Differences in the activity of adenosine deaminase and of purine nucleoside phosphorylase and in the sensitivity of deoxypurine nucleosides between subpopulations of mouse thymocytes

The activities of adenosine deaminase (ADA) and of purine nucleoside phosphorylase (PNP) were measured in thymocyte subpopulations separated by peanut agglutinin (PNA), in unseparated thymocytes, in lymph node and in spleen cells. The PNA⁺ thymocyte subpopulation exhibited the highest ADA activity of all cells studied. The lowest PNP activity was found in the PNA^- subpopulation of thymocytes. PNA⁺ cells, moreover exhibited a more intensive DNA synthesis than the PNA^- cells, and a greater sensitivity to deoxyadenosine toxicity in the presence of erythro-9-(2-hydroxy-3-nonyl)-adenine (EHNA). The two thymocyte subpopulations exhibited a similar sensitivity to deoxyguanosine (dG) toxicity.