Different IL-8 production by T and NK lymphocytes in elderly subjects

Impact and potential value of immunosenescence on solid gastrointestinal tumors

Solid gastrointestinal tumors often respond poorly to immunotherapy for the complex tumor microenvironment (TME), which is exacerbated by immune system alterations. Immunosenescence is the process of increased diversification of immune genes due to aging and other factors, leading to a decrease in the recognition function of the immune system. This process involves immune organs, immune cells, and the senescence-associated secretory phenotype (SASP). The most fundamental change is DNA damage, resulting in TME remodeling. The main manifestations are worsening inflammation, increased immunosuppressive SASP production, decreased immune cell antitumor activity, and the accumulation of tumor-associated fibroblasts and myeloid-derived suppressor cells, making antitumor therapy less effective. Senotherapy strategies to remove senescent cells and block key senescence processes can have synergistic effects with other treatments. This review focuses on immunoenescence and its impact on the solid TME. We characterize the immunosenescent TME and discuss future directions for antitumor therapies targeting senescence.

Increased PD-1+ NK Cell Subset in the Older Population

Background

The aging of the immune system is associated with various diseases. It is worth exploring the changes of the immune system in aging. Previous studies have shown that aged T cells have enhanced expression of co-inhibitory molecules. However, it remains unclear whether aged NK cells exhibit similar characteristics to aged T cells. The objective of our research was to clarify this aspect.

Patients and Methods

This study included 98 adults aged 24-90 years (50 males and 48 females). We detected the subset of peripheral blood NK cells and the expression of various receptors on NK cells among donors of different age groups by flow cytometry. Immune subsets were initially defined by forward and side-scatter characteristics and then staining with the appropriate marker.

Results

The absolute number and subset distribution of NK cells were not associated with age. However, CD57 expression and CD69 expression were correlated with age. Furthermore, we found that PD-1 was up-regulated on NK cells in older people, associated with aging, while no such change was observed in other co-inhibitory molecules, including 2B4, CTLA-4, TIM-3, BTLA, CD70, CD39, CD160, and TIGIT. PD-1+ NK cells expressed high levels of CD57 and CD69, indicating PD-1+ NK cells displayed a phenotype of over-activation and aging.

Discussion

This study indicated that PD-1+ NK cells were one of the characteristics of NK cells in older people.

Conclusion

This study indicated that PD-1+ NK cells were one of the characteristics of NK cells in older people. Those findings provided new ideas to explore the underlying drivers of NK aging.

The aging of the immune system and its implications for transplantation

By the last third of life, most mammals, including humans, exhibit a decline in immune cell numbers, immune organ structure, and immune defense of the organism, commonly known as immunosenescence. This decline leads to clinical manifestations of increased susceptibility to infections, particularly those caused by emerging and reemerging microorganisms, which can reach staggering levels-infection with SARS-CoV-2 has been 270-fold more lethal to older adults over 80 years of age, compared to their 18-39-year-old counterparts. However, while this would be expected to be beneficial to situations where hyporeactivity of the immune system may be desirable, this is not always the case. Here, we discuss the cellular and molecular underpinnings of immunosenescence as they pertain to outcomes of solid organ and hematopoietic transplantation.

Age-related increase of mitochondrial content in human memory CD4+ T cells contributes to ROS-mediated increased expression of proinflammatory cytokines

Cellular metabolism modulates effector functions in human CD4⁺ T (Th) cells by providing energy and building blocks. Conversely, cellular metabolic responses are modulated by various influences, e.g., age. Thus, we hypothesized that metabolic reprogramming in human Th cells during aging modulates effector functions and contributes to “inflammaging”, an aging-related, chronic, sterile, low-grade inflammatory state characterized by specific proinflammatory cytokines. Analyzing the metabolic response of human naive and memory Th cells from young and aged individuals, we observed that memory Th cells exhibit higher glycolytic and mitochondrial fluxes than naive Th cells. In contrast, the metabolism of the latter was not affected by donor age. Memory Th cells from aged donors showed a higher respiratory capacity, mitochondrial content, and intracellular ROS production than those from young donors without altering glucose uptake and cellular ATP levels, which finally resulted in higher secreted amounts of proinflammatory cytokines, e.g., IFN-γ, IP-10 from memory Th cells taken from aged donors after TCR-stimulation which were sensitive to ROS inhibition. These findings suggest that metabolic reprogramming in human memory Th cells during aging results in an increased expression of proinflammatory cytokines through enhanced ROS production, which may contribute to the pathogenesis of inflammaging.

