Immunosenescence: a review

Endothelial dysfunction in neurodegenerative disease: Is endothelial inflammation an overlooked druggable target?

Neurological diseases with a neurodegenerative component have been associated with alterations in the cerebrovasculature. At the anatomical level, these are centred around changes in cerebral blood flow and vessel organisation. At the molecular level, there is extensive expression of cellular adhesion molecules and increased release of pro-inflammatory mediators. Together, these has been found to negatively impact blood-brain barrier integrity. Systemic inflammation has been found to accelerate and exacerbate endothelial dysfunction, neuroinflammation and degeneration. Here, we review the role of cerebrovasculature dysfunction in neurodegenerative disease and discuss the potential contribution of intermittent pro-inflammatory systemic disease in causing endothelial pathology, highlighting a possible mechanism that may allow broad-spectrum therapeutic targeting in the future.

Targeting brain-peripheral immune responses for secondary brain injury after ischemic and hemorrhagic stroke

The notion that the central nervous system is an immunologically immune-exempt organ has changed over the past two decades, with increasing evidence of strong links and interactions between the central nervous system and the peripheral immune system, both in the healthy state and after ischemic and hemorrhagic stroke. Although primary injury after stroke is certainly important, the limited therapeutic efficacy, poor neurological prognosis and high mortality have led researchers to realize that secondary injury and damage may also play important roles in influencing long-term neurological prognosis and mortality and that the neuroinflammatory process in secondary injury is one of the most important influences on disease progression. Here, we summarize the interactions of the central nervous system with the peripheral immune system after ischemic and hemorrhagic stroke, in particular, how the central nervous system activates and recruits peripheral immune components, and we review recent advances in corresponding therapeutic approaches and clinical studies, emphasizing the importance of the role of the peripheral immune system in ischemic and hemorrhagic stroke.

Intranasal delivery of LaAg vaccine improves immunity of aged mice against visceral Leishmaniasis

There are no approved vaccines yet for human visceral leishmaniasis (VL), the most severe form of the leishmaniasis clinical manifestations that is fatal in over 95 % of untreated cases. It is well-accepted that immunological changes during aging have deleterious impact on the efficacy of vaccines and response to infections. In this work, we compared the response of young and aged mice to intranasal vaccination with killed Leishmania amazonensis promastigote antigens (LaAg) that were then challenged with L. infantum infection, a species that causes visceral leishmaniasis. Intranasal vaccination with LaAg induced a similar reduction in parasitism and hepatosplenomegaly in both young and aged mice compared to their unvaccinated counterparts. Following infection, there was also a less prominent inflammatory profile particularly in the vaccinated aged group, with lower production of TNF-α and nitrite compared to the respective unvaccinated group. Interestingly, the LaAg intranasal vaccination promoted increased production of IFN-γ that was observed in both young- and aged vaccinated groups. Additionally, CD4+ and CD8+T cells from both vaccinated groups presented decreased expression of the inhibitory receptors PD-1 and KLRG1 compared to their unvaccinated controls. Interestingly, a strong positive correlation was observed between the expression of both inhibitory receptors PD-1 and KLRG1 and parasitism, which was more conspicuous in the unvaccinated-aged mice than in the others. Overall, this study helps define new strategies to improve vaccine effectiveness and provides a perspective for prophylactic alternatives against leishmaniasis.

Unraveling lipid and inflammation interplay in cancer, aging and infection for novel theranostic approaches

The synergistic relationships between Cancer, Aging, and Infection, here referred to as the CAIn Triangle, are significant determinants in numerous health maladies and mortality rates. The CAIn-related pathologies exhibit close correlations with each other and share two common underlying factors: persistent inflammation and anomalous lipid concentration profiles in the membranes of affected cells. This study provides a comprehensive evaluation of the most pertinent interconnections within the CAIn Triangle, in addition to examining the relationship between chronic inflammation and specific lipidic compositions in cellular membranes. To tackle the CAIn-associated diseases, a suite of complementary strategies aimed at diagnosis, prevention, and treatment is proffered. Our holistic approach is expected to augment the understanding of the fundamental mechanisms underlying these diseases and highlight the potential of shared features to facilitate the development of novel theranostic strategies.

Administration of krill oil extends lifespan of fish Nothobranchius guentheri via enhancement of antioxidant system and suppression of NF-κB pathway

Krill oil (KO) extracted from Antarctic krill (Euphausia superba) mainly comprises phospholipids and triglycerides. KO has been shown to prolong the median lifespan of the nematode Caenorhabditis elegans, but to shorten the lifespan of long-lived F1 mice; therefore, it remains controversial over the life-extending property of KO. In this study, we clearly demonstrated that dietary intake of KO extended both the mean and maximum lifespans of aged male Nothobranchius guentheri (p < 0.05), reduced the accumulation of lipofuscin (LF) (p < 0.05) in the gills and senescence-associated β-galactosidase (SA-β-Gal) (p < 0.05) in the caudal fins, and lowered the levels of protein oxidation (p < 0.05), lipid peroxidation (p < 0.01), and reactive oxygen species (ROS) (p < 0.01) in the muscles and livers, indicating that KO possesses rejuvenation and anti-aging activity. We also showed that KO enhanced the activities of antioxidant enzymes catalase (CAT) (p < 0.05), superoxide dismutase (SOD) (p < 0.05), and glutathione peroxidase (GPX) (p < 0.05) in aged male N. guentheri. In addition, KO administration effectively reversed histological lesions including inflammatory cell infiltration and structural collapse in the muscles and livers of aged N. guentheri and suppressed the nuclear factor kappa-B (NF-κB) signaling pathway (p < 0.05), a master regulator of inflammation. Altogether, our study indicates that KO has anti-aging and rejuvenation property. It also suggests that KO exerts its anti-aging and rejuvenation effects via enhancement of the antioxidant system and suppression of the NF-κB signaling pathway.

Vaccination of Immunocompromised Cats

Immunocompromise is a common condition in cats, especially due to widespread infections with immunosuppressive viruses, such as feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV), but also due to chronic non-infectious diseases, such as tumours, diabetes mellitus, and chronic kidney disease, as well as treatment with immunosuppressive drugs, such as glucocorticoids, cyclosporins, or tumour chemotherapy. In this review, the European Advisory Board on Cat Diseases (ABCD), a scientifically independent board of experts in feline medicine from eleven European countries, discusses the current knowledge and rationale for vaccination of immunocompromised cats. So far, there are few data available on vaccination of immunocompromised cats, and sometimes studies produce controversial results. Thus, this guideline summarizes the available scientific studies and fills in the gaps with expert opinion, where scientific studies are missing. Ultimately, this review aims to help veterinarians with their decision-making in how best to vaccinate immunocompromised cats.

