Extracellular ATP triggers reduction of CD62L on CD4 and CD8 T-cell surfaces. (A) IMP was injected into Ampd3^−/− and control mice, and the percentages of naive CD4⁺ and CD8⁺ T cells in peripheral blood were analyzed by flow cytometry before and after the treatment (n = 5 for each genotype). (B) Different doses of ATP or IMP were added to the media of in vitro–cultured T cells (Control = nothing added). After overnight culture, the percentages of CD62L^hiCD44^lo naive CD4⁺ T cells and naive CD8⁺ T cells were analyzed by flow cytometry (n = 3 for each condition). (C) MFI of CD62L and CD44 of T cells. (D) Percentages of CD62L^hiCD44^lo naive CD4⁺ T cells and naive CD8⁺ T cells after mouse splenocytes were cultured in vitro with lower doses of ATP (n = 3 for each condition). *P ≤ .05, **P ≤ .01, ***P ≤ .001. ns, not significant (P > .05).