title: Telomere maintenance in human B lymphocytes.
abstract: Telomere shortening has been causally linked to replicative senescence in human cells. To characterize telomere-length heterogeneity in peripheral blood cells of normal individuals, we analysed the mean length of telomeric repeat sequences in subpopulations of peripheral blood leucocytes, using fluorescence in situ hybridization and flow cytometry (flow-FISH). Although the telomere length of most haematopoietic subsets was within the same range, the mean telomere length was found to be 15% higher in B compared with T lymphocytes in adult peripheral blood. Whereas telomere loss with ageing corresponded to 33 base pairs (bp) per year in T cells, telomere shortening was slower in B cells, corresponding to 15 bp per year. Separation of adult B-lymphocyte subpopulations based on CD27 expression revealed that telomere length was almost 2 kb longer in CD19+CD27+ (memory) compared with CD19+CD27- (naive) cells. Furthermore, peripheral blood B cells were activated in vitro. Whereas B-cell activation with Staphylococcus aureus Cowan strain (SAC) did not increase telomere length, a striking telomere elongation was observed when cells were stimulated with SAC and interleukin 2 to induce plasma cell differentiation. Our observations support the concept that telomere dynamics in B cells are distinct from other haematopoietic cell lineages and that telomere elongation may play an essential role in the generation of long-term B memory cells.
authors.affiliation: Freiburg University Medical Centre, Department of Haematology/Oncology, Germany. martens@ukl.uni-freiburg.de
authors.forename: Uwe M
authors.initials: UM
authors.lastname: Martens
authors.forename: Volker
authors.initials: V
authors.lastname: Brass
authors.forename: Lucie
authors.initials: L
authors.lastname: Sedlacek
authors.forename: Milena
authors.initials: M
authors.lastname: Pantic
authors.forename: Carolin
authors.initials: C
authors.lastname: Exner
authors.forename: Yalin
authors.initials: Y
authors.lastname: Guo
authors.forename: Monika
authors.initials: M
authors.lastname: Engelhardt
authors.forename: Peter M
authors.initials: PM
authors.lastname: Lansdorp
authors.forename: Cornelius F
authors.initials: CF
authors.lastname: Waller
authors.forename: Winand
authors.initials: W
authors.lastname: Lange
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D001402:B-Lymphocytes / Q000166:cytology* / Q000201:enzymology; D002648:Child; D005312:Fetal Blood / Q000166:cytology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008213:Lymphocyte Activation / Q000502:physiology; D008875:Middle Aged; D013601:T-Lymphocytes / Q000166:cytology* / Q000201:enzymology; D019098:Telomerase / Q000378:metabolism; D016615:Telomere
chemical_list: D019098:Telomerase