Age-related immune alterations and cerebrovascular inflammation

Aging is associated with chronic systemic inflammation, which contributes to the development of many age-related diseases, including vascular disease. The world's population is aging, leading to an increasing prevalence of both stroke and vascular dementia. The inflammatory response to ischemic stroke is critical to both stroke pathophysiology and recovery. Age is a predictor of poor outcomes after stroke. The immune response to stroke is altered in aged individuals, which contributes to the disparate outcomes between young and aged patients. In this review, we describe the current knowledge of the effects of aging on the immune system and the cerebral vasculature and how these changes alter the immune response to stroke and vascular dementia in animal and human studies. Potential implications of these age-related immune alterations on chronic inflammation in vascular disease outcome are highlighted.

The Impact of Acute and Chronic Exercise on Immunoglobulins and Cytokines in Elderly: Insights From a Critical Review of the Literature

The level of immunoglobulins and cytokines changes with an ageing immune system. This review summarizes findings from studies that have examined the impact of acute and chronic exercise on immunoglobulins and cytokines in the elderly. Our literature analysis revealed that acute endurance exercise resulted in increased secretory salivary immunoglobulin A (SIgA), while acute bouts of muscle strengthening exercise (i.e., isokinetic, eccentric, knee extensor exercise) increased plasma/muscle interleukin (IL)-6, IL-8 and tumor necrosis factor alpha (TNF-α) levels. Chronic exercise in the form of short-term endurance training (i.e., 12-16 weeks) and long-term combined endurance and resistance training (i.e., 6-12 months) induced increases in salivary SIgA concentration. We additionally identified that short-term endurance training at moderate intensities and the combination of endurance, strength, balance, and flexibility training increase plasma IL-10 and reduce plasma IL-6 and TNF-α in healthy elderly adults and male patients with chronic heart failure. Strength training for 6-12 weeks did not alter plasma IL-1β, IL-2, IL-6 and TNF-α concentration in healthy elderly adults and patients with chronic-degenerative diseases, while 12 weeks of resistance training decreased muscle TNF-α mRNA in frail elderly individuals. Short-term (i.e., 10-24 weeks) moderate- to high-intensity strength training reduced LPS–IL-6, LPS, IL-1β, LPS–TNF-α and circulating concentrations of TNF-α and increased IL-10 in healthy elderly women and older people with cognitive impairment, respectively. In conclusion, it appears that acute bouts of endurance exercise and short-term chronic exercise training exercise are appropriate methods to enhance mucosal immune function, reduce systemic markers of inflammation, and promote anti-inflammatory processes in elderly individuals.

Coronavirus disease in children: A multicentre study from the Kingdom of Saudi Arabia

BACKGROUND

The COVID-19 global pandemic caused by severe acute respiratory syndrome coronavirus 2 infection, warranted attention for whether it has unique manifestations in children. Children tend to develop less severe disease with a small percentage present with clinical manifestations of paediatric multisystem inflammatory syndrome and have poor prognosis. We studied the characteristics of COVID-19 in children requiring hospitalisation in the Kingdom of Saudi Arabia and assessed the clinical presentation and the risk factors for mortality, morbidity, and paediatric intensive care (PICU) admission.

METHODS

We conducted a retrospective analysis of COVID-19 patients under 15 years hospitalised at three tertiary academic hospitals between 1 March and 30 June 2020.

RESULTS

Eighty-eight children were enrolled (>20% were infants). Seven (8%) were in critical condition and required PICU admission, and 4 (4.5%) died of which 3 met the full diagnostic criteria of multi-system inflammatory syndrome and had a high Paediatric Risk of Mortality (PRISM) score at the time of admission. The initial polymerase chain reaction (PCR) test result was positive for COVID-19 in most patients (97.7%), and the remaining two patients had positive result in the repeated confirmatory test. In a subset of patients (20 subjects), repeated PCR testing was performed until conversion to negative result, and the average duration for conversion was 8 (95% CI: 5.2-10.5) days Children requiring PICU admission presented with signs of respiratory distress, dehydration, and heart failure. Most had fever (71.4%) and tonsillitis; 61.4% were discharged within 7 days of hospitalisation. Risk factors for mortality included skin rash, hypotension, hypoxia, signs of heart failure, chest radiograph suggestive of acute respiratory distress syndrome, anaemia, leucocytosis, hypernatraemia, abnormal liver enzymes, and high troponin I, and risk factors for prolonged hospitalisation (>7 days) included the presence of comorbidities, leucopaenia, hyponatraemia, and elevated C-reactive protein.

CONCLUSIONS

The majority of hospitalised children had a brief febrile illness and made a full recovery, but a minority had severe disease.

Nutraceuticals-Based Immunotherapeutic Concepts and Opportunities for the Mitigation of Cellular Senescence and Aging: A Narrative Review

The role of increased tissue senescent cell (SC) burden in driving the process of ageing and associated disorders is rapidly gaining attention. Amongst various plausible factors, impairment in immune functions is emerging as a critical regulator of known age-associated accumulation of SC. Immune cells dysfunctions with age are multi-faceted and are uniquely attributed to the independent processes of immunosenescence and cellular senescence which may collectively impair immune system mediated clearance of SC. Moreover, being functionally and phenotypically heterogenic, immune cells are also liable to be affected by senescence microenvironment in other tissues. Therefore, strategies aimed at improving immunosenescence and cellular senescence in immune cells can have pleiotropic effects on ageing physiology including the accumulation of SC. In this regard, nutraceutical's immunomodulatory attributes are well documented which may have implications in developing nutrition-oriented immunotherapeutic approaches against SC. In particular, the three diverse sources of bioactive ingredients, viz., phytochemicals, probiotic bacteria and omega-3-fatty acids have shown promising anti-immunosenescence and anti-cellular senescence potential in immune cells influencing aging and immunity in ways beyond modest stimulation of immune responses. The present narrative review describes the preventive and therapeutic attributes of phytochemicals such as polyphenols, probiotic microbes and omega-3-fatty acids in influencing the emerging nexus of immunosenescence, cellular senescence and SC during aging. Outstanding questions and nutraceuticals-based pro-longevity and niche research areas have been deliberated. Further research using integrative approaches is recommended for developing nutrition-based holistic immunotherapeutic strategies for 'healthy ageing'.

The untwining of immunosenescence and aging

From a holistic point of view, aging results from the cumulative erosion of the various systems. Among these, the immune system is interconnected to the rest as immune cells are present in all organs and recirculate through bloodstream. Immunosenescence is the term used to define the remodelling of immune changes during aging. Because immune cells-and particularly lymphocytes-can further differentiate after their maturation in response to pathogen recognition, it is therefore unclear when senescence is induced in these cells. Additionally, it is also unclear which signals triggers senescence in immune cells (i) aging per se, (ii) specific response to pathogens, (iii) underlying conditions, or (iv) inflammaging. In this review, we will cover the current knowledge and concepts linked to immunosenescence and we focus this review on lymphocytes and T cells, which represent the typical model for replicative senescence. With the evidence presented, we propose to disentangle the senescence of immune cells from chronological aging.

