An adenosine receptor agonist does not mimic and an adenosine receptor antagonist does not prevent the effects of ADA deficiency in FTOC. FTOCs were performed with C57BL/6 thymuses at day 15 of gestation in the presence of (a) 0.1% DMSO (carrier for NECA), (b) 100 μM NECA, (c) 0.1 mM acetic acid (carrier for XAC), (d) 5 μM dCF, (e) 25 μM XAC, or (f) 25 μM XAC plus 5 μM dCF. At the end of culture (6 days for DMSO and NECA or 2 days for XAC with or without dCF), thymocytes were harvested, counted, and stained with FITC-anti-CD4, PE-anti-CD8, and PI to exclude dead cells. The data are representative of one experiment out of six for NECA and one out of three for XAC.