Science.gov

Sample records for b-cell safety cleanout

  1. Quality assurance program plan for 324 Building B-Cell safety cleanout project (BCCP)

    SciTech Connect

    Tanke, J.M.

    1997-05-22

    This Quality Assurance Program Plan (QAPP) provides information on how the Quality Assurance Program is implemented for the 324 Building B-Cell Safety Cleanout Project (BCCP). This QAPP is responsive to the Westinghouse Hanford Company Quality Assurance Program and Implementation Plan, WHC-SP-1131, for 10 CFR 830.120, Nuclear Safety Management, Quality Assurance Requirements; and DOE Order 5700.6C, Quality Assurance. This QAPP supersedes PNNL PNL-MA-70 QAP Quality Assurance Plan No. WTC-050 Rev. 2, issue date May 3, 1996. This QAPP has been developed specifically for the BCCP. It applies to those items and tasks which affect the completion of activities identified in the work breakdown structure of the Project Management Plan (PMP). These activities include all aspects of decontaminating B-Cell and project related operations within the 324 Building as it relates to the specific activities of this project. General facility activities (i.e. 324 Building Operations) are covered in the Building 324 QAPP. In addition, this QAPP supports the related quality assurance activities addressed in CM-2-14, Hazardous Material Packaging and Shipping, and HSRCM-1, Hanford Site Radiological Control Manual, The 324 Building is currently transitioning from being a Pacific Northwest National Laboratory (PNNL) managed facility to a B and W Hanford Company (BWHC) managed facility. During this transition process existing, PNNL procedures and documents will be utilized until replaced by BWHC procedures and documents. These documents conform to the requirements found in PNL-MA-70, Quality Assurance Manual and PNL-MA-8 1, Hazardous Materials Shipping Manual. The Quality Assurance Program Index (QAPI) contained in Table 1 provides a matrix which shows how project activities relate to 10 CFR 83 0.120 and 5700.6C criteria. Quality Assurance program requirements will be addressed separate from the requirements specified in this document. Other Hanford Site organizations/companies may be

  2. Review of alternative residual contamination guides for the 324 Building B-Cell Cleanout Project. Phase 1

    SciTech Connect

    Vargo, G.J.; Durham, J.S.; Brackenbush, L.W.

    1995-09-01

    This report provides a proposed residual contamination guide (RCG) for the 324 Building B-Cell Cleanout Project, Phase 1, at the Hanford Site. The RCG is expressed as a fraction of the amount of highly dispersible radioactive material that would result in offsite doses equal to the Pacific Northwest Laboratory radiological risk guidelines following the worst credible accident scenario for release of the holdup material. The proposed RCG is 10{sup {minus}1} to 10{sup {minus}2} of the PNL radiological risk guidelines. As part of the development of the RCG, a number of factors were considered. These include the need to provide an appropriate level of flexibility for other activities within the 324 Building that could contribute to the facility`s overall radiological risk, uncertainties inherent in safety analyses, and the possible contribution of other 300 Area facilities to overall radiological risk. Because of these factors and the nature of the cleanout project, the RCG is expressed as a range rather than a point value. This report also provides guidance on determining conformance to the RCG, including inspection and measurement techniques, quality assurance requirements, and consideration of uncertainty.

  3. 40 CFR 262.213 - Laboratory clean-outs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Laboratory clean-outs. 262.213 Section....213 Laboratory clean-outs. (a) One time per 12 month period for each laboratory, an eligible academic entity may opt to conduct a laboratory clean-out that is subject to all the applicable requirements...

  4. 40 CFR 262.213 - Laboratory clean-outs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Laboratory clean-outs. 262.213 Section....213 Laboratory clean-outs. (a) One time per 12 month period for each laboratory, an eligible academic entity may opt to conduct a laboratory clean-out that is subject to all the applicable requirements...

  5. 40 CFR 262.213 - Laboratory clean-outs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Laboratory clean-outs. 262.213 Section....213 Laboratory clean-outs. (a) One time per 12 month period for each laboratory, an eligible academic entity may opt to conduct a laboratory clean-out that is subject to all the applicable requirements...

  6. 40 CFR 262.213 - Laboratory clean-outs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Determination and Accumulation of Unwanted Material for Laboratories Owned by Eligible Academic Entities § 262.213 Laboratory clean-outs. (a) One time per 12 month period for each laboratory, an eligible academic... hazardous waste; and (3) For the purposes of off-site management, an eligible academic entity must count...

  7. 21 CFR 225.65 - Equipment cleanout procedures.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Equipment cleanout procedures. 225.65 Section 225.65 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR MEDICATED FEEDS Product Quality Control §...

  8. 21 CFR 225.165 - Equipment cleanout procedures.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Equipment cleanout procedures. 225.165 Section 225.165 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DRUGS: GENERAL CURRENT GOOD MANUFACTURING PRACTICE FOR MEDICATED FEEDS Product Quality Assurance §...

  9. 10. SETTLING TANK CLEANOUT DOORS, SOUTH SIDE; USED TO CLEAN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. SETTLING TANK CLEAN-OUT DOORS, SOUTH SIDE; USED TO CLEAN DEBRIS FROM SURFACE OF WATER IN SETTLING TANK. - Hondius Water Line, 1.6 miles Northwest of Park headquarters building & 1 mile Northwest of Beaver Meadows entrance station, Estes Park, Larimer County, CO

  10. Cleanout and Decontamination of a Mustard Agent Ton Container.

    DTIC Science & Technology

    1997-06-01

    HD TCs using pressurized hot water and steam. ERDEC has successfully decontaminated two HD TCs in an ERDEC Toxic Test Chamber to a 3X condition using...this process. 14. SUBJECT TERMS 15. NUMBER OF PAGES Ton Containers HD Decontamination Alternative Technology Program 143 3X Condition Heel Hot Water ...the interior of the TC with pressurized hot water . The demonstration was designed to confirm the results of the first HD TC Cleanout Demonstration, and

  11. Adeno-Associated Virus-Like Particles as New Carriers for B-Cell Vaccines: Testing Immunogenicity and Safety in BALB/c Mice

    PubMed Central

    Manzano-Szalai, Krisztina; Thell, Kathrin; Willensdorfer, Anna; Weghofer, Margit; Pfanzagl, Beatrix; Singer, Josef; Ritter, Mirko; Stremnitzer, Caroline; Flaschberger, Ingo; Michaelis, Uwe

    2014-01-01

    Abstract Adeno-associated viruses (AAVs) are established vectors for gene therapy of different human diseases. AAVs are assembled of 60 capsomers, which can be genetically modified, allowing high-density display of short peptide sequences at their surface. The aim of our study was to evaluate the immunogenicity and safety of an adeno-associated virus-like particle (AAVLP)-displayed B-cell peptide epitope taking ovalbumin (OVA) as a model antigen or allergen from egg, respectively. An OVA-derived B-cell epitope was expressed as fusion protein with the AAV-2 capsid protein of VP3 (AAVLP-OVA) and for control, with the nonrelated peptide TP18 (AAVLP-TP18). Cellular internalization studies revealed an impaired uptake of AAVLP-OVA by mouse BMDC, macrophages, and human HeLa cells. Nevertheless, BALB/c mice immunized subcutaneously with AAVLP-OVA formed similarly high titers of OVA-specific IgG1 compared to mice immunized with the native OVA. The extent of the immune response was independent whether aluminum hydroxide or water in oil emulsion was used as adjuvant. Furthermore, in mice immunized with native OVA, high OVA-specific IgE levels were observed, which permitted OVA-specific mast-cell degranulation in a β-hexosaminidase release assay, whereas immunizations with AAVLP-OVA rendered background IgE levels only. Accordingly, OVA-immunized mice, but not AAVLP-OVA immunized mice, displayed an anaphylactic reaction with a significant drop of body temperature upon intravenous OVA challenge. From this mouse model, we conclude that AAVLPs that display B-cell epitope peptides on their surface are suitable vaccine candidates, especially in the field of allergy. PMID:25247267

  12. Safety and Efficacy of a Genetic Vaccine Targeting Telomerase Plus Chemotherapy for the Therapy of Canine B-Cell Lymphoma

    PubMed Central

    Gavazza, Alessandra; Lubas, George; Fridman, Arthur; Peruzzi, Daniela; Impellizeri, Joseph A.; Luberto, Laura; Marra, Emanuele; Roscilli, Giuseppe; Ciliberto, Gennaro

    2013-01-01

    Abstract Client-owned pet dogs represent exceptional translational models for advancement of cancer research because they reflect the complex heterogeneity observed in human cancer. We have recently shown that a genetic vaccine targeting dog telomerase reverse transcriptase (dTERT) and based on adenovirus DNA electro-gene-transfer (Ad/DNA-EGT) technology can induce strong cell-mediated immune responses against this tumor antigen and increase overall survival of dogs affected by B-cell lymphosarcoma (LSA) in comparison with historical controls when combined with a cyclophosphamide, vincristine, and prednisone (COP) chemotherapy regimen. Here, we have conducted a double-arm clinical trial with an extended number of LSA patients, measured the antigen-specific immune response, and evaluated potential toxic effects of the immunotherapy along with a follow-up of patients survival for 3.5 years. The immune response was measured by enzyme-linked immunospot assay. The expression of dTERT was quantified by quantitative polymerase chain reaction. Changes in hematological parameters, local/systemic toxicity or organic dysfunction and fever were monitored over time during the treatment. dTERT-specific cell-mediated immune responses were induced in almost all treated animals. No adverse effects were observed in any dog patient that underwent treatment. The overall survival time of vaccine/COP-treated dogs was significantly increased over the COP-only cohort (>76.1 vs. 29.3 weeks, respectively, p<0.0001). There was a significant association between dTERT expression levels in LSA cells and overall survival among vaccinated patients. In conclusion, Ad/DNA-EGT-based cancer vaccine against dTERT in combination with COP chemotherapy is safe and significantly prolongs the survival of LSA canine patients. These data confirm the therapeutic efficacy of dTERT vaccine and support the evaluation of this approach for other cancer types as well as the translation of this approach to human

  13. Diffuse large B-cell lymphoma associated with the use of biologic and other investigational agents: the importance of long-term post-marketing safety surveillance.

    PubMed

    Goddard, Allison; Borovicka, Judy H; West, Dennis P; Evens, Andrew M; Laumann, Anne

    2011-01-01

    This case report describes a patient who developed diffuse large B-cell lymphoma (DLBCL) after receiving courses of two investigational biologic agents and cyclosporine followed by more than four years of subcutaneous efalizumab for the treatment of extensive chronic plaque psoriasis. Three years later, the patient remains free of lymphoma and his psoriasis is well controlled with thrice-weekly narrow-band ultraviolet phototherapy. This case emphasizes the importance of continued long-term post-marketing safety surveillance and the early reporting of all possible serious side effects, including cancers, related to the use of any newly available product. In particular, surveillance should focus on the immunomodulating biologic agents in order to identify possible dangerous sequelae.

  14. Safety and efficacy of rituximab plus bendamustine in relapsed or refractory diffuse large B-cell lymphoma patients: an Italian retrospective multicenter study.

    PubMed

    Arcari, Annalisa; Chiappella, Annalisa; Spina, Michele; Zanlari, Luca; Bernuzzi, Patrizia; Valenti, Vanessa; Tani, Monica; Marasca, Roberto; Cabras, Maria Giuseppina; Zambello, Renato; Santagostino, Alberto; Ilariucci, Fiorella; Carli, Giuseppe; Musto, Pellegrino; Savini, Paolo; Marino, Dario; Ghio, Francesco; Gentile, Massimo; Cox, Maria Christina; Vallisa, Daniele

    2016-08-01

    Relapsed or refractory diffuse large B-cell lymphoma (DLBCL) not suitable for high dose chemotherapy with autologous stem cell transplantation (ASCT) has a dismal prognosis and no standard therapy. We designed an Italian multicenter retrospective study aimed at evaluating the safety and efficacy of rituximab plus bendamustine (R-B) as salvage treatment in patients not eligible for ASCT because of age and/or comorbidity or in patients with post-ASCT recurrence. Fifty-five patients with a median age of 76 years were included. The overall response rate was 50%, including 28% complete remission and 22% partial remission. The median overall survival (OS) was 10.8 months. The median progression free survival (PFS) was 8.8 months. Eleven patients are still alive and in complete remission at last follow-up (12-71 months). Toxicity was moderate, mainly grades 1 and 2. R-B showed promising efficacy results with an acceptable toxicity profile and should be further investigated, possibly in combination with novel drugs.

