Abstract
Experiments were carried out on 14‐day fetal mouse thymic stem cells which were treated with agents known to increase cellular cAMP levels for a period of 90 min at 37 °C. When compared to controls, a high proportion of treated stem cells were found to develop Thy‐1 (θ) antigen as indicated by dye exclusion tests using anti‐Thy‐1 serum and complement.