Persistent LCMV clone 13 infection is ultimately cleared in B6 mice by day 60, and epitope-specific CD8 T cells return, except for the high affinity NP396 T cells, which are eliminated by apoptosis (4, 14, 20) in the presence of functional LCMV-specific CD4 T cells (21, 22). The gene discussed is CD4; the disease is infection.