FIG. 6.
Entry mediated by chimeric envelopes into PBMC, MT-2 cells, or macrophages. One, two, or three domains from D-X4 envelopes were introduced into the T-X4 V1 to V5 background of HIV-1LAI using the strategy outlined in Fig. 1. Black boxes, D-X4 regions; white boxes, T-X4 regions. Entry into PBMC, MT-2 cells, or macrophages mediated by chimeric envelopes was compared to entry mediated by D-X4 V1 to V5 parental envelopes that produced levels of luciferase enzyme activity ranging from 0.3 × 105 to 5 × 105 RLU (100%). Luciferase enzyme levels produced by mock-pseudotyped viruses were ≤2 × 102 RLU.