COVID-19 in children and adolescents in Europe: a multinational, multicentre cohort study

BACKGROUND

To date, few data on paediatric COVID-19 have been published, and most reports originate from China. This study aimed to capture key data on children and adolescents with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection across Europe to inform physicians and health-care service planning during the ongoing pandemic.

METHODS

This multicentre cohort study involved 82 participating health-care institutions across 25 European countries, using a well established research network-the Paediatric Tuberculosis Network European Trials Group (ptbnet)-that mainly comprises paediatric infectious diseases specialists and paediatric pulmonologists. We included all individuals aged 18 years or younger with confirmed SARS-CoV-2 infection, detected at any anatomical site by RT-PCR, between April 1 and April 24, 2020, during the initial peak of the European COVID-19 pandemic. We explored factors associated with need for intensive care unit (ICU) admission and initiation of drug treatment for COVID-19 using univariable analysis, and applied multivariable logistic regression with backwards stepwise analysis to further explore those factors significantly associated with ICU admission.

FINDINGS

582 individuals with PCR-confirmed SARS-CoV-2 infection were included, with a median age of 5·0 years (IQR 0·5-12·0) and a sex ratio of 1·15 males per female. 145 (25%) had pre-existing medical conditions. 363 (62%) individuals were admitted to hospital. 48 (8%) individuals required ICU admission, 25 (4%) mechanical ventilation (median duration 7 days, IQR 2-11, range 1-34), 19 (3%) inotropic support, and one (<1%) extracorporeal membrane oxygenation. Significant risk factors for requiring ICU admission in multivariable analyses were being younger than 1 month (odds ratio 5·06, 95% CI 1·72-14·87; p=0·0035), male sex (2·12, 1·06-4·21; p=0·033), pre-existing medical conditions (3·27, 1·67-6·42; p=0·0015), and presence of lower respiratory tract infection signs or symptoms at presentation (10·46, 5·16-21·23; p<0·0001). The most frequently used drug with antiviral activity was hydroxychloroquine (40 [7%] patients), followed by remdesivir (17 [3%] patients), lopinavir-ritonavir (six [1%] patients), and oseltamivir (three [1%] patients). Immunomodulatory medication used included corticosteroids (22 [4%] patients), intravenous immunoglobulin (seven [1%] patients), tocilizumab (four [1%] patients), anakinra (three [1%] patients), and siltuximab (one [<1%] patient). Four children died (case-fatality rate 0·69%, 95% CI 0·20-1·82); at study end, the remaining 578 were alive and only 25 (4%) were still symptomatic or requiring respiratory support.

INTERPRETATION

COVID-19 is generally a mild disease in children, including infants. However, a small proportion develop severe disease requiring ICU admission and prolonged ventilation, although fatal outcome is overall rare. The data also reflect the current uncertainties regarding specific treatment options, highlighting that additional data on antiviral and immunomodulatory drugs are urgently needed.

FUNDING

ptbnet is supported by Deutsche Gesellschaft für Internationale Zusammenarbeit.

Age-Associated B Cells

The age-associated B cell subset has been the focus of increasing interest over the last decade. These cells have a unique cell surface phenotype and transcriptional signature, and they rely on TLR7 or TLR9 signals in the context of Th1 cytokines for their formation and activation. Most are antigen-experienced memory B cells that arise during responses to microbial infections and are key to pathogen clearance and control. Their increasing prevalence with age contributes to several well-established features of immunosenescence, including reduced B cell genesis and damped immune responses. In addition, they are elevated in autoimmune and autoinflammatory diseases, and in these settings they are enriched for characteristic autoantibody specificities. Together, these features identify age-associated B cells as a subset with pivotal roles in immunological health, disease, and aging. Accordingly, a detailed understanding of their origins, functions, and physiology should make them tractable translational targets in each of these settings.

Parasite burden in a short-lived chameleon, Furcifer labordi

Life history theory predicts that species with shorter lifespan should show higher investments into growth and reproduction at the expense of immune defenses. Labord's chameleon (Furcifer labordi) is the tetrapod with the shortest known life span. To investigate to which extent immunosenescence influences the die-off of these chameleons when they are only about 6 months old, we examined the gastrointestinal-, blood- and ectoparasite burden in F. labordi in Kirindy Forest (western Madagascar) and compared them with sympatric and longer living F. cf. nicosiai. Moreover, we included data from wild F. labordi that were singly housed under ambient conditions with daily food and water supply. Gastrointestinal parasite prevalence of wild F. labordi increased dramatically during the last 3 months of their lives, which include the reproductive period. Furcifer cf. nicosiai was found to have a belated increase in gastrointestinal parasites compared to F. labordi. In F. cf. nicosiai higher prevalence of blood parasites were found, which probably result from the longer exposure to the arthropod intermediate host. Both species showed infestations with ectoparasites, which peaked in the rainy season but disappeared towards the dry season. Male F. labordi showed a significantly higher prevalence of gastrointestinal - and ectoparasites and higher intensities of coccidians and ectoparasites than females. Males of F. cf. nicosiai exhibited higher prevalence of blood- and ectoparasites, as well as higher intensities in ectoparasites. Caged individuals of both sexes showed delayed senescence, reduced parasite burden and lived longer than their wild conspecifics. Overall, the increase in the prevalence in gastrointestinal - and blood parasites towards the disappearance of the wild population of F. labordi indicates that this species invests comparatively less energy in efficient immune system function, supporting the prediction of life history theory.

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Wild F. labordi show an increase of parasites towards their die-off

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Male F. labordi exhibit higher parasite burden than longer living females

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Longer living F. cf. nicosiai show belated increase in parasite burden

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Captive F. labordi were less infected and longer living than wild specimens

Seasonal influenza immunisation: Strategies for older adults

Adults over the age of 60-65 years suffer disproportionally from seasonal influenza, experiencing high rates of complications, exacerbation of underlying medical comorbidities, and excess mortality. Thus, older adults are an important priority for influenza immunisation campaigns. Unfortunately, older adults generally display lower immune responses to standard influenza vaccines because of immunosenescence, with resulting suboptimal vaccine effectiveness. Thus, the development of improved vaccines that heighten immune responses and improve effectiveness is an important medical need. To this end, enhanced influenza vaccines specifically targeting this age group have been developed, which seek to overcome the inherent limitations in the immune responses of older adults. Both the licensed high-dose trivalent influenza vaccine (hdTIV) containing fourfold higher antigen contents than standard vaccine, and the MF59^® -adjuvanted trivalent influenza vaccine (aTIV) have been proven to be safe and well-tolerated while enhancing the immune response. Healthcare providers for populations of older adults should be advised to routinely use these enhanced influenza vaccines in seasonal immunisation campaigns to provide improved immunity against influenza and its consequences in this particularly susceptible age group.

