TY - JOUR. T1 - Aged mice exhibit distinct B cell precursor phenotypes differing in activation, proliferation and apoptosis. AU - Van der Put, Elaine. AU - Sherwood, Erin M.. AU - Blomberg, Bonnie B. AU - Riley, Richard L. PY - 2003/10/1. Y1 - 2003/10/1. N2 - Senescence in murine models is associated with a reduction, albeit heterogeneous, in bone marrow pre-B cells. We have categorized aged BALB/c mice into two phenotypes based on their patterns of pre-B/pro-B cell loss. Each phenotype is characterized by distinct responses to the growth cytokine IL-7 and capacity for survival in vitro. A moderate loss of late-stage pre-B cells (25-80%) coincided with decline in proliferation to rmIL-7. This was also associated with a decrease in the frequency of pro-B cells which increased phosphotyrosine content upon IL-7 stimulation, an indicator of early activation events. A severe loss of pre-B cells (,80%) resulted in a reduced pro-B cell pool which retained normal activation and proliferative ...
Our views regarding the origins and functions of splenic marginal zone B cells have changed considerably over the past few years. Perspectives regarding the development and function of these cells vary considerably between investigators studying human and rodent immunology. Marginal zone B cells are …
The development of an effective Ab response to TD Ag requires collaboration between T and B cells. Several lines of evidence support the idea that the ability of B cells to induce both naive T cell priming and tolerance depends on their resting vs activated state (28, 29, 30, 39, 40, 41, 42, 43, 44). In agreement with previous results, we found that both resting MZ and FO B cells were unable to induce T cell responses in vivo and in vitro. However, within a few hours of in vivo Ag priming, MZ B cells were far superior to FO B cells in the activation of naive CD4+ T cells in vitro. MD4 B cell populations have been shown to be a little different in the phenotype of their subsets, in that IgM on FO B cells tended to persist at higher levels than on FO B in normal mice. However, we sorted FO and MZ B cell subsets based on their expression of CD23 and CD21. In this respect the MZ B cells are clearly distinguishable from their FO counterparts. Despite this anomaly in MD4 transgenic mice MZ and FO B ...
The mechanisms that establish immune tolerance in immature and mature B cells appear to be distinct. Membrane-bound autoantigen is thought to induce developmental arrest and receptor editing in immature B cells, whereas mature B cells have shortened lifespans when exposed to the same stimulus. In this study, we used Emu-bcl-2-22 transgenic (Tg) mice to test the prediction that enforced expression of the Bcl-2 apoptotic inhibitor in B cells would rescue mature, but not immature, B cells from tolerance induction. To monitor tolerance to the natural membrane autoantigen H-2Kb, we bred 3-83mudelta (anti-Kk,b) Ig Tg mice to H-2(b) mice or to mice expressing transgene-driven Kb in the periphery. In 3-83mudelta/bcl-2 Tg mice, deletion of autoreactive B cells induced by peripheral Kb antigen expression in the liver (MT-Kb Tg) or epithelia (KerIV-Kb Tg), was partly or completely inhibited, respectively. Furthermore, Bcl-2 protected peritoneal B-2 B cells from deletion mediated by acute antigen exposure, ...
Quantitative variation in the expression of MHC-encoded class II (Ia) glycoproteins has been associated with stages of lymphocyte development and a number
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The uniqueness of each BCR and width of the B cell repertoire are due to the DNA rearrangements at HC and LC loci. B cells leave the bone marrow at the transitional stage carrying a wide array of germline-encoded and randomly assembled Ig genes. Transitional B cells migrate with the blood to the spleen. They are not fully functional in the immune responses: they are not able to respond to inflammatory chemokines, and engagement of the BCR leads to their apoptotic cell death. These are safety measures against autoreactivity preventing self-reactive transitional B cells from further development and migration to sites rich in cytokines and stimulatory cells. In contrast to the mortal effect of BCR cross-linking, engagement of TLR9 leads to differentiation of transitional B cells. In response to CpG, a fraction of the transitional B cells (26%) proliferates and acquires the phenotype of memory B cells or directly matures into plasma cells. The remaining cells start to express the markers of ...
In the past decade, the suppressive effects, mainly through the secretion of IL-10, of regulatory B cells on inflammatory responses have been reported in a variety of immune disorders (33-36). Additionally, immune regulation through the interaction of immune cells with the intrinsic phenotype of regulatory B cells (e.g., CD1dhiCD5+, T2-MZP, Tim-1+, and CD9+) were demonstrated in various diseases, and it plays a critical role in autoimmune diseases (37). In recent studies, functional studies in cancer diseases are emerging (38-40). In particular, the change of the distribution of regulatory B cells in cancer tissue is considered to one of important indicators (8-10). Emerging evidence suggests that regulatory B cells suppress effector immune cells including IFN-γ-producing cytotoxicity cells in various cancer diseases through the secretion of IL-10 (11). Although regulatory B cells have to play the suppressive role on the effector function of T cells in autoimmune diseases to cure diseases (41), ...
