Figure 2.

Influence of CTL efficacypon the dynamics of early infection with changing or constant setpoint viral load. (a) Copies/mL of WT virus (black) and drug resistant mutant K65R (red), and number/μL of CTLs (green), uninfected CD4+ cells/mL (blue) and infected CD4+ cells/mL (magenta), for ten p values spaced between 0 and 10^-4. Lighter shading corresponds to smaller values of p, and arrows point in the direction of increasing p to show its influence on the trajectories. (b) Calculated estimate of the basic reproductive ratio for WT virus and K65R mutant as a function of p. (c) Simulated WT viral load after 500 days, sweeping over p while holding all other parameters constant, reveals that the final viral load drops toward zero as p reduces the R₀ of WT toward 1. (d) Increasing p and correspondingly decreasing f according to Equation 9 maintains the steady-state viral load at 51,000 copies/mL, but raises the acute phase peak and leads to a longer “shoulder” before the viral load reaches setpoint. (Same color scheme as (a), but with a timescale of only 60 days to show the details of acute phase dynamics.) The effects on the height and timing of the peak are shown in (e) and (f), respectively, over the same range of p as in (b) and (c).