Figure 6.

Model (5) is able to generate viral blips with intermittent antigenic activation (panels (b)(d)). The probability p_L is fixed at 0.58 in the presence of antigen. N = 3000 and ∈ = 0.8. The other parameter values are the same as in Table 1. The top panels: activations occur at 50 and 100 days; The bottom panels: activations occur more frequently at 20, 40, 60, and 80 days. Each activation lasts 5 days. Occasional replenishment from asymmetric division prevents rapid depletion of the latent reservoir (panels (a)(c)). Although asymmetric division of latent cells is able to generate blips, the viral load decreases to an unreasonably low level between two successive activations (panel (b)). This problem can be overcome with more frequent antigenic stimulation (panel (d)). However, the viral load is still sensitive to the drug efficacy in this case.