Fig. 5

Folate targeting/retargeting of GOS/MV-Edm. HeLa and A549 cells were infected with naked MV-Edm or GOS/MV-Edm in FA⁻ DMEM (DMEM with FA depleted from the cell medium) or FA⁺ DMEM (DMEM with abundant FA (10 mM) to give only a few available free FRs on the cell surfaces). a Syncytium formation was observed by phase-contrast microscopy (left panel) and further analyzed using ImageJ software (right panel) 48 h postinfection. b The oncolytic effect (cell death) was quantified by trypan blue exclusion in cells at 48 h postinfection in FA⁻ or FA⁺ medium. The expression of N viral structural genes was quantified by qRT-PCR in cells 48 h postinfection c or 4 h postinfection d. e CD46 expression on the surfaces of human cells (HeLa and A549 cells) and murine cells (4 T1 and LLC cells) was determined by flowcytometry using anti-CD46 and isotype-matched control antibodies, respectively. f The surface expression of FR in murine cells (4 T1 and LLC cells) was determined by fluorescence-activated cell sorting analysis using Rho-FA and Rho-FA-GOS. G Fluorescence images of cells 60 h postinfection. GOS/MV-Edm-eGFP infected the murine cells (4 T1 and LLC cells), but the naked MV-Edm absolutely could not infect the murine cells. h The murine cells (4 T1 and LLC cells) were infected with MV-Edm-Luc or GOS/MV-Edm-Luc (10⁸ TCID50/ml) at an MOI of 1 and 0.15 mg/ml GOS, and the ratio is v/v. Luciferase activity was monitored by a luminescence system 48 h after virus infection. Mean of triplicates, #p indicates not significant, *p < 0.05, **p < 0.01