FIG. 3.

Therapeutic vaccination (a) and CD8⁺ T-cell depletion (b). Considering the chronic phase, we ignore the naive T cells. In panel a, P in equation 5 is replaced with P + D, where D is antigen-loaded dendritic cells that are introduced at day zero and that disappear exponentially [D(t) = 10⁵e^−0.02t]. Note that a small increase in the immune response (dashed line) markedly decreases the viral load (solid line). In panel b, the specific CD8⁺ T-cell response is depleted to 10% of its steady-state value at day zero. Parameters are described in the legend of Fig. 1e, i.e., p = k = 10.