FIG. 3.
HIV-1 Env-mediated fusion of target cells with different surface densities of CCR5. The figure shows the fusion of HIV-1Ba-L-expressing HeLa cells with HeLa cells expressing high (J53, gray bars) and low (J10, black bars) levels of CCR5. The treatment with MβCD was performed at 37°C for 30 min. Expression levels of CD4 and CCR5 are summarized in Table 1. The fusion activity was monitored as described in Materials and Methods.