  15. 324 Facility B-Cell quality process plan

    SciTech Connect

    Carlson, J.L.

    1998-06-10

    B-Cell is currently being cleaned out (i.e., removal of equipment, fixtures and residual radioactive materials) and deactivated. TPA Milestone M-89-02 dictates that all mixed waste and equipment be removed from B-Cell by 5/31/99. The following sections describe the major activities that remain for completion of the TPA milestone. This includes: (1) Size Reduce Tank 119 and Miscellaneous Equipment. This activity is the restart of hotwork in B-Cell to size reduce the remainder of Tank 119 and other miscellaneous pieces of equipment into sizes that can be loaded into a grout container. This activity also includes the process of preparing the containers for shipment from the cell. The specific activities and procedures used are detailed in a table. (2) Load and Ship Low-Level Waste. This activity covers the process of taking a grouted LLW container from B-Cell and loading it into the cask in the REC airlock and Cask Handling Area (CHA) for shipment to the LLBG. The detailed activities and procedures for this part of cell cleanout are included in second table.

  16. Effects of a legal drain clean-out on wetlands and waterbirds: a recent case history

    USGS Publications Warehouse

    Krapu, Gary L.

    1996-01-01

    Repairs to legal drains in the United States may be regulated to protect adjacent wetlands under Section 404 of the Federal Water Pollution Control Act, commonly known as the Clean Water Act (CWA). However, few studies have examined effects of legal drain clean-outs on adjacent wetlands and associated migratory waterbird populations. I compare water regimes, cover-to-open water ratios, and waterbird use on Bruns, Big, Meszaros, and Kraft sloughs (BBMK) in Sargent County, North Dakota before and after the clean-out of Crete-Cogswell Drain No. 11, and relate wetland habitat loss to observed disease-related mortality among staging waterfowl in fall 1990 and spring 1991. Water regimes of BBMK were exceptionally stable, with few records of drawdowns before 1984 when the clean-out began. After the clean-out (1987-90), BBM were dry by mid-summer in all years and open area declined by 96% by 1990, whereas Kraft Slough (a control area) had water throughout all years and percent open area did not change. Numerous species of waterbirds nested in BBMK before the clean-out, and mean ranks of waterbird density were similar. After the clean-out, waterbirds failed to breed successfully in all years at BBM, and use as major waterfowl staging areas and for waterfowl hunting also ended. At Kraft Slough, use by breeding and staging waterbirds continued in all years, as did waterfowl hunting. Reduced access to fresh water after the Drain No. 11 clean-out may have contributed to a dieoff of 487 lesser snow geese (Chen caerulescens) from necrotic enteritis in Kraft Slough in November 1990. Loss of three major staging areas in Sargent County as a result of the drain clean-out has further concentrated migrant waterfowl, particularly during drought periods, increasing the magnitude of risk when epizootics occur in southeastern North Dakota. Ducks and geese banded in Sargent County have been recovered from 34 and 14 states, 7 and 6 provinces of Canada, and 13 and 1 other countries

  17. Silver removal process development for the MEO cleanout

    SciTech Connect

    Hsu, P.C.; Chiba, Z.; Schumacher, B.J.; Murguia, L.C.; Adamson, M.G.

    1996-02-01

    The Mediated Electrochemical Oxidation (MEO) system is an aqueous process which treats low-level mixed wastes by oxidizing the organic components of he waste into carbon dioxide and water. As MEO system continues to run, dissolved ash and radionuclides slowly accumulate in the anolyte and must be removed to maintain process efficiency. At such time, all of the anolyte is pumped into a still feed tank, and the silver ions need to be removed before sending the solution to a thin-film evaporator for further concentration. The efficiency of removing silver ions in the solution needs to be high enough such that the residual silver sent to Final Forms would be less than 1% wt. The purpose of this work is to develop an efficient process to remove silver ions during the MEO cleanout and to demonstrate the capability of centrifugation for separating small silver chloride particles from the solution. This development work includes lab scale experiments and bench scale tests. This report summarizes the results.

  18. B cell depletion in diffuse progressive systemic sclerosis: safety, skin score modification and IL-6 modulation in an up to thirty-six months follow-up open-label trial

    PubMed Central

    2010-01-01

    Introduction An over-expression of CD19 has been shown in B cells of systemic sclerosis (SSc) and B cells are thought to contribute to the induction of skin fibrosis in the tight skin mouse model. The aim was to define the outcome on safety and the change in skin score after rituximab therapy in SSc patients and to correlate the clinical characteristics with the levels of interleukin (IL)-6 and with the immune cell infiltrate detected by immunohistochemistry. Methods Nine patients with SSc with mean age 40.9 ± 11.1 years were treated with anti-CD20, 1 g at time 0 and after 14 days. Skin biopsy was performed at baseline and during the follow-up. B-cell activating factor (BAFF) and IL-6 levels were also determined at the follow-up times. Results After 6 months patients presented a median decrease of the skin score of 43.3% (range 21.1-64.0%), and a decrease in disease activity index and disease severity index. IL-6 levels decreased permanently during the follow up. After treatment, a complete depletion of peripheral blood B cells was observed in all but 2 patients. Only 3 patients presented CD20 positive cells in the biopsy of the involved skin at baseline. Conclusions Anti-CD20 treatment has been well tolerated and SSc patients experienced an improvement of the skin score and of clinical symptoms. The clear fall in IL-6 levels could contribute to the skin fibrosis improvement, while the presence of B cells in the skin seems to be irrelevant with respect to the outcome after B cell depletion. Trial registration ISRCTN77554566. PMID:20338043

  19. B cell helper assays.

    PubMed

    Abrignani, Sergio; Tonti, Elena; Casorati, Giulia; Dellabona, Paolo

    2009-01-01

    Activation, proliferation and differentiation of naïve B lymphocytes into memory B cells and plasma cells requires engagement of the B cell receptor (BCR) coupled to T-cell help (1, 2). T cells deliver help in cognate fashion when they are activated upon recognition of specific MHC-peptide complexes presented by B cells. T cells can also deliver help in a non-cognate or bystander fashion, when they do not find specific MHC-peptide complexes on B cells and are activated by alternative mechanisms. T-cell dependent activation of B cells can be studied in vitro by experimental models called "B cell helper assays" that are based on the co-culture of B cells with activated T cells. These assays allow to decipher the molecular bases for productive T-dependent B cell responses. We show here examples of B cell helper assays in vitro, which can be reproduced with any subset of T lymphocytes that displays the appropriate helper signals.

  20. Memory B cells.

    PubMed

    Kurosaki, Tomohiro; Kometani, Kohei; Ise, Wataru

    2015-03-01

    The immune system can remember a previously experienced pathogen and can evoke an enhanced response to reinfection that depends on memory lymphocyte populations. Recent advances in tracking antigen-experienced memory B cells have revealed the existence of distinct classes of cells that have considerable functional differences. Some of these differences seem to be determined by the stimulation history during memory cell formation. To induce rapid recall antibody responses, the contributions of other types of cells, such as memory T follicular helper cells, have also now begun to be appreciated. In this Review, we discuss these and other recent advances in our understanding of memory B cells, focusing on the underlying mechanisms that are required for rapid and effective recall antibody responses.

  1. Radioactive Air Emissions Notice of Construction (NOC) for the 300 Area Process Sewer Cleanout

    SciTech Connect

    MENARD, N.M.

    2000-06-16

    This document serves as a NOC pursuant to the requirements of Washington Administrative Code (WAC) 246-247-060, and as a request for approval to construct pursuant to 40 Code of Federal Regulations (CFR) 61.07, for the cleanout of sections of the 300 Area PS. Approval of the NOC will allow the pressure washing of certain pipe sections, the sump in the TEDF lift station, and the cleaning of PS 16 of the 300 Area PS that contains low levels of radioactivity. Section 15.0 of this NOC discusses the estimated total effective dose equivalent (TEDE) to the offsite maximally exposed individual (MEI) resulting from the unabated emissions from these cleaning activities. Using the currently approved unit dose conversion factors in HNF-3602, the estimated potential TEDE to the MEI resulting from the unabated, fugitive emissions from cleanout of the 300 Area PS is 4.70 E-05 millirem (mrem) per year. This dose was derived by conservatively estimating the doses from both the pressure washing and the use of the Guzzler{trademark} for removal of the liquid/soil mixture, as described in Section 5.0. and adding these doses together.

  2. Memory B cells in Transplantation

    PubMed Central

    Chong, Anita S.; Sciammas, Roger

    2014-01-01

    Much of the research on the humoral response to allografts has focused on circulating serum antibodies and the long-lived plasma cells that produce these antibodies. In contrast, the interrogation of the quiescent memory B cell compartment is technically more challenging and thus has not been incorporated into the clinical diagnostic or prognostic toolkit. In this review, we discuss new technologies that have allowed this heretofore enigmatic subset of B cells to be identified at quiescence and during a recall response. These technologies in experimental models are providing new insights into memory B cell heterogeneity with respect to their phenotype, cellular function and the antibodies they produce. Similar technologies are also allowing for the identification of comparable memory alloreactive B cells in transplant recipients. While much of the focus in transplant immunology has been on controlling the alloreactive B cell population, long-term transplant patient survival is critically dependent on protection by pathogen-specific memory B cells. Techniques are also available that allow the interrogation of memory B cell response to pathogen re-encounter. Thus we are poised in our ability toinvestigate how immunosuppression affects allo- as well as pathogen-specific memory B cells, and reason that these investigation can yield new insights that will be beneficial for graft as well as patient survival. PMID:25525921

  3. 324 and 325 Building Hot Cell Cleanout Program: Air lock cover block refurbishment

    SciTech Connect

    Katayama, Y.B.; Holton, L.K. Jr.; Gale, R.M.

    1989-05-01

    The high-density concrete cover blocks shielding the pipe trench in the hot-cell air lock of the 324 Building Radiochemical Engineering Cells had accumulated fixed radioactivity ranging from 1100 to 22, 000 mrad/hr. A corresponding increase in the radiation exposure to personnel entering the air lock, together with ALARA concerns, led to the removal of the contaminated concrete surface with a hydraulic spaller and the emplacement of a stainless steel covering over a layer of grout. The resultant saving in radiation exposure is estimated to be 7200 mrad for personnel completing burial box runs for the 324 and 325 Building Hot Cell Cleanout Program. Radiation exposure to all staff members entering the air lock is now at least 50% lower. 3 refs., 22 figs., 1 tab.

  4. B Cell Subsets in Atherosclerosis

    PubMed Central

    Perry, Heather M.; Bender, Timothy P.; McNamara, Coleen A.

    2012-01-01

    Atherosclerosis, the underlying cause of heart attacks and strokes, is a chronic inflammatory disease of the artery wall. Immune cells, including lymphocytes modulate atherosclerotic lesion development through interconnected mechanisms. Elegant studies over the past decades have begun to unravel a role for B cells in atherosclerosis. Recent findings provide evidence that B cell effects on atherosclerosis may be subset-dependent. B-1a B cells have been reported to protect from atherosclerosis by secretion of natural IgM antibodies. Conventional B-2 B cells can promote atherosclerosis through less clearly defined mechanism that may involve CD4 T cells. Yet, there may be other populations of B cells within these subsets with different phenotypes altering their impact on atherosclerosis. Additionally, the role of B cell subsets in atherosclerosis may depend on their environmental niche and/or the stage of atherogenesis. This review will highlight key findings in the evolving field of B cells and atherosclerosis and touch on the potential and importance of translating these findings to human disease. PMID:23248624

  5. White paper: cleanout of tank 241-AP-108 for storage of phase 1 pretreated low-activity waste

    SciTech Connect

    PLACE, D.E.

    1999-06-24

    This white paper evaluates the feasibility of cleaning tank 241-AP-108 for storage of pretreated low-activity waste. The maximum allowable heel inventories for {sup 90}Sr, {sup 99}Tc, {sup 137}Cs, and TRu are established. Cesium-137 was found to be the limiting radionuclide for tank 241-AP-108 cleanout. Equipment requirements for cleanout are identified and risks associated with extended storage of pretreated low-activity waste are discussed. This evaluation assumes that tank 241-AP-108 will be used for storage of pretreated low-activity waste from tanks 241-AZ-101 and 241-AZ-102 in accordance with the 1996 Tank Waste Remediation System Privatization Contract with BNFL Inc. Alternatives are currently under development that would not require this storage function. This document is being issued to capture the work performed to date.

