FIG 1.

Acute infection followed by ART at day 150 in the two-stage model of equation 8. The behaviors of the early killing regime (a and c) and of the late-killing scenario (b and d) are shown. Data are shown for 1 immune response, with k₁ = 10 (a and b), and 10 immune responses, with k_i = 1 for i = 1,2,…,10 (c and d). The rate at which the viral load, V ∝ I₂, increases during acute infection is 1.5 day⁻¹ in both cases, and the rate at which it decreases during ART is approximately δ = 1 day⁻¹. We use the function F(T) = s − d_TT to complete equation 7a for the target cells and set s = d_T to scale the uninfected steady state to one and the function G(E_i,V) = pVE_i/(h_i + V + E_i) with V = I₂ to complete equation 7b of the CTL (39, 47). We here set k₁ = 10 day⁻¹ or k_i = 1 day⁻¹, h_i = i/1,000, and E_i(0) = 0.001/i for i = 1,2,…,n. For the early killing scenario, we set β = 8.75 and d₁ = d₂ = 1, and for the late-killing regime, we set β = 9.1, d₁ = 0.1, and d₂ = 2 day⁻¹ (Table 1). By equation 13, both settings account for a realistic initial replication rate in macaques of ρ(0) = 1.5 day⁻¹. See Table 1 for all other parameter values.