title: Double negative (CD19+IgG+IgD-CD27-) B lymphocytes: a new insight from telomerase in healthy elderly, in centenarian offspring and in Alzheimer's disease patients.
abstract: Immunosenescence is characterized by the impairment of humoral immunity with changes in the memory/naive B cell compartment. In particular we have previously reported the percentage increase of a Memory IgD(-)CD27(-) (Double Negative, DN) B cell population in aged people. In this study, we have further characterized DN B cells with the aim to better understand their contribution to immunosenescence. As DN B cells show a poor ability to proliferate in vitro, we have evaluated the expression of the inhibitory receptors CD307d and CD22 on these cells from young and old individuals. In addition we have evaluated the ability to activate DN B cells by the simultaneous use of innate (CpG) and adaptive (α-Ig/CD40) ligands. Our data demonstrate that the refractoriness to proliferate of DN B cells does not depend on the expression of inhibitory receptors, but it is due to the kind of stimulation. Indeed, when DN B cells are stimulated engaging both BCR and TLR9, they become able to proliferate and reactivate the telomerase enzyme. In the present study, we have also compared the telomerase activity in a group of people genetically advantaged for longevity as centenarian offspring (CO) and in a group of moderate-severe Alzheimer's disease (AD) patients, who represent a model of unsuccessful aging. Our study suggests that telomerase reactivation of DN B cells, as well as their number and ability in activating, depend essentially by the biological age of the subjects studied, so the evaluation of DN B cells might allow to gain insight to healthy and unsuccessful aging.
authors.affiliation: Immunosenescence Unit, Department of Pathobiology and Medical and Forensic Biotechnologies (DIBIMEF), University of Palermo, Italy.
authors.forename: Adriana
authors.initials: A
authors.lastname: Martorana
authors.affiliation: Immunosenescence Unit, Department of Pathobiology and Medical and Forensic Biotechnologies (DIBIMEF), University of Palermo, Italy.
authors.forename: Carmela Rita
authors.initials: CR
authors.lastname: Balistreri
authors.affiliation: Immunosenescence Unit, Department of Pathobiology and Medical and Forensic Biotechnologies (DIBIMEF), University of Palermo, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Bulati
authors.affiliation: Immunosenescence Unit, Department of Pathobiology and Medical and Forensic Biotechnologies (DIBIMEF), University of Palermo, Italy.
authors.forename: Silvio
authors.initials: S
authors.lastname: Buffa
authors.affiliation: Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Italy.
authors.forename: Delia Maria
authors.initials: DM
authors.lastname: Azzarello
authors.affiliation: Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Italy.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Camarda
authors.affiliation: Department of Experimental Biomedicine and Clinical Neurosciences, University of Palermo, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Monastero
authors.affiliation: Immunosenescence Unit, Department of Pathobiology and Medical and Forensic Biotechnologies (DIBIMEF), University of Palermo, Italy.
authors.forename: Calogero
authors.initials: C
authors.lastname: Caruso
authors.affiliation: Immunosenescence Unit, Department of Pathobiology and Medical and Forensic Biotechnologies (DIBIMEF), University of Palermo, Italy. Electronic address: giuseppina.colonnaromano@unipa.it.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Colonna-Romano
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000276:immunology* / Q000378:metabolism*; D000954:Antigens, Surface / Q000378:metabolism; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism*; D016922:Cellular Senescence; D006801:Humans; D007156:Immunologic Memory; D016130:Immunophenotyping; D008213:Lymphocyte Activation / Q000276:immunology; D008875:Middle Aged; D010641:Phenotype; D011947:Receptors, Antigen, B-Cell / Q000378:metabolism; D012720:Severity of Illness Index; D019098:Telomerase / Q000378:metabolism; D055815:Young Adult
chemical_list: D000954:Antigens, Surface; D011947:Receptors, Antigen, B-Cell; D019098:Telomerase
keywords: Aging; Alzheimer; B lymphocytes; Centenarian offspring; Inflammation; Telomerase