As we observed a small difference in proliferation of CD8+ T cells in vitro, we hypothesized there could be a defect in the anti-viral proliferative response, but T-Hk2−/− mice show an antigen-specific CD8+ T cell expansion following infection with LCMV identical to that of WT mice; CD8+ T cells expand rapidly and then slowly contract (Fig. 6a). The gene discussed is HK2; the disease is infection.