Aging of the Immune System: Focus on Natural Killer Cells Phenotype and Functions

Aging is the greatest risk factor for nearly all major chronic diseases, including cardiovascular diseases, cancer, Alzheimer’s and other neurodegenerative diseases of aging. Age-related impairment of immune function (immunosenescence) is one important cause of age-related morbidity and mortality, which may extend beyond its role in infectious disease. One aspect of immunosenescence that has received less attention is age-related natural killer (NK) cell dysfunction, characterized by reduced cytokine secretion and decreased target cell cytotoxicity, accompanied by and despite an increase in NK cell numbers with age. Moreover, recent studies have revealed that NK cells are the central actors in the immunosurveillance of senescent cells, whose age-related accumulation is itself a probable contributor to the chronic sterile low-grade inflammation developed with aging (“inflammaging”). NK cell dysfunction is therefore implicated in the increasing burden of infection, malignancy, inflammatory disorders, and senescent cells with age. This review will focus on recent advances and open questions in understanding the interplay between systemic inflammation, senescence burden, and NK cell dysfunction in the context of aging. Understanding the factors driving and enforcing NK cell aging may potentially lead to therapies countering age-related diseases and underlying drivers of the biological aging process itself.

The impact of aging on innate and adaptive immunity in the human female genital tract

Mucosal tissues in the human female reproductive tract (FRT) are primary sites for both gynecological cancers and infections by a spectrum of sexually transmitted pathogens, including human immunodeficiency virus (HIV), that compromise women's health. While the regulation of innate and adaptive immune protection in the FRT by hormonal cyclic changes across the menstrual cycle and pregnancy are being intensely studied, little to nothing is known about the alterations in mucosal immune protection that occur throughout the FRT as women age following menopause. The immune system in the FRT has two key functions: defense against pathogens and reproduction. After menopause, natural reproductive function ends, and therefore, two overlapping processes contribute to alterations in immune protection in aging women: menopause and immunosenescence. The goal of this review is to summarize the multiple immune changes that occur in the FRT with aging, including the impact on the function of epithelial cells, immune cells, and stromal fibroblasts. These studies indicate that major aspects of innate and adaptive immunity in the FRT are compromised in a site‐specific manner in the FRT as women age. Further, at some FRT sites, immunological compensation occurs. Overall, alterations in mucosal immune protection contribute to the increased risk of sexually transmitted infections (STI), urogenital infections, and gynecological cancers. Further studies are essential to provide a foundation for the development of novel therapeutic interventions to restore immune protection and reverse conditions that threaten women's lives as they age.

Immune system and COVID-19 by sex differences and age

In COVID-19 disease, are reported gender differences in relation to severity and death. The aim of this review is to highlight gender differences in the immune response to COVID-19. The included studies were identified using PubMed, until 30 October 2020. The search included the following keywords: SARS-CoV-2, COVID-19, gender, age, sex, and immune system. Literature described that females compared to males have greater inflammatory, antiviral, and humoral immune responses. In female, estrogen is a potential ally to alleviate SARS-COV-2 disease. In male, testosterone reduces vaccination response and depresses the cytokine response. In the older patients, and in particular, in female older patients, it has been reported a progressive functional decline in the immune systems. Differences by gender were reported in infection diseases, including SARS-CoV-2. These data should be confirmed by the other epidemiological studies.

Immunesenescence: A Predisposing Risk Factor for the Development of COVID-19?

Bearing a strong resemblance to the phenotypic and functional remodeling of the immune system that occurs during aging (termed immunesenescence), the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of Coronavirus disease 2019 (COVID-19), is characterized by an expansion of inflammatory monocytes, functional exhaustion of lymphocytes, dysregulated myeloid responses and the presence of highly activated senescent T cells. Alongside advanced age, male gender and pre-existing co-morbidities [e.g., obesity and type 2 diabetes (T2D)] are emerging as significant risk factors for COVID-19. Interestingly, immunesenescence is more profound in males when compared to females, whilst accelerated aging of the immune system, termed premature immunesenescence, has been described in obese subjects and T2D patients. Thus, as three distinct demographic groups with an increased susceptibility to COVID-19 share a common immune profile, could immunesenescence be a generic contributory factor in the development of severe COVID-19? Here, by focussing on three key aspects of an immune response, namely pathogen recognition, elimination and resolution, we address this question by discussing how immunesenescence may weaken or exacerbate the immune response to SARS-CoV-2. We also highlight how aspects of immunesenescence could render potential COVID-19 treatments less effective in older adults and draw attention to certain therapeutic options, which by reversing or circumventing certain features of immunesenescence may prove to be beneficial for the treatment of groups at high risk of severe COVID-19.