Marginal zone (MZ) B cells are thought to be responsible for the first wave of Abs against bacterial Ags. In this study, we assessed the in vivo response of MZ B cells in mice immunized with viral particles derived from the RNA phage Qbeta. We found that both follicular (FO) and MZ B cells responded to immunization with viral particles. MZ B cells responded with slightly faster kinetics, but numerically, FO B cells dominated the response. B1 B cells responded similarly to MZ B cells. Both MZ and FO B cells underwent isotype switching, with MZ B cells again exhibiting faster kinetics. In fact, almost all Qbeta-specific MZ B cells expressed surface IgG by day 5. Histological analysis demonstrated that a population of activated B cells remain associated with the MZ, probably due to the elevated integrin levels expressed by these cells. Thus, both MZ and FO B cells respond with rapid proliferation to viral infection and both populations undergo isotype switching, but MZ B cells remain in the MZ and may be
We originally cloned and identified murine Zizimin2 (Ziz2, Dock11) as a guanine nucleotide exchange factor (GEF) for Cdc42 and demonstrated that it activated the formation of filopodia. Since its expression pattern is restricted in immune tissues and Rho GTPases such as Cdc42 function in B cell deve …
New insights into human B cell biology. B cells are highly important white blood cells known as lymphocytes and are part of the adaptive immune system. B cells have a specialised receptor on their cell surface (B cell receptor, BCR) which recognises specific proteins. Upon activation, B cells produce antibodies which bind antigens like e.g. molecules from pathogens or vaccines. The drawback of a vast range of different B cell receptors is the potential that some of the receptors recognise self-antigens which can then result in auto-immune disorders. The bone marrow continuously releases immature B cells into the blood stream. A high proportion of these so-called transitional B cells are able to recognise self-antigens via their BCR. It has been unknown where in the body these auto-reactive cells are checked and removed from the circulation. A recent publication by Anna Vossenkämper and Jo Spencer (Kings College) tracked the fate of human transitional B cells and identified that these cells ...
Notch2 interaction with its ligand, Dll1, is required in the mouse to drive MZP into the MZB cell lineage (Saito et al., 2003; Hozumi et al., 2004). Preliminary data based on humanized mouse models have also proposed a Notch2 dependence for the differentiation of IgM+IgD+CD27+ B cells (Scheeren et al., 2008). Accordingly, we searched for an MZP in the spleen from young children, taking as diagnostic criteria its capacity to acquire an MZ phenotype when cultured in presence of OP9 cells expressing human DLL1, a differentiation which, moreover, should be specifically inhibited in presence of anti-NOTCH2 blocking antibodies. This precursor subset was identified using the recently described MEM55 antibody, which marks a glycosylated variant of the CD45RB molecule, harbored by CD27+ B cells and an immature B cell subset (Koethe et al., 2011). Surprisingly, these MZPs were further characterized as expressing the ABCB1 transporter reported so far as the unique hallmark of naive B cells (Wirths and ...
Vol. 203, No. 11, October 30, 2006. Pages 2425-2431.. Please note that an error appeared in the original online early release version of this article. A portion of text from the second paragraph in the Results and Discussion section was erroneously deleted. The current html, print, and pdf versions appear correctly. For reference, the corrected paragraph appears below in its entirety.. We next assessed if these long-lived t(14;18)-bearing B cells in HI already transited through the GCs. Circulating naive and memory B cells can be distinguished on the basis of the CD27 cell surface marker and sIg isotypes (11-13). Fresh PBMCs from 10 healthy donors were collected, and IgD+/CD27− naive, IgD+/CD27+ memory, and IgD−/CD27+ switched memory B cell subsets isolated by cell sorting (Fig. 2 A). The occurrence of t(14;18) was then assessed in total PBMCs and in each fraction by the short-range BCL2/JH PCR assay (Fig. 2 B and Table II). As a first approach, we pooled data from the two CD27+ memory ...
The production of antibody to a thymus-dependent Ag requires cooperation between the B cell and an Ag-specific Th cell. MHC restriction of this interaction implies that the Th cell recognizes Ag on the B cell surface in the context of MHC molecules and that the Ag-specific B cell gets help by acting as an APC for the Th cell. However, a number of studies have suggested that normal resting B cells are ineffective as APC, implying that the B cell must leave the resting state before it can interact specifically with a Th cell. Other studies, including our own with rabbit globulin-specific mouse T cell lines and hybridomas, show that certain T cell lines can be efficiently stimulated by normal resting B cells. One possible explanation for the above contradiction is that our B cells have become activated before presentation. Here we show that presentation by size-selected small B cells is not the result of nonspecific activation signals generated by the T cells or components of the medium. Also, although LPS
As with people, identity is vital to cells. When a cell loses its identity, it can stop working properly and a range of illnesses can result. The immune system, which protects our bodies from disease, includes cells with many different identities. When these cells lose their identity it can cause certain cancers or increase the risk of infections.. Complex networks of signals and genes create and maintain the identity of different cells. New research from the Babraham Institute, Cambridge and the University of Birmingham has revealed how a protein called ZFP36L1 helps cells known as marginal zone B cells (MZ B cells) to maintain their identity.. For cells, identity describes how they are adapted to have a specialised function. Blood cells are specialised for transportation, nerve cells for communication and the immune system fights infections. Each cell becomes specialised to do its job as a result of unique combinations of genetic instructions, which influence how the cell works.. MZ B cells ...
