title: Decreased 5'-nucleotidase activity in suppressor (OKT8) T lymphocytes from homosexuals with AIDS-related complex: nonassociation with enhanced deoxynucleoside toxicity.
abstract: The purine metabolic enzymes adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), and 5'nucleotidase (5NT) have been shown to be important for normal lymphocyte maturation. Abnormalities of these enzymes have been associated with hereditary as well as acquired immunodeficiency states. Enzyme activity was measured in helper (OKT4) and suppressor (OKT8) lymphocyte subsets from 10 homosexuals with AIDS-related complex (ARC) and in 10 healthy controls. There were no significant differences in either mean ADA activity or mean PNP activity between ARC OKT4 cells and control OKT4 cells and between ARC OKT8 cells and control OKT8 cells. By contrast, mean 5NT activity was slightly decreased in OKT4 cells from ARC patients compared with that of controls and more significantly diminished in ARC OKT8 cells compared with that of controls. Both deoxyadenosine and deoxyguanosine, when incubated separately with OKT4 and OKT8 cells in the presence of EHNA, an ADA inhibitor, did not significantly inhibit lymphocyte blastogenesis to a greater extent in ARC patients than in controls. Hence, the decreases in 5NT activity most likely reflect lymphocyte immaturity and are not associated with biochemical abnormalities leading to increased deoxynucleoside toxicity.
mesh_terms: D015720:5'-Nucleotidase; D000386:AIDS-Related Complex / Q000201:enzymology*; D002455:Cell Division / Q000187:drug effects; D004261:DNA Replication / Q000187:drug effects*; D003853:Deoxyribonucleosides / Q000494:pharmacology*; D005260:Female; D006716:Homosexuality; D006801:Humans; D008297:Male; D009708:Nucleotidases / Q000172:deficiency*; D006377:T-Lymphocytes, Helper-Inducer / Q000201:enzymology; D050378:T-Lymphocytes, Regulatory / Q000201:enzymology*
chemical_list: D003853:Deoxyribonucleosides; D009708:Nucleotidases; D015720:5'-Nucleotidase