LN stromal cell subsets express distinct groups of PTA that vary in their dependence on Aire. Tyrosinase (Tyr), A33, Mart1, Gad67, Aire, and β-actin mRNAs were amplified by 40-cycle RT-PCR from the indicated subpopulations of LN stromal cells isolated from either C57BL/6 or Aire^−/− mice. Data from C57BL/6 mice sorted with gp38 and CD31 are representative of six independent experiments. Data from C57BL/6 mice sorted with 10.1.1 and CD31 are representative of three independent experiments. Data from Aire^−/− mice sorted with gp38 and CD31 are representative of two independent experiments.