Immunesenescence and inflammaging: A contributory factor in the poor outcome of the geriatric trauma patient

Compared to younger patients, traumatic injury in older patients is associated with increased mortality and a range of adverse outcomes such as higher rates of infectious episodes, longer length of hospital stay and poor functional outcome at follow up. Data emerging from human and murine-based studies suggest age-related changes in immune function, collectively termed immunesenescence, and the chronic sub-clinical systemic inflammatory state of older adults, termed inflammaging, may contribute to these poor outcomes. Here, we review the findings of these studies, whose results demonstrate that the geriatric trauma patient elicits an immune response to injury that is distinct to that of younger adults, being characterised by reduced immune cell activation, impaired function and abnormal haematopoiesis, defects that are accompanied by an altered inflammatory response that fails to return to a homeostatic baseline in the days following injury. Although considerable evidence is accumulating that demonstrates clear and significant age-related differences in the immune and inflammatory response to traumatic injury, our current understanding of the mechanism(s) that underlie these changes is limited. Future studies that provide a mechanistic explanation for the unique immune and inflammatory response of older adults to traumatic injury are therefore essential if we are to determine whether manipulation of the immune system has potential as a future therapeutic strategy by which to improve the outcome of the geriatric trauma patient.

Influence of galacto-oligosaccharide mixture (B-GOS) on gut microbiota, immune parameters and metabonomics in elderly persons

It is recognised that ageing induces various changes to the human colonic microbiota. Most relevant is a reduction in bifidobacteria, which is a health-positive genus. Prebiotics, such as galacto-oligosaccharides (GOS), are dietary ingredients that selectively fortify beneficial gut microbial groups. Therefore, they have the potential to reverse the age-related decline in bifidobacteria and modulate associated health parameters. We assessed the effect of GOS mixture (Bimuno (B-GOS)) on gut microbiota, markers of immune function and metabolites in forty elderly (age 65-80 years) volunteers in a randomised, double-blind, placebo (maltodextrin)-controlled, cross-over study. The intervention periods consisted of 10 weeks with daily doses of 5·5 g/d with a 4-week washout period in between. Blood and faecal samples were collected for the analyses of faecal bacterial populations and immune and metabolic biomarkers. B-GOS consumption led to significant increases in bacteroides and bifidobacteria, the latter correlating with increased lactic acid in faecal waters. Higher IL-10, IL-8, natural killer cell activity and C-reactive protein and lower IL-1β were also observed. Administration of B-GOS to elderly volunteers may be useful in positively affecting the microbiota and some markers of immune function associated with ageing.

Blue journal conference. Aging and susceptibility to lung disease

The aging of the population in the United States and throughout the developed world has increased morbidity and mortality attributable to lung disease, while the morbidity and mortality from other prevalent diseases has declined or remained stable. Recognizing the importance of aging in the development of lung disease, the American Thoracic Society (ATS) highlighted this topic as a core theme for the 2014 annual meeting. The relationship between aging and lung disease was discussed in several oral symposiums and poster sessions at the annual ATS meeting. In this article, we used the input gathered at the conference to develop a broad framework and perspective to stimulate basic, clinical, and translational research to understand how the aging process contributes to the onset and/or progression of lung diseases. A consistent theme that emerged from the conference was the need to apply novel, systems-based approaches to integrate a growing body of genomic, epigenomic, transcriptomic, and proteomic data and elucidate the relationship between biologic hallmarks of aging, altered lung function, and increased susceptibility to lung diseases in the older population. The challenge remains to causally link the molecular and cellular changes of aging with age-related changes in lung physiology and disease susceptibility. The purpose of this review is to stimulate further research to identify new strategies to prevent or treat age-related lung disease.

Innate immunesenescence: underlying mechanisms and clinical relevance

A well-established feature of physiological ageing is altered immune function, a phenomenon termed immunesenescence. Thought to be responsible in part for the increased incidence and severity of infection reported by older adults, as well as the age-related decline in vaccine efficacy and autoimmunity, immunesenescence affects both the innate and adaptive arms of the immune system. Whilst much is known regarding the impact of age on adaptive immunity, innate immunity has received far less attention from immune gerontologists. However, over the last decade it has become increasingly apparent that this non-specific arm of the immune response undergoes considerable functional and phenotypical alterations with age. Here, we provide a detailed overview of innate immunesenescence and its underlying molecular mechanisms, and highlight those studies whose results indicate that changes in innate immunity with age have a significant impact upon the health and well-being of older adults.

