Figure 5

Fitness comparison among the T/F virus and CTL escape mutants in the multiple passage assay. Same amount (5 ng p24) of each virus (T/F and CTL escape mutant) was mixed and used to infect CD4⁺ T cells in triplicates. Cell-free viruses were harvested 3 or 4 days after infection, and 200 μl of supernatants were used to infect fresh CD4⁺ T cells. The same amounts of viruses were subsequently harvested and used to infect fresh CD4+ T cells for four passages. The proportion of each compared virus harvested from each passage was determined by PASS analysis. The relative viral fitness was estimated using the newly developed mathematical model that does not assume constant exponential growth. Relative fitness was determined for (A) T/F versus T242N (s _ij = -0.42 ± 0.03), (B) T242N versus NIA (s _ij = 0.37 ± 0.14), (C) T/F versus NIA (s _ij = -0.03 ± 0.03), and (D) T/F versus TK (s _ij = 0.05 ± 0.02). Similar results were obtained in two independent experiments and data from one experiment is shown. Means ± standard deviations are plotted.