title: Altered memory B-cell homeostasis in human aging.
abstract: Previous studies of age-associated immune system changes revealed alterations in expressed immunoglobulin heavy chain variable domain repertoires, and variability in the fraction of expressed heavy chain variable domain genes with mutations. To test whether the latter finding reflected a variation in memory B-cell numbers, we measured circulating memory B cells of 11 healthy elderly subjects, 173 nursing-home residents, and 34 healthy young adults. A large fraction of old adults have low values for memory cells both as a percentage of all B cells and as an absolute memory B-cell concentration. The range of both values is much wider in old adults than in young adults, and it is much wider than the range of T-cell concentrations. Memory B-cell concentration, which was positively correlated with memory T-cell concentrations but inversely related to in vitro T-cell responses to mitogens, may reflect highly individual rates of immune senescence, and it may serve as an amplified marker of underlying T-cell function.
authors.affiliation: Department of Biochemistry, Tufts University School of Medicine, and the Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts 02111, USA.
authors.forename: Eyal
authors.initials: E
authors.lastname: Breitbart
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Wang
authors.forename: Lynette S
authors.initials: LS
authors.lastname: Leka
authors.forename: Gerard E
authors.initials: GE
authors.lastname: Dallal
authors.forename: Simin Nikbin
authors.initials: SN
authors.lastname: Meydani
authors.forename: B David
authors.initials: BD
authors.lastname: Stollar
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000276:immunology* / Q000502:physiology; D000704:Analysis of Variance; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D016022:Case-Control Studies; D002454:Cell Differentiation; D002455:Cell Division; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000032:analysis* / Q000276:immunology; D007156:Immunologic Memory / Q000276:immunology / Q000502:physiology*; D016014:Linear Models; D008297:Male; D008568:Memory / Q000502:physiology*; D012494:Sampling Studies; D012680:Sensitivity and Specificity
chemical_list: D007143:Immunoglobulin Heavy Chains