The impact of ageing on natural killer cell function and potential consequences for health in older adults

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Roles are emerging for natural killer (NK) cells beyond removing transformed cells.

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These include immune regulation and the elimination of senescent cells.

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Human ageing is associated with a decline in NK cell function.

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We propose some aspects of human ageing are due in part to reduced NK cell function.

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These include reduced vaccination efficacy and delayed resolution of inflammation.

Forming the first line of defence against virally infected and malignant cells, natural killer (NK) cells are critical effector cells of the innate immune system. With age, significant impairments have been reported in the two main mechanisms by which NK cells confer host protection: direct cytotoxicity and the secretion of immunoregulatory cytokines and chemokines. In elderly subjects, decreased NK cell activity has been shown to be associated with an increased incidence and severity of viral infection, highlighting the clinical implications that age-associated changes in NK cell biology have on the health of older adults. However, is an increased susceptibility to viral infection the only consequence of these age-related changes in NK cell function? Recently, evidence has emerged that has shown that in addition to eliminating transformed cells, NK cells are involved in many other biological processes such as immune regulation, anti-microbial immune responses and the recognition and elimination of senescent cells, novel functions that involve NK-mediated cytotoxicity and/or cytokine production. Thus, the decrease in NK cell function that accompanies physiological ageing is likely to have wider implications for the health of older adults than originally thought. Here, we give a detailed description of the changes in NK cell biology that accompany human ageing and propose that certain features of the ageing process such as: (i) the increased reactivation rates of latent Mycobacterium tuberculosis, (ii) the slower resolution of inflammatory responses and (iii) the increased incidence of bacterial and fungal infection are attributable in part to an age-associated decline in NK cell function.

Phagocyte dysfunction in polymyalgia rheumatica and other age-related, chronic, inflammatory conditions

This study was conducted to evaluate phagocyte function in patients with age-related chronic inflammatory conditions. It included 95 patients with PMR, 17 with GCA, 40 with EORA, and 25 age-matched HCs. Serum IL-8 was determined with a bead array. The chemotactic capacity, phagocytic ability, and oxidative burst activity of circulating leukocytes were determined with flow cytometry kits. Patients with active chronic inflammatory diseases showed a significant increase in circulating levels of IL-8 that remained elevated in patients with PMR or EORA, despite treatment. No correlation was found between circulating IL-8 and the migratory capacity of neutrophils. Neutrophils from patients with active EORA without stimulus and after fMLP stimuli showed a higher capacity to migrate than those of the HCs (P=0.033). The phagocytic activity of granulocytes in the patients with GCA was significantly higher than in the HCs and the patients with PMR or EORA (P<0.05). The percentage and MFI of phagocytes that produce ROIs when stimulated with Escherichia coli was significantly reduced in neutrophils and monocytes from the patients with age-restricted inflammatory conditions. We concluded that the effector functions of phagocytes, determined to be chemotaxis, phagocytosis, and oxidative burst, are deregulated in age-restricted inflammatory disorders and may have a pathogenic role.

Oxidative stress and immunosenescence: therapeutic effects of melatonin

Age-associated deterioration in the immune system, which is referred to as immunosenescence, contributes to an increased susceptibility to infectious diseases, autoimmunity, and cancer in the elderly. A summary of major changes associated with aging in immune system is described in this paper. In general, immunosenescence is characterized by reduced levels of peripheral naïve T cells derived from thymus and the loss of immature B lineage cells in the bone marrow. As for macrophages and granulocytes, they show functional decline with advancing age as evidenced by their diminished phagocytic activity and impairment of superoxide generation. The indole melatonin is mainly secreted in the pineal gland although it has been also detected in many other tissues. As circulating melatonin decreases with age coinciding with the age-related decline of the immune system, much interest has been focused on melatonin's immunomodulatory effect in recent years. Here, we underlie the antioxidant and immunoenhancing actions displayed by melatonin, thereby providing evidence for the potential application of this indoleamine as a “replacement therapy” to limit or reverse some of the effects of the changes that occur during immunosenescence.