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Normal peripheral B cells can be activated by and cultured in interleukin 4 and anti-CD40 monoclonal antibodies. Is it possible to perform either stable or transient transfection assays in these cells ? Thanks for references if any. I am particularly interested in studying the expression of various p53 mutants ...
Martin, VG, Wu, Y-CB, Townsend, CL, Lu, GH, OHare, JS, Mozeika, A, Coolen, AC, Kipling, D, Fraternali, F and Dunn-Walters, Deborah (2016) Transitional B cells in early human B cell development - time to revisit the paradigm? ...
This lesson will focus in on the generalities of B-cells, such as their place of generation, maturation, and training, as well as some specific...
B Cell小鼠单克隆抗体[CA2.1D6](ab34125)可与马, 猫样本反应并经IP, IHC, Flow Cyt实验严格验证,被3篇文献引用。所有产品均提供质保服务,中国75%以上现货。
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Memory B cells are generated in germinal centers (GC) and contribute to serological immunity by rapidly differentiating into plasma cells. Human memory B cells can be identified by the expression of CD27. These cells exhibit more rapid responses than naive (CD27-) B cells following stimulation in vitro, consistent with the heightened kinetics of secondary responses in vivo. CD27+ B cells express mutated Ig V region genes; however a significant proportion continue to express IgM, suggesting the existence of IgM+ memory B cells. The observation that mutated IgM+CD27+ B cells are generated in humans who cannot form GC led to the conclusions that these cells are generated independently of GC and thus are not memory cells and that they mediate responses to T cell-independent Ag. Although some studies support the idea that IgM+CD27+ B cells participate in T cell-independent responses, many others do not. In this review we will provide alternate interpretations of the biology of IgM+CD27+ B cells and propose
Results High expression levels of TLR7 in SLE patients positively correlated with IFN signature and disease activity, but not with BAFF titers. SLE patients with high levels of TLR7 (TLR7hi group) showed an expansion of CD19+CD38highCD24highCD10+ TR B cells. Overall, frequencies of TR B cells positively correlated with the levels of TLR7, but not TLR9. SLE patients, carrying a risk G allele, had increased TLR7 expression and TR cell frequencies, compared to non-risk allele carriers. TLR7hi SLE patients showed increased autoantibody titers and skewing towards Sm/RNP antigens. Upon IFNα priming, TR B cells up-regulated TLR7 and differentiated into plasmablasts in response to TLR7-ligand stimulation. ...
Carole Goutsmedt, Laëtitia Le Pottier, Jacques-Olivier Pers. Identification of an antigen-specific regulatory B cell subset in humans.. 35th European Workshop for Rheumatology Research, Mar 2015, Budapest, Hungary. 74 (Supplément 1 A1.27), pp.A11, 2015, Annals of the Rheumatic Diseases. 〈hal-01128705〉 ...
B cells are known to play an important role in auto-immune diseases by activating T cells, secreting inflammatory cytokines and autoreactive antibodies. However, a sub-type of B cells named regulatory B cells or Bregs has recently shown capacities to prevent or cure arthritis in mouse models. Bregs have also been identified in humans. Main objective: To study Bregs abnormalities in patients with rheumatoid arthritis (RA) at different stages of the disease compared to subjects with mechanical pathologies.Secondary objectives:- To evaluate the specificity of any abnormalities identified in RA by studying Bregs in patients with other autoimmune or other inflammatory joint diseases.- To evaluate the effect of biological and synthetic treatments on Bregs in patients with RA. - To assess whether the rate of Bregs before treatment is predictive of response to biological and synthetic treatments ...
Original citation: J. Clin. Invest.112:286-297 (2003). doi:10.1172/JCI18025.. Citation for this corrigendum: J. Clin. Invest.113:1069 (2004). doi:10.1172/JCI18025E1.. The legends for Figures 6 and 7 contained inaccuracies, and the correct versions appear below. The conclusions of the article are unaffected.. Figure 6 BAFF increases the generation of ISC from activated memory B cells. (a and b) Memory B cells were preactivated with CD40L and IL-2/IL-10 for 4 days and then recultured with (a) media (black bars), or (b) IL-2/IL-10 alone (black bars) or in the presence of CD40L (white bars) or BAFF (gray bars). Each value represents the mean Ig secretion ± SEM of five (a) or seven (b) experiments using cells from different donors. *P , 0.05; **P , 0.01. (c) Secondary B cell cultures were performed in the absence (black bars) or presence (white bars) of soluble TACI-Ig (20 μg/ml). The values represent the mean IgA ± SD of duplicate samples. (d) Memory B cells were preactivated with ...