  6. Evolution of B Cell Immunity

    PubMed Central

    Sunyer, J. Oriol

    2013-01-01

    Two types of adaptive immune strategies are known to have evolved in vertebrates: the VLR-based system, which is present in jawless organisms and is mediated by VLRA and VLRB lymphocytes, and the BCR/TCR-based system, which is present in jawed species and is provided by B and T cell receptors expressed on B and T cells, respectively. Here we summarize features of B cells and their predecessors in the different animal phyla, focusing the review on B cells from jawed vertebrates. We point out the critical role of nonclassical species and comparative immunology studies in the understanding of B cell immunity. Because nonclassical models include species relevant to veterinary medicine, basic science research performed in these animals contributes to the knowledge required for the development of more efficacious vaccines against emerging pathogens. PMID:25340015

  7. B-cell survival factors in autoimmune rheumatic disorders

    PubMed Central

    Morais, Sandra A.; Vilas-Boas, Andreia

    2015-01-01

    Autoimmune rheumatic disorders have complex etiopathogenetic mechanisms in which B cells play a central role. The importance of factors stimulating B cells, notably the B-cell activating factor (BAFF) and A proliferation inducing ligand (APRIL) axis is now recognized. BAFF and APRIL are cytokines essential for B-cell proliferation and survival from the immature stages to the development of plasma cells. Their levels are increased in some subsets of patients with autoimmune disorders. Several recent biologic drugs have been developed to block this axis, namely belimumab [already licensed for systemic lupus erythematosus (SLE) treatment], tabalumab, atacicept and blisibimod. Many clinical trials to evaluate the safety and efficacy of these drugs in several autoimmune disorders are ongoing, or have been completed recently. This review updates the information on the use of biologic agents blocking BAFF/APRIL for patients with SLE, rheumatoid arthritis, Sjögren’s syndrome and myositis. PMID:26288664

  8. 324 and 325 Building hot cell cleanout program: Decontamination of C-Cell

    SciTech Connect

    Katayama, Y.B.; Holton, L.K. Jr.

    1989-10-01

    During FY 1989 the decontamination of C-Cell of Hanford's 324 Building was completed as part of the 324 and 325 Building Hot Cell Cleanout Program sponsored by the DOE Nuclear Energy's Surplus Facilities Management Program. The decontamination effort was completed using a series of remote and contact decontamination techniques. Initial radiation readings in C-Cell averaged 50 rad/hr and were reduced remotely to less than 200 mrad/hr using an alkaline foam cleaner followed by a 5000-psi water flush. Contact decontamination was then permissible using ultra high-pressure water, at 36,000 psi, further reducing the average radiation level in the cell to less than 86 mrem/hr. The approach used in decontaminating C-Cell resulted in a savings in radiation exposure of 87% and a cost savings of 39% compared to a hands-on procedure used in A-Cell, 324 Building in 1987. The radiation dose and the costs to achieve a 244-fold reduction in radiation contamination were 1.65 mrem per ft{sup 2} and $96 per ft{sup 2} of cell surface area. 14 figs., 4 tabs.

  9. Memory B cells: total recall.

    PubMed

    Phan, Tri Giang; Tangye, Stuart G

    2017-03-28

    Immunological memory is a cornerstone of adaptive immune responses in higher vertebrates. The remarkable ability to generate memory cells following Ag exposure, in the context of natural infection or immunization, provides long-lived protection against infectious diseases, often for the hosts' lifetime. Indeed, the generation of memory B cells and long-lived plasma cells underpins the success of most vaccines. The concept of immunological memory is not new-it was first proposed nearly 2500 years ago. While our understanding of the complexities of humoral and cell-mediated memory continues to evolve, important aspects of this process remain unresolved. Here, we will provide an overview of recent advances in B-cell memory in mice and humans, and in health and disease.

  10. B-cell tolerance and autoimmunity

    PubMed Central

    Tsubata, Takeshi

    2017-01-01

    Self-reactive B cells are tolerized at various stages of B-cell development and differentiation, including the immature B-cell stage (central tolerance) and the germinal center (GC) B-cell stage, and B-cell tolerance involves various mechanisms such as deletion, anergy, and receptor editing. Self-reactive B cells generated by random immunoglobulin variable gene rearrangements are tolerized by central tolerance and anergy in the periphery, and these processes involve apoptosis regulated by Bim, a pro-apoptotic member of the Bcl-2 family, and regulation of B-cell signaling by various phosphatases, including SHIP-1 and SHP-1. Self-reactive B cells generated by somatic mutations during GC reaction are also eliminated. Fas is not directly involved in this process but prevents persistence of GC reaction that allows generation of less stringently regulated B cells, including self-reactive B cells. Defects in self-tolerance preferentially cause lupus-like disease with production of anti-nuclear antibodies, probably due to the presence of a large potential B-cell repertoire reactive to nucleic acids and the presence of nucleic acid-induced activation mechanisms in various immune cells, including B cells and dendritic cells. A feed-forward loop composed of anti-nuclear antibodies produced by B cells and type 1 interferons secreted from nucleic acid-activated dendritic cells plays a crucial role in the development of systemic lupus erythematosus.

  11. B cell activating factor (BAFF) selects IL-10(-)B cells over IL-10(+)B cells during inflammatory responses.

    PubMed

    Ma, Ning; Zhang, Yu; Liu, Qilin; Wang, Zhiding; Liu, Xiaoling; Zhu, Gaizhi; Yu, Dandan; Han, Gencheng; Chen, Guojiang; Hou, Chunmei; Wang, Tianxiao; Ma, Yuanfang; Shen, Beifen; Li, Yan; Xiao, He; Wang, Renxi

    2017-05-01

    B cell activating factor (BAFF) regulates B cell maturation, survival, function, and plays a critical pathogenic role in autoimmune diseases. It remains unclear how BAFF affects IL-10(-)B cells versus regulatory B cells (Bregs) in inflammatory responses. In this study, we found that IL-10-expressing Bregs decreased in lupus-prone MRL/lpr mice and experimental allergic encephalomyelitis (EAE) mice. On blockade of the effects of BAFF with TACI-IgG, IL-10(+) Bregs were upregulated in MRL/lpr and EAE mice. In addition, BAFF expanded IL-10(+)B cells over IL-10(-)B cells under noninflammatory conditions in vitro, whereas it expanded IL-10(-)B cells over IL-10(+)B cells during inflammatory responses, such as stimulation with autoantigen and LPS. Finally, the selection of IL-10(-)B cells over IL-10(+)B cells by BAFF was dependent on BAFF receptors (BAFFR, TACI, and BCMA) that were upregulated by inflammatory responses. This study suggests that BAFF selects IL-10(-)B cells over IL-10(+) regulatory B cells via BAFF receptors in inflammatory responses.

  12. Optimization of Operation Parameters for Helical Flow Cleanout with Supercritical CO2 in Horizontal Wells Using Back-Propagation Artificial Neural Network.

    PubMed

    Song, Xianzhi; Peng, Chi; Li, Gensheng; He, Zhenguo; Wang, Haizhu

    2016-01-01

    Sand production and blockage are common during the drilling and production of horizontal oil and gas wells as a result of formation breakdown. The use of high-pressure rotating jets and annular helical flow is an effective way to enhance horizontal wellbore cleanout. In this paper, we propose the idea of using supercritical CO2 (SC-CO2) as washing fluid in water-sensitive formation. SC-CO2 is manifested to be effective in preventing formation damage and enhancing production rate as drilling fluid, which justifies tis potential in wellbore cleanout. In order to investigate the effectiveness of SC-CO2 helical flow cleanout, we perform the numerical study on the annular flow field, which significantly affects sand cleanout efficiency, of SC-CO2 jets in horizontal wellbore. Based on the field data, the geometry model and mathematical models were built. Then a numerical simulation of the annular helical flow field by SC-CO2 jets was accomplished. The influences of several key parameters were investigated, and SC-CO2 jets were compared to conventional water jets. The results show that flow rate, ambient temperature, jet temperature, and nozzle assemblies play the most important roles on wellbore flow field. Once the difference between ambient temperatures and jet temperatures is kept constant, the wellbore velocity distributions will not change. With increasing lateral nozzle size or decreasing rear/forward nozzle size, suspending ability of SC-CO2 flow improves obviously. A back-propagation artificial neural network (BP-ANN) was successfully employed to match the operation parameters and SC-CO2 flow velocities. A comprehensive model was achieved to optimize the operation parameters according to two strategies: cost-saving strategy and local optimal strategy. This paper can help to understand the distinct characteristics of SC-CO2 flow. And it is the first time that the BP-ANN is introduced to analyze the flow field during wellbore cleanout in horizontal wells.

  13. HCV Infection and B-Cell Lymphomagenesis

    PubMed Central

    Ito, Masahiko; Kusunoki, Hideki; Mochida, Keiko; Yamaguchi, Kazunari; Mizuochi, Toshiaki

    2011-01-01

    Hepatitis C virus (HCV) has been recognized as a major cause of chronic liver diseases worldwide. It has been suggested that HCV infects not only hepatocytes but also mononuclear lymphocytes including B cells that express the CD81 molecule, a putative HCV receptor. HCV infection of B cells is the likely cause of B-cell dysregulation disorders such as mixed cryoglobulinemia, rheumatoid factor production, and B-cell lymphoproliferative disorders that may evolve into non-Hodgkin's lymphoma (NHL). Epidemiological data indicate an association between HCV chronic infection and the occurrence of B-cell NHL, suggesting that chronic HCV infection is associated at least in part with B-cell lymphomagenesis. In this paper, we aim to provide an overview of recent literature, including our own, to elucidate a possible role of HCV chronic infection in B-cell lymphomagenesis. PMID:21789042

  14. B Cell Immunity in Solid Organ Transplantation

    PubMed Central

    Karahan, Gonca E.; Claas, Frans H. J.; Heidt, Sebastiaan

    2017-01-01

    The contribution of B cells to alloimmune responses is gradually being understood in more detail. We now know that B cells can perpetuate alloimmune responses in multiple ways: (i) differentiation into antibody-producing plasma cells; (ii) sustaining long-term humoral immune memory; (iii) serving as antigen-presenting cells; (iv) organizing the formation of tertiary lymphoid organs; and (v) secreting pro- as well as anti-inflammatory cytokines. The cross-talk between B cells and T cells in the course of immune responses forms the basis of these diverse functions. In the setting of organ transplantation, focus has gradually shifted from T cells to B cells, with an increased notion that B cells are more than mere precursors of antibody-producing plasma cells. In this review, we discuss the various roles of B cells in the generation of alloimmune responses beyond antibody production, as well as possibilities to specifically interfere with B cell activation. PMID:28119695

  15. Memory B cells in mouse models.

    PubMed

    Bergmann, B; Grimsholm, O; Thorarinsdottir, K; Ren, W; Jirholt, P; Gjertsson, I; Mårtensson, I-L

    2013-08-01

    One of the principles behind vaccination, as shown by Edward Jenner in 1796, and host protection is immunological memory, and one of the cells central to this is the antigen-experienced memory B cell that responds rapidly upon re-exposure to the initiating antigen. Classically, memory B cells have been defined as progenies of germinal centre (GC) B cells expressing isotype-switched and substantially mutated B cell receptors (BCRs), that is, membrane-bound antibodies. However, it has become apparent over the last decade that this is not the only pathway to B cell memory. Here, we will discuss memory B cells in mice, as defined by (1) cell surface markers; (2) multiple layers; (3) formation in a T cell-dependent and either GC-dependent or GC-independent manner; (4) formation in a T cell-independent fashion. Lastly, we will touch upon memory B cells in; (5) mouse models of autoimmune diseases.

  16. Rationale for B cell targeting in SLE

    PubMed Central

    Sanz, Iñaki

    2014-01-01

    B cells are central pathogenic players in Systemic Lupus Erythematosus and multiple other autoinmune diseases through antibody production as well as antibody independent functiona. At the same time, B cells are known to play important regulatory functions that may protect against autoimmune manifestations. Yet, the functional role of different B cell populations and their contribution to disease remain to be understood. The advent of agents that specifically target B cells, in particular anti-CD20 and ant-BLyS antibodies, have demonstrated the efficacy of this approach for the treatment of human autoimmunity. The analysis of patients treated with these and other B cell agents provide a unique opportunity to understand the correlates of clinical response and the significance of different B cell subsets. Here we discuss this information and how it could be used to better understand SLE and improve the rational design of B cell directed therapies in this disease. PMID:24763533

  17. Differential radiosensitivity among B cell subpopulations

    SciTech Connect

    Riggs, J.E.

