Figure 2.

TEC subsets characterized by costaining for expression of K5, MTS10, and UEA-1 ligand. Cryosections of a normal adult thymus were costained for expression of K5 (red) and MTS10 (green) by using fluorescein isothiocynate (FITC)- or Texas red-conjugated anti-Ig second steps. Alternatively, the slides were costained for K5 (red) and biotyinylated UEA-1 followed by FITC-conjugated streptavidin (green). The microscopic fields shown include medullary and cortico-medullary junction TECs. Single filter and computer-generated image overlays are shown. The original magnification was ×300. Although K5⁺MTS10⁺ stellate cells are present in the inner medulla, K5⁺ TECs at the cortico-medullary junction do not coexpress MTS10 ligand. Distinct populations of medullary TECs express K5 and the ligand for UEA-1.