Figure 2. Peripheral CD4⁺ RTEs and MNTs from CD4-cre Runx1 cKO mice are phenotypically and functionally immature.

(a) CD4⁺ RTEs or MNTs from Rag1-GFP WT or Rag1-GFP CD4-cre Runx1 cKO mice were examined for the expression of the maturation markers, CD55, CD45RB and Qa2. CD4⁺ RTEs were gated on CD62L⁺ CD44⁻Rag1-GFP⁺ while CD4⁺ MNTs were gated on CD62L⁺ CD44⁻Rag1-GFP⁻. Data are representative of seven Rag1-GFP WT and eight Rag1-GFP CD4-cre Runx1 cKO mice from five independent experiments. (b) Splenocytes from Rag1-GFP WT or Rag1-GFP CD4-cre Runx1 cKO were either left unstimulated or stimulated overnight with α-CD3ε and α-CD28. The following day, CD44^lo CD4 and CD8 Rag1-GFP⁻ MNTs and Rag1-GFP⁺ RTEs were examined for intracellular TNF-α production by flow cytometry. The top row shows the gating strategy for RTEs and MNTs within the naïve CD4 T cell pool. For examination of TNF-α production, the filled histogram represents unstimulated cells, and the solid line represents cells that were stimulated with α-CD3ε/α-CD28. The gate indicates the percentage in each stimulated sample that expresses TNF-α. Data are representative of four Rag1-GFP WT and four Rag1-GFP CD4-cre Runx1 cKO mice from three independent experiments.