Premature Immunosenescence Impairs Immune Surveillance Allowing the Endometriotic Stem Cell to Migrate: The Cytokine Profile as a Common Denominator

While endometriosis, one of the most common reasons for infertility, remains a multifactorial condition and its exact cause highly speculative, there are data pointing to novel pathways of disease initiation which involve a stem cell and its ability to migrate and implant after it differentiates into an endometriotic stem cell. Thus, the mechanisms conferring immune surveillance, which would also normally expel the mesenchymal endometriotic cell, impairing its migration and implantation, appear to be negatively influenced by a state of endometriotic premature immunosenescence. This interplay between the two immunological mechanisms and endometriosis is influenced by a number of common factors having an active role in the host's protection process that inhibits harmful diseases and maintains cellular homeostasis. It appears more than coincidental that production/inhibition of IFN-γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-15, IL-18, TNF-α, VEGF, ICAM-1, and the number of Tolllike receptors is the same in immunosenescent states and in conditions with reduced immune surveillance, while the same variations are recorded in endometriotic patients. It is probable that these are common to all process signals, guide the endometriotic stem cell and dictate its fate according to the stochastic, transdifferentiation (plasticity) or deterministic model to become capable of migration and tissue invasion. It is currently unknown whether the pathway taken by the hemopoietic stem cell to become endometriotic represents a normal or aberrant route of development. This prompts research into its isolation and in vitro study of its behavior in order to reveal its potential function and role in endometriosis. (Journal of Endometriosis 2010; 2: 7–18)

Immunosenescence in persons with spinal cord injury in relation to urinary tract infections -a cross-sectional study

BACKGROUND

Individuals with a spinal cord injury (SCI), despite specialized rehabilitation and good health care, have a reduced life expectancy. Infectious diseases, such as pneumonias, infected pressure sores and urinary tract infections (UTI) have been identified as the leading causes of mortality. We hypothesise that a premature onset of immune frailty occurs in SCI, possibly caused also by recurrent urinary tract infections.A cross sectional study was performed comparing blood and urine samples between able bodied controls (n = 84) and persons with spinal cord injury (n = 85). The results were grouped according to age (below and above 60 years). Assessed were the abundancies of immune cells, the concentration of soluble biomarkers, the in vitro functioning of lymphocytes as well as phenotypic exhaustion of T-cells in blood and urine. Further, the leucocyte telomere length and the cytomegalovirus (CMV) serological status were compared between the groups.

RESULTS

We observed in people with SCI lower proportions of naïve T-cells, more memory T-cells, reduced T-cell proliferation and higher CMV prevalence compared to age-matched controls. SCI participants older than 60 years had a higher prevalence of UTI compared with SCI persons younger than 60 years.

CONCLUSION

The immune system of people with SCI shows traits of an increased immunological strain and a premature onset of immune frailty. The role of UTI in the onset of immune frailty remains to be elucidated as we did not see significantly higher abundancies of circulating UTI-bacteria specific T-cell clones in persons with SCI. We assume that any impact of UTI on the immune system might be compartmentalized and locally restricted to the urinary tract.

Immune monitoring as prerequisite for transplantation tolerance trials

Ever since its first application in clinical medicine, scientists have been urged to induce tolerance towards foreign allogeneic transplants and thus avoid rejection by the recipient's immune system. This would circumvent chronic use of immunosuppressive drugs (IS) and thus avoid development of IS-induced side effects, which are contributing to the still unsatisfactory long-term graft and patient survival after solid organ transplantation. Although manifold strategies of tolerance induction have been described in preclinical models, only three therapeutic approaches have been utilized successfully in a still small number of patients. These approaches are based on (i) IS withdrawal in spontaneous operational tolerant (SOT) patients, (ii) induction of a mixed chimerism and (iii) adoptive transfer of regulatory cells. Results of clinical trials utilizing these approaches show that tolerance induction does not work in all patients. Thus, there is a need for reliable biomarkers, which can be used for patient selection and post-therapeutic immune monitoring of safety, success and failure. In this review, we summarize recent achievements in the identification and validation of such immunological assays and biomarkers, focusing mainly on kidney and liver transplantation. From the published findings so far, it has become clear that indicative biomarkers may vary between different therapeutic approaches applied and organs transplanted. Also, patient numbers studied so far are very small. This is the main reason why nearly all described parameters lack validation and reproducibility testing in large clinical trials, and are therefore not yet suitable for clinical practice.

Does baseline innate immunity change with age? A multi-year study in great tits

Throughout their life animals progressively accumulate mostly detrimental changes in cells, tissues and their functions, causing a decrease in individual performance and ultimately an increased risk of death. The latter may be amplified if it also leads to a deterioration of the immune system which forms the most important protection against the permanent threat of pathogens and infectious diseases. Here, we investigated how four baseline innate immune parameters (natural antibodies, complement activity, concentrations of haptoglobin and concentrations of nitric oxide) changed with age in free-living great tits (Parus major). We applied both cross-sectional and longitudinal approaches as birds were sampled for up to three years of their lives. Three out of the four selected innate immune parameters were affected by age. However, the shape of the response curves differed strongly among the innate immune parameters. Natural antibody levels increased during early life until mid-age to decrease thereafter when birds aged. Complement activity was highest in young birds, while levels slightly decreased with increasing age. Haptoglobin levels on the other hand, showed a linear, but highly variable increase with age, while nitric oxide concentrations were unaffected by age. The observed differences among the four studied innate immune traits not only indicate the importance of considering several immune traits at the same time, but also highlight the complexity of innate immunity. Unraveling the functional significance of the observed changes in innate immunity is thus a challenging next step.

Influence of age, sex and HCMV-serostatus on blood lymphocyte subpopulations in healthy adults

Using a standardized immunophenotyping procedure we studied thirty-eight distinct subpopulations of T, B and NK lymphocytes in 253 healthy blood donors aged from 19 to 67. We analysed the influence of age, sex and HCMV seropositivity on each lymphocyte subpopulations and established reference ranges. We observed that aging influences the largest number of lymphocyte subpopulations with a slow increase of CD8+ EMRA T lymphocytes and of the numbers of circulating Tregs. The proportion of HLA-DR+ cells among Tregs increased with age and was correlated to the proportion of HLA-DR+ cells among effector T CD4+ lymphocytes. Sex had a major impact on absolute counts of CD4+ T cells which were higher in females. HCMV-seropositivity was associated with higher frequencies of CD8+ EMRA memory T lymphocytes while a high frequency of terminally differentiated EMRA CD4+ T cells was observed in 80% of HCMV-positive individuals and in none of the HCMV seronegative individuals.

Lifewide profile of cytokine production by innate and adaptive immune cells from Brazilian individuals

Background

Immunosenescence is associated with several changes in adaptive and innate immune cells. Altered cytokine production is among the most prominent of these changes. The impact of age-related alterations on cytokine global profiles produced by distinct populations of leukocytes from healthy Brazilian individuals was studied. We analysed frequencies of cytokine-producing lymphocytes and innate immune cells from individuals at several ages spanning a lifetime period (0–85 years).

Results

Healthy adult individuals presented a balanced profile suggestive of a mature immune system with equal contributions of both innate and adaptive immunity and of both categories of cytokines (inflammatory and regulatory). In healthy newborns and elderly, innate immune cells, especially neutrophils and NK-cells, contributed the most to a balanced profile of cytokines.

