Figure 2.

Effects of single CXCR2 domains in CXCR4 on coreceptor function. Receptor chimeras composed of single CXCR2 domains in a CXCR4 background were tested for function. HeLa cells expressing the BH8, 89.6, BK132, RF, or HIV-2_SBL6669 env proteins in conjunction with T7 RNA polymerase as a consequence of infection with the appropriate recombinant vaccinia virus vectors were mixed with quail QT6 cells transfected with plasmids expressing CD4, the indicated chemokine receptor, and luciferase under control of the T7 promoter. After 8 h at 37°C, the cells were lysed, and the amount of luciferase activity was measured in relative light units and expressed relative to wild-type CXCR4. The signal/noise values for wild-type CXCR4 were typically greater than 50:1.