Figure 5.

Tg CD25⁺4⁺ cells require expression of endogenous TCRα chains for their development. (A) Tg CD4⁺ cells coexpressing endogenous TCRα chains are enriched in the CD25⁺ subset. cDNA was synthesized from the indicated sorted T/R⁺ CD4⁺ subpopulations (1 × 10⁵ with ≥97% purity), and semiquantitative PCR analyses were conducted with a Cα (or Cβ-)-specific and a Vα (or Vβ-)-specific primer, or with CD3ɛ-specific primers as a control. (B) Absence of the Tg CD25⁺4⁺ T cell population in TCR Cα^−/− background (T/α⁻) but not in Cα^+/− (T/α⁺) littermates. LN cells were stained for CD25, CD4, and Tg-TCR (3H12) and gated on the CD4⁺ population. The results are representative of four animals in each group.