In vitro characterization of RT-SHIV. Replication of RT-SHIV in cultures of PBMCs from humans (huPBMC) and macaques (Macaca nemestrina, mnePBMC; Macaca fascicularis, mfaPBMC) is shown in panel A. The coreceptor tropism of RT-SHIV is shown in five different human CD4+T cell lines in panel B. The specific coreceptor usage by RT-SHIV is shown in panel C where human PBMC cultures were treated with or without coreceptor antagonist TAK-779 or AMD-3100 before incubating with RT-SHIV. Relative virus replication levels (core antigen SIV p27) measured in the culture supernatants after 7 days post incubation, are shown at the left of the panels. Values shown here are representative of three independent experiments.