Conclusions

Our results support the hypothesis that ageing is not associated with a progressive pro-inflammatory cytokine production by all leukocytes but rather with distinct fluctuations in the frequency of cytokine-producing cells throughout life.

Electronic supplementary material

The online version of this article (doi:10.1186/s12979-017-0084-5) contains supplementary material, which is available to authorized users.

Host sex and age influence endoparasite burdens in the gray mouse lemur

Introduction

Immunosenescence (deteriorating immune function at old age) affects humans and laboratory animals, but little is known about immunosenescence in natural populations despite its potential importance for population and disease dynamics and individual fitness. Although life histories and immune system profiles often differ between the sexes, sex-specific effects of aging on health are rarely studied in the wild. Life history theory predicts that due to their shorter lifespan and higher investment into reproduction at the expense of immune defences, males might experience accelerated immunosenescence. We tested this hypothesis by examining sex-specific age trajectories of endoparasite burden (helminth prevalence and morphotype richness measured via fecal egg counts), an indicator of overall health, in wild gray mouse lemurs (Microcebus murinus). To account for potential interactions between seasonality and host sex or age we examined the predictors of parasite burdens separately for the dry and rainy season.

Results

Contrary to the prediction of immunosenescence, parasite prevalence and morphotype richness decreased at old age in the dry season, indicating acquired immunity by older animals. This pattern was primarily caused by within-individual decline in parasite loads rather than the earlier mortality of highly parasitized individuals. With the exception of an increasing cestode prevalence in males from yearlings to prime age in the rainy season, no evidence was found of male-biased ageing in parasite resistance. Besides this sex*age interaction, host age was uncorrelated with rainy season parasite loads. Seasonality did not affect the overall parasite loads but seasonal patterns were found in the predictors of parasite prevalence and morphotype richness.

Conclusions

These results provide rare information about the age-related patterns of health in a wild vertebrate population and suggest improvement rather than senescence in the ability to resist helminth infections at old age. Overall, males appear not to suffer from earlier immunosenescence relative to females. This may partially reflect the earlier mortality of males, which can render senescence difficult to detect. While helminth infections are not strongly associated with survival in wild gray mouse lemurs, parasite load may, however, reflect overall good phenotypic quality of long-lived individuals, and is a potential correlate of fitness.

Electronic supplementary material

The online version of this article (doi:10.1186/s12983-015-0118-9) contains supplementary material, which is available to authorized users.

Association of Polymorphisms in Innate Immunity Genes TLR9 and DEFB1 with Human Longevity

The distribution of polymorphic variants of innate immunity genes TLR9 (+2848G>A) and DEFB1(-20G>A; -44C>G; -52G>A) was evaluated in long-living individuals. No significant differences were found in the distribution of genotypes and alleles of the TLR9 gene. The following features were revealed: increase in the frequency of AA and GG genotypes and decrease in the frequency of the AG genotype of the DEFB1(-20G>A) gene; increase in the frequency of the CC genotype and C allele and decrease in the frequency of CG and GG genotypes and G allele of the DEFB1(44C>G) gene; and increase in the frequency of AA and AG genotypes and A allele and decrease in the frequency of the GG genotypes and G allele of the DEFB1(-52G>A) gene. Genotypes and alleles of the DEFB1 gene found in long-living individuals can be considered as the factors that increase the probability of longevity and favorable course of age-related diseases.

Changes in adipose tissue macrophages and T cells during aging

Adipose tissue historically was believed to be an inert tissue, functioning primarily in the storage of energy and thermal homeostasis. However, recent discoveries point toward a critical role for adipocytes in endocrine function as well as immune regulation. Excess body fat, accumulated through aging and/or a calorie-rich diet, is associated with many chronic metabolic and inflammatory diseases. Within the stromal vascular fraction of adipose tissue, macrophages and T cells accumulate with increasing tissue mass, secreting pro- or anti-inflammatory cytokines. In this review we discuss the current understanding of immune cell function in both diet-induced and age-related obesity. In both models of obesity, the classically activated, pro-inflammatory (M1) subtype takes precedence over the alternatively activated, anti-inflammatory (M2) macrophages, causing tissue necrosis and releasing pro-inflammatory cytokines like interleukin-6. Other distinct adipose tissue macrophage subtypes have been identified by surface marker expression and their functions characterized. Adipose tissue T cell recruitment to adipose tissue is also different between aging- and diet-induced obesity. Under both conditions, T cells exhibit restricted T-cell receptor diversity and produce higher levels of pro-inflammatory signals like interferon-γ and granzyme B relative to young or healthy mice. However, numbers of regulatory T cells are dramatically different between the 2 models of obesity. Taken together, these findings suggest models of age- and diet-induced obesity may be more distinct than previously thought, with many questions yet to be resolved in this multidimensional disease.

Marital distress prospectively predicts poorer cellular immune function

OBJECTIVE

Distressed marriages enhance risk for a variety of health problems. Immune dysregulation is one potential mechanism; cross-sectional studies have demonstrated that marital distress is linked to maladaptive immune alterations. The current study filled an important gap in the literature by examining the ability of marital distress to prospectively predict immune alterations over a two-year period.

METHOD

Participants were 90 couples (N=180 individuals; Mage=25.67) married less than a year at the time of their first study visit. Both members of a couple completed a baseline assessment of marital quality and provided blood samples at baseline and two years later. 63 couples (N=123 individuals) completed the follow-up assessment.

RESULTS

Spouses in more distressed marriages had larger declines in cellular immune function over time than spouses in less distressed marriages. Furthermore, the results were highly consistent across two different indices, proliferative responses to two mitogens, concanavalin A (Con A) and phytohemagglutinin (PHA).

CONCLUSIONS

Marital distress has a variety of negative health consequences. The current study provided important evidence that marital distress has longer-term immune consequences. Accordingly, the present results provide a glimpse into the pathways through which marital distress may impact health over time.

Proinflammatory profile of in vitro monocytes in the ageing is affected by lymphocytes presence

Background

Aging is associated with complex and constant remodeling of the immune function, resulting in an increasing susceptibility to infection and others diseases. The infections caused by Gram-negative microorganisms, present in nursing homes and hospitals, constitute one of the most common infections in the elderly, and are mainly combated by innate immune cells. Although the functions of innate immunity seem more preserved during aging than of adaptive immune mechanisms, two systems operate in an integrated way in the body, so that injury in one part of the immune system inevitably affects the other as they are part of a defensive network. The aim of this study was to investigate the in vitro production of proinflammatory (TNF-α, IL-6, IL-1β, CXCL-8 and MCP-1) and anti-inflammatory (TGF-β and IL-10) cytokines by monocytes, stimulated or not (basal) with lipopolysaccharide, from healthy young and elderly subjects. By means of PBMCs, we also studied if cytokine profile is altered in these different patient groups, in the presence of lymphocytes, under the same experimental conditions.