TY - JOUR. T1 - The CD40 ligand expressed by human B cells costimulates B cell responses. AU - Grammer, A. C.. AU - Bergman, M. C.. AU - Miura, Y.. AU - Fujita, K.. AU - Davis, L. S.. AU - Lipsky, P. E.. PY - 1995/1/1. Y1 - 1995/1/1. N2 - The possibility that activated B cells might express a ligand for CD40 that was of functional importance for B cell responses was examined by using highly purified human peripheral blood B cells, as well as a variety of B lymphoblastoid cell lines and hybridomas. Following stimulation with the combination of a calcium ionophore and a phorbol ester, human B cells bound a soluble fusion protein containing the extracellular portion of CD40 and the Fc region of lgG1 (CD40.lg). A variety of B cell lines and hybridomas also bound CD40.1g, either constitutively or after activation. In addition, CD40.Ig specifically immunoprecipitated a 33-kDa glycoprotein from surface 125I-labeled activated B cells. The nucleotide sequence of the coding region of the CD40 ligand mRNA ...
Scientists already knew that the formation of memory B lymphocytes is not as effective in elderly population, putting them at greater risk when facing new pathogens such as the SARS-CoV-2 coronavirus.. The study in Melameds lab revealed that as part of the aging process, existing memory B lymphocytes use hormonal signals to obstruct the production of new ones. As a result, the immune system becomes better at responding to pathogens it encountered before, but less capable of adapting to new threats.. Seeking a solution for this problem, Melameds lab collaborated with the departments of hematology and rheumatology at Tel Aviv Sourasky Medical Center and Rambam Health Care Campus in Haifa, respectively.. They examined elderly patients who had undergone B-cell depletion as a treatment for conditions such as lupus, lymphoma and multiple sclerosis. They found that after a significant amount of memory B lymphocytes were removed, the patients immune system was rejuvenated and began producing new, ...
Results Exogenously added IL-7 did not activate B cells directly, in line with the absence of surface IL-7R. However, in the presence of T cells, IL-7 activated both T and B cells (Ki67+ CD4 cells from 1.1±0.2% to 14.4±3.7%, p,0.01 and Ki67+ B cells from 1.9±0.3% to 4.1±0.9%, p,0.05). TLR7A induced B cell activation, as measured by increased proliferation (%Ki67 from 1.2±0.2% to 9.3±1.4%) and up regulation of activation markers on B cells, which was facilitated in the presence of monocytes. TLR7-induced B cell activation in T/B or T/B/monocyte co-cultures was not associated with T cell activation. IL-7 added to TLR7A synergistically increased both B cell (TLR7A vs. IL-7/TLR7A; 9.3±1.4% vs. 33.4±7.3%) and T cell proliferation (IL-7 vs. IL-7/TLR7A; 0.8±0.1% vs. 29.2±5.2%), which for B cells again was further increased by monocytes (TLR7A vs. IL-7/TLR7A; 30.2±8.9% vs. 63.0±8.0%). Similar results were observed for activation marker expression on B cells (CD19, HLA-DR CD25) and on T cells ...
B1 cells are a sub-class of B cell lymphocytes that are involved in the humoral immune response. They are not part of the adaptive immune system, as they have no memory, but otherwise, B1 cells perform many of the same roles as other B cells: making antibodies against antigens and acting as antigen presenting cells. Notably, most B1 cells do not develop into memory B cells. B1b cells have been shown to be capable of memory responses. See B1b lymphocytes confer T cell-independent long-lasting immunity. B1 cells are first produced in the fetus and most B1 cells undergo self-renewal in the periphery, unlike conventional B cells (B2 cells) that are produced after birth and replaced in the bone marrow. In January 2011, human B1 cells were found to have marker profile of CD20+CD27+CD43+CD70- and could either be CD5+ or CD5-, which has been debated since. CD5-CD72 is thought to mediate B cell-B cell interaction. B-1 B cells, in the mouse, can be further subdivided into B-1a (CD5+) and B-1b (CD5−) ...
To determine the phenotype of isolated B cells and differentiation on day 14 of culture, a gating strategy was developed for analysis of cells by flow cytometry. After debris and doublets were excluded, viable CD19+ cells were selected and analyzed for the proportions of naive and memory cells according to their CD27 and IgD expression. Viable plasma cells were determined as CD138+CD38+ cells. B cells cultured with the kit seemed to resemble untreated B cells in their subset distribution. The amounts of naive B cells decreased on day 14. This is in line with reports describing that naive B cells have a shorter survival rate. In contrast, the amounts of non-switched memory B cells increased in both the unstimulated culture and the culture expanded by the B Cell Expansion Kit indicating a greater survival capacity of this subset.. ...
This study demonstrates that patients with active, untreated IgG4-RD have significant elevations in their circulating plasmablast counts regardless of their serum IgG4 concentrations, and that patients with multi-organ IgG4-RD have higher absolute plasmablast counts than those with involvement of only one or two organs. In addition, plasmablast levels appear to be superior to serum IgG4 concentrations as a biomarker for IgG4-RD. Plasmablast counts decline swiftly following peripheral B cell depletion, and this decline is accompanied by corresponding decreases in disease activity as measured by the IgG4-RD RI. IgG4-RD thus represents an unusual example of an immune-mediated condition in which measurement of a single cell type may play a central role in diagnosing, monitoring and managing the disease.. The identification of circulating plasmablast expansion in IgG4-RD has substantial implications for clinical care. The diagnosis of IgG4-RD remains dependent upon biopsy and is therefore subject to ...
