Search results for "Naive B cell"
showing 10 items of 19 documents
From lymphopoiesis to plasma cells differentiation, the age-related modifications of B cell compartment are influenced by “inflamm-ageing”
2017
Ageing is a complex process characterized by a general decline in physiological functions with increasing morbidity and mortality. The most important aspect of ageing is the chronic inflammatory status, named âinflamm-ageingâ, strictly associated with the deterioration of the immune function, termed âimmunosenescenceâ. Both are causes of increased susceptibility of elderly to infectious diseases, cancer, dementia, cardiovascular diseases and autoimmunity, and of a decreased response to vaccination. It has been widely demonstrated that ageing has a strong impact on the remodelling of the B cell branch of immune system. The first evident effect is the significant decrease in circulati…
SAT0025 THE EFFECT OF DIMETHYL FUMARATE ON PLASMABLAST DIFFERENTIATION TRANSCRIPTIONAL PROGRAMMES IN SYSTEMIC LUPUS ERYTHEMATOSUS
2019
Background: Dimethyl fumarate (DMF), is an immunomodulatory drug approved for the treatment of Multiple Sclerosis (MS) and Psoriasis. The exact mechanism of action of DMF is not entirely known. Anti-inflammatory and immunomodulatory effects have been observed, including the upregulation of NRF-2, the inhibition of TIGAR and the block of the E2 ubiquitin-conjugating enzyme UBEL3. Further evidence from MS patients suggests a modulation on B cell activation. Although beneficial effects of DMF have been observed in animal models of lupus nephritis and limited cases human cutaneous lupus, the effect of DMF on B cell maturation transcriptional programmes in systemic Lupus Erythematosus (SLE) has …
Trafficking phenotype and production of granzyme B by double negative B cells (IgG(+)IgD(-)CD27(-)) in the elderly.
2013
The impairment of humoral immune response in elderly humans has been extensively demonstrated. We have reported the increase of memory B cells (IgG(+)IgD(-)CD27(-), double negative, DN) population in the elderly, in which there is also a typical inflammatory micro-environment. In order to evaluate whether this pro-inflammatory status could influence the trafficking phenotype of naïve/memory B cells, we have assessed the expression of CCR7, CCR6, CXCR3, CXCR4, CXCR5 and CD62L on naïve/memory B cell subpopulations in young and elderly subjects. Moreover, the combination of pro-inflammatory interleukin-21 (IL-21) and B cell receptor (BCR) stimulation enables B cells to produce and secrete gran…
B cell immunosenescence: different features of naive and memory B cells in elderly.
2011
Elderly people show a reduced protection against new infections and a decreased response to vaccines as a consequence of impairment of both cellular and humoral immunity. In this paper we have studied memory/naive B cells in the elderly, evaluating surface immunoglobulin expression, production of the pro- and anti-inflammatory cytokines, tumor necrosis factor (TNF)-α and interleukin (IL)-10, and presence of somatic hypermutation, focusing on the IgG(+)IgD(-)CD27(-) double negative (DN) B cells that are expanded in the elderly. Our results show that naive B cells from young donors need a sufficiently strong stimulus to be activated "in vitro", while naive B cells from old subjects are able t…
Dimethyl Fumarate Treatment Mediates an Anti-Inflammatory Shift in B Cell Subsets of Patients with Multiple Sclerosis
2017
Abstract The therapeutic mode of action of dimethyl fumarate (DMF), approved for treating patients with relapsing-remitting multiple sclerosis, is not fully understood. Recently, we and others demonstrated that Ab-independent functions of distinct B cell subsets are important in mediating multiple sclerosis (MS) relapsing disease activity. Our objective was to test whether and how DMF influences both the phenotype and functional responses of disease-implicated B cell subsets in patients with MS. High-quality PBMC were obtained from relapsing-remitting MS patients prior to and serially after initiation of DMF treatment. Multiparametric flow cytometry was used to monitor the phenotype and fun…
CD27 distinguishes two phases in bone marrow infiltration of splenic marginal zone lymphoma.
2004
Aims: To investigate CD27 expression in splenic marginal zone lymphoma (SMZL), an indolent low-grade B-cell lymphoma with constant involvement of the bone marrow, especially with an intrasinusoidal pattern. It is not clear if the neoplastic clone is composed of virgin or somatically mutated B cells. CD27 is reported to be a hallmark of memory B cells. Methods and results: We evaluated 64 bone marrow biopsy specimens (BMBs) from 36 patients with SMZL for the expression of CD27. For comparison, splenectomy specimens of patients with traumatic splenic rupture or with SMZL were used. All BMBs showed lymphomatous infiltration. When located in the marrow sinusoids, neoplastic cells were CD27– i…
Double Negative (CD19+IgG+IgD-CD27-) B Lymphocytes: A New Insight from Telomerase in Healthy Elderly, in Centenarian Offspring, and in Alzheimer’s Di…
2014
Background: We have previously reported the increase of IgD-CD27- (Double Negative, DN) B cell population in the aged. These memory B cells have short telomeres and poor abilities to proliferate in vitro. Here, we investigated whether the low ability of DN B cells to proliferate depends on the expression levels of the CD307d and CD22 inhibitory receptors or whether DN B cells can proliferate and reactivate telomerase by the engagement of both innate and adaptive immune receptors. Methods: Phenotypic analyses were made by using flow cytometry. Quantitative analysis of telomerase activity was made by using a TRAP and a photometric enzyme immunoassay in young, healthy elderly, centenarian offs…
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.…
B Cells Compartment in Centenarian Offspring and Old People
2010
Immunosenescence is considered a major contributory factor to the increased frequency of morbidity and mortality among elderly. On the other hand centenarians are considered the best example of successful ageing. To gain insight into mechanisms of immunosenescence and its clinical relevance, a possible model is represented by centenarians and/or their offspring. Nowadays centenarians are not more a curiosity, but in Europe are 1/8000 inhabitants and it has been demonstrated that the centenarian offspring, who are typically in their 70s and 80s, have a survival advantage when compared with age-matched controls whose parents died at an average life expectancy. Then again, studies on immunosen…
Molecular Basis for the Interaction of the Hepatitis B Virus Core Antigen with the Surface Immunoglobulin Receptor on Naive B Cells
2001
ABSTRACTThe nucleocapsid of the hepatitis B virus (HBV) is composed of 180 to 240 copies of the HBV core (HBc) protein. HBc antigen (HBcAg) capsids are extremely immunogenic and can activate naive B cells by cross-linking their surface receptors. The molecular basis for the interaction between HBcAg and naive B cells is not known. The functionality of this activation was evidenced in that low concentrations of HBcAg, but not the nonparticulate homologue HBV envelope antigen (HBeAg), could prime naive B cells to produce anti-HBc in vitro with splenocytes from HBcAg- and HBeAg-specific T-cell receptor transgenic mice. The frequency of these HBcAg-binding B cells was estimated by both hybridom…