Intracellular cytokine staining of antigen-experienced (CD44hi) OT-1 cells revealed a high-level production of IFN-γ in response to OVA257–264 peptide stimulation, which was observed exclusively in newly primed OT-1 cells transferred in the chronic phase of infection, but not in OT-1 cells transferred prior to FV-OVA infection (thus, those primed in the early phase of infection) (Figure 8A, E, F). Here, IFNG is linked to infection.