Results

The monocytes from elderly presented higher basal production of TNF-α, MCP-1 and lower of TGF-β than young monocytes. PBMC showed similar cytokines production, irrespective age or stimulation presence. In the presence of lymphocytes, the spontaneous production of IL-10 was higher and of TGF-β was lower than monocytes, regardless of age. After LPS-stimulation, the presence of lymphocytes resulted in increased IL-6, IL-1β, MCP-1 and IL-10 and decreased CXCL-8 and TGF-β in comparison to pure culture of monocytes from young patients. With age, the same differences were observed, except for CXCL-8 and TGF-β which production was the same between monocytes and PBMC stimulated with LPS.

Conclusion

These findings reinforce the systemic state of inflamm-aging frequently reported in elderly and considered a factor of susceptibility to numerous diseases. Still, the cytokine production from just monocytes of the elderly showed alterations, while in the lymphocyte presence not, suggesting an immunomodulator role of lymphocytes on monocytes. In addition, the differences between the production patterns by LPS-stimulated PBMC between young and elderly volunteers can be related with an imbalance in response against Gram-negative bacteria in throughout life.

The influence of age, smoking, antiretroviral therapy, and esophagitis on the local immunity of the esophagus in patients with AIDS

Studies have shown immunological and morphological alterations in the esophagus during the course of AIDS. Esophageal postmortem samples of 22 men with AIDS autopsied in a teaching hospital between 1982 and 2009 were collected. We carried out revision of the autopsy reports and medical records, morphometric analysis (Image J and KS-300 Kontron-Zeiss), and immunohistochemical (anti-S100, anti-IgA, anti-IgG, and anti-IgM) analysis of the esophagus. In accordance with most of the parameters evaluated, age and the smoking habit harmed the esophageal local immunity, whereas the use of antiretroviral therapy improved the immune characteristics of this organ. Patients with esophagitis also presented immunological fragility of the esophagus. This leads to the conclusion that alterations in the esophageal epithelium of patients with AIDS are not only caused by direct action of HIV but also the clinical and behavioral characteristics of the patient.

Pathological examination of lung tissues in influenza a virus-infected mice

This study examined pathological changes in the lung tissues of young and aged mice infected with influenza virus. Young mice inoculated with influenza virus showed body weight loss at 4 days post-infection (dpi), meanwhile body weight decrease started from 9 dpi in the aged mice. We histopathologically examined the lungs of these mice. Immunohistochemical examination revealed that viral antigen-positive bronchiolar and alveolar epithelial cell numbers at 3 dpi were significantly higher in young mice than in the aged ones. Further, viral antigen-positive cells were observed at 9 dpi in the aged mice, but not in the young ones. Diffuse and severe bronchointerstitial pneumonia characterized by the accumulation of polymorphonuclear leukocytes (PMNs) was observed in young mice at 6 dpi. Histopathological changes in the aged mice were milder than those in the young mice. Moreover, T cell and macrophage accumulation in the lungs was significantly higher in the young mice than in the aged mice at 9 dpi. These results suggest that there may be a correlation between the relatively low level of infiltration of PMNs, macrophages, and T lymphocytes and the delayed body weight loss and longer lasting infections observed in the lungs of the aged mice. These findings provide detailed insights into the age-specific course of infection in young and aged populations with associated differences in lung pathology.

Influence of gender on cardiac and encephalic inflammation in the elderly with cysticercosis: a case control study

Background. The present study explores the influence of the host's age and gender upon the inflammatory infiltrate. We aimed to quantify the inflammatory infiltrate caused by cysticercosis, which is related to aging, in the heart and in the encephalon. Methods. 75 autopsy protocols with cysticercosis diagnosis from department of pathology at a university hospital from 1970 to 2008 were reviewed. Two groups were formed: elderly with cysticercosis and nonelderly with cysticercosis. We used KS-300 (Kontron-Zeiss) software for morphometric analysis of the inflammation. Results. The elderly had an average of 3.1 ± 2.5 cysticerci, whereas the non-elderly had 2.7 ± 3.8 parasites. The non-elderly group with cysticercosis had significantly more inflammation, both cardiac and encephalic, than the elderly group. The elderly females with cysticercosis had more cardiac and encephalic inflammation. Conclusions. In this study, we showed that the non-elderly had significantly more cardiac and encephalic inflammation than the elderly, and that such inflammatory infiltrate decreases with age and depends upon the evolutionary stage of the cysticercus. Furthermore, there are differences concerning gender in the intensity of the inflammatory response due to cysticerci in the heart and brain parenchyma during senescence. Even during this period, women continue to have a more intense response to the parasitosis.

Probiotics in the gastrointestinal diseases of the elderly

Changes of the gut microflora in elderly appear to involve a reduction in numbers of healthy bacteria (lactobacilli and bifidobacteria) and an increase in numbers of potentially pathogenic species. These changes are generally described as gastrointestinal disorders and infections. This review analyses benefits of probiotics in old people, with particular interesting for the latest researches relevant to elderly people, e.g. trials examining enteric infections, antibiotic-associated diarrhea and Clostridium difficile associated diarrhea, functional bowel problems (constipation and irritable bowel syndrome), inflammatory bowel diseases, stimulation of the immune system and prevention of cancer. A growing number of researches indicates that some probiotic strains may help to maintain the health in old people, suggesting both health and cost-saving benefits in offering fermented dairy products. These benefits include: establishment of balanced intestinal microflora; improving colonization resistance and or prevention of diarrhea; reduction of fecal enzymes; reduction of serum cholesterol; reduction of potential mutagenes; reduction of lactose intolerance; synthesis of vitamins; predigestion of proteins.

Effect of Thuja occidentalis and its polysaccharide on cell-mediated immune responses and cytokine levels of metastatic tumor-bearing animals

CONTEXT

Tumor microenvironment induces an active immune tolerance and escapes immune surveillance. In order to achieve an effective antitumor immune response, appropriately activated immune cells should maintain their antitumor activity to overcome the immune suppressive tumor microenvironment.

OBJECTIVES

This study focuses on the effect of Thuja occidentalis L. (Cupressaceae) extract and its polysaccharide (TPS) on cell-mediated immune response (CMI) in metastasis bearing mice.

MATERIALS AND METHODS

Metastasis was induced by injecting B16F-10 melanoma cells in mice through the tail vein and effector mechanisms of CMI was studied by analyzing cytotoxic T-lymphocyte (CTL) activity, natural killer (NK) cell activity, antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent complement-mediated cytotoxicity (ACC). The effect of T. occidentalis and TPS on pro-inflammatory cytokines and tissue inhibitor matrix metalloproteinases (TIMP) levels were also analyzed.

RESULTS AND DISCUSSION

Administration of T. occidentalis and TPS enhanced the NK cell activity, ADCC and ACC much earlier than the control tumor-bearing animals. T. occidentalis and TPS were also found to decrease the elevated level of pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, GM-CSF and tumor necrosis factor (TNF)-α in the serum of metastatic tumor-bearing animals. The level of antitumor factors such as IL-2 and TIMP was elevated by the treatment with T. occidentalis and TPS in the serum, which was lowered in the untreated tumor-bearing animals.