Ageing and the gut

The goal of this brief review is to address the role of the ageing gut in the genesis of malnutrition in the elderly. We assess the burden of malnutrition in the elderly, exploring the role of comorbid conditions and neurohumoral changes that take place to contribute towards the process of anorexia associated with ageing. Following this, the review assesses physiological changes that occur in each part of the gastrointestinal (GI) tract and what implication they may have in clinical practice. In the oropharynx and the oesophagus, changes in swallowing and oesophageal motility associated with ageing can be demonstrated using physiological testing. However, in the absence of comorbid disease, they often have little, if any, clinical significance. In the stomach, reduced fundal compliance may contribute to early satiety; however, the primary change is hypochlorhydria, which may predispose to malabsorption or bacterial overgrowth further along the GI tract. Almost uniquely, the small bowel, particularly its absorptive function, is unaffected by age and we review the literature demonstrating this. In the colon, there is evidence of a prolonged transit time related to a reduction in both neurotransmitters and receptors. Although this may cause symptoms, this aspect is unlikely to contribute to malnutrition. In addition, we assess the potential changes in the gut microbiome and how this may interact with the immune system in the process of 'inflamm-ageing'. We conclude by summarising the main changes and their impact for the clinician along with recommendations for future areas of research.

Innate immunosenescence: effect of aging on cells and receptors of the innate immune system in humans

Components of the innate immune response, including neutrophils and macrophages, are the first line of defense against infections. Their role is to initiate an inflammatory response, phagocyte and kill pathogens, recruit natural killer cells (NK), and facilitate the maturation and migration of dendritic cells that will initiate the adaptive immune response. Extraordinary advances have been made in the last decade on the knowledge of the receptors and mechanisms used by cells of the innate immunity not only to sense and eliminate the pathogen but also to communicate each other and collaborate with cells of adaptive immunity to mount an effective immune response. The analysis of innate immunity in elderly humans has evidenced that aging has a profound impact on the phenotype and functions of these cells. Thus altered expression and/or function of innate immunity receptors and signal transduction leading to defective activation and decreased chemotaxis, phagocytosis and intracellular killing of pathogens have been described. The phenotype and function of NK cells from elderly individuals show significant changes that are compatible with remodeling of the different NK subsets, with a decrease in the CD56bright subpopulation and accumulation of the CD56dim cells, in particular those differentiated NK cells that co-express CD57, as well as a decreased expression of activating natural cytotoxicity receptors. These alterations can be responsible of the decreased production of cytokines and the lower per-cell cytotoxicity observed in the elderly. Considering the relevance of these cells in the initiation of the immune response, the possibility to reactivate the function of innate immune cells should be considered in order to improve the response to pathogens and to vaccination in the elderly.

Expansions of NK-like αβT cells with chronologic aging: novel lymphocyte effectors that compensate for functional deficits of conventional NK cells and T cells

As the repertoire of αβT cell receptors (TCR) contracts with advancing age, there is an associated age-dependent accumulation of oligoclonal T cells expressing of a variety of receptors (NKR), normally expressed on natural killer (NK) cells. Evidences for differential regulation of expression of particular NKRs between T cells and NK cells suggest that NKR expression on T cells is physiologically programmed rather than a random event of the aging process. Experimental studies show NKRs on aged αβT cells may function either as independent receptors, and/or as costimulatory receptors to the TCR. Considering the reported deficits of conventional αβTCR-driven activation and also functional deficits of classical NK cells, NKR(+) αβT cells likely represent novel immune effectors that are capable of combining innate and adaptive functions. Inasmuch as immunity is a determinant of individual fitness, the type and density of NKRs could be important contributing factors to the wide heterogeneity of health characteristics of older adults, ranging from institutionalized frail elders who are unable to mount immune responses to functionally independent community-dwelling elders who exhibit protective immunity. Understanding the biology of NKR(+) αβT cells could lead to new avenues for age-specific intervention to improve protective immunity.

Susceptibility of the aging lung to environmental injury

With an ever-increasing number of elderly individuals in the world, a better understanding of the issues associated with aging and the environment is needed. The respiratory system is one of the primary interfaces between the body and the external environment. An expanding number of studies suggest that the aging pulmonary system (>65 years) is at increased risk for adverse health effects from environmental insult, such as by air pollutants, infection, and climate change. However, the mechanism(s) for increased susceptibility in this subpopulation are not well understood. In this review, we provide a limited but comprehensive overview of how the lung ages, examples of environmental exposures associated with injury to the aging lung, and potential mechanisms underlying the increased vulnerability of the aging lung to injury from environmental factors.

