Figure 4.

Inhibition of thymic corticosteroid production induces apoptosis of DP thymocytes bearing TCRs with low-to-moderate avidity for self antigen/MHC. Thymi from 1-2-d-old female RAG-2−/− H-Y/ D^b-specific TCR transgenic mice homozygous for either H-2^d (n = 10) or H-2^b (n = 10) were separated into lobes and cultured in medium alone or with 200 μg/ml of freshly diluted metyrapone. After 18 h, the amount of apoptosis in the DP population was determined on the FACScan^® by gating for expression of both CD4 and CD8 and analysis of dUTP-FITC incorporation.