CONCLUSION

This study clearly suggests that T. occidentalis and TPS effectively stimulate cell-mediated immune system and decrease pro-inflammatory cytokines, thereby inhibiting metastasis of tumor cells.

Immunogenetics of ageing

The ageing process is very complex. Human longevity is a multifactorial trait which is determined by genetic and environmental factors. Twin and family studies imply that up to 25% of human lifespan is heritable. The longevity gene candidates have generally fallen into the following categories: inflammatory and immune-related factors, stress response elements, mediators of glucose and lipid metabolism, components of DNA repair and cellular proliferation and mitochondrial DNA haplogroups. Because of the central role of HLA molecules in the development of protective immunity and the extraordinary degree of polymorphism of HLA genes, many studies have addressed the possible impact of these genes on human longevity. Most of the data available so far demonstrated a possible role of HLA class II specificities in human longevity but definitive evidence has remained elusive. Although the data are limited and controversial, it has been hypothesized that longevity could be associated with cytokine gene polymorphisms correlating with different levels of cytokine production, thereby modulating immune responses in health and disease. Because of the essential role of cytokines in immune responses, the regulation of cytokine gene expression and their polymorphic nature, the genetic variations of these loci with functional significance could be appropriate immunogenetic candidate markers implicated in the mechanism of successful ageing and longevity. In addition, several other genes such as Toll-like receptor genes, Cycloxygenases (COX)/Lipoxygenases (LOX), CCR5, NK receptor genes and MBL2 have been assessed as a possible biomarkers associated with ageing. This review will summarize the data on the role of these immune genes in human longevity.

Non-melanoma skin cancers in elderly patients

Non-melanoma skin cancers are a common reality worldwide. The principal cause that determines the occurrence of these diseases is the exposition of the sun, which principally causes an alteration in the immune system. Therefore, it is possible that other forms of innate or acquired alterations of the immune system could favor the occurrence of non-melanoma skin cancers. For example, several studies have demonstrated that immunosenescence creates an immunosuppressive state that encourages the development of malignances, and new discoveries have noted the importance of T cells and in particular of T regulatory cells (Treg) and T receptor CD28 in this mechanism. Similar results are obtained analyzing the effect of immunosuppressive drugs. The importance of the immune system and its alteration in the genesis of non-melanoma skin cancers is fundamental for the creation of a new therapeutic and less invasive approach.

Growing old with the immune system: a study of immunosenescence in the zebra finch (Taeniopygia guttata)

Immunosenescence has not received much attention in birds and the few existing studies indicate that the occurrence of immunosenescence and/or its extent may differ between species. In addition, not much information is available on the immunosenescence patterns of different immune parameters assessed simultaneously in both sexes within a single species. The present study reports the results on immunosenescence in innate immunity and both cellular and humoral acquired immunity of both sexes in a captive population of zebra finch (Taeniopygia guttata) using three age groups (approximately 0.2, 2.5 and 5.1 years). Both male and female finches showed an inverse U-shaped pattern in cellular immune function with age, quantified by a PHA response. Males showed stronger responses than females at all ages. In contrast, an increase with age in humoral immunity, quantified through total plasma immunoglobulin Y levels, was found in both sexes. However, our measurements of innate immunity measured through the bacteria-killing ability against Escherichia coli gave inconclusive results. Still, we conclude that both cellular and humoral acquired immunity are susceptible to immunosenescence, and that the sexes differ in cellular immunity.

Side-by-side analysis of five clinically tested anti-EpCAM monoclonal antibodies

Background

Epithelial cell adhesion molecule (EpCAM) is frequently and highly expressed on human carcinomas. The emerging role of EpCAM as a signalling receptor and activator of the wnt pathway, and its expression on tumor-initiating cells, further add to its attractiveness as target for immunotherapy of cancer. Thus far, five conventional monoclonal IgG antibodies have been tested in cancer patients. These are murine IgG2a edrecolomab and its murine/human chimeric IgG1 antibody version, and humanized, human-engineered and fully human IgG1 antibodies 3622W94, ING-1, and adecatumumab (MT201), respectively. Here we compared all anti-EpCAM antibodies in an attempt to explain differences in clinical activity and safety.

Methods

We recombinantly produced all antibodies but murine edrecolomab and investigated them for binding affinity, EpCAM epitope recognition, ADCC and CDC, and inhibition of breast cancer cell proliferation.

Results

ING-1 and 3622W94 bound to EpCAM with much higher affinity than adecatumumab and edrecolomab. Edrecolomab, ING-1, and 3622W94 all recognized epitopes in the exon 2-encoded N-terminal domain of EpCAM, while adecatumumab recognized a more membrane proximal epitope encoded by exon 5. All antibodies induced lysis of EpCAM-expressing cancer cell lines by both ADCC and CDC with potencies that correlated with their binding affinities. The chimeric version of edrecolomab with a human Fcγ1 domain was much more potent in ADCC than the murine IgG2a version. Only adecatumumab showed a significant inhibition of MCF-7 breast cancer cell proliferation in the absence of complement and immune cells.

Conclusion

A moderate binding affinity and recognition of a distinct domain of EpCAM may best explain why adecatumumab showed a larger therapeutic window in cancer patients than the two high-affinity IgG1 antibodies ING-1 and 3622W94, both of which caused acute pancreatitis.

B7-H1 expression on old CD8+ T cells negatively regulates the activation of immune responses in aged animals

T cell responses are compromised in the elderly. The B7-CD28 family receptors are critical in the regulation of immune responses. We evaluated whether the B7-family and CD28-family receptors were differentially expressed in dendritic cells, macrophages, and CD4(+) and CD8(+) T cells from young and old mice, which could contribute to the immune dysfunction in the old. Although most of the receptors were equally expressed in all cells, >85% of the old naive CD8(+) T cells expressed B7-H1 compared with 25% in the young. Considering that B7-H1 negatively regulates immune responses, we hypothesized that expression of B7-H1 would downregulate the function of old CD8(+) T cells. Old CD8(+) T cells showed reduced ability to proliferate, but blockade of B7-H1 restored the proliferative capacity of old CD8(+) T cells to a level similar to young CD8(+) T cells. In vivo blockade of B7-H1 restored antitumor responses against the B7-H1(-) BM-185-enhanced GFP tumor, such that old animals responded with the same efficiency as young mice. Our data also indicate that old CD8(+) T cells express lower levels of TCR compared with young CD8(+) T cells. However, following antigenic stimulation in the presence of B7-H1 blockade, the levels of TCR expression were restored in old CD8(+) T cells, which correlated with stronger T cell activation. These studies demonstrated that expression of B7-H1 in old CD8(+) T cells impairs the proper activation of these cells and that blockade of B7-H1 could be critical to optimally stimulate a CD8 T cell response in the old.

