In order to quantify the contribution of CD8+ T cells to the lifespan of productively infected cells in vivo, we quantified this parameter in the presence or absence of CD8+ T cells by analyzing the viral decline after initiation of ART using the equation:(1)where A = (NkTo)/(c−δ), C = (c−NkTo)/(c−μ) and V0 is the initial viral load, k is the infection rate, N is the viral burst size, δ is the death rate of short-lived productively infected cells, μ is the death rate of long-lived productively infected cells, and c is the rate of virion clearance [22] (Figure 4). The gene discussed is CD8A; the disease is infection.