Skip to main content
. 2004 Feb;78(3):1069–1079. doi: 10.1128/JVI.78.3.1069-1079.2004

FIG. 4.

FIG. 4.

Infectivity of HEK293T- and MT4-produced virus. (A) Viruses were produced by transfection of either 293T or MT4 cells as indicated underneath the x axis. Virus-containing supernatants normalized by p24 capsid were added to P4.R5 indicator cells that contain β-galactosidase under control of the HIV-1 LTR. Following 2 days of incubation, cells were stained with X-Gal and blue foci were counted. Infectivity data are expressed as a ratio of the number of blue cells per ng of p24 inoculum normalized to wild type. The 293T data shown are the averages of duplicates, and the MT4 data shown are the averages between two independent assays. (B) Infectivity of 293-produced virus compared in two distinct assays as indicated underneath the x axis. The P4 assay was performed as described in panel A. For the syncytium induction assay, HeLa-CD4 cells (clone 1022) were infected with viruses normalized by p24 capsid concentration and incubated for 3 days. Cells were stained with crystal violet, and the syncytia were counted. Data shown are the averages of duplicates. (C) Infectivity of various 293T-produced EnvY712 mutants tested in the P4 infectivity assay as above. Data shown are the averages of duplicates. Error bars indicate standard deviation.