B cell subsets have been found to exhibit a negative regulatory function, like Tregs. The present study investigates the effects of CD5+CD19+ interleukin (IL)-10 (B10) on the occurrence and development of oesophageal carcinoma by analysing B10 levels in the peripheral blood of patients with...
Clone REA450 recognizes the rat CD45R antigen, an molecule which is expressed on B lymphocytes throughout their development from early pro-B stages onwards and is down-regulated upon terminal differentiation to plasma cells. Expression levels of CD45R are different among distinct B cell subpopulations and appears to be an indicator of maturational stages.Additional information: Clone REA450 displays negligible binding to Fc receptors. - Italia
B cells are crucial players in the human immune system which secrete antibodies that can eliminate bacterial antigens. An agent-based model is implemented to study the behaviour between B cell-antigen interactions during a bacterial infection. We have determined that infection in the system occurs when 69% of antigens are eliminated. Cellular lifetime of B cells plays a role in clearing the antigens, exhibiting three distinct phases - the lag phase, exponential growth phase, and the stationary phase. A Gompertz curve fit demonstrates that the B cell population curve mimics a biologically realistic phenomena. Studying the population dynamics of the system shows that B cell population peaks at around 60%-70% of antigens are eliminated, further supporting the determined point of infection.. ...
Xu S, Huo J, Huang Y, Aw M, Chen S, Mak S, Yip LY, Ho YS, Ng SW, Tan AH, Lee A, Ou X, Lam KP. von Hippel-Lindau Protein Maintains Metabolic Balance to Regulate the Survival of Naive B Lymphocytes. iScience. 2019 Jul 26;17:379-392 ...
TIM-1 defines a human regulatory B cell (Bregs) population that is altered in frequency and function in systemic sclerosis (SSc) patients. TIM-1 is a unique marker for the identification of a human IL-10+ Breg subpopulation which is partially superimposed with transitional B cells. Alterations in TIM-1+ B cells could contribute to the development of autoimmune diseases such as SSc. PubMed, Arthritis Res Ther, 2017 Jan 19;19(1):8. (Also see B Cells and T Cells) This item was posted in the ISN Newsroom. Please check the newsroom daily for updates on scleroderma and other related articles ...
Cd19 B Cell Activation, Bcr, Tcr, B Cell Co-receptor - B Cell Activation Cd21 Clipart is high quality 1023*612 transparent png stocked by PikPng. Download it free and share it with more people.
Regulation of inhibitory IgSF receptors in memory B cells by IL-4. Naive and memory B cells were purified from peripheral blood and cultured either in medium al
The process in which immature B cells from the bone marrow acquire the specialized features of T1 stage B cells in the spleen. T1 stage B cells do not express either CD23 or CD21.
Stimulation by antigen through the B cell receptor (BCR) followed by cognate T cell help drives proliferation and differentiation of antigen-specific naı̈ve B lymphocytes into memory B cells and plasma cells (1, 2). Memory B cells carrying somatically mutated immunoglobulin (Ig) genes survive in secondary lymphoid organs in the absence of antigen (3) and mediate secondary immune responses upon rechallenge. In contrast, plasma cells are terminally differentiated, nondividing cells that home to spleen and bone marrow and are the main source of antibody, which they secrete at a high rate. Mouse plasma cells can be long-lived and are able to sustain antibody production for several months in the absence of memory B cells or antigen (4, 5). However, it is less likely that long-lived plasma cells produced during an immune response will maintain a constant supply of specific antibody over a human life-span, because even long-lived plasma cells would eventually need to be replenished over a human ...
Secretory IgA (S-IgA) is a hallmark antibody principally produced at mucosal sites and plays an important role in the creation of immunological surveillance and homeostasis at mucosa. In addition to the IgA induction through gut-associated lymphoid tissues (e.g., Peyers patch), peritoneal B cells have been considered to be another source of S-IgA, especially specific for the T-independent antigen. Here we show that the trafficking of peritoneal B cells is principally regulated by sphingosine 1-phosphate (S1P). Peritoneal B cells expressed high levels of the type 1 S1P receptor. Thus, disruption of S1P-mediated signaling caused a rapid disappearance of peritoneal B cells. These changes did not affect natural plasma antibody production or phosphorylcholine (PC)-specific antibody production in serum after peritoneal immunization with heat-killed streptococcal pneumoniae. However, it dramatically reduced peritoneal B cell-derived natural intestinal S-IgA production without affecting the expression ...
