Functional characterization of ecto-5'-nucleotidase-positive and - negative human T lymphocytes

• Published in: The Journal of immunology (1950) Vol. 142; no. 5; pp. 1518 - 1522
• Main Authors: Thompson, LF, Ruedi, JM
• Format: Journal Article
• Language: English
• Published: United States Am Assoc Immnol 01.03.1989
• Subjects: 5'-Nucleotidase; Antigens, Surface - analysis; B-Lymphocytes - metabolism; Humans; Immunoglobulins - biosynthesis; Lymphocyte Activation - drug effects; Lymphocyte Culture Test, Mixed; Nucleotidases - immunology; Phenotype; Phytohemagglutinins; Pokeweed Mitogens; T-Lymphocytes - classification; T-Lymphocytes - enzymology; T-Lymphocytes - immunology; T-Lymphocytes, Helper-Inducer - enzymology; T-Lymphocytes, Helper-Inducer - immunology; Tetradecanoylphorbol Acetate - pharmacology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.142.5.1518

Functional studies were performed on human peripheral blood T lymphocytes stained with goat anti-5'-nucleotidase antibodies and separated into ecto-5'-nucleotidase (ecto-5'-NT)-positive and -negative populations using the FACSTAR fluorescence-activated cell sorter. On the average, ecto-5'-NT+ T cells contained 34 +/- 13% CD4+ and 55 +/- 15% CD8+ cells, whereas ecto-5'-NT-T cells contained 65 +/- 12% CD4+ and 23 +/- 8% CD8+ cells. Staining with anti-5'-NT antibodies did not significantly alter the ability of unseparated T cells to proliferate in response to PHA or PMA, or in a MLR. However, prior incubation with anti-5'-NT antibodies did inhibit the ability of irradiated T cells to provide help for PWM-stimulated Ig synthesis by as much as 55%. In five separate experiments, ecto-5'-NT-T cells demonstrated an equal or better ability to incorporate [3H]TdR after PHA stimulation or in a MLR, as compared with ecto-5'-NT+ T cells. Similarly, ecto-5'-NT- T cells were not diminished in their ability to provide help for autologous B cells in a PWM-driven system. Clearly, the inability of ecto-5'-NT- T cells from patients with a variety of immunodeficiency diseases to function in these assays cannot be explained solely by their lack of ecto-5'-NT activity. In contrast, ecto-5'-NT-positive and -negative T cells showed markedly different dose-response curves for proliferation in response to PMA. Ecto-5'-NT+ T cells responded to lower doses of PMA (1.0 ng/ml) than did ecto-5'-NT- T cells and showed a two- to eight-fold greater rate of [3H]TdR incorporation at 3 to 10 ng of PMA per ml. Ecto-5'-NT+ T cells may have a protein kinase C that is more accessible or more easily activated or may utilize an alternate pathway of activation when stimulated with low concentrations of PMA.