 overexpression on H37Rv-mCherry infection, we utilized ImageStream technology, which allowed us to capture images of individual cells containing intracellular MTb. After eliminating cells from the analysis that exhibited H37Rv-mCherry surface attachment (Figures 3B and 3C; Figure S4 ), we used IDEAS software to measure mCherry pixel intensity in IFITM3-overexpressing and control cells. There was a significant decrease in mean per-cell mCherry intensity in the IFITM3overexpressing THP-1 cells (p = 0.007) ( Figure 3B ). By contrast, there was a significant increase in mean per-cell mCherry intensity in the IFITM-KD versus control THP-1 cells (p < 0.0001) ( Figure 3C ), consistent with the fluorescence-activated cell sorting (FACS) and CFU data, further supporting a role for the IFITMs-and IFITM3 in particular-in restriction of MTb growth.