The Impact of Variation in the Number of CD8+T-Cell Precursors on the Outcome of Virus Infection

We investigated the role of varying the initial number of naive antiviral CTL precursors on the dynamics of LCMV–DOCILE infection. C57BL/6 mice, exhibiting LCMV-specific CTLp frequencies of about 50, are protected against virus persistence over a range of infectious doses up to 104pfu. With 10-fold higher doses, a 100-fold increase in CTLp is required to restore virus control. With doses above 106pfu, elevation of the initial CTLp number leads only to lethal immunopathology. Similarly, a 1000-fold increase in the number of initial naı̈ve CTLp enhances the overall kinetics of virus elimination, but cannot limit early virus spread within the first 48 h after low-dose infection (500 pfu). Increases in initial naı̈ve virus-specific CTLp numbers are of limited benefit in antiviral control. In addition to the number of virus-specific T cells, the time period needed to reach cytolytic effector function is a limiting parameter.