    1988-01-01

    The selective radiosensitivity of sIgM >> sIgD marginal zone B cells is associated with the selective loss of B cell function. The simultaneous restoration of impaired function and recovery of these cells with time supports this premise. B cell recovery, delayed one week after irradiation, is in progress at two weeks, and virtually complete by three weeks. XID mice reveal similar recovery kinetics although there are fewer recovering cells and these bear reduced levels of Ia. This observation represents additional evidence that xid B cells are distinct from those of normal mice. The simultaneous loss, and concurrent recovery, of sIgM >> sIgD B cells and TI-2 responsiveness in irradiated mice suggests the existence of a unique B cell subpopulation possessing both phenotypes. Additional support for this hypothesis is provided by demonstrating that splenocytes, depleted of IgD{sup +} cells adoptively reconstitute this response in XID mice. The peritoneal B cell pool, which, compared to the spleen, consist of increased numbers of sIgM >> sIgD B cells, is shown to be a source of radiosensitive B cells that are TI-2 responsive. These observations represent additional evidence for an association between sIgM >> sIgD B cells and TI-2 responsiveness.

  18. Role of MYC in B Cell Lymphomagenesis.

    PubMed

    Korać, Petra; Dotlić, Snježana; Matulić, Maja; Zajc Petranović, Matea; Dominis, Mara

    2017-04-04

    B cell lymphomas mainly arise from different developmental stages of B cells in germinal centers of secondary lymphoid tissue. There are a number of signaling pathways that affect the initiation and development of B cell lymphomagenesis. The functions of several key proteins that represent branching points of signaling networks are changed because of their aberrant expression, degradation, and/or accumulation, and those events determine the fate of the affected B cells. One of the most influential transcription factors, commonly associated with unfavorable prognosis for patients with B cell lymphoma, is nuclear phosphoprotein MYC. During B cell lymphomagenesis, oncogenic MYC variant is deregulated through various mechanisms, such as gene translocation, gene amplification, and epigenetic deregulation of its expression. Owing to alterations of downstream signaling cascades, MYC-overexpressing neoplastic B cells proliferate rapidly, avoid apoptosis, and become unresponsive to most conventional treatments. This review will summarize the roles of MYC in B cell development and oncogenesis, as well as its significance for current B cell lymphoma classification. We compared communication networks within transformed B cells in different lymphomas affected by overexpressed MYC and conducted a meta-analysis concerning the association of MYC with tumor prognosis in different patient populations.

  19. Selection of natural autoreactive B cells.

    PubMed

    Hardy, Richard R; Hayakawa, Kyoko

    2015-01-01

    Natural antibodies produced by CD5+ B1 B cells include anti-thymocyte autoantibody (ATA). Transgenic mice bearing the Ig-μ heavy chain of a prototypic ATA, V(H)3609Vκ21c, demonstrated a critical requirement for self-antigen in the accumulation of ATA B cells and production of high levels of serum ATA. Further work with ATA-μκ transgenic mice revealed that, while development of most B cells were blocked at an immature stage in spleen, some mature ATA B cells were present. ATA-μκ transgenic mice with varying levels of Thy-1 autoantigen showed a clear relationship between BCR crosslinking and B cell fate, with low levels generating marginal zone ATA B cells and complete antigen absence allowing maturation to follicular ATA B cells. Finally, different fates of developing ATA B cells encountering high levels self-antigen may be accounted for by variations in the response of newly formed B cells arising from foetal and adult development.

  20. B-Cell Hematologic Malignancy Vaccination Registry

    ClinicalTrials.gov

    2016-12-28

    Monoclonal Gammopathy of Undetermined Significance; Multiple Myeloma; Waldenstrom Macroglobulinemia; Lymphocytosis; Lymphoma, Non-Hodgkin; B-Cell Chronic Lymphocytic Leukemia; Hematological Malignancies

  1. Production of RANKL by Memory B Cells

    PubMed Central

    Meednu, Nida; Zhang, Hengwei; Owen, Teresa; Sun, Wen; Wang, Victor; Cistrone, Christopher; Rangel-Moreno, Javier; Xing, Lianping; Anolik, Jennifer H.

    2016-01-01

    Objective Rheumatoid arthritis (RA) is a systemic autoimmune disease that often leads to joint damage. The mechanisms of bone damage in RA are complex, involving activation of bone-resorbing osteoclasts (OCs) by synoviocytes and Th17 cells. This study was undertaken to investigate whether B cells play a direct role in osteoclastogenesis through the production of RANKL, the essential cytokine for OC development. Methods RANKL production by total B cells or sorted B cell subpopulations in the peripheral blood and synovial tissue from healthy donors or anti–cyclic citrullinated peptide–positive patients with RA was examined by flow cytometry, real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and immunohistochemical analysis. To define direct effects on osteoclastogenesis, B cells were cocultured with CD14+ monocytes, and OCs were enumerated by tartrate-resistant acid phosphatase staining. Results Healthy donor peripheral blood B cells were capable of expressing RANKL upon stimulation, with switched memory B cells (CD27+IgD−) having the highest propensity for RANKL production. Notably, switched memory B cells in the peripheral blood from RA patients expressed significantly more RANKL compared to healthy controls. In RA synovial fluid and tissue, memory B cells were enriched and spontaneously expressed RANKL, with some of these cells visualized adjacent to RANK+ OC precursors. Critically, B cells supported OC differentiation in vitro in a RANKL-dependent manner, and the number of OCs was higher in cultures with RA B cells than in those derived from healthy controls. Conclusion These findings reveal the critical importance of B cells in bone homeostasis and their likely contribution to joint destruction in RA. PMID:26554541

  2. Regulatory B cells in autoimmune diseases

    PubMed Central

    Yang, Min; Rui, Ke; Wang, Shengjun; Lu, Liwei

    2013-01-01

    B cells are generally considered to be positive regulators of the immune response because of their capability to produce antibodies, including autoantibodies. The production of antibodies facilitates optimal CD4+ T-cell activation because B cells serve as antigen-presenting cells and exert other modulatory functions in immune responses. However, certain B cells can also negatively regulate the immune response by producing regulatory cytokines and directly interacting with pathogenic T cells via cell-to-cell contact. These types of B cells are defined as regulatory B (Breg) cells. The regulatory function of Breg cells has been demonstrated in mouse models of inflammation, cancer, transplantation, and particularly in autoimmunity. In this review, we focus on the recent advances that lead to the understanding of the development and function of Breg cells and the implications of B cells in human autoimmune diseases. PMID:23292280

  3. Epigenetic Control of B Cell Development and B-Cell-Related Immune Disorders.

    PubMed

    Bao, Yan; Cao, Xuetao

    2016-06-01

    B lymphocytes are generally recognized as the essential component of humoral immunity and also a regulator of innate immunity. The development of B cells is precisely regulated by a variety of factors via different mechanisms, including cytokine/cytokine receptors, signal transduction molecules, and transcription factors. Recent findings suggest that epigenetic factors, such as DNA methylation, histone modification, and non-coding RNA, play critical roles in establishing B cell lineage-specific gene expression profiles to define and sustain B cell identity and function. Epigenetic modifications are also sensitive to external stimuli and might bridge genetic and environmental factors in the pathogenesis or control of B-cell-related immune disorders, such as autoimmune diseases, lymphoma, and leukemia. Better understanding of the epigenetic mechanisms for regulating B cell development and involving B cell abnormal differentiation and function will shed light on the design of new therapeutic approaches to B-cell-related diseases, and potential candidates of epigenetic modulators may be identified to target epigenetic pathways to prevent or treat B cell disorders. We summarize the relevance of epigenetic marks and landscapes in the stages of B cell development, discuss the interaction of the transcriptional networks and epigenetic changes, and review the involvement of epigenetic risk in the pathogenesis of B-cell-related diseases. Understanding how specific epigenetic alterations contribute to the development of B-cell-related autoimmunity and malignancies is instrumental to control B cell disorders.

  4. Optimization of Operation Parameters for Helical Flow Cleanout with Supercritical CO2 in Horizontal Wells Using Back-Propagation Artificial Neural Network

    PubMed Central

    Song, Xianzhi; Peng, Chi; Li, Gensheng

    2016-01-01

    Sand production and blockage are common during the drilling and production of horizontal oil and gas wells as a result of formation breakdown. The use of high-pressure rotating jets and annular helical flow is an effective way to enhance horizontal wellbore cleanout. In this paper, we propose the idea of using supercritical CO2 (SC-CO2) as washing fluid in water-sensitive formation. SC-CO2 is manifested to be effective in preventing formation damage and enhancing production rate as drilling fluid, which justifies tis potential in wellbore cleanout. In order to investigate the effectiveness of SC-CO2 helical flow cleanout, we perform the numerical study on the annular flow field, which significantly affects sand cleanout efficiency, of SC-CO2 jets in horizontal wellbore. Based on the field data, the geometry model and mathematical models were built. Then a numerical simulation of the annular helical flow field by SC-CO2 jets was accomplished. The influences of several key parameters were investigated, and SC-CO2 jets were compared to conventional water jets. The results show that flow rate, ambient temperature, jet temperature, and nozzle assemblies play the most important roles on wellbore flow field. Once the difference between ambient temperatures and jet temperatures is kept constant, the wellbore velocity distributions will not change. With increasing lateral nozzle size or decreasing rear/forward nozzle size, suspending ability of SC-CO2 flow improves obviously. A back-propagation artificial neural network (BP-ANN) was successfully employed to match the operation parameters and SC-CO2 flow velocities. A comprehensive model was achieved to optimize the operation parameters according to two strategies: cost-saving strategy and local optimal strategy. This paper can help to understand the distinct characteristics of SC-CO2 flow. And it is the first time that the BP-ANN is introduced to analyze the flow field during wellbore cleanout in horizontal wells. PMID

  5. Differential radiosensitivity among B cell subpopulations

    SciTech Connect

    Riggs, J.E.; Lussier, A.M.; Lee, S.K.; Appel, M.C.; Woodland, R.T.

    1988-09-15

    We have previously shown that low doses of ionizing radiation selectively impair a functionally defined B cell subpopulation. Normal mice, after exposure to 200 rad of ionizing radiation, have normal or near normal splenic plaque-forming cell responses to thymus-independent type 1 Ag, but reduced responses to thymus-independent type 2 Ag. Here, we confirm and extend the original findings by using hapten-specific serum RIA to demonstrate this differential radiosensitivity is systemic. We also examined splenocytes stained with a panel of lymphocyte surface Ag by FACS analysis to determine if these functional changes are accompanied by a physical alteration of the B cell pool of irradiated mice. Single-parameter FACS analyses demonstrate a diminution in both B cell number and the heterogeneity of membrane Ag expression within the surviving B cell pool after irradiation. In contrast, T cells are relatively radioresistant as the relative percentage of T cells in the irradiated splenocyte pool increases, whereas the heterogeneity of membrane Ag expression remains constant. Multiparameter FACS analyses indicate that B cells with the sIgM much greater than sIgD phenotype are more radiosensitive than B cells of the sIgM much less than sIgD phenotype. In addition, immunohistochemical analysis of splenic sections stained with anti-IgM or anti-IgD reveal the enhanced radiosensitivity of marginal zone B cells.

  6. Expression cloning of human B cell immunoglobulins.

    PubMed

    Wardemann, Hedda; Kofer, Juliane

    2013-01-01

    The majority of lymphomas originate from B cells at the germinal center stage or beyond. Preferential selection of B cell clones by a limited set of antigens has been suggested to drive lymphoma development. However, little is known about the specificity of the antibodies expressed by lymphoma cells, and the role of antibody-specificity in lymphomagenesis remains elusive. Here, we describe a strategy to characterize the antibody reactivity of human B cells. The approach allows the unbiased characterization of the human antibody repertoire on a single cell level through the generation of recombinant monoclonal antibodies from single primary human B cells of defined origin. This protocol offers a detailed description of the method starting from the flow cytometric isolation of single human B cells, to the RT-PCR-based amplification of the expressed Igh, Igκ, and Igλ chain genes, and Ig gene expression vector cloning for the in vitro production of monoclonal antibodies. The strategy may be used to obtain information on the clonal evolution of B cell lymphomas by single cell Ig gene sequencing and on the antibody reactivity of human lymphoma B cells.

