Activity of luciferase-containing pseudotyped virus and virus-like particles in the entry assay.

ND, not determined; VLPs do not encode an expressed transgene to allow titer determination.aPseudotyped virus particles or VLPs were pelleted through sucrose and resuspended in 0.01 volumes of the original culture volume. A total of 0.2 ml of virus was used per assay with 106 cells and values were measured after 3 h of incubation.bVirus was prepared as above and used to infect HEK293-mCAT-1 cells. Titer was determined by limiting dilution using GFP reporter expression to count infected cells. Values for titer and entry assay are the mean±SD of 3 independent experiments.