While CD8+ T cell-mediated CTL activity may play a key role in killing infected cells before they start producing virus and/or in “elite controller” SIV-infected RMs with very low viremia, this study is consistent with a model wherein, during chronic SIVmac239 infection of RMs with high viremia, the main antiviral effect of CD8+ lymphocytes may be due to non-cytolytic mechanisms that do not impact the average lifespan of infected cells. The gene discussed is CD8A; the disease is infection.