69 research outputs found

    Immunity, ageing and cancer

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    Compromised immunity contributes to the decreased ability of the elderly to control infectious disease and to their generally poor response to vaccination. It is controversial as to how far this phenomenon contributes to the well-known age-associated increase in the occurrence of many cancers in the elderly. However, should the immune system be important in controlling cancer, for which there is a great deal of evidence, it is logical to propose that dysfunctional immunity in the elderly would contribute to compromised immunosurveillance and increased cancer occurrence. The chronological age at which immunosenescence becomes clinically important is known to be influenced by many factors, including the pathogen load to which individuals are exposed throughout life. It is proposed here that the cancer antigen load may have a similar effect on "immune exhaustion" and that pathogen load and tumor load may act additively to accelerate immunosenescence. Understanding how and why immune responsiveness changes in humans as they age is essential for developing strategies to prevent or restore dysregulated immunity and assure healthy longevity, clearly possible only if cancer is avoided. Here, we provide an overview of the impact of age on human immune competence, emphasizing T-cell-dependent adaptive immunity, which is the most sensitive to ageing. This knowledge will pave the way for rational interventions to maintain or restore appropriate immune function not only in the elderly but also in the cancer patient

    Multiparameter flow cytometric analysis of CD4 and CD8 T cell subsets in young and old people

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    <p>Abstract</p> <p>Background</p> <p>T cell-mediated immunity in elderly people is compromised in ways reflected in the composition of the peripheral T cell pool. The advent of polychromatic flow cytometry has made analysis of cell subsets feasible in unprecedented detail.</p> <p>Results</p> <p>Here we document shifts in subset distribution within naĆÆve (N), central memory (CM) and effector memory (EM) cells defined by CD45RA and CCR7 expression in the elderly, additionally using the costimulatory receptors CD27 and CD28, as well as the coinhibitory receptors CD57 and KLRG-1, to further dissect these. Although differences between young and old were more marked in CD8 than in CD4 cells, a similar overall pattern prevailed in both. Thus, the use of all these markers together, and inclusion of assays of proliferation and cytokine secretion, may enable the construction of a differentiation scheme applicable to CD4 as well as CD8 cells, with the model (based on Romero et al.) suggesting the progression Nā†’CMā†’EM1ā†’EM2ā†’pE1ā†’pE2ā†’EM4ā†’EM3ā†’E end-stage non-proliferative effector cells.</p> <p>Conclusion</p> <p>Overall, the results suggest that both differences in subset distribution and differences between subsets are responsible for age-related changes in CD8 cells but that differences within rather than between subsets are more prominent for CD4 cells.</p

    Age-associated alterations in Ī³Ī“ T-cells are present predominantly in individuals infected with Cytomegalovirus

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    BACKGROUND: Despite the common perception that latent Cytomegalovirus (CMV) infection is usually symptom-free, emerging epidemiological evidence suggests that it may in fact be associated with higher mortality over extended follow-up. Mechanisms responsible for this potentially important effect are unclear. CMV infection is known to have a large impact on the distribution of T cell phenotypes, especially the accumulation of late-stage differentiated CD8(+), as well as VĪ“2(-) Ī³Ī“ T-cells, which are the main subset of Ī³Ī“ T-cells involved in anti-CMV immunity. Its impact on Ī³Ī“ T-cells in the aging context is less well-defined. RESULTS: Here, we investigated a group of healthy individuals aged between 21 and 89 years, in order to correlate the frequency and differentiation status of Ī³Ī“ T-cells with age. We found that these parameters were only marginally influenced by age, but were marked in people with a latent CMV infection. Thus, we observed a significant age-associated accumulation of late-differentiated T-cells within the VĪ“2(-) population, but only in CMV-seropositive donors. There was also a strong trend towards reduced frequency of early-differentiated cells within the VĪ“2(-) phenotype. Older people had significantly higher anti-CMV IgG titers, which in turn correlated significantly with a lower VĪ“2(+)/VĪ“2(-) ratio and a shift from early- to a late-differentiated VĪ“2(-) T-cell phenotype. CONCLUSIONS: Our findings demonstrate a strong influence of CMV on Ī³Ī“ T-cells during human ageing, similar to that observed for Ī±Ī² T-cells. Differences between donors of different ages are more marked in CMV-infected individuals. The biological implications of this potent age-associated CMV-mediated immune-modulation require clarification

    Computer Interfaces to Organizations: Perspectives on Borg-Human Interaction Design

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    We use the term borg to refer to the complex organizations composed of people, machines, and processes with which users frequently interact using computer interfaces and websites. Unlike interfaces to pure machines, we contend that borg-human interaction (BHI) happens in a context combining the anthropomorphization of the interface, conflict with users, and dramatization of the interaction process. We believe this context requires designers to construct the human facet of the borg, a structure encompassing the borg's personality, social behavior, and embodied actions; and the strategies to co-create dramatic narratives with the user. To design the human facet of a borg, different concepts and models are explored and discussed, borrowing ideas from psychology, sociology, and arts. Based on those foundations, we propose six design methodologies to complement traditional computer-human interface design techniques, including play-and-freeze enactment of conflicts and the use of giant puppets as interface prototypes.Comment: 10 page

