Figure 4. PD-1KO OT-I cells exhibit enhanced proliferation and activation compared to wild-type OT-I cells when co-cultured with OVA-expressing K14-mOVA keratinocytes (KC).

(A) Whole epidermal cells (ECs), CD11c⁺cell-depleted ECs, CD3⁺cell-depleted ECs and CD45⁺cell-depleted ECs (keratinocytes; KCs) from K14-mOVA mice or B6 mice were co-cultured with GFP⁺ wild-type OT-I cells. (B) CD45⁺cell-depleted ECs (keratinocytes; KCs) from K14-mOVA mice or B6 mice were co-cultured with GFP⁺ wild-type or PD-1-KO OT-I cells, or GFP⁺ CD8 T cells. Cell numbers of the GFP⁺ cells per well were counted by flow cytometry 2 days later. The bars present means ± SD of 3 wells. (B) Expression of CD44 and CD69 on the cultured GFP⁺ cells 3 days later. (C) MFIs ± SD of the markers. (D) Expression of PD-1 on the GFP⁺ cells 3 days later. (E) Concentrations ± SD of interferon (IFN)-γ and granzyme B in culture supernatants from wells of the GFP⁺ cells co-cultured with KCs for 3 days. *P<0.05, **P<0.01, t test. Data is representative of 4 separate experiments.