Antibody affinity maturation occurs in germinal centers (GCs) through iterative rounds of somatic hypermutation and selection. Selection involves B cells competing for T cell help based on the amount of antigen they capture and present on their MHC class II (MHCII) proteins. How GC B cells are able to rapidly and repeatedly transition between mutating their B cell receptor genes and then being selected shortly after is not known. We report that MHCII surface levels and degradation are dynamically regulated in GC B cells. Through ectopic expression of a photoconvertible MHCII-mKikGR chimeric gene, we found that individual GC B cells differed in the rates of MHCII protein turnover. Fluctuations in surface MHCII levels were dependent on ubiquitination and the E3 ligase March1. Increases in March1 expression in centroblasts correlated with decreases in surface MHCII levels, whereas CD83 expression in centrocytes helped to stabilize MHCII at that stage. Defects in MHCII ubiquitination caused GC B cells to
Affinity maturation of antibodies during immune responses is achieved by multiple rounds of somatic hypermutation and subsequent preferential selection of those B cells that express B cell receptors with improved binding characteristics for the antigen. The mechanism underlying B cell selection has not yet been defined. By employing an agent-based model, we show that for physiologically reasonable parameter values affinity maturation can be driven by competition for neither binding sites nor antigen--even in the presence of competing secreted antibodies. Within the tested mechanisms, only clonal competition for T cell help or a refractory time for the interaction of centrocytes with follicular dendritic cells is found to enable affinity maturation while generating the experimentally observed germinal centre characteristics and tolerating large variations in the initial antigen density.
Immunity to individual group A rotavirus (RV), a major cause of viral gastroenteritis in infants, involves B lymphocytes that provide RV-specific antibodies. VP7 interactions with B cells were mediated by surface immunoglobulins and probably by their Fab portions. VP7-reactive B lymphocytes were mainly detected from RV-experienced patients and almost exclusively in the CD27-positive memory cell fraction. Conversely, VP6-reactive B lymphocytes were detected at comparable and high frequencies in adult, infant, and neonate samples. In adult samples, VP6 reacted with about 2% of the CD27-unfavorable (CD27neg) naive B cells. These results demonstrated that this VP6 RV protein interacted with a large fraction of naive B lymphocytes from both adults and neonates. We propose that naive B cell-VP6 conversation might impact the power and quality from the obtained immune system response and really should be looked at for elaborating RV vaccine strategies. Individual group A rotavirus (RV) is regarded as a ...
A naive (or inexperienced) B cell is one which belongs to a clone which has never encountered the epitope to which it is specific. In contrast, a memory B cell is one which derives from an activated naive or memory B cell. The activation of a naive or a memory B cell is followed by a manifold proliferation of that particular B cell, most of the progeny of which terminally differentiate into plasma B cells;[note 8] the rest survive as memory B cells. So, when the naive cells belonging to a particular clone encounter their specific antigen to give rise to the plasma cells, and also leave a few memory cells, this is known as the primary immune response. In the course of proliferation of this clone, the B cell receptor genes can undergo frequent (one in every two cell divisions)[8] mutations in the genes coding for paratopes of antibodies. These frequent mutations are termed somatic hypermutation. Each such mutation alters the epitope-binding ability of the paratope slightly, creating new clones of ...
We show here that approximately 25% of the mature peripheral B cells can survive in the mouse for at least 2 months without Syk, in a manner that requires BAFF‐R and CD19 signaling. In contrast, deletion of the Syk gene in early B cells results in the appearance of a small number of immature IgM+ B cells, which, however, fail to give rise to any mature B cells in the periphery (Cheng et al, 1995). Thus, pre‐B and mature B cells have different requirements for Syk. Indeed, the pre‐BCR is an autonomously signaling receptor that continuously engages Syk, whereas the BCR forms an autoinhibited oligomer on mature B cells that is not in contact with Syk. This notion is supported by a proximity ligation analysis showing that Syk is localized near the BCR only after BCR activation (Infantino et al, 2010; Klasener et al, 2014).. The presence of large amounts of Syk‐negative mature B cells in the induced mb1‐CreERT2;Sykfl/fl mice allowed us to analyze the in vivo role of this kinase in the ...
We show here that approximately 25% of the mature peripheral B cells can survive in the mouse for at least 2 months without Syk, in a manner that requires BAFF‐R and CD19 signaling. In contrast, deletion of the Syk gene in early B cells results in the appearance of a small number of immature IgM+ B cells, which, however, fail to give rise to any mature B cells in the periphery (Cheng et al, 1995). Thus, pre‐B and mature B cells have different requirements for Syk. Indeed, the pre‐BCR is an autonomously signaling receptor that continuously engages Syk, whereas the BCR forms an autoinhibited oligomer on mature B cells that is not in contact with Syk. This notion is supported by a proximity ligation analysis showing that Syk is localized near the BCR only after BCR activation (Infantino et al, 2010; Klasener et al, 2014).. The presence of large amounts of Syk‐negative mature B cells in the induced mb1‐CreERT2;Sykfl/fl mice allowed us to analyze the in vivo role of this kinase in the ...
