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Immune Senescence (immune + senescence)
Selected AbstractsAgeing and the neutrophil: no appetite for killing?IMMUNOLOGY, Issue 4 2000S. Butcher Summary In the armoury of the immune system developed to combat the various micro-organisms that could invade the host, the neutrophil forms the first line of defence against rapidly dividing bacteria and fungi. However, as humans age they become more susceptible to infection with these microbes and this has been ascribed to a decline in immune status, termed immune senescence. Here we summarize the literature specifically concerning the attenuation of neutrophil function with age and the possible mechanisms underlying their reduced response to infectious agents. [source] Human NK cells display major phenotypic and functional changes over the life spanAGING CELL, Issue 4 2010Magali Le Garff-Tavernier Summary Aging is generally associated with an increased predisposition to infectious diseases and cancers, related in part to the development of immune senescence, a process that affects all cell compartments of the immune system. Although many studies have investigated the effects of age on natural killer (NK) cells, their conclusions remain controversial because the diverse health status of study subjects resulted in discordant findings. To clarify this situation, we conducted the first extensive phenotypic and functional analysis of NK cells from healthy subjects, comparing NK cells derived from newborn (cord blood), middle-aged (18,60 years), old (60,80 years), and very old (80,100 years) subjects. We found that NK cells in cord blood displayed specific features associated with immaturity, including poor expression of KIR and LIR-1/ILT-2 and high expression of both NKG2A and IFN-,. NK cells from older subjects, on the other hand, preserved their major phenotypic and functional characteristics, but with their mature features accentuated. These include a profound decline of the CD56bright subset, a specific increase in LIR-1/ILT-2, and a perfect recovering of NK-cell function following IL2-activation in very old subjects. We conclude that the preservation of NK cell features until very advanced age may contribute to longevity and successful aging. [source] Effects of Bifidobacterium bifidum on adaptive immune senescence in aging miceMICROBIOLOGY AND IMMUNOLOGY, Issue 10 2010Yu-Rong Fu ABSTRACT Bifidobacteria are a natural component of the bacterial flora of the human body and have a symbiotic bacteria-host relationship with human beings. Aging is associated with reduced numbers of beneficial colonic Bifidobacteria and impaired immunity. The possible anti-senescence effects of Bifidobacteria are presently unknown. The aims of the present study were to investigate possible anti-senescence effects of B. bifidum on naturally senescent mice and to explore their mechanisms. After treatment with B. bifidum, mice were killed and samples collected. Cytokine production in serum and lymphocyte culture supernatant, anti-oxidation activity and gene expression were measured. B. bifidum significantly increased cytokine IL-2 and IFN-, levels but decreased proinflammatory cytokines IL-6 and TNF-, concentrations. Moreover, B. bifidum improved anti-oxidation activity and reduced lipid peroxidation in thymus and spleen. In addition, B. bifidum down-regulated p16 expression in thymus and spleen. Taken together, the results indicate, for the first time, that B. bifidum delays senescence by several mechanisms, including enhancement of anti-oxidation activity in thymus and spleen, alteration of gene expression and improvement in immune function. [source] Age-related EBV-associated B-cell lymphoproliferative disorders: Diagnostic approach to a newly recognized clinicopathological entityPATHOLOGY INTERNATIONAL, Issue 12 2009Yoshie Shimoyama EBV is prevalent among healthy individuals, and is implicated in numerous reactive and neoplastic processes in the immune system. The authors originally identified a series of senile or age-related EBV-associated B-cell lymphoproliferative disorders (LPD) bearing a resemblance to immunodeficiency-associated ones, which may be associated with immune senescence in the elderly and which are now incorporated into the 2008 World Health Organization lymphoma classification as EBV-positive diffuse large B-cell lymphoma (DLBCL) of the elderly. This newly described disease is pathologically characterized by a proliferation of atypical large B cells including Reed,Sternberg-like cells with reactive components, which pose a diagnostic problem for pathologists. Clinically, this disease may present with lymphadenopathy, and is often extranodal, frequently involving the skin, gastrointestinal tract, or lung. Onset is usually after the age of 50; the median patient age is 70,79 years, and incidence continues to increase with age, providing additional support to the nosological term of EBV+ DLBCL of the elderly. These patients have a worse prognosis than those with EBV-negative DLBCL or EBV+ classical Hodgkin lymphoma (CHL). The aim of the present review was to summarize the clinicopathological profile of age-related EBV+ LPD and EBV+ Hodgkin lymphoma to facilitate diagnostic approach. [source] Thymic function and immune senescence in juvenile idiopathic arthritis: Comment on the article by Prelog et alARTHRITIS & RHEUMATISM, Issue 1 2009A. R. Lorenzi MA No abstract is available for this article. [source] The number of human peripheral blood CD4+ CD25high regulatory T cells increases with ageCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2005R. Gregg Summary Ageing is associated with evidence of immune deficiency and dysregulation. Key changes in the immune system with ageing include a progressive reduction in naive T cell output associated with thymic involution and peripheral expansion of oligoclonal memory T cells. These features are associated with evidence of impaired immune responsiveness both in vitro and in vivo, termed immune senescence. CD4+ CD25+ T cells have recently been recognized as mediators of peripheral immune regulation and play a role in the control of autoimmune and pathogen-specific immune responses. The significance of CD4+ CD25+ regulatory T cells in the context of immunosenescence is not known. We have investigated the number, phenotype and function of CD4+ CD25+ T cells in healthy volunteers over a wide age range. We demonstrate that the number of CD4+ CD25+ and CD4+ CD25high T cells in healthy volunteers increases with age. In both age groups CD4+ CD25+ T cells showed a phenotype consistent with that described for regulatory T cells. Further analysis of CD4+ CD25high T cells in young and elderly donors showed equivalent expression of intracellular CTLA-4 and surface expression of activation markers. In vitro, functional titration assays of CD4+ CD25high T cells demonstrated equivalent regulatory function in both young and elderly donors, with suppression of proliferation and cytokine production in response to polyclonal T cell stimulation. These observations demonstrate an increase in peripheral blood CD4+ CD25high regulatory T cells associated with ageing. The relevance of these expanded cells in relation to the immune senescence seen in the elderly as yet remains unclear. [source] | |||||||||||||