Nonhuman Primate IFITM Proteins Are Potent Inhibitors of HIV and SIV

Wilkins, Jordan; Zheng, Yi-Min; Yu, Jingyou; Liang, Chen; Liu, Shan-Lu

Entry of HIV-1 has previously been shown to be restricted by human IFITM proteins in target cells [15, 53] . We asked if this function was conserved in OWM IFITM. To analyze entry of HIV-1 in SupT1 cells stably expressing various primate IFITMs, we utilized the ß-lactamase-Vpr (BlaM-Vpr) virion fusion assay described in [43] . HIV-1 virions were generated by cotransfecting HEK293T cells with BlaM-Vpr and HIV-1-NL4.3. Purified virus particles were used to infect SupT1 cells loaded with the BlaM-specific fluorescent substrate CCF2. Successful HIV-1 virion entry was detected by measuring BlaM cleavage of CCF2, which shifts CCF2 fluorescence emission from 520 nm (green) to 447 nm (blue) (Fig 4A) . The virion fusion assay results demonstrate that the ability of IFITM to restrict HIV-1 entry is conserved in nonhuman primate IFITMs, particularly IFITM3 (Fig 4A and 4B ).