The role of immune response in ageing and longevity. A focus on B cell compartment

The improvement of the quality of life of elderly people is going to become a priority because of the continuous increase in the number of centenarians. This render the studies of the processes involved in ageing of critical importance. Centenarians are a widely accepted model of successful ageing, a complex process which is influenced by several biological, environmental and lifestyle factors, because they have reached the extreme limits of life span overcoming the major age-related diseases. In centenarians model, several aspects have been studied, as inflammation, immune system, genetics and metabolism, to understand the secret of their long survival. It has been proposed that centenarians are characterized by more efficient protective molecules and biochemical pathways, and show well preserved immune functions

Immunosenescence, inflammation and Alzheimer’s disease

Ageing impacts negatively on the development of the immune system and its ability to fight pathogens. Progressive changes in the T-cell and B-cell systems over the lifespan of individuals have a major impact on the capacity to respond to immune challenges. The cumulative age-associated changes in immune competence are termed immunosenescence that is characterized by changes where adaptive immunity deteriorates, while innate immunity is largely conserved or even upregulated with age. On the other hand, ageing is also characterized by “inflamm-ageing”, a term coined to explain the inflammation commonly present in many age-associated diseases. It is believed that immune inflammatory processes are relevant in Alzheimer’s disease, the most common cause of dementia in older people. In the present paper we review data focusing on changes of some immunoinflammatory parameters observed in patients affected by Alzheimer’s diseas

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

The impairment of humoral immune response in elderly humans has been extensively demonstrated. We have reported the increase of memory B cells (IgG+IgD−CD27−, double negative, DN) population in the elderly, in which there is also a typical inflammatory micro-environment. In order to evaluate whether this pro-inflammatory status could influence the trafficking phenotype of naïve/memory B cells, we have assessed the expression of CCR7, CCR6, CXCR3, CXCR4, CXCR5 and CD62L on naïve/memory B cell subpopulations in young and elderly subjects. Moreover, the combination of pro-inflammatory interleukin-21 (IL-21) and B cell receptor (BCR) stimulation enables B cells to produce and secrete granzyme B (GrB), which plays a critical role in early anti-viral immune responses, in the regulation of autoimmune mechanisms and in cancer immunosurveillance. Our data demonstrate that in the elderly, naïve/memory B cell populations present a different expression of the studied receptors that could be discussed in terms of “inflamm-aging”. In particular IgG+IgD−CD27− DN B cells show a tissue trafficking phenotype and they can be stimulated to produce GrB

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

The B cell arm of adaptive immunity undergoes significant modifications with age. Elderly people are characterized by impaired B cell responses reflected in a reduced ability to effectively respond against viruses and bacteria. Alterations of immunity with advancing age (immunosenescence) have been widely studied in centenarians who are considered a good example of successful aging. In recent years, attention has shifted to centenarian offspring (CO) as a model of people genetically advantaged for healthy aging and longevity. Here, we describe the preliminary characterization of a proposed new population of memory B cells, defined as CD19(+)CD38(-)CD24(-), which we find at higher frequencies in the elderly but less so in CO than healthy age-matched random controls. In addition, we found a decreased expression of RP105 (CD180), a toll-like receptor-associated molecule, on these cells. CD180 downregulation may potentially be a marker of immunosenescence. Moreover, we show that these CD19(+)CD38(-)CD24(-) B cells produce TNF and hypothesize that their observed expansion in the elderly might contribute to the increased inflammatory status sometimes designated "inflamm-aging

B Cells Compartment in Centenarian Offspring and Old People

Immunosenescence is considered a major contributory factor to the increased frequency of morbidity and mortality among elderly. On the other hand centenarians are considered the best example of successful ageing. To gain insight into mechanisms of immunosenescence and its clinical relevance, a possible model is represented by centenarians and/or their offspring. Nowadays centenarians are not more a curiosity, but in Europe are 1/8000 inhabitants and it has been demonstrated that the centenarian offspring, who are typically in their 70s and 80s, have a survival advantage when compared with age-matched controls whose parents died at an average life expectancy. Then again, studies on immunosenescence focus mainly on T cell impairment, although B cells are also affected. So, in the present preliminary report, we have studied B cell compartment in two classes of individuals, old people and centenarian offspring. B cell compartment was analysed using anti-IgD and CD27 antibodies which characterize naïve B cells (IgD+ CD27-), memory unswitched B cells (IgD+CD27+), memory switched B cells(IgD-CD27+) and double negative B cells (DN) (IgD-CD27-), i.e. exhausted memory cells. As expected, in both cohorts we observed a decreased B cell count. However, in centenarian offspring, naïve B cells are more abundant whereas exhausted memory cells (DN B cells, IgD-CD27-) do not show the increase that we have previously demonstrated in healthy elderly donors. These data are similar to that found in previously experiments on young subjects. So, our preliminary results show that centenarian offspring do not have the typical trend of memory/naive B cell subsets observed in elderly people and this is in agreement with the higher levels of IgM in the serum of centenarian offspring in comparison with data obtained in age-matched controls. This reservoir of naive B cell might be one of the causes that make centenarian offspring able to keep fighting off new infections, hence prolonging their life. So, B cell subset changes could represent a hallmark of successful or unsuccessful ageing and could be used as a biomarker of human life span, potentially useful for the evaluation of anti-ageing treatment

A double-negative (IgD CD27 ) B cell population is increased in the peripheral blood of elderly people