  7. The early history of B cells.

    PubMed

    Cooper, Max D

    2015-03-01

    The separate development of functionally intertwined lineages of lymphocytes known as B cells and T cells is now recognized as a fundamental organizing principle of the adaptive immune system in all vertebrates. Immunologists strive to define the different sublineages of the clonally diverse B cells and T cells, how they interact with each other and how they interact with innate lymphoid cells and other elements of the innate immune system to counter infections, cancer and the development of autoimmune and inflammatory diseases. On the 50th anniversary of the recognition of B cells as a discrete cell lineage, this Timeline article recounts some of the milestones marking the development of the concept that B cells are a functionally and developmentally distinct arm of the adaptive immune system.

  8. Enhanced Cultivation Of Stimulated Murine B Cells

    NASA Technical Reports Server (NTRS)

    Sammons, David W.

    1994-01-01

    Method of in vitro cultivation of large numbers of stimulated murine B lymphocytes. Cells electrofused with other cells to produce hybridomas and monoclonal antibodies. Offers several advantages: polyclonally stimulated B-cell blasts cultivated for as long as 14 days, hybridomas created throughout culture period, yield of hybridomas increases during cultivation, and possible to expand polyclonally in vitro number of B cells specific for antigenic determinants first recognized in vivo.

  9. MYSM1-dependent checkpoints in B cell lineage differentiation and B cell-mediated immune response.

    PubMed

    Förster, Michael; Farrington, Kyo; Petrov, Jessica C; Belle, Jad I; Mindt, Barbara C; Witalis, Mariko; Duerr, Claudia U; Fritz, Jörg H; Nijnik, Anastasia

    2017-03-01

    MYSM1 is a chromatin-binding histone deubiquitinase. MYSM1 mutations in humans result in lymphopenia whereas loss of Mysm1 in mice causes severe hematopoietic abnormalities, including an early arrest in B cell development. However, it remains unknown whether MYSM1 is required at later checkpoints in B cell development or for B cell-mediated immune responses. We analyzed conditional mouse models Mysm1(fl/fl)Tg.mb1-cre, Mysm1(fl/fl)Tg.CD19-cre, and Mysm1(fl/fl)Tg.CD21-cre with inactivation of Mysm1 at prepro-B, pre-B, and follicular B cell stages of development. We show that loss of Mysm1 at the prepro-B cell stage in Mysm1(fl/fl)Tg.mb1-cre mice results in impaired B cell differentiation, with an ∼2-fold reduction in B cell numbers in the lymphoid organs. Mysm1(fl/fl)Tg.mb1-cre B cells also showed increased expression of activation markers and impaired survival and proliferation. In contrast, Mysm1 was largely dispensable from the pre-B cell stage onward, with Mysm1(fl/fl)Tg.CD19-cre and Mysm1(fl/fl)Tg.CD21-cre mice showing no alterations in B cell numbers and largely normal responses to stimulation. MYSM1, therefore, has an essential role in B cell lineage specification but is dispensable at later stages of development. Importantly, MYSM1 activity at the prepro-B cell stage of development is important for the normal programming of B cell responses to stimulation once they complete their maturation process.

  10. Characterization of the Contaminated Soil Under the Hanford 324 Building B Cell, Washington, USA - 12182

    SciTech Connect

    Josephson, Walter S.

    2012-07-01

    The 324 Building on the Hanford site played a key role in radiochemical and metallurgical research programs conducted by DOE. The B hot cell in the 324 Building was the site of high-level waste vitrification research. During clean-out operations in November 2009, a tear was noted in the stainless steel liner on the floor of B Cell. Exposure rate readings taken at various locations in the soil about 0.5 meters below B Cell reached 8,900 Roentgen (R) per hour, confirming the existence of a significant soil contamination field. The source of the radioactive material was likely a 510 L spill from the Canister Fabrication Project, consisting of purified, concentrated Cs-137 and Sr-90 solutions totaling 48,000 TBq (1.3 MCi). MCNP modeling was used to estimate that the measured exposure rates were caused by 5,900 TBq (160 kCi) of Sr- 90 and Cs-137, although additional contamination was thought to exist deeper in the soil column. Two physical soil samples were obtained at different depths, which helped verify the contamination estimates. A detailed exposure rate survey inside B Cell was combined with additional MCNP modeling to estimate that an additional 1,700 TBq (460 kCi) is present just below the floor. Based on the results of the sampling campaign, it is likely that the radioactive material below B Cell is primarily consists of feed solutions from the FRG Canister Fabrication Project, and that it contains purified Sr-90 and Cs-137 with enough actinide carryover to make some of the soil transuranic. The close agreement between the Geoprobe calculations and the physical samples adds confidence that there are more than 3700 TBq (100,000 Ci) of Sr-90 and Cs-137 in the soil approximately 1 meter below the cell floor. The majority of the Cs-137 is contained in the first meter of soil, while significant Sr-90 contamination extends to 10 meters below the cell floor. It is also likely that an additional 15,000 TBq (400,000 Ci) of Cs-137 and Sr-90 activity is present directly

  11. Type B Investigation Report for 241-SY-101 Pump Start and 241-C-106 Pit Cleanout

    SciTech Connect

    Ewalt, J.R.

    1993-09-01

    In accordance with the direction of the Department of Energy (DOE) Manager, Richland Operations Office, a Type ``B`` investigation in accordance with the DOE Order 5484.1, Environmental Protection, Safety and Health Protection Information Reporting Requirements, has been conducted. The scope of the investigation included two events: The ``Inadvertent Mixer Pump Operation at 241-SY-101`` (RL-WHC-TANK FARM-1993-069); ``Inadequate Work Control Results in Personnel Skin Contamination at 241-C-106, Pit B`` (RL-WHC-TANK FARM-1993-071) events. Additionally, at the request of the President of the WHC, a broader investigation into Waste Tank Farm ``safety practices`` and ``Conduct of Operations`` was also conducted. The review was focused on (1) WHC organizations performing operations, maintenance, and radiological safety tasks; and (2) KEH organizations performing major maintenance tasks.

  12. Inflammatory monocytes hinder antiviral B cell responses

    PubMed Central

    Sammicheli, Stefano; Kuka, Mirela; Di Lucia, Pietro; de Oya, Nereida Jimenez; De Giovanni, Marco; Fioravanti, Jessica; Cristofani, Claudia; Maganuco, Carmela G.; Fallet, Benedict; Ganzer, Lucia; Sironi, Laura; Mainetti, Marta; Ostuni, Renato; Larimore, Kevin; Greenberg, Philip D.; de la Torre, Juan Carlos; Guidotti, Luca G.; Iannacone, Matteo

    2016-01-01

    Antibodies are critical for protection against viral infections. However, several viruses, such as lymphocytic choriomeningitis virus (LCMV), avoid the induction of early protective antibody responses by poorly understood mechanisms. Here we analyzed the spatiotemporal dynamics of B cell activation to show that, upon subcutaneous infection, LCMV-specific B cells readily relocate to the interfollicular and T cell areas of the draining lymph node where they extensively interact with CD11b+Ly6Chi inflammatory monocytes. These myeloid cells were recruited to lymph nodes draining LCMV infection sites in a type I interferon-, CCR2-dependent fashion and they suppressed antiviral B cell responses by virtue of their ability to produce nitric oxide. Depletion of inflammatory monocytes, inhibition of their lymph node recruitment or impairment of their nitric oxide-producing ability enhanced LCMV-specific B cell survival and led to robust neutralizing antibody production. In conclusion, our results identify inflammatory monocytes as critical gatekeepers that prevent antiviral B cell responses and suggest that certain viruses take advantage of these cells to prolong their persistence within the host. PMID:27868108

  13. Receptor Dissociation and B-Cell Activation.

    PubMed

    Yang, Jianying; Reth, Michael

    2016-01-01

    The B-cell antigen receptor (BCR) is one of the most abundant receptors on the surface of B cells with roughly 100,000-200,000 copies per cell. Signaling through the BCR is crucial for the activation and differentiation of B cells. Unlike other receptors, the BCR can be activated by a large set of structurally different ligands, but the molecular mechanism of BCR activation is still a matter of controversy. Although dominant for a long time, the cross-link model (CLM) of BCR activation is not supported by recent studies of the nanoscale organization of the BCR on the surface of resting B cells. In contrast to the prediction of CLM, the numerous BCR complexes on these cells are not randomly distributed monomers but rather form oligomers which reside within membrane confinements. This finding is more in line with the dissociation activation model (DAM), wherein B-cell activation is accompanied by an opening of the auto-inhibited BCR oligomers instead of a cross-linking of the BCR monomers. In this review, we discuss in detail the new findings and their implications for BCR signaling.

  14. Human norovirus culture in B cells

    PubMed Central

    Jones, Melissa K; Grau, Katrina R; Costantini, Veronica; Kolawole, Abimbola O; de Graaf, Miranda; Freiden, Pamela; Graves, Christina L; Koopmans, Marion; Wallet, Shannon M; Tibbetts, Scott A; Schultz-Cherry, Stacey; Wobus, Christiane E; Vinjé, Jan; Karst, Stephanie M

    2015-01-01

    Human noroviruses (HunoVs) are a leading cause of foodborne disease and severe childhood diarrhea, and they cause a majority of the gastroenteritis outbreaks worldwide. However, the development of effective and long-lasting HunoV vaccines and therapeutics has been greatly hindered by their uncultivability. We recently demonstrated that a HunoV replicates in human B cells, and that commensal bacteria serve as a cofactor for this infection. In this protocol, we provide detailed methods for culturing the GII.4-sydney HunoV strain directly in human B cells, and in a coculture system in which the virus must cross a confluent epithelial barrier to access underlying B cells. We also describe methods for bacterial stimulation of HunoV B cell infection and for measuring viral attachment to the surface of B cells. Finally, we highlight variables that contribute to the efficiency of viral replication in this system. Infection assays require 3 d and attachment assays require 3 h. analysis of infection or attachment samples, including rna extraction and rt-qpcr, requires ~6 h. PMID:26513671

  15. Transitional B cells are the target of negative selection in the B cell compartment

    PubMed Central

    1995-01-01

    B lymphocytes recognize antigen through membrane-bound antigen- receptors, membrane IgM and IgD (mIgM and mIgD). Binding to foreign antigens initiates a cascade of biochemical events that lead to activation and differentiation. In contrast, binding to self-antigens leads to death or to inactivation. It is commonly believed that the B cells acquire the ability to discriminate between self and nonself in the early phases of development. We report here that immature B cells, which have just emerged from the mIgMneg, B220pos pool, are not deleted upon binding of self-antigen. In vivo, developing B cells become sensitive to tolerance induction in a relatively late window of differentiation, when they are in transition from the immature (HSAbright, B220dull) to the mature (HSAdull, B220bright) stage. In the transitional B cells, early markers of differentiation such as Pgp1 (CD44) and ThB reach the highest level of expression, while the expression of CD23 and mIgD, late markers of differentiation, and expression of class II MHC, progressively increases. Most of the transitional B cells, but only few of the mature and of the immature B cells, express the fas antigen, while mature B cells, but not immature and transitional B cells, express bcl-2 protein. mIgM is present in low amounts in immature B cells, reaches the highest level of expression in transitional B cells and is down-regulated in mature resting B cells, where it is coexpressed with mIgD. The high expression of mIgM, the presence of the fas antigen and the absence of bcl-2 protein is compatible with the high sensitivity of transitional B cells to negative selection. In vitro, immature B cells die rapidly by apoptosis after cross-linking of mIgM. This result, combined with the resistance of immature B cells to elimination in vivo, suggests that early in development the stroma cell microenvironment modulates signals transduced through mIgM. The functional and phenotypic division of IgMpos bone marrow B cells in

