LCMV-cl13 infection with CD4 T cell depletion is a better mirror of the kinetics of many human chronic viral infections where there is an initial stage of rapid viral replication resulting in a high viral load, followed by a balance between the immune response and viral replication that results in a plateau of viral load at a lower level than the initial peak that persists for the life of the host [87,95]. This evidence concerns the gene CD4 and infection.