Susceptibility of wild-type HIV-1 and HIV-2 isolates to dolutegravir in the single-cycle assay. (A) Representative dose-response profiles for HIV-1NL4-3 and HIV-2ROD9. Virus stocks were generated by transient transfection of chloroquine-treated 293T/17 cultures with plasmids pNL4-3 and pROD9, respectively. Dolutegravir was obtained from Selleck Chemicals, Inc. Titers are expressed as the percentage of no-drug (solvent-only) controls and are the means of two independent cultures at each drug concentration. Curve fits were generated using the sigmoid dose-response function of Prism version 6.0 (GraphPad Software, Inc.). (B) Comparison of the activity of dolutegravir (DTG), raltegravir (RAL), and elvitegravir (EVG) against wild-type HIV-2ROD9. Values for RAL and EVG include data from two previously-published studies of HIV-2 from our group [14,15] plus additional determinations; all data were obtained using the single-cycle assay. Bars indicate mean 50% effective concentrations (EC50); the number of independent determinations (n) for each strain is shown below the x-axis. P values were obtained via analysis of variance (ANOVA) of log10-transformed EC50 values with Tukey’s post test (Prism v6.0). No cytotoxic effects were observed in dolutegravir-treated MAGIC-5A cultures at concentrations as high as 10,000 nM. (C) Activity of dolutegravir against wild-type HIV-1 and HIV-2 isolates. Group/subtype designations are shown in parentheses. HIV-1NL4-3 and HIV-2ROD9 were generated as in panel A. HIV-2EHO was kindly provided by Jan McClure (University of Washington). The remaining isolates were obtained from the National Institutes of Health AIDS Reagent Program (www.aidsreagent.org). *, significantly greater than HIV-2ROD9, HIV-2MVP15132, HIV-2CBL20, and all HIV-1 isolates listed (p < 0.05, ANOVA with Tukey’s post test). In all panels, error bars indicate standard deviations.