LDH analysis of human thymocytes and thymocyte subsets.
The lactate dehydrogenase (LDH) isoenzyme pattern (expressed as the B:A subunit ratio) and two enzymes of the purine metabolism adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) (expressed as the ADA/PNP ratio) were studied in human prenatal thymocytes, in subsets of human infant thymocytes, and in peripheral T lymphocytes. Prothymocytes were enriched by E rosette depletion, cortical thymocytes were enriched with a monoclonal antibody rosette technique using OKT6, and medullary thymocytes were enriched either with a monoclonal antibody rosette technique using OKT3 or with complement-mediated cytolysis using normal fresh rabbit serum. Peripheral T lymphocytes were isolated from normal adult peripheral blood by E rosette sedimentation. Prenatal thymocytes had the lowest B:A ratio. In the infant thymuses, prothymocytes had a lower B:A ratio (0.99 +/- 0.10) than the cortical thymocytes (1.04 +/- 0.08). The medullary thymocytes obtained either by OKT3 selection or normal rabbit serum cytotoxic treatment had higher B:A ratios (1.30 +/- 0.15 and 1.42 +/- 0.17, respectively). The highest B:A ratio is found in peripheral T lymphocytes (2.07 +/- 0.28) together with the lowest ADA/PNP ratio (0.50 +/- 0.07). The B:A ratios are paralleled by a progressive decrease in the ADA/PNP ratio. These findings indicate that during intrathymic T cell development, important changes occur not only in the activities of the enzymes of the purine metabolism but also in the distribution of the LDH isoenzymes.
D000243:Adenosine Deaminase / Q000097:blood / Q000378:metabolism; D000375:Aging; D002462:Cell Membrane / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000097:blood / Q000378:metabolism*; D011247:Pregnancy; D011683:Purine-Nucleoside Phosphorylase / Q000097:blood / Q000378:metabolism; D012397:Rosette Formation; D013601:T-Lymphocytes / Q000145:classification / Q000201:enzymology*; D013950:Thymus Gland / Q000166:cytology / Q000502:physiology
D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase; D011683:Purine-Nucleoside Phosphorylase; D000243:Adenosine Deaminase