2.8 Viral infectivity assay
5×105 293T cells were seeded in 6-well plates 12 h
before transfection. 293T cells were co-transfected with
pcDNA3.1-FLAG-GP-ΔMLD/VSV-G, pNL-Luc-ΔEnv, and MARCH expression vectors.
Forty-eight hours post-transfection, virion-containing supernatants were
collected to infect the indicator Vero cells. Before infection,
supernatants were subjected to ultracentrifugation at 40000 × g for 1 h,
and pellets were used for WB or P24Gag ELISA quantity
assay. Thirty-six hours post-infection, Vero cells were lysed, and viral
infectivity was assessed via luciferase activity assay.