Fig. 1. Sensitivity of TZM-bl cells to replication competent HIV-1.

a) Acutely infected HIV-1^BaL-positive CD4⁺ T lymphocytes (30% infection frequency as determined by flow cytometry of intracellular p24) were serially diluted with uninfected CD8⁺ T cell- PBMC. 1×10⁵ cells from each serial dilution were added to 5×10⁴ TZM-bl cells in a 96-well plate. β-gal activity was measured by chemiluminesence 48 h later. The relative light units (RLU) for the control (460,000 +/− 56,000) were subtracted from each assay sample. b) Latently HIV-1 infected ACH-2 cells were treated with 100nM PMA, serially diluted with uninfected CD8⁺ T cell-depleted PBMC, and added to TZM-bl cells, as described above. c) Correlation between the TCID₅₀ for HIV-1^BaL and β-gal activity in the TZM-bl cells. TZM-bl cells were infected with HIV-1^BaL and β-gal activity was measured 48 h later. d) Correlation between the β-gal activity for HIV-1^BaL 48 h post infection and virus production (assessed by extracellular virion associated HIV-1 RNA 10 days post-infection) e) Detection of β-gal activity in the TZM-bl cells as a function of HIV-1_BaL TCID₅₀. We observed a linear relationship between β-gal activity and TCID₅₀ down to a TCID₅₀ of 0.001. f) Detection of extracellular virion-associated RNA as a function of HIV-1_BaL TCID₅₀. We observed a linear relationship between extracellular virion-associated RNA and TCID₅₀ down to a TCID₅₀ of 1. P values (cited in the text) for c, d, e and f were obtained using the Pearson test.