Search results for " Immune system"
showing 10 items of 893 documents
B cells in the aged: CD27, CD5, and CD40 expression.
2003
Ageing is characterized by numerous changes in lymphocyte subpopulations. In the present paper we have focused on B cells carrying the surface markers CD27, CD5 and CD40. CD27 is considered a marker of primed (memory) cells and its engagement promotes the differentiation of memory B cells into plasma cells. CD5 is expressed on B1 cells, which are considered to be responsible for T cell-independent antibody production other than autoantibodies. The CD40 molecule binds CD40L (CD154) and is necessary for T-dependent antibody responses. Here we show that the absolute number of CD5+ and CD40+ B cells is decreased in the elderly, while CD27+ B lymphocytes only marginally decrease in centenarians.…
The labyrinth of autoinflammatory disorders: a snapshot on the activity of a third-level center in Italy.
2015
Autoinflammatory disorders (AIDs) are a novel class of diseases elicited by mutations in genes regulating the homeostasis of innate immune complexes, named inflammasomes, which lead to uncontrolled oversecretion of the proinflammatory cytokine interleukin-1β. Protean inflammatory symptoms are variably associated with periodic fever, depicting multiple specific conditions. Childhood is usually the lifetime in which most hereditary AIDs start, though still a relevant number of patients may experience a delayed disease onset and receive a definite diagnosis during adulthood. As a major referral laboratory for patients with recurrent fevers, we have tested samples from 787 patients in the perio…
The role of regulatory T cell (Treg) subsets in gestational diabetes mellitus.
2014
Physiological changes during normal pregnancy are characterized by an inflammatory immune response and insulin resistance. Therefore, we hypothesize that gestational diabetes mellitus (GDM) may be caused by an inappropriate adaption of the maternal immune system to pregnancy. In this study we examined the role of regulatory T cell (Treg) differentiation for the development of GDM during pregnancy. We used six-colour flow cytometric analysis to demonstrate that the total CD4(+) CD127(low+/-) CD25(+) forkhead box protein 3 (FoxP3(+)) T(reg) pool consists of four different T(reg) subsets: naive CD45RA(+) T(regs), HLA-DR(-) CD45RA(-) memory T(regs) (DR(-) T(regs)) and the highly differentiated …
In the presence of IL-21 human cord blood T cells differentiate to IL-10-producing Th1 but not Th17 or Th2 cells.
2012
Abstract IL-21, a member of the IL-2 cytokine family, is mainly produced by activated CD4+ T cells and controls the activity of immune and also non-immune cells. As a pleiotropic cytokine, IL-21 acts on both innate and adaptive immune responses, suggesting that IL-21 may be a master regulator of the T-cell-dependent adaptive immune response. Although IL-21 is described as mostly promoting inflammation, evidence also suggests inhibitory effects of IL-21. However, its role, particularly in the human neonatal immune system, has not been detailed so far. Here, we assessed the effect of IL-21 in the specific context of the neonatal immune response and delineated differences between the human new…
Biology of Longevity: Role of the Innate Immune System
2006
Genetic factors play a relevant role in the attainment of longevity because they are involved in cell maintenance systems, including the immune system. In fact, longevity may be correlated with optimal functioning of clonotypic and natural immunity. The aging of the immune system, known as immunosenescence, is the consequence of the continuous attrition caused by chronic antigenic overload. The antigenic load results in the progressive generation of inflammatory responses involved in age-related diseases. Most of the parameters influencing immunosenescence appear to be under genetic control, and immunosenescence fits with the basic assumptions of evolutionary theories of aging, such as anta…
Expression of Toll-Like Receptors in the Developing Brain
2012
Toll-like receptors (TLR) are key players of the innate and adaptive immune response in vertebrates. The original protein Toll in Drosophila melanogaster regulates both host defense and morphogenesis during development. Making use of real-time PCR, in situ hybridization, and immunohistochemistry we systematically examined the expression of TLR1-9 and the intracellular adaptor molecules MyD88 and TRIF during development of the mouse brain. Expression of TLR7 and TLR9 in the brain was strongly regulated during different embryonic, postnatal, and adult stages. In contrast, expression of TLR1-6, TLR8, MyD88, and TRIF mRNA displayed no significant changes in the different phases of brain develop…
Inflammation and oxidative stress in vertebrate host–parasite systems
2008
Innate, inflammation-based immunity is the first line of vertebrate defence against micro-organisms. Inflammation relies on a number of cellular and molecular effectors that can strike invading pathogens very shortly after the encounter between inflammatory cells and the intruder, but in a non-specific way. Owing to this non-specific response, inflammation can generate substantial costs for the host if the inflammatory response, and the associated oxygen-based damage, get out of control. This imposes strong selection pressure that acts to optimize two key features of the inflammatory response: the timing of activation and resolution (the process of downregulation of the response). In this p…
Tif1γ regulates the TGF-β1 receptor and promotes physiological aging of hematopoietic stem cells.
2014
The hematopoietic system declines with age. Myeloid-biased differentiation and increased incidence of myeloid malignancies feature aging of hematopoietic stem cells (HSCs), but the mechanisms involved remain uncertain. Here, we report that 4-mo-old mice deleted for transcription intermediary factor 1γ (Tif1γ) in HSCs developed an accelerated aging phenotype. To reinforce this result, we also show that Tif1γ is down-regulated in HSCs during aging in 20-mo-old wild-type mice. We established that Tif1γ controls TGF-β1 receptor (Tgfbr1) turnover. Compared with young HSCs, Tif1γ(-/-) and old HSCs are more sensitive to TGF-β signaling. Importantly, we identified two populations of HSCs specifical…
B cells and immunosenescence: a focus on IgG+IgD-CD27- (DN) B cells in aged humans.
2010
Immunosenescence contributes to the decreased ability of the elderly to control infectious diseases, which is also reflected in their generally poor response to new antigens and vaccination. It is known that the T cell branch of the immune system is impaired in the elderly mainly due to expansion of memory/effector cells that renders the immune system less able to respond to new antigens. B lymphocytes are also impaired in the elderly in terms of their response to new antigens. In this paper we review recent work on B cell immunosenescence focusing our attention on memory B cells and a subset of memory B cells (namely IgG(+)IgD(-)CD27(-)) that we have demonstrated is increased in healthy el…
The Transcription Factor T-bet Is Induced by IL-15 and Thymic Agonist Selection and Controls CD8αα+ Intraepithelial Lymphocyte Development
2014
Summary CD8αα + intraepithelial lymphocytes (IELs) are instrumental in maintaining the epithelial barrier in the intestine. Similar to natural killer cells and other innate lymphoid cells, CD8αα + IELs constitutively express the T-box transcription factor T-bet. However, the precise role of T-bet for the differentiation or function of IELs is unknown. Here we show that mice genetically deficient for T-bet lacked both TCRαβ + and TCRγδ + CD8αα + IELs and thus are more susceptible to chemically induced colitis. Although T-bet was induced in thymic IEL precursors (IELPs) as a result of agonist selection and interleukin-15 (IL-15) receptor signaling, it was dispensable for the generation of IEL…