title: Cutting edge: antigen-dependent regulation of telomerase activity in murine T cells.
abstract: Telomeres, structures on the ends of linear chromosomes, function to maintain chromosomal integrity. Telomere shortening occurs with cell division and provides a mechanism for limiting the replicative potential of normal human somatic cells. Telomerase, a ribonucleoprotein enzyme, synthesizes telomeric repeats on chromosomal termini, potentially extending the capacity for cell division. The present study demonstrates that resting T cells express little/no activity, and optimal Ag-specific induction of telomerase activity in vitro requires both TCR and CD28-B7 costimulatory signals. Regulation of telomerase in T cells during in vivo Ag-dependent activation was also assessed by adoptive transfer of TCR transgenic T cells and subsequent Ag challenge. Under these conditions, telomerase was induced in transgenic T cells coincident with a phase of extensive clonal expansion. These findings suggest that telomerase may represent an adoptive response that functions to preserve replicative potential in Ag-reactive lymphocytes.
authors.affiliation: Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. KarenvHathcock@nih.gov
authors.forename: K S
authors.initials: KS
authors.lastname: Hathcock
authors.forename: N P
authors.initials: NP
authors.lastname: Weng
authors.forename: R
authors.initials: R
authors.lastname: Merica
authors.forename: M K
authors.initials: MK
authors.lastname: Jenkins
authors.forename: R
authors.initials: R
authors.lastname: Hodes
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D000938:Antigen-Presenting Cells / Q000276:immunology; D018122:B7-1 Antigen / Q000276:immunology; D018106:CD28 Antigens / Q000276:immunology; D002478:Cells, Cultured; D004789:Enzyme Activation; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000166:cytology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D013154:Spleen / Q000166:cytology; D013601:T-Lymphocytes / Q000276:immunology*; D019098:Telomerase / Q000378:metabolism*
chemical_list: D018122:B7-1 Antigen; D018106:CD28 Antigens; D016693:Receptors, Antigen, T-Cell, alpha-beta; C075784:T cell receptor Vbeta8; D019098:Telomerase