The aging immune system and its relationship to the development of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease of the lungs that usually manifests late in life. Physiologic and immunologic changes that occur in COPD often mimic changes seen in the aging lung. This has led some to characterize COPD as an "accelerated aging phenotype." At the molecular level, COPD and aging share common mechanisms and are associated with significant dysregulation of the immune systems. Aging and COPD are characterized by increases in proinflammatory cytokines such as interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha, which are implicated in aging-related inflammatory diseases and correlate with degree of obstruction in COPD. There is an age-dependent decline in naïve T cells with oligoclonal expansion of CD8(+) CD28(null) T cells from chronic antigenic stimulation. The increase in CD8(+) CD28 (null) T regulatory cells inhibits antigen-specific CD4(+) T cell responses, leading to a decline in adaptive immune response. To compensate for the decline in the adaptive immune function there is a paradoxical up-regulation of innate immune system resulting in a proinflammatory state. The dysregulated adaptive immune system with activated innate immune responses seen with aging results in recruitment and retention of neutrophils, macrophages, and CD4(+) and CD8(+) T cells in the lungs of smokers with COPD. Once the inflammation is triggered, there is a self-perpetuating cascade of inflammation and lung parenchymal damage. This review will focus on how the aging immune system may contribute to COPD development later in life in susceptible individuals.

The role of immunity in elderly cancer

The increased incidence of malignancies in elderly patients living in industrialized countries has led to both identify the causes that alter the normal homeostatic balance in elderly and designate the specific treatments. The progressive decline of the immune system (immunosenescence) involving cellular and molecular alterations impact both innate and adaptive immunity. The immunosenescence leads to increased incidence of infectious diseases morbidity and mortality as well as heightened rates of other immune disorders such as autoimmunity, cancer, and inflammatory conditions. Here, we summarize the knowledge on the major changes in the immune system associated with aging in primary lymphoid organs as well as a description of molecular mechanisms, and the impact on cancer development.

Lung injury after hemorrhage is age dependent: role of peroxisome proliferator-activated receptor gamma

OBJECTIVE

The incidence of multiple organ failure in pediatric trauma victims is lower than in the adult population. However, the molecular mechanisms are not yet defined. We investigated whether the pathophysiologic characteristics of hemorrhage-induced lung injury may be age dependent and may be regulated by the peroxisome proliferator-activated receptor gamma (PPARgamma).

DESIGN

Prospective, laboratory investigation that used an established rodent model of hemorrhagic shock.

SETTING

University hospital laboratory.

SUBJECTS

Young (n = 67; 3-5 months old) and mature (n = 66; 11-13 months old) male rats.

INTERVENTIONS

Hemorrhagic shock was induced in young and mature rats by withdrawing blood to a mean arterial blood pressure of 50 mm Hg. After 3 hours, rats were rapidly resuscitated by infusing the shed blood and killed 3 hours thereafter.

MEASUREMENTS AND MAIN RESULTS

In young rats, lung injury was characterized by accumulation of red cells and neutrophils at the end of the resuscitation period; on Western blot analysis, lung expression of intercellular adhesion molecule-1 was increased. In contrast, the severity of lung injury was more pronounced in mature rats. Lung myeloperoxidase activity and expression of constitutive and inducible intercellular adhesion molecule-1 was significantly higher in mature rats compared with young rats. Mature rats also had higher plasma levels of cytokines and chemokines compared with young rats. This heightened inflammation was associated with higher degree of activation of nuclear factor-kappaB and down-regulation of PPARgamma and heat shock factor-1 in the lung of mature rats compared with young rats. Treatment with the PPARgamma ligand, the cyclopentenone prostaglandin 15-deoxy-Delta-prostaglandin J2, ameliorated lung injury in young, but not in mature animals.

CONCLUSIONS

Lung injury after severe hemorrhage is age dependent and may be secondary to a diverse regulation of PPARgamma.

Innate immunity and aging

Advanced age is associated with defects in all of the cells of the innate immune system, including numbers, function, and early stages of activation. This review, presents the current state of the field on the impact of age on the innate immune system. The analysis of the literature suggests that a dysfunctional innate immune system is a contributing factor to aberrant outcomes after injury or infection and to the development of many of the diseases observed in the elderly. Gaining an understanding of the nature of the defects in innate immune cells may allow the development of therapeutic strategies aimed to restore innate immune function in aged individuals.

Epigenetics, aging, and autoimmunity

Immune senescence is associated with a decline in T- and B-cell immune responses. It is, therefore, perhaps surprising that aging is linked to the appearance of serological and clinical autoimmunity. Here we review the mechanisms that contribute to the increase in inflammatory and autoimmune responses in aging. The bulk of this review will focus on aging-associated changes in epigenetic mechanisms, and in particular DNA methylation, as this has emerged as an attractive mechanistic link between aging and autoimmunity.