  16. Alloantigen presentation by B cells: analysis of the requirement for B-cell activation.

    PubMed Central

    Wilson, J L; Cunningham, A C; Kirby, J A

    1995-01-01

    This paper describes a model for investigation of the functional implications of B-cell activation for antigen presentation. Mixed lymphocyte cultures were used to assess the ability of freshly isolated B cells, mitogen-activated B cells and Epstein-Barr virus (EBV)-transformed B-cell lines to stimulate the activation and proliferation of allogeneic T cells under a variety of experimental conditions. It was found that resting B cells presented antigen poorly, while activated cells were highly immunogenic. Paraformaldehyde fixation completely eliminated antigen presentation by resting B cells, despite constitutive expression of class II MHC antigens. However, fixation had little effect on antigen presentation by activated B cells that expressed B7-1 and B7-2 in addition to class II major histocompatibility complex (MHC) molecules. Arrest of B-cell activation by serial fixation after treatment with F(ab')2 fragments of goat anti-human IgM produced cells with variable antigen-presenting capacity. Optimal antigen presentation was observed for cells fixed 72 hr after the initiation of B-cell activation. Although both B7-1 and B7-2 antigen expression increased after B-cell activation, it was found that the rate of T-cell proliferation correlated most closely with B7-2 expression. Stimulation of T cells by fixed activated B lymphocytes could be blocked by antibodies directed at class II MHC molecules, indicating involvement of the T-cell antigen receptor. In addition, T-cell proliferation was inhibited by antibodies specific for B7-1 and B7-2 and by the fusion protein CTLA4-Ig, demonstrating a requirement for CD28 signal transduction. The sole requirement of B7 family expression for antigen presentation by B lymphocytes was shown by demonstration of T-cell stimulation by fixed resting B cells in the presence of CD28 antibody as a source of artificial costimulation. PMID:8550066

  17. B cell suppression in primary glomerular disease.

    PubMed

    Rood, Ilse M; Hofstra, Julia M; Deegens, Jeroen K J; Wetzels, Jack F M

    2014-03-01

    Membranous nephropathy, focal segmental glomerulosclerosis (FSGS), and minimal change disease (MCD) are the most common causes of idiopathic nephrotic syndrome. For many years prednisone, alkylating agents, and calcineurin inhibitors have been the standard of therapy for these patients. More effective or better tolerated treatment modalities are needed. B cell targeted therapy was recently introduced in clinical practice. In this review, we briefly summarize the current standard therapy and discuss the efficacy of B cell targeted therapy in primary glomerular diseases. Observational, short-term studies suggest that rituximab is effective and comparable to standard therapy in maintaining remissions in patients with frequently relapsing or steroid-dependent MCD or FSGS. In contrast, response is limited in patients with steroid-resistant nephrotic syndrome. Rituximab also induces remissions in patients with membranous nephropathy. Controlled clinical trials on kidney endpoints are urgently needed to position B cell targeted therapy in clinical practice.

  18. Safety.

    ERIC Educational Resources Information Center

    Education in Science, 1996

    1996-01-01

    Discusses safety issues in science, including: allergic reactions to peanuts used in experiments; explosions in lead/acid batteries; and inspection of pressure vessels, such as pressure cookers or model steam engines. (MKR)

  19. Targeting B cells with biologics in SLE

    PubMed Central

    La Cava, Antonio

    2010-01-01

    Importance of the field The use of biologics as immune modulators in several autoimmune diseases has provided new tools to the physician's therapeutic armamentiarium and has led to improved patients' outcomes and quality of life. By producing autoantibodies, B cells in SLE are key players in the pathogenesis of the disease and in its clinical manifestations. Therefore, biologics that target B cells in SLE aims at reducing the activity of these cells for the induction of remissions and/or amelioration of disease activity, reduction of organ involvement, and limitation of the complications and side effects caused by immunosuppressive therapies. Areas covered in this review This review describes the past and current clinical trials with B cell-targeted biologics in SLE, to provide a historical perspective and the state-of-the-art on the topic. What the reader will gain We will review how the disappointment in the field from promising agents has been instrumental in providing valuable lessons leading to an improved design of new trials that are now giving encouraging results Take home message In systemic lupus erythematosus (SLE), the use of B cell-based biologics in clinical trials has shown both disappointment and promise PMID:20919800

  20. Interaction of Staphylococci with Human B cells

    PubMed Central

    Nygaard, Tyler K.; Kobayashi, Scott D.; Freedman, Brett; Porter, Adeline R.; Voyich, Jovanka M.; Otto, Michael; Schneewind, Olaf; DeLeo, Frank R.

    2016-01-01

    Staphylococcus aureus is a leading cause of human infections worldwide. The pathogen produces numerous molecules that can interfere with recognition and binding by host innate immune cells, an initial step required for the ingestion and subsequent destruction of microbes by phagocytes. To better understand the interaction of this pathogen with human immune cells, we compared the association of S. aureus and S. epidermidis with leukocytes in human blood. We found that a significantly greater proportion of B cells associated with S. epidermidis relative to S. aureus. Complement components and complement receptors were important for the binding of B cells with S. epidermidis. Experiments using staphylococci inactivated by ultraviolet radiation and S. aureus isogenic deletion mutants indicated that S. aureus secretes molecules regulated by the SaeR/S two-component system that interfere with the ability of human B cells to bind this bacterium. We hypothesize that the relative inability of B cells to bind S. aureus contributes to the microbe’s success as a human pathogen. PMID:27711145

  1. Memory B cell subpopulations in the aged.

    PubMed

    Colonna-Romano, Giuseppina; Aquino, Alessandra; Bulati, Matteo; Di Lorenzo, Gabriele; Listì, Florinda; Vitello, Salvatore; Lio, Domenico; Candore, Giuseppina; Clesi, Gioacchino; Caruso, Calogero

    2006-01-01

    The literature on immunosenescence has focused mainly on T cell impairment. With the aim of gaining insight into B cell immunosenescence, the authors investigated the serum IgD levels in 24 young and 21 old people and analyzed their relationship with the number of CD19+CD27+ memory cells. Serum IgD were quantified by the use of radial immunodiffusion and the lymphocyte population CD19+CD27+ was identified by a FACScan flow cytometer. Serum IgD levels were significantly lower (p < 0.0001) in old subjects, and the percentage of CD19+CD27+ lymphocytes were significantly increased (p = 0.01) in old subjects. Finally, a significant negative correlation was found (p = 0.01) between serum concentrations of IgD and CD19+CD27+. The present results show that the levels of IgD are negatively age-related to the amount of B memory cells. This suggests that the B repertoire available to respond to new antigenic challenges is decreased in the elderly. In fact, many memory IgD- B cells fill immunologic space, and the number of naïve IgD+ B cells is dramatically decreased. Therefore, these preliminary results suggest that a decrease of naïve IgD+CD27- B cells and a concomitant increase of memory IgD-CD27+ B cells could represent hallmarks of B immunosenescence, might provide biomarkers related to the lifespan of humans, and could be useful for the evaluation of antiaging treatments.

  2. Comparative In Vitro Immune Stimulation Analysis of Primary Human B Cells and B Cell Lines

    PubMed Central

    Van Belle, Kristien; Herman, Jean; Boon, Louis; Waer, Mark

    2016-01-01

    B cell specific immunomodulatory drugs still remain an unmet medical need. Utilisation of validated simplified in vitro models would allow readily obtaining new insights in the complexity of B cell regulation. For this purpose we investigated which human B lymphocyte stimulation assays may be ideally suited to investigate new B lymphocyte immunosuppressants. Primary polyclonal human B cells underwent in vitro stimulation and their proliferation, production of immunoglobulins (Igs) and of cytokines, and expression of cell surface molecules were analysed using various stimuli. ODN2006, a toll-like receptor 9 (TLR9) agonist, was the most potent general B cell stimulus. Subsequently, we investigated on which human B cell lines ODN2006 evoked the broadest immunostimulatory effects. The Namalwa cell line proved to be the most responsive upon TLR9 stimulation and hence may serve as a relevant, homogeneous, and stable B cell model in an in vitro phenotypic assay for the discovery of new targets and inhibitors of the B cell activation processes. As for the read-out for such screening assay, it is proposed that the expression of activation and costimulatory surface markers reliably reflects B lymphocyte activation. PMID:28116319

  3. A monoclonal antibody that recognizes B cells and B cell precursors in mice

    PubMed Central

    1981-01-01

    The monoclonal antibody, RA3-2C2, appears to be specific for cells within the B cell lineage. This antibody does not recognize thymocytes, peripheral T cells, or nonlymphoid hematopoietic cells in the spleen or bone marrow. Nor does it recognize the pluripotent hematopoietic stem cells, the spleen colony-forming unit, All sIg+ B cells and most plasma cells are RA3-2C2+. In addition, approximately 20% of nucleated bone marrow cells are RA3-2C2+ but sIg-. This population contains B cell precursors that can give rise to sIg+ cells within 2 d in vitro. PMID:6787164

  4. Progenitors for Ly-1 B cells are distinct from progenitors for other B cells

    PubMed Central

    1985-01-01

    Data from previous multiparameter fluorescence-activated cell sorter (FACS) analysis and sorting studies define a subset of murine B cells that expresses the Ly-1 surface determinant in conjunction with IgM, IgD, Ia, and other typical B cell markers. These Ly-1 B cells are physically and functionally distinct. They express more IgM and less IgD than most other B cells; they are not normally found in lymph node or bone marrow; they are always present at low frequencies (1-5%) in normal spleens, and, as we show here, they comprise about half of the B cells (10-20% of total cells) recovered from the peritoneal cavity in normal mice. Furthermore, most of the commonly studied IgM autoantibodies in normal and autoimmune mice are produced by these Ly-1 B cells, even though they seldom produce antibodies to exogenous antigens such as trinitrophenyl-Ficoll or trinitrophenyl-keyhole limpet hemocyanin. Cell transfer studies presented here demonstrate that the progenitors of Ly-1 B cells are different from the progenitors of the predominant B cell populations in spleen and lymph node. In these studies, we used FACS analysis and functional assays to characterize donor-derived (allotype-marked) B cells present in lethally irradiated recipients 1-2 mo after transfer. Surprisingly, adult bone marrow cells typically used to reconstitute B cells in irradiated recipients selectively failed to reconstitute the Ly-1 B subset. Liver, spleen, and bone marrow cells from young mice, in contrast, reconstituted all B cells (including Ly-1 B), and peritoneal "washout" cells (PerC) from adult mice uniquely reconstituted Ly-1 B. Bone marrow did not block Ly- 1 B development, since PerC and newborn liver still gave rise to Ly-1 B when jointly transferred with marrow. These findings tentatively assign Ly-1 B to a distinct developmental lineage originating from progenitors that inhabit the same locations as other B cell progenitors in young animals, but move to unique location(s) in adults. PMID

  5. B Cell-Activating Factor Regulates Different Aspects of B Cell Functionality and Is Produced by a Subset of Splenic B Cells in Teleost Fish

    PubMed Central

    Tafalla, Carolina; González, Lucia; Castro, Rosario; Granja, Aitor G.

    2017-01-01

    In mammals, B cell functionality is greatly influenced by cytokines released by innate cells, such as macrophages or dendritic cells, upon the early recognition of common pathogen patterns through invariant receptors. B cell-activating factor (BAFF) is one of these innate B cell-helper signals and plays a key role in the survival and differentiation of B cells. Although, evolutionarily, teleost fish constitute the first animal group in which adaptive immunity based on Ig receptors is present, fish still rely greatly on innate responses. In this context, we hypothesized that BAFF would play a key role in the control of B cell responses in fish. Supporting this, our results show that teleost BAFF recapitulates mammalian BAFF stimulating actions on B cells, upregulating the expression of membrane MHC II, improving the survival of fish naïve B cells and antibody-secreting cells, and increasing the secretion of IgM. Surprisingly, we also demonstrate that BAFF is not only produced in fish by myeloid cells but is also produced by a subset of splenic B cells. Thus, if this B cell-produced BAFF proves to be actively regulating this same B cell subset, our findings point to an ancient mechanism to control B cell differentiation and survival in lower vertebrates, which has been silenced in mammals in physiological conditions, but reemerges under pathological conditions, such as B cell lymphomas and autoimmune diseases. PMID:28360916

  6. Switched-memory B cells remodel B cell receptors within secondary germinal centers

    PubMed Central

    Okitsu, Shinji L.; McHeyzer-Williams, Michael G.