Free online memory games. metro match is the classic memory game with a twist. Aj and ep are extremes on the spectrum of human memory. and their cases say more than any brain scan about the extent to which our memories make us who we. The game will be opened inside a popup window. please turn off any block popup program before clicking on the play button. Here, we show that human memory b lymphocytes. proliferate and differentiate into plasma cells in response to polyclonal stimuli, .. Is human memory similar to to the ram in a pc? discussion by michael freed, aerospace human factors, nasa ames research center. Exploiting human memory to create secure and emorable passwords they are difficult to remember because there are limits to human memory. Basic perofrmance data were obtained on the effect of critical task variables in unaided multiobject tracking behavior. .forgetmenot. intimate computing in support of human memory. a prototype device for memory support, an example of contextbased ...
B-cells go through a variety of stages during their development which is discussed in B-cell Development. However, the major functionally important stages to be aware of are the final stages known as the Plasma Cell and Memory B Cell stages. Plasma Cells are B-cells specialized for high levels of antibody synthesis and secretion. Memory B Cells are quiescent antigen-sepecific cells which differentiate following a primary immune response to a particular microbe which can become rapidly activated to differentiate into Plasma Cells if the microbe if re-encountered. B-cells can also be classified based on the subtype of antibody which they secrete ...
The B cell receptor (BCR) consists of an antigen-binding membrane immunoglobulin (mIg) associated with the CD79α and CD79β heterodimer. Naïve B cells express the IgM and IgD isotypes, which have very short cytoplasmic tails and therefore depend on CD79α and CD79β for signal transduction. After antigenic stimulation, B cells undergo isotype switching to yield IgG, IgE, or IgA. Recent research suggests that the ability of the B cell coreceptor CD22 to regulate BCR signaling depends on the isotype of the mIg cytoplasmic tail. Cell lines that express a BCR with the cytoplasmic tail from IgG, the isotype found in memory B cells, are not subject to CD22 regulation, whereas cell lines that express BCRs with IgM cytoplasmic tails are subject to CD22 regulation. Moreover, stimulation through BCRs containing an IgG cytoplasmic tail causes increased numbers of antigen-specific clones to accumulate. These observations are a valuable step toward understanding the difference in B cell signaling between ...
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Combination checkpoint blockade (CCB) targeting inhibitory CTLA4 and PD1 receptors holds promise for cancer therapy. Immune-related adverse events (IRAEs) remain a major obstacle for the optimal application of CCB in cancer. Here, we analyzed B cell changes in patients with melanoma following treatment with either anti-CTLA4 or anti-PD1, or in combination. CCB therapy led to changes in circulating B cells that were detectable after the first cycle of therapy and characterized by a decline in circulating B cells and an increase in CD21lo B cells and plasmablasts. PD1 expression was higher in the CD21lo B cells, and B cell receptor sequencing of these cells demonstrated greater clonality and a higher frequency of clones compared with CD21hi cells. CCB induced proliferation in the CD21lo compartment, and single-cell RNA sequencing identified B cell activation in cells with genomic profiles of CD21lo B cells in vivo. Increased clonality of circulating B cells following CCB occurred in some patients. ...
As there is growing evidence for the tumor microenvironments (TME) role in tumorigenesis, we investigated the role of fibroblast-expressed kinases in triple negative breast cancer (TNBC). Using a high-throughput kinome screen combined with 3D invasion assays, we identified fibroblast-expressed PIK3Cδ (f-PIK3Cδ) as a key regulator of progression. Although PIK3Cδ was expressed in primary fibroblasts derived from TNBC patients, it was undetectable in breast cancer cell lines. Genetic and pharmacologic gain- and loss-of functions experiments verified the contribution of f-PIK3Cδ in TNBC cell invasion. Integrated secretomics and transcriptomics analyses revealed a paracrine mechanism via which f-PIK3Cδ confers its pro-tumorigenic effects. Inhibition of f-PIK3Cδ promoted the secretion of factors, including PLGF and BDNF, which led to upregulation of NR4A1 in TNBC cells where it acts as a tumor suppressor. Inhibition of PIK3Cδ in an orthotopic BC mouse model reduced tumor growth only after ...
Combination checkpoint blockade (CCB) targeting inhibitory CTLA4 and PD1 receptors holds promise for cancer therapy. Immune-related adverse events (IRAEs) remain a major obstacle for the optimal application of CCB in cancer. Here, we analyzed B cell changes in patients with melanoma following treatment with either anti-CTLA4 or anti-PD1, or in combination. CCB therapy led to changes in circulating B cells that were detectable after the first cycle of therapy and characterized by a decline in circulating B cells and an increase in CD21lo B cells and plasmablasts. PD1 expression was higher in the CD21lo B cells, and B cell receptor sequencing of these cells demonstrated greater clonality and a higher frequency of clones compared with CD21hi cells. CCB induced proliferation in the CD21lo compartment, and single-cell RNA sequencing identified B cell activation in cells with genomic profiles of CD21lo B cells in vivo. Increased clonality of circulating B cells following CCB occurred in some patients. ...
