As all the naïve, endogenous and non-transgenic DbNP366+CD8+, and DbPA224+CD8+ T cells are recruited into the primary immune response [36], there would be no naïve precursors left to mount a primary CD8+ T cell responses after re-challenge for these three sets of influenza-specific CD8+ T cell populations, unless new precursors had emerged subsequently from the thymus. The gene discussed is CD8A; the disease is influenza.