The T cell branch of the immune system has been extensively studied in the elderly and it is known that the elderly have impaired immune function, mainly due to the chronic antigenic load that ultimately causes shrinkage of the T cell repertoire and filling of the immunologic space with memory T cells. In the present paper,we describe the IgD CD27 double-negative B cell population which (aswe have recently described) is higher in the elderly. Most of these cells were IgG+. Evaluation of the telomere length and expression of the ABCB1 transporter and anti-apoptotic molecule, Bcl2, shows that they have the markers of memory B cells. We also show that these cells do not act as antigen presenting cells, as indicated by the low levels of CD80 and DR, nor do they express significant levels of the CD40 molecule necessary to interact with T lymphocytes through the ligand, CD154. Hence, we hypothesize that these expanded cells are late memory or exhausted cells that have down-modulated the expression of CD27 and filled the immunologic space in the elderly. These cells might be the age-related manifestation of time-enduring stimulation or dysregulation of the immune system

Tissue-Resident Innate Immune Cell-Based Therapy: A Cornerstone of Immunotherapy Strategies for Cancer Treatment

Cancer immunotherapy has led to impressive advances in cancer treatment. Unfortunately, in a high percentage of patients is difficult to consistently restore immune responses to eradicate established tumors. It is well accepted that adaptive immune cells, such as B lymphocytes, CD4+ helper T lymphocytes, and CD8+ cytotoxic T-lymphocytes (CTLs), are the most effective cells able to eliminate tumors. However, it has been recently reported that innate immune cells, including natural killer cells (NK), dendritic cells (DC), macrophages, myeloid-derived suppressor cells (MDSCs), and innate lymphoid cells (ILCs), represent important contributors to modulating the tumor microenvironment and shaping the adaptive tumor response. In fact, their role as a bridge to adaptive immunity, make them an attractive therapeutic target for cancer treatment. Here, we provide a comprehensive overview of the pleiotropic role of tissue-resident innate immune cells in different tumor contexts. In addition, we discuss how current and future therapeutic approaches targeting innate immune cells sustain the adaptive immune system in order to improve the efficacy of current tumor immunotherapies

Centenarian Offspring: A Model for Understanding Longevity

Abstract: A main objective of current medical research is to improve the life quality of elderly people as priority of the continuous increase of ageing population. This phenomenon implies several medical, economic and social problems because of dramatic increase in number of non autonomous individuals affected by various pathologies. Accordingly, the research interest is focused on understanding the biological mechanisms involved in determining the positive ageing phenotype, i.e. the centenarian phenotype. In achieving this goal the choice of an appropriate study models is fundamental. Centenarians have been used as an optimal model for successful ageing. However, this model shows several limitations, i.e. the selection of appropriate controls and the use itself of the centenarians as a suitable model for healthy ageing. Thus, the interest has been centered on centenarian offspring, healthy elderly people. They may represent a model for understanding exceptional longevity for the following reasons: they exhibit a protective genetic background, cardiovascular and immunological profile, as well as a reduced rate of cognitive decline than age-matched people without centenarian relatives. Several of these aspects are summarized in this review based on the literature and the results of our studies

Expression of calpain-calpastatin system (CCS) member proteins in human lymphocytes of young and elderly individuals; pilot baseline data for the CALPACENT project.

Ubiquitous system of regulatory, calcium-dependent, cytoplasmic proteases – calpains – and their endogenous inhibitor – calpastatin – is implicated in the proteolytic regulation of activation, proliferation, and apoptosis of many cell types. However, it has not been thoroughly studied in resting and activated human lymphocytes yet, especially in relation to the subjects’ ageing process. The CALPACENT project is an international (Polish-Italian) project aiming at verifying the hypothesis of the role of calpains in the function of peripheral blood immune cells of Polish (Pomeranian) and Italian (Sicilian) centenarians, apparently relatively preserved in comparison to the general elderly population. In this preliminary report we aimed at establishing and comparing the baseline levels of expression of μ- and m-calpain and calpastatin in various, phenotypically defined, populations of human peripheral blood lymphocytes for healthy elderly Sicilians and Poles, as compared to these values observed in young cohort

Biomarkes of aging.

Ageing is a complex process that negatively impacts the development of the different systems and its ability to function. On the other hand, the rate of ageing in humans is not uniform, due to genetic heterogeneity and the influence of environmental factors. Thus, the ageing rate, measured as the decline of functional capacity and stress resistance, seems to be different in every individual. Therefore, attempts have been made to analyse this individual age, the so-called biological age, in comparison to chronological age. Age-related changes in body function or composition that could serve as a measure of biological age and predict the onset of age-related diseases and/or residual lifetime are termed biomarkers of ageing. Such biomarkers of ageing should help on the one hand to characterise this biological age and, as age is a major risk factor in many degenerative diseases, could be subsequently used on the other hand to identify individuals at high risk of developing age-associated diseases or disabilities. Unfortunately, most of the markers under discussion are related to age-related diseases rather than to age, so none of these markers discussed in literature is a true biomarker of ageing. Hence, we discuss some disease-related biomarkers useful for a better understanding of ageing and the development of new strategies to counteract it, essential for improving the quality of life of the elderly population. Biomarkers discussed are based on immunosenescence, inflammatory responses and oxidative stress, since the review is based on data from author laboratories rather than on an extensive review of the literature. However, this kind of knowledge is useful to anti-ageing strategies aimed to slow ageing and to postpone death by preventing infectious diseases and delaying the onset of age-related diseases