Cancer, aging and immunotherapy: lessons learned from animal models

Aging of the immune system is associated with a dramatic reduction in responsiveness as well as functional dysregulation. This deterioration of immune function with advancing age is associated with an increased incidence of cancer. Although there is a plethora of reports evaluating the effect of immunotherapy in stimulating antitumor immune responses, the majority of these studies do not pay attention to the effect aging has on the immune system. Studies from our group and others indicate that immunotherapies could be effective in the young, are not necessarily effective in the old. To optimally stimulate an antitumor immune response in the old, it is necessary to (1) identify and understand the intrinsic defects of the old immune system and (2) use relevant models that closely reflect those of cancer patients, where self-tolerance and aging are present simultaneously. The present review summarizes some defects found in the old immune system affecting the activation of antitumor immune responses, the strategies used to activate stronger antitumor immune response in the old and the use of a tolerant animal tumor model to target a self-tumor antigen for the optimization of immunotherapeutic interventions in the old.

Inflammation in aging part 1: physiology and immunological mechanisms

During the aging process, remodeling of several body systems occurs, and these changes can have a startling effect upon the immune system. The reduction in sex steroids and growth hormones and declines in vitamin D concentration that accompany the aging process are associated with increases in the baseline levels of inflammatory proteins. At the same time, inflammation arising from atherosclerosis and other chronic diseases further contributes to the inflammatory milieu and effects a state of chronic inflammation. This chronic inflammation, or ''inflammaging'' as it has been termed, seems to be associated with a host of adverse effects contributing to many of the health problems that increase morbidity and decrease both quality of life and the ability to maintain independence in old age. For nurses to be truly informed when caring for older people and to ensure that they have a detailed understanding of the complexities of older people's health needs, they must have a knowledge of the physiological and immunological changes with age. This is the first of a two-part article on inflammatory processes in aging. These age-related changes are presented here, including an examination of the impact of genetic and lifestyle factors. The effect of these changes on the health of the individual and implications for practice are described in Part 2.

B cells and aging: molecules and mechanisms

Recent advances allow aging-associated changes in B-cell function to be approached at a mechanistic level. Reduced expression of genes crucial to lineage commitment and differentiation yield diminished B-cell production. Moreover, intrinsic differences in the repertoire generated by B-cell precursors in aged individuals, coupled with falling B-cell generation rates and life-long homeostatic competition, result in narrowed clonotypic diversity. Similarly, reductions in gene products crucial for immunoglobulin class switch recombination and somatic hypermutation impact the efficacy of humoral immune responses. Together, these findings set the stage for integrated analyses of how age-related changes at the molecular, cellular and population levels interact to yield the overall aging phenotype.

Pandemic influenza vaccines

Since their compositions remain uncertain, universal pandemic vaccines are yet to be created. They would aim to protect globally against pandemic influenza viruses that have not yet evolved. Thus they differ from seasonal vaccines to influenza virus, which are updated annually in spring to incorporate the latest circulating viruses, and are then produced and delivered before the peak influenza season starts in late fall and winter. The efficacy of seasonal vaccines is linked to their ability to induce virus-neutralizing antibodies, which provide subtype-specific protection against influenza A viruses. If pandemic vaccines were designed to resemble current vaccines in terms of composition and mode of action, they would have to be developed, tested, and mass-produced after the onset of a pandemic, once the causative virus had been identified. The logistic problems of generating a pandemic vaccine from scratch, conducting preclinical testing, and producing billions of doses within a few months for global distribution are enormous and may well be insurmountable. Alternatively, the scientific community could step up efforts to generate a universal vaccine against influenza A viruses that provides broadly cross-reactive protection through the induction of antibodies or T cells to conserved regions of the virus.

Implicações da imunossenescência na vacinação de idosos

Resumo A prevalência de indivíduos idosos em relação aos indivíduos jovens compreende um quadro comum na população mundial. Estima-se que, em 2050, cerca de 22% da população mundial será constituída por indivíduos idosos. No Brasil, o número de idosos (≥ 60 anos de idade) passou de 3 milhões em 1960 para 7 milhões em 1975 e 14 milhões em 2002 (um aumento de 500% em 40 anos), e estima-se que alcançará 32 milhões em 2020. Este fenômeno se deve ao advento de drogas antibacterianas, a vacinações em larga escala e a outros avanços no tratamento médico. Contudo, a eficácia de uma vacina depende, sobretudo, da habilidade dos indivíduos para exibir uma resposta imune adequada. Assim, esta revisão apresenta os principais efeitos da imunossenescência na resposta imune a uma vacina. Além disto, discute algumas estratégias que aumentam os níveis de proteção das imunizações neste grupo etário. A compreensão dos fatores envolvidos na geração de uma resposta imunológica durante a senescência e a introdução de estratégias que melhoram a eficácia de vacinas nos indivíduos idosos reduz a incidência e a severidade de doenças infecciosas, tendo forte impacto na qualidade de vida destes indivíduos.

Aging and immune response in chronic human schistosomiasis

There has been no systematic study of the immune response of individuals over 60 residing in areas endemic for Schistosoma mansoni infection although senescence is reportedly associated with susceptibility to infection and progressive decline in immune function. We have shown previously, in two endemic areas in Minas Gerais, Brazil, that the frequency of individuals over 60 with chronic schistosomiasis is no longer negligible. Several aging-related immunological alterations are already described in medical literature, mostly in the T-cell compartment. Since aging is associated with a decline in T-cell function, it is not surprising that individuals over 60 would be more susceptible to infection. However, not all aged individuals in endemic areas have high intensity of infection; some of them display a negative stool-screening test for the presence of schistosome eggs and low levels of serum antibodies reactive with S. mansoni antigens indicating they are not infected. Non-infected, negative individuals may develop compensatory mechanisms to cope with immune dysfunction and to generate protective responses against the constant threat of infection in these areas. Herein, we reviewed previous reports from our group showing that two mechanisms contribute to distinguish between infected and egg negative aged individuals. First, egg negative aged individuals develop innate immune responses to replace the decline in T-cell function that is observed with aging. Second, chronically activated regulatory T cells, that may impair protective immune responses, are more vigorous in infected aged individuals. We propose that egg negative individuals may be considered as an example of healthy aging in areas endemic for infectious disease.

Acquired immunity: immunosenescence and physical activity

Several lines of evidence indicate that infectious diseases, cancer, and autoimmune disorders occur more frequently in elderly people, thus suggesting that altered function of immune organs and cells, such as thymus and T and B lymphocytes are of primary importance in the pathogenesis of these diseases. Furthermore, old subjects are less responsive to vaccine than younger because of immune changes. The most common changes accompanying the adaptive immune system include decrement of T and B cells proliferation, repertoire degeneracy, increase of the memory cell type, decreased numbers of naive cells, and shift from T helper1 (Th1) to T helper2 (Th2) response. Regular exercise in the elderly may improve the alterations in acquired immunity which follow the physiological process of aging, allowing a major resistance against external pathogens and a better quality of life.