Cytokine-driven immortalization of in vitro activated human T lymphocytes. CD28 expression correlates inversely with cell population doublings.
Like other normal human somatic cells, T lymphocytes are believed to have a finite in vitro life span. However, continuous T lymphocyte cell lines can often be established from chronic inflammatory skin diseases when the culture medium is supplemented with IL-2 and IL-4 but without antigen and accessory cells added. Based on the assumption that these continuous T lymphocyte cell lines were activated by antigen during the chronic inflammation taking place in vivo, I investigated whether peripheral blood T lymphocytes could be induced to cytokine-dependent continuous growth following antigen activation. Upon allostimulation, peripheral blood CD4+ T lymphocytes reproducibly escape from cellular senescence. These IL-2- and IL-4-dependent continuous T cell lines show high telomerase activity. Withdrawal of either IL-2 or IL-4 results in cell growth arrest concomitant with down-regulation of telomerase activity. When cultured continuously, these CD4+ human T lymphocytes gradually lose expression of CD28.
Institute of Human Genetics, The Bartholin Building, University of Aarhus, Aarhus, Denmark. kaltoft@humgen.aau.dk
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D018106:CD28 Antigens / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000201:enzymology / Q000276:immunology*; D002455:Cell Division; D002460:Cell Line; D016207:Cytokines / Q000494:pharmacology*; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D007519:Isoantigens / Q000008:administration & dosage; D008213:Lymphocyte Activation; D019098:Telomerase / Q000378:metabolism
D018106:CD28 Antigens; D016207:Cytokines; D007376:Interleukin-2; D007519:Isoantigens; D015847:Interleukin-4; D019098:Telomerase