    2015-01-01

    Effective vaccines induce high-affinity memory B cells and durable antibody responses through accelerated mechanisms of natural selection. Secondary changes in antibody repertoires after vaccine boosts suggest progressive B cell receptor (BCR) re-diversification, but underlying mechanisms remain unresolved. Here integrated specificity and function of individual memory B cell progeny reveal ongoing evolution of polyclonal antibody specificities through germinal center (GC) specific transcriptional activity. At the clonal and sub-clonal levels, single cell expression of Cd83 and Pol□ segregates the secondary GC transcriptional program into 4 stages that regulate divergent mechanisms of memory BCR evolution. These studies demonstrate that vaccine boosts re-activate a cyclic program of GC function in switched-memory B cells to remodel existing antibody specificities and enhance durable immune protection. PMID:25642821

  7. Memory B Cells of Mice and Humans.

    PubMed

    Weisel, Florian; Shlomchik, Mark

    2017-01-30

    Wecomprehensively review memory B cells (MBCs), covering the definition of MBC and their identities and subsets, how MBCs are generated, where they are localized, how they are maintained, and how they are reactivated. Whereas naive B cells adopt multiple fates upon stimulation, MBCs are more restricted in their responses. Evolving work reveals that the MBC compartment in mice and humans consists of distinct subpopulations with differing effector functions. We discuss the various approaches to define subsets and subset-specific roles. A major theme is the need to both deliver faster effector function upon reexposure and readapt to antigenically variant pathogens while avoiding burnout, which would be the result if all MBCs generated only terminal effector function. We discuss cell-intrinsic differences in gene expression and signaling that underlie differences in function between MBCs and naive B cells and among MBC subsets and how this leads to memory responses. Expected final online publication date for the Annual Review of Immunology Volume 35 is April 26, 2017. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  8. Curative drug treatment of trypanosomosis leads to the restoration of B-cell lymphopoiesis and splenic B-cell compartments.

    PubMed

    Cnops, J; Bockstal, V; De Trez, C; Miquel, M C; Radwanska, M; Magez, S

    2015-09-01

    African trypanosomosis is a parasitic disease affecting both humans (sleeping sickness) and animals (nagana). In murine trypanosomosis, the B-cell compartment is rapidly destroyed after infection. In addition, B-cell lymphopoiesis in the bone marrow is abrogated, B-cell subsets in the spleen are irreversibly depleted, and B-cell memory is destroyed. Here, we investigated the effect of cure of infection on the B-cell compartment. Suramin and diminazene aceturate were used in this study as these drugs exhibit different modes of uptake and different mechanisms of trypanocidal action. Curative drug treatment of trypanosomosis infection led to the re-initiation of B-cell lymphopoiesis in the bone marrow, and to the repopulation of splenic B-cell subsets, independent of the drug used. Neither of these drugs by itself induced measurable effects on B-cell lymphopoiesis in the bone marrow or B-cell homoeostasis in the spleen in healthy, naïve animals.

  9. A B-Cell Superantigen Induces the Apoptosis of Murine and Human Malignant B Cells

    PubMed Central

    Lorenzo, Daniela; Duarte, Alejandra; Mundiñano, Juliana; Berguer, Paula; Nepomnaschy, Irene; Piazzon, Isabel

    2016-01-01

    B-cell superantigens (Sags) bind to conserved sites of the VH or VL regions of immunoglobulin molecules outside their complementarity-determining regions causing the apoptosis of normal cognate B cells. No attempts to investigate whether B-cell Sags are able to induce the apoptosis of cognate malignant B cells were reported. In the present study we show that protein L (PpL), secreted by Finegoldia magna, a B-cell Sag which interacts with κ+ bearing cells, induces the apoptosis of murine and human κ+ lymphoma B cells both in vitro and in vivo. Apoptosis was not altered by caspase-8 inhibitor. No alterations in the levels of Bid, Fas and Fas-L were found suggesting that PpL does not activate the extrinsic pathway of apoptosis. The involvement of the intrinsic pathway was clearly indicated by: i) alterations in mitochondrial membrane potential (ΔΨm) both in murine and human lymphoma cells exposed to PpL; ii) decreased levels of apoptosis in the presence of caspase-9 inhibitor; iii) significant increases of Bim and Bax protein levels and downregulation of Bcl-2; iv) the translocation from the cytoplasm to the mitochondria of Bax and Bim pro-apoptotic proteins and its inhibition by caspase-9 inhibitor but not by caspase-8 inhibitor and v) the translocation of Bcl-2 protein from the mitochondria to the cytosol and its inhibition by caspase-9 inhibitor but not by caspase-8 inhibitor. The possibility of a therapeutic use of Sags in lymphoma/leukemia B cell malignancies is discussed. PMID:27603942

  10. Treatment of ongoing autoimmune encephalomyelitis with activated B-cell progenitors maturing into regulatory B cells

    PubMed Central

    Korniotis, Sarantis; Gras, Christophe; Letscher, Hélène; Montandon, Ruddy; Mégret, Jérôme; Siegert, Stefanie; Ezine, Sophie; Fallon, Padraic G.; Luther, Sanjiv A.; Fillatreau, Simon; Zavala, Flora

    2016-01-01

    The influence of signals perceived by immature B cells during their development in bone marrow on their subsequent functions as mature cells are poorly defined. Here, we show that bone marrow cells transiently stimulated in vivo or in vitro through the Toll-like receptor 9 generate proB cells (CpG-proBs) that interrupt experimental autoimmune encephalomyelitis (EAE) when transferred at the onset of clinical symptoms. Protection requires differentiation of CpG-proBs into mature B cells that home to reactive lymph nodes, where they trap T cells by releasing the CCR7 ligand, CCL19, and to inflamed central nervous system, where they locally limit immunopathogenesis through interleukin-10 production, thereby cooperatively inhibiting ongoing EAE. These data demonstrate that a transient inflammation at the environment, where proB cells develop, is sufficient to confer regulatory functions onto their mature B-cell progeny. In addition, these properties of CpG-proBs open interesting perspectives for cell therapy of autoimmune diseases. PMID:27396388

  11. B Cell Receptor Affinity for Insulin Dictates Autoantigen Acquisition and B Cell Functionality in Autoimmune Diabetes

    PubMed Central

    Packard, Thomas A.; Smith, Mia J.; Conrad, Francis J.; Johnson, Sara A.; Getahun, Andrew; Lindsay, Robin S.; Hinman, Rochelle M.; Friedman, Rachel S.; Thomas, James W.; Cambier, John C.

    2016-01-01

    B cells have been strongly implicated in the development of human type 1 diabetes and are required for disease in the NOD mouse model. These functions are dependent on B cell antigen receptor (BCR) specificity and expression of MHC, implicating linked autoantigen recognition and presentation to effector T cells. BCR-antigen affinity requirements for participation in disease are unclear. We hypothesized that BCR affinity for the autoantigen insulin differentially affects lymphocyte functionality, including tolerance modality and the ability to acquire and become activated in the diabetogenic environment. Using combined transgenic and retrogenic heavy and light chain to create multiple insulin-binding BCRs, we demonstrate that affinity for insulin is a critical determinant of the function of these autoreactive cells. We show that both BCR affinity for insulin and genetic background affect tolerance induction in immature B cells. We also find new evidence that may explain the enigmatic ability of B cells expressing 125 anti-insulin BCR to support development of TID in NOD mice despite a reported affinity beneath requirements for binding insulin at in vivo concentrations. We report that when expressed as an antigen receptor the affinity of 125 is much higher than determined by measurements of the soluble form. Finally, we show that in vivo acquisition of insulin requires both sufficient BCR affinity and permissive host/tissue environment. We propose that a confluence of BCR affinity, pancreas environment, and B cell tolerance-regulating genes in the NOD animal allows acquisition of insulin and autoimmunity. PMID:27834793

  12. Regulation of B cell fate by chronic activity of the IgE B cell receptor

    PubMed Central

    Yang, Zhiyong; Robinson, Marcus J; Chen, Xiangjun; Smith, Geoffrey A; Taunton, Jack; Liu, Wanli; Allen, Christopher D C

    2016-01-01

    IgE can trigger potent allergic responses, yet the mechanisms regulating IgE production are poorly understood. Here we reveal that IgE+ B cells are constrained by chronic activity of the IgE B cell receptor (BCR). In the absence of cognate antigen, the IgE BCR promoted terminal differentiation of B cells into plasma cells (PCs) under cell culture conditions mimicking T cell help. This antigen-independent PC differentiation involved multiple IgE domains and Syk, CD19, BLNK, Btk, and IRF4. Disruption of BCR signaling in mice led to consistently exaggerated IgE+ germinal center (GC) B cell but variably increased PC responses. We were unable to confirm reports that the IgE BCR directly promoted intrinsic apoptosis. Instead, IgE+ GC B cells exhibited poor antigen presentation and prolonged cell cycles, suggesting reduced competition for T cell help. We propose that chronic BCR activity and access to T cell help play critical roles in regulating IgE responses. DOI: http://dx.doi.org/10.7554/eLife.21238.001 PMID:27935477

  13. Regulation of B cell fate by chronic activity of the IgE B cell receptor.

    PubMed

    Yang, Zhiyong; Robinson, Marcus J; Chen, Xiangjun; Smith, Geoffrey A; Taunton, Jack; Liu, Wanli; Allen, Christopher D C

    2016-12-09

    IgE can trigger potent allergic responses, yet the mechanisms regulating IgE production are poorly understood. Here we reveal that IgE(+) B cells are constrained by chronic activity of the IgE B cell receptor (BCR). In the absence of cognate antigen, the IgE BCR promoted terminal differentiation of B cells into plasma cells (PCs) under cell culture conditions mimicking T cell help. This antigen-independent PC differentiation involved multiple IgE domains and Syk, CD19, BLNK, Btk, and IRF4. Disruption of BCR signaling in mice led to consistently exaggerated IgE(+) germinal center (GC) B cell but variably increased PC responses. We were unable to confirm reports that the IgE BCR directly promoted intrinsic apoptosis. Instead, IgE(+) GC B cells exhibited poor antigen presentation and prolonged cell cycles, suggesting reduced competition for T cell help. We propose that chronic BCR activity and access to T cell help play critical roles in regulating IgE responses.

  14. Leukemia - B-Cell Prolymphocytic Leukemia and Hairy Cell Leukemia

    MedlinePlus

    ... and Hairy Cell Leukemia: Introduction Request Permissions Leukemia - B-cell Prolymphocytic Leukemia and Hairy Cell Leukemia: Introduction ... t k e P Types of Cancer Leukemia - B-cell Prolymphocytic Leukemia and Hairy Cell Leukemia Guide ...

  15. NKT Cell Responses to B Cell Lymphoma

    PubMed Central

    Li, Junxin; Sun, Wenji; Subrahmanyam, Priyanka B.; Page, Carly; Younger, Kenisha M.; Tiper, Irina V.; Frieman, Matthew; Kimball, Amy S.; Webb, Tonya J.

    2014-01-01

    Natural killer T (NKT) cells are a unique subset of CD1d-restricted T lymphocytes that express characteristics of both T cells and natural killer cells. NKT cells mediate tumor immune-surveillance; however, NKT cells are numerically reduced and functionally impaired in lymphoma patients. Many hematologic malignancies express CD1d molecules and co-stimulatory proteins needed to induce anti-tumor immunity by NKT cells, yet most tumors are poorly immunogenic. In this study, we sought to investigate NKT cell responses to B cell lymphoma. In the presence of exogenous antigen, both mouse and human NKT cell lines produce cytokines following stimulation by B cell lymphoma lines. NKT cell populations were examined ex vivo in mouse models of spontaneous B cell lymphoma, and it was found that during early stages, NKT cell responses were enhanced in lymphoma-bearing animals compared to disease-free animals. In contrast, in lymphoma-bearing animals with splenomegaly and lymphadenopathy, NKT cells were functionally impaired. In a mouse model of blastoid variant mantle cell lymphoma, treatment of tumor-bearing mice with a potent NKT cell agonist, α-galactosylceramide (α-GalCer), resulted in a significant decrease in disease pathology. Ex vivo studies demonstrated that NKT cells from α-GalCer treated mice produced IFN-γ following α-GalCer restimulation, unlike NKT cells from vehicle-control treated mice. These data demonstrate an important role for NKT cells in the immune response to an aggressive hematologic malignancy like mantle cell lymphoma. PMID:24955247

  16. Complement activation by a B cell superantigen.

    PubMed

    Kozlowski, L M; Soulika, A M; Silverman, G J; Lambris, J D; Levinson, A I

    1996-08-01

    Staphylococcal protein A (SpA), acting as a B cell superantigen, binds to the Fab region of human VH3+ Igs. Using SpA abrogated of its IgG Fc binding activity (Mod SpA) as a model B cell superantigen, we determined whether such an interaction causes complement activation. Addition of Mod SpA to human serum led to complement consumption and the generation of C3a. To determine whether this complement activation 1) was due to an interaction between VH3+ Igs and the Fab binding site of SpA and 2) proceeded via the classical complement pathway, we tested a panel of monoclonal IgM proteins for the ability to hind C1q following interaction with SpA. C1q binding was restricted to SpA-reactive, VH3+ IgM proteins. To formally determine whether the binding of SpA to the reactive VH3+ IgM proteins led to complement activation, we reconstituted the serum from a hypogammaglobulinemic patient with monoclonal IgM proteins and measured complement consumption and C3a generation following the addition of Mod SpA. We observed complement consumption and C3a production only in Mod SpA-treated serum reconstituted with a VH3+, SpA-binding, IgM protein. Taken together, these results provide compelling evidence that the interaction of the Fab binding site of SpA and VH3+ Igs can lead to complement activation via the classical pathway. This novel interaction may have significant implications for the in vivo properties of a B cell superantigen.