Natural killer cells and exercise training in the elderly: a review

Consistent reports of the positive relationship between regular physical activity and immunosenescence have generated much excitement in the field of exercise immunology. It is generally accepted that natural killer (NK) cell activity per NK cell decreases with age; decreases in NKCA have been associated with infection and death in the aged. The effects of exercise and training on natural killer cells, components of the innate immune system, have been studied extensively in young people. However, the published research on the elderly population is limited. Generally it has been found that training increases or does not change natural killer cell activity or counts in the elderly. The clinical relevance of these results is yet to be fully explored. In addition, the limitations of these studies on immune function have been many, and studies are often difficult to compare due to differences in their methods and presentation of results.

Immunoprevention and immunotherapy of cancer in ageing

Over the last few years there has been a growing interest in geriatric oncology, mainly because of the evidence that advanced age is the greatest risk factor for the development of cancer and that, since the elderly population is rapidly expanding, so too will the number of cancer patients. This forecast necessitates the development of new and more specific strategies for the prevention and cure of cancer in the elderly and as a result an ever-increasing need for oncologists, geriatricians and researchers to work closely together. The increased incidence of cancer in elderly people has been related to the age-associated changes occurring in the immune system, the so-called immunosenescence. This phenomenon is best characterised by a remodelling of the immune system, which appears early on and progresses throughout a person's life and mainly involves a decrease in cellular functions. This review aims to provide a rationale for the development of specific immunotherapeutic and immunopreventive regimens for the elderly. We also include a discussion on the influence that immunosenescence has on the growth of tumours and the effectiveness of immunogene therapy and cancer vaccination following a brief analysis of the age-related alterations of the cell populations involved in antitumour immunity.

Age-associated alterations in CXCL1 chemokine expression by murine B cells

Background

The CXCL1 chemokines, macrophage inflammatory protein-2 (MIP-2) and cytokine-induced neutrophil chemoattractant (KC), have been shown to play a role in a number of pathophysiological disease states including endotoxin-induced inflammation and bacterial meningitis. While the expression of these chemokines has been identified in a variety of cell types in the mouse, little is known about their expression with murine B-lymphocytes.

Results

Here, we demonstrate that highly purified murine splenic B cells are capable of expressing both MIP-2 and KC protein and mRNA upon activation with lipopolysaccharide (LPS) but not in response to anti-μ and anti-CD40 in combination with interleukin-4 (IL-4) stimulation. Moreover, these chemokines are expressed at higher levels in B cells derived from young (4 m) compared to old (24–29 m) mice. Upon fractionation into distinct B-cell subsets, we found that the expression of MIP-2 and KC by aged follicular (FO) B cells is significantly decreased when compared to the same cells from younger mice, while only MIP-2 production was found to be diminished in aged marginal zone (MZ) B cells. Interestingly, MIP-2 and KC production by newly formed (NF) B cells did not significantly differ with age. Moreover, the potential relevance of these findings is supported by the poor ability of LPS-activated aged B cells to specifically mediate CXCL1-dependent leukocyte recruitment when compared to younger B cells.

Conclusion

Overall, the decreased expression of CXCL1 chemokines by aged B cells in response to LPS may have potential implications on the secondary recruitment of leukocytes to sites of microbial infections and inflammation possibly contributing to the increased susceptibility of older subjects to pathogen challenge.

Aging Is Associated With Increased T-Cell Chemokine Expression in C57Bl/6 Mice

To better understand the contribution of the chemokine system in immune senescence, we determined the aging effect on CD4+ and CD8+ T-cell chemokine expression by microarray screening and ribonuclease protection assays. Compared with young C57BL/6 mice, freshly isolated CD4+ cells from aged mice express increased level of interferon-gamma-inducible protein 10 (IP-10), macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, regulated upon activation, normal T-cell expressed and secreted (RANTES), and lymphotactin (Ltn). T-cell receptor (TCR)/coreceptor stimulation up-regulates MIP-1alpha, MIP-1beta, and Ltn, and down-regulates IP-10 and RANTES expression in CD4+ T cells. A similar increase in chemokine expression was demonstrated in the CD8+ T cell. Enzyme-linked immunosorbent assays confirmed increased T-cell chemokine protein production in old CD4+ and CD8+ T cells. Finally, supernatant of cultured T cells from old animals caused an enhanced leukocyte chemotaxis response compared with that from young animals, suggesting that the age-related difference in T-cell chemokine expression has an important functional consequence.

