Figure 3. Comparison of coreceptor usage among different T/F viruses from the same HIV-1-infected individual.

Same amount of T/F Env-pseudoviruses (200 TCID₅₀) was used to infect NP-2 cell lines expressing CD4 together with one of other coreceptors (CCR5, CXCR4, FPRL1, APJ, CCR3 or GPR5). The parental NP-2 cell line expressing CD4 but not any coreceptor was used as a control. The luciferase activity was measured 3 days post infection. The positive virus replication was defined if a virus gave luciferase activity three times above its background luciferase activity in the NP-2 parental cell line. All infections were performed in triplicates.