  17. Activation-Induced Cytidine Deaminase Expression in Human B Cell Precursors Is Essential for Central B Cell Tolerance.

    PubMed

    Cantaert, Tineke; Schickel, Jean-Nicolas; Bannock, Jason M; Ng, Yen-Shing; Massad, Christopher; Oe, Tyler; Wu, Renee; Lavoie, Aubert; Walter, Jolan E; Notarangelo, Luigi D; Al-Herz, Waleed; Kilic, Sara Sebnem; Ochs, Hans D; Nonoyama, Shigeaki; Durandy, Anne; Meffre, Eric

    2015-11-17

    Activation-induced cytidine deaminase (AID), the enzyme-mediating class-switch recombination (CSR) and somatic hypermutation (SHM) of immunoglobulin genes, is essential for the removal of developing autoreactive B cells. How AID mediates central B cell tolerance remains unknown. We report that AID enzymes were produced in a discrete population of immature B cells that expressed recombination-activating gene 2 (RAG2), suggesting that they undergo secondary recombination to edit autoreactive antibodies. However, most AID+ immature B cells lacked anti-apoptotic MCL-1 and were deleted by apoptosis. AID inhibition using lentiviral-encoded short hairpin (sh)RNA in B cells developing in humanized mice resulted in a failure to remove autoreactive clones. Hence, B cell intrinsic AID expression mediates central B cell tolerance potentially through its RAG-coupled genotoxic activity in self-reactive immature B cells.

  18. Rationally designed BCL6 inhibitors target activated B cell diffuse large B cell lymphoma

    PubMed Central

    Cardenas, Mariano G.; Yu, Wenbo; Beguelin, Wendy; Teater, Matthew R.; Geng, Huimin; Goldstein, Rebecca L.; Oswald, Erin; Hatzi, Katerina; Yang, Shao-Ning; Cohen, Joanna; Shaknovich, Rita; Vanommeslaeghe, Kenno; Cheng, Huimin; Liang, Dongdong; Cho, Hyo Je; Tam, Wayne; Du, Wei; Leonard, John P.; Elemento, Olivier; Cierpicki, Tomasz; Xue, Fengtian; MacKerell, Alexander D.; Melnick, Ari M.

    2016-01-01

    Diffuse large B cell lymphomas (DLBCLs) arise from proliferating B cells transiting different stages of the germinal center reaction. In activated B cell DLBCLs (ABC-DLBCLs), a class of DLBCLs that respond poorly to current therapies, chromosomal translocations and amplification lead to constitutive expression of the B cell lymphoma 6 (BCL6) oncogene. The role of BCL6 in maintaining these lymphomas has not been investigated. Here, we designed small-molecule inhibitors that display higher affinity for BCL6 than its endogenous corepressor ligands to evaluate their therapeutic efficacy for targeting ABC-DLBCL. We used an in silico drug design functional-group mapping approach called SILCS to create a specific BCL6 inhibitor called FX1 that has 10-fold greater potency than endogenous corepressors and binds an essential region of the BCL6 lateral groove. FX1 disrupted formation of the BCL6 repression complex, reactivated BCL6 target genes, and mimicked the phenotype of mice engineered to express BCL6 with corepressor binding site mutations. Low doses of FX1 induced regression of established tumors in mice bearing DLBCL xenografts. Furthermore, FX1 suppressed ABC-DLBCL cells in vitro and in vivo, as well as primary human ABC-DLBCL specimens ex vivo. These findings indicate that ABC-DLBCL is a BCL6-dependent disease that can be targeted by rationally designed inhibitors that exceed the binding affinity of natural BCL6 ligands. PMID:27482887

  19. Rationally designed BCL6 inhibitors target activated B cell diffuse large B cell lymphoma.

    PubMed

    Cardenas, Mariano G; Yu, Wenbo; Beguelin, Wendy; Teater, Matthew R; Geng, Huimin; Goldstein, Rebecca L; Oswald, Erin; Hatzi, Katerina; Yang, Shao-Ning; Cohen, Joanna; Shaknovich, Rita; Vanommeslaeghe, Kenno; Cheng, Huimin; Liang, Dongdong; Cho, Hyo Je; Abbott, Joshua; Tam, Wayne; Du, Wei; Leonard, John P; Elemento, Olivier; Cerchietti, Leandro; Cierpicki, Tomasz; Xue, Fengtian; MacKerell, Alexander D; Melnick, Ari M

    2016-09-01

    Diffuse large B cell lymphomas (DLBCLs) arise from proliferating B cells transiting different stages of the germinal center reaction. In activated B cell DLBCLs (ABC-DLBCLs), a class of DLBCLs that respond poorly to current therapies, chromosomal translocations and amplification lead to constitutive expression of the B cell lymphoma 6 (BCL6) oncogene. The role of BCL6 in maintaining these lymphomas has not been investigated. Here, we designed small-molecule inhibitors that display higher affinity for BCL6 than its endogenous corepressor ligands to evaluate their therapeutic efficacy for targeting ABC-DLBCL. We used an in silico drug design functional-group mapping approach called SILCS to create a specific BCL6 inhibitor called FX1 that has 10-fold greater potency than endogenous corepressors and binds an essential region of the BCL6 lateral groove. FX1 disrupted formation of the BCL6 repression complex, reactivated BCL6 target genes, and mimicked the phenotype of mice engineered to express BCL6 with corepressor binding site mutations. Low doses of FX1 induced regression of established tumors in mice bearing DLBCL xenografts. Furthermore, FX1 suppressed ABC-DLBCL cells in vitro and in vivo, as well as primary human ABC-DLBCL specimens ex vivo. These findings indicate that ABC-DLBCL is a BCL6-dependent disease that can be targeted by rationally designed inhibitors that exceed the binding affinity of natural BCL6 ligands.

  20. Multiple layers of B cell memory with different effector functions.

    PubMed

    Dogan, Ismail; Bertocci, Barbara; Vilmont, Valérie; Delbos, Frédéric; Mégret, Jérome; Storck, Sébastien; Reynaud, Claude-Agnès; Weill, Jean-Claude

    2009-12-01

    Memory B cells are at the center of longstanding controversies regarding the presence of antigen for their survival and their re-engagement in germinal centers after secondary challenge. Using a new mouse model of memory B cell labeling dependent on the cytidine deaminase AID, we show that after immunization with a particulate antigen, B cell memory appeared in several subsets, comprising clusters of immunoglobulin M-positive (IgM(+)) and IgG1(+) B cells in germinal center-like structures that persisted up to 8 months after immunization, as well as IgM(+) and IgG1(+) B cells with a memory phenotype outside of B cell follicles. After challenge, the IgG subset differentiated into plasmocytes, whereas the IgM subset reinitiated a germinal center reaction. This model, in which B cell memory appears in several layers with different functions, reconciles previous conflicting propositions.

  1. CNS accumulation of regulatory B cells is VLA-4-dependent

    PubMed Central

    Lehmann-Horn, Klaus; Sagan, Sharon A.; Winger, Ryan C.; Spencer, Collin M.; Bernard, Claude C.A.; Sobel, Raymond A.

    2016-01-01

    Objective: To investigate the role of very late antigen-4 (VLA-4) on regulatory B cells (Breg) in CNS autoimmune disease. Methods: Experimental autoimmune encephalomyelitis (EAE) was induced in mice selectively deficient for VLA-4 on B cells (CD19cre/α4f/f) by immunization with myelin oligodendrocyte glycoprotein (MOG) peptide (p)35–55 or recombinant human (rh) MOG protein. B-cell and T-cell populations were examined by flow cytometry and immunohistochemistry. Breg were evaluated by intracellular IL-10 staining of B cells and, secondly, by coexpression of CD1d and CD5. Results: As previously reported, EAE was less severe in B-cell VLA-4-deficient vs control CD19cre mice when induced by rhMOG, a model that is B-cell-dependent and leads to efficient B-cell activation and antibody production. Paradoxically, B-cell VLA-4-deficient mice developed more severe clinical disease than control mice when EAE was induced with MOG p35-55, a B-cell-independent encephalitogen that does not efficiently activate B cells. Peripheral T-cell and humoral immune responses were not altered in B-cell VLA-4-deficient mice. In MOG p35-55-induced EAE, B-cell VLA-4 deficiency reduced CNS accumulation of B but not T cells. Breg were detected in the CNS of control mice with MOG p35-55-induced EAE. However, more severe EAE in B-cell VLA-4-deficient mice was associated with virtual absence of CNS Breg. Conclusions: Our results demonstrate that CNS accumulation of Breg is VLA-4-dependent and suggest that Breg may contribute to regulation of CNS autoimmunity in situ. These observations underscore the need to choose the appropriate encephalitogen when studying how B cells contribute to pathogenesis or regulation of CNS autoimmunity. PMID:27027096

  2. The majority of human memory B cells recognizing RhD and tetanus resides in IgM+ B cells.

    PubMed

    Della Valle, Luciana; Dohmen, Serge E; Verhagen, Onno J H M; Berkowska, Magdalena A; Vidarsson, Gestur; Ellen van der Schoot, C

    2014-08-01

    B cell memory to T cell-dependent (TD) Ags are considered to largely reside in class-switched CD27(+) cells. However, we previously observed that anti-RhD (D) Igs cloned from two donors, hyperimmunized with D(+) erythrocytes, were predominantly of the IgM isotype. We therefore analyzed in this study the phenotype and frequency of D- and tetanus toxoid-specific B cells by culturing B cells in limiting dilution upon irradiated CD40L-expressing EL4.B5 cells and testing the culture supernatant. Most Ag-specific B cells for both TD Ags were found to reside in the IgM-expressing B cells, including CD27(-) B cells, in both hyperimmunized donors and nonhyperimmunized volunteers. Only shortly after immunization a sharp increase in Ag-specific CD27(+)IgG(+) B cells was observed. Next, B cells were enriched with D(+) erythrocyte ghosts and sorted as single cells. Sequencing of IGHV, IGLV, IGKV, and BCL6 genes from these D-specific B cell clones demonstrated that both CD27(-)IgM(+) and CD27(+)IgM(+) B cells harbored somatic mutations, documenting their Ag-selected nature. Furthermore, sequencing revealed a clonal relationship between the CD27(-)IgM(+), CD27(+)IgM(+), and CD27(+)IgG(+) B cell subsets. These data strongly support the recently described multiple layers of memory B cells to TD Ags in mice, where IgM(+) B cells represent a memory reservoir which can re-enter the germinal center and ensure replenishment of class-switched memory CD27(+) B cells from Ag-experienced precursors.

  3. Impairment of B-cell functions during HIV-1 infection.

    PubMed

    Amu, Sylvie; Ruffin, Nicolas; Rethi, Bence; Chiodi, Francesca

    2013-09-24

    A variety of B-cell dysfunctions are manifested during HIV-1 infection, as reported early during the HIV-1 epidemic. It is not unusual that the pathogenic mechanisms presented to elucidate impairment of B-cell responses during HIV-1 infection focus on the impact of reduced T-cell numbers and functions, and lack of germinal center formation in lymphoid tissues. To our understanding, however, perturbation of B-cell phenotype and function during HIV-1 infection may begin at several different B-cell developmental stages. These impairments can be mediated by intrinsic B-cell defects as well as by the lack of proper T-cell help. In this