T cell chemokine receptor expression in aging

Changes in chemokine receptor expression are important in determining T cell migration and the subsequent immune response. To better understand the contribution of the chemokine system in immune senescence we determined the effect of aging on CD4(+) T cell chemokine receptor function using microarray, RNase protection assays, Western blot, and in vitro chemokine transmigration assays. Freshly isolated CD4(+) cells from aged (20-22 mo) mice were found to express a higher level of CCR1, 2, 4, 5, 6, and 8 and CXCR2-5, and a lower level of CCR7 and 9 than those from young (3-4 mo) animals. Caloric restriction partially or completely restored the aging effects on CCR1, 7, and 8 and CXCR2, 4, and 5. The aging-associated differences in chemokine receptor expression cannot be adequately explained by the age-associated shift in the naive/memory or Th1/Th2 profile. CD4(+) cells from aged animals have increased chemotactic response to stromal cell-derived factor-1 and macrophage-inflammatory protein-1alpha, suggesting that the observed chemokine receptor changes have important functional consequences. We propose that the aging-associated changes in T cell chemokine receptor expression may contribute to the different clinical outcome in T cell chemokine receptor-dependent diseases in the elderly.

A diet supplemented with thiolic anti-oxidants improves leucocyte function in two strains of prematurely ageing mice

1. According to previous studies, Swiss mice of the same age showed striking interindividual differences in behaviour when exposed to a T-maze test, with a slow performance being linked to an impaired immune function, hyperemotional response to stress and a shorter life span compared with mice that quickly explore the maze. These facts led us to propose the slow mice as a model of prematurely ageing mice (PAM). 2. In the present study, we investigated whether this prematurely ageing model could be found in other strains of mice, such as BALB/c mice, by analysing several lymphocytes functions, such as adherence, chemotaxis, proliferative response to the mitogen concanavalin A (Con A), interleukin (IL)-2 release and natural killer (NK) activity. In addition, we tested the probable beneficial effects on these functions of dietary supplementation with thioproline (TP) plus N-acetylcysteine (NAC; 0.1% w/w of each anti-oxidant) in female Swiss and BALB/c mice. 3. Our model of premature ageing, previously reported in Swiss mice, has also been reproduced in the inbred BALB/c mouse strain, in which PAM showing an immunosenescence in several lymphocyte functions, such as lower chemotaxis, proliferative response to Con A, IL-2 release and NK activity, as well as higher adherence, were observed. A short-term (5 week) ingestion of TP + NAC by female Swiss and BALB/c mice improved leucocyte function, increasing chemotaxis, the proliferative response to Con A, IL-2 release and NK activity and decreasing the adherence of lymphocytes. These effects are greatest in cells from PAM of both strains. 4. In conclusion, our model of premature ageing has been reproduced in an inbred strain. In addition, the ingestion of a diet supplemented with two thiolic anti-oxidants, such as NAC and TP, has been shown to be beneficial to the immune response in PAM.

Acute generalized exanthematous pustulosis, a clue to neutrophil-mediated inflammatory processes orchestrated by T cells

PURPOSE OF REVIEW

Circumstantial evidence exists that certain neutrophilic inflammatory processes are regulated by T cells, but how this occurs is not well understood. The present review presents data on how T cells may directly orchestrate a neutrophilic inflammation by specific release of the neutrophil-attracting chemokine CXCL8 (formerly known as interleukin-8).

RECENT FINDINGS

Acute generalized exanthematous pustulosis (AGEP) is an uncommon cutaneous eruption that is most often provoked by drugs, by acute infections with enteroviruses, or by mercury. It is characterized by acute, extensive formation of nonfollicular sterile pustules on an erythematous background, fever and elevated numbers of blood neutrophils. Involvement of T cells in drug-induced AGEP was suggested by positive patch tests and lymphocyte transformation tests. Moreover, drug-specific CD4+ and CD8+ T cells could be isolated and propagated in vitro from patch test sites and blood from AGEP patients. Their main characteristic is a high level of CXCL8 production.

SUMMARY

T cells are involved even in some neutrophil-rich inflammatory responses, and they may orchestrate the immune reaction directly by high CXCL8 production or indirectly via interleukin-17 production, which induces CXCL8 production in various cell types. AGEP serves as a valuable model for characterizing T cells with a particular function--namely production of CXCL8--leading to neutrophilic inflammation. It is tempting to speculate that elucidation of this pathomechanism will help to improve our understanding of similar neutrophilic eruptions (e.g. pustular psoriasis) and may reveal new targets for pharmacotherapeutic interventions in such diseases.