    Prothymosin a and a prothymosin Ī±-derived peptide enhance TH1-type immune responses against defined HER-2/neu epitopes

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    Background: Active cancer immunotherapies are beginning to yield clinical benefit, especially those using peptide-pulsed dendritic cells (DCs). Different adjuvants, including Toll-like receptor (TLR) agonists, commonly co-administered to cancer patients as part of a DC-based vaccine, are being widely tested in the clinical setting. However, endogenous DCs in tumor-bearing individuals are often dysfunctional, suggesting that ex vivo educated DCs might be superior inducers of anti-tumor immune responses. We have previously shown that prothymosin alpha (proTĪ±) and its immunoreactive decapeptide proTĪ±(100ā€“109) induce the maturation of human DCs in vitro. The aim of this study was to investigate whether proTĪ±- or proTĪ±(100ā€“109)-matured DCs are functionally competent and to provide preliminary evidence for the mode of action of these agents. Results: Monocyte-derived DCs matured in vitro with proTĪ± or proTĪ±(100ā€“109) express co-stimulatory molecules and secrete pro-inflammatory cytokines. ProTĪ±- and proTĪ±(100ā€“109)-matured DCs pulsed with HER-2/neu peptides induce TH1-type immune responses, prime autologous naĆÆve CD8-positive (+) T cells to lyse targets expressing the HER-2/neu epitopes and to express a polyfunctional profile, and stimulate CD4+ T cell proliferation in an HER-2/neu peptide-dependent manner. DC maturation induced by proTĪ± and proTĪ±(100ā€“109) is likely mediated via TLR-4, as 25 shown by assessing TLR-4 surface expression and the levels of the intracellular adaptor molecules TIRAP, MyD88 and TRIF. Conclusions: Our results suggest that proTĪ± and proTĪ±(100ā€“109) induce both the maturation and the T cell stimulatory capacity of DCs. Although further studies are needed, evidence for a possible proTĪ± and proTĪ±(100ā€“109) interaction with TLR-4 is provided. The initial hypothesis that proTĪ± and the proTĪ±-derived immunoactive decapeptide act as ā€œalarminsā€, provides a rationale for their eventual use as adjuvants in DC-based anti-cancer immunotherapy

    Cytomegalovirus seropositivity is associated with glucose regulation in the oldest old. Results from the Leiden 85-plus Study

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    Background: Cytomegalovirus (CMV) infection has been reported to contribute to the pathogenesis of type 1 diabetes and post-transplantation diabetes. However, CMV infection has not been evaluated as a possible risk factor for type 2 diabetes. Our aim was to investigate potential associations between CMV seropositivity, CMV IgG antibody level and glucose regulation in the oldest old.Results: CMV seropositive subjects were more likely to have type 2 diabetes (17.2% vs 7.9%, p = 0.016), had a higher level of HbA1c (p = 0.014) and higher non-fasting glucose (p = 0.024) in the oldest olds. These associations remained significant after adjustment for possible confounders. CMV IgG antibody level was not significantly associated with glucose regulation (all p > 0.05).Conclusions: In the oldest old, CMV seropositivity is significantly associated with various indicators of glucose regulation. This finding suggests that CMV infection might be a risk factor for the development of type 2 diabetes in the elderly

    Income and Markers of Immunological Cellular Aging

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    Socioeconomic disadvantage may contribute to poor health through immune-related biological mechanisms. We examined the associations between socioeconomic status, as measured by annual household income, and T-cell markers of aging, including the ratios of CD4 and CD8 effector cells to naĆÆve cells (E:N ratio) and the CD4:CD8 T-cell ratio. We hypothesized that participants with a lower income would have higher E:N ratios and lower CD4:CD8 ratios compared to participants with a higher income, and that these associations would be partially mediated by elevated cytomegalovirus (CMV) IgG antibody levels, a virus implicated in aging and clonal expansion of T-cells

    Immunosenescence and Cytomegalovirus: where do we stand after a decade?

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    AbstractSince Looney at al. published their seminal paper a decade ago it has become clear that many of the differences in T cell immunological parameters observed between young and old people are related to the age-associated increasing prevalence of infection with the persistent beta-herpesvirus HHV-5 (Cytomegalovirus). Ten years later, studies suggest that hallmark age-associated changes in peripheral blood T cell subset distribution may not occur at all in people who are not infected with this virus. Whether the observed changes are actually caused by CMV is an open question, but very similar, rapid changes observed in uninfected patients receiving CMV-infected kidney grafts are consistent with a causative role. This meeting intensively discussed these and other questions related to the impact of CMV on human immune status and its relevance for immune function in later life.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
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