Combination checkpoint blockade (CCB) targeting inhibitory CTLA4 and PD1 receptors holds promise for cancer therapy. Immune-related adverse events (IRAEs) remain a major obstacle for the optimal application of CCB in cancer. Here, we analyzed B cell changes in patients with melanoma following treatment with either anti-CTLA4 or anti-PD1, or in combination. CCB therapy led to changes in circulating B cells that were detectable after the first cycle of therapy and characterized by a decline in circulating B cells and an increase in CD21lo B cells and plasmablasts. PD1 expression was higher in the CD21lo B cells, and B cell receptor sequencing of these cells demonstrated greater clonality and a higher frequency of clones compared with CD21hi cells. CCB induced proliferation in the CD21lo compartment, and single-cell RNA sequencing identified B cell activation in cells with genomic profiles of CD21lo B cells in vivo. Increased clonality of circulating B cells following CCB occurred in some patients. ...
Combination checkpoint blockade (CCB) targeting inhibitory CTLA4 and PD1 receptors holds promise for cancer therapy. Immune-related adverse events (IRAEs) remain a major obstacle for the optimal application of CCB in cancer. Here, we analyzed B cell changes in patients with melanoma following treatment with either anti-CTLA4 or anti-PD1, or in combination. CCB therapy led to changes in circulating B cells that were detectable after the first cycle of therapy and characterized by a decline in circulating B cells and an increase in CD21lo B cells and plasmablasts. PD1 expression was higher in the CD21lo B cells, and B cell receptor sequencing of these cells demonstrated greater clonality and a higher frequency of clones compared with CD21hi cells. CCB induced proliferation in the CD21lo compartment, and single-cell RNA sequencing identified B cell activation in cells with genomic profiles of CD21lo B cells in vivo. Increased clonality of circulating B cells following CCB occurred in some patients. ...
Combination checkpoint blockade (CCB) targeting inhibitory CTLA4 and PD1 receptors holds promise for cancer therapy. Immune-related adverse events (IRAEs) remain a major obstacle for the optimal application of CCB in cancer. Here, we analyzed B cell changes in patients with melanoma following treatment with either anti-CTLA4 or anti-PD1, or in combination. CCB therapy led to changes in circulating B cells that were detectable after the first cycle of therapy and characterized by a decline in circulating B cells and an increase in CD21lo B cells and plasmablasts. PD1 expression was higher in the CD21lo B cells, and B cell receptor sequencing of these cells demonstrated greater clonality and a higher frequency of clones compared with CD21hi cells. CCB induced proliferation in the CD21lo compartment, and single-cell RNA sequencing identified B cell activation in cells with genomic profiles of CD21lo B cells in vivo. Increased clonality of circulating B cells following CCB occurred in some patients. ...
Combination checkpoint blockade (CCB) targeting inhibitory CTLA4 and PD1 receptors holds promise for cancer therapy. Immune-related adverse events (IRAEs) remain a major obstacle for the optimal application of CCB in cancer. Here, we analyzed B cell changes in patients with melanoma following treatment with either anti-CTLA4 or anti-PD1, or in combination. CCB therapy led to changes in circulating B cells that were detectable after the first cycle of therapy and characterized by a decline in circulating B cells and an increase in CD21lo B cells and plasmablasts. PD1 expression was higher in the CD21lo B cells, and B cell receptor sequencing of these cells demonstrated greater clonality and a higher frequency of clones compared with CD21hi cells. CCB induced proliferation in the CD21lo compartment, and single-cell RNA sequencing identified B cell activation in cells with genomic profiles of CD21lo B cells in vivo. Increased clonality of circulating B cells following CCB occurred in some patients. ...
AC50 of HA-specific GC B cells can be used as a proxy for population avidity to PR8 HA. (A) Overview of AC50. GC B cell rHA staining frequency is plotted agains
Our immune system efficiently protects us against the daily onslaught of foreign pathogens. However, the targeting, strength and extent...
The main cell types in humoral immune responses is B cell which acts as antigen presenting cells, developing antibodies to fight foreign antigens and prepare plasma cells or memory B cells. Isolation of B cells can be done with the help of the cell isolation kits which are fast and easy to isolate highly and purified functional B cells for research purpose. StemCell organization helps to make these researches successful with their high quality product, providing consistent as well as all the required support from their dedicated staff available on board. They have also received the ISO certificate for research, manufacturing and shipping facilities to France, Canada, USA, to name a few ...
Researchers at the University of Gothenburgs Sahlgrenska Academy have looked at B cells, a type of white blood cell that produces antibodies that can protect the body against infection and play a key role in the development of allergies. By studying 65 healthy newborn babies in the Västra Götaland region, researcher Anna-Carin Lundell and her colleagues were able to show that infants whose gut is colonised by E. coli bacteria during the first few weeks of life had a higher number of memory B cells at the age of both four and 18 months ...
Reimer, D and Lee, AYS and Bannan, J and Fromm, P and Kara, EE and Comerford, I and McColl, S and Wiede, F and Mielenz, D and Korner, H, Early CCR6 expression on B cells modulates germinal centre kinetics and efficient antibody responses, Immunology and Cell Biology, 95, (1) pp. 33-41. ISSN 0818-9641 (2017) [Refereed Article ...
A type of white blood cell that matures in the bone marrow. B cells make antibodies against antigens and create new B cells that remember the antigens old B cells already encountered ...