The metabolism of adenosine and distribution of adenosine receptor lymphocytes in two human circulating T cell subsets.

Abstract

Human circulating E rosette forming cells (ERFC), rerosetted with sheep erythrocytes in the presence of adenosine, yielded two T-lymphocyte subpopulations: a major fraction forming E-rosettes (E resistant = ER) and a minor non-rosetting fraction (E sensitive - ES). Both T cell subpopulations converted adenosine mainly into inosine. However, ES cells metabolized adenosine more extensively than ER cells. Adenosine deaminase (ADA) activity was significantly higher in ES cells. Purine nucleoside phosphorylase (PNP) activity, as well as hypoxanthine guanosine phosphoribosyl transferase (HGPRT) activity were similar in both T cell subsets. The ratio of ADA/PNP in ES cells relative to ER cells was 1.8 suggesting that ES cells are at an earlier stage of differentiation. Enrichment of lymphocytes bearing a receptor for adenosine was demonstrated in ES cells.