B cell immunosenescence: different features of naive and memory B cells in elderly

Abstract

Elderly people show a reduced protection against new infections and a decreased response to vaccines as a consequence of impairment of both cellular and humoral immunity. In this paper we have studied memory/naïve B cells in the elderly, evaluating surface immunoglobulin expression, production of the pro-and anti-inflammatory cytokines, tumor necrosis factor (TNF)-a and interleukin (IL)-10, and presence of somatic hypermutation, focusing on the IgG ? IgD -CD27 -double negative (DN) B cells that are expanded in the elderly. Our results show that naïve B cells from young donors need a sufficiently strong stimulus to be activated ''in vitro'', while naïve B cells from old subjects are able to produce IL-10 and TNF-a when stimulated ''physiologically'' (a-CD40/IL-4), suggesting that these cells might play a role in the control of the immuno-inflammatory environment in the elderly. In addition, in the elderly there is an accumulation of DN B cells with a reduced rate of somatic hypermutation. Thus, DN B lymphocytes may be exhausted cells that are expanded and accumulate as a by-product of persistent stimulation or impaired germinal center formation.

A novel B cell population revealed by a CD38/CD24 gating strategy: CD38−CD24− B cells in centenarian offspring and elderly people

“…We have confirmed data from the literature demonstrating impairment decrease of IgM B lymphocytes in the elderly (Shi et al 2005;Buffa et al 2011). On the contrary, a further evaluation of CO B cell populations revealed that the percentage of these cells are not reduced to the same extent as their age-matched controls and remain more similar to that observed in young people.…”

“…5a). A comparison between our subjects confirmed (Shi et al 2005;Buffa et al 2011) a different distribution of B cells identified on the basis of these markers between young and old donors and revealed that CO possess a more "youthfully" distributed immune profile compared with age-matched controls. Indeed, the percentage of IgM + CD27…”

“…A more detailed examination of CO B cells was then performed to evaluate the expression of CD27, IgM, and IgD. It is known that IgM memory B cells are reduced in the elderly, thus predisposing them to pneumococcal infection (Shi et al 2005;Buffa et al 2011). Here again, we show that CO have a "younger" B cell profile.…”

“…+ memory B cells that we and others have described as being decreased in the elderly (Shi et al 2005;Buffa et al 2011). Probably, their low percenta g e d o e s n o t i n f l u e n c e t h e p e r c e n t a g e o f CD19…”

Trafficking phenotype and production of granzyme B by double negative B cells (IgG+IgD−CD27−) in the elderly

“…For this reason the deep knowledge of B cell subsets and functions provides crucial information on immune assessment. Moreover B lymphocytes, due to their ability to present antigen to T lymphocytes, produce cytokines and synthesize granzymes, are now recognized as eclectic and essential cells for an exhaustive immune response (Blair et al, 2010;Bouaziz et al, 2010;Buffa et al, 2011;Hagn et al, 2009Mauri, 2010;Vitale et al, 2010). The different B cell subsets have been identified using many cellular markers by which many functional subsets, as transitional, naïve, memory and plasmablasts may be recognized.…”