In contrast to robust expansion of WT OT1 T cells detected in the peripheral blood, DKO OT1 T cell expansion was blunted on day 7 after infection (Figure 1a-1b), revealed by decreased CD8+TCRVα2+ cells and decreased donor-derived CD45.1−CD45.2+ OT1 T cells within these CD8+TCRVα2+ cells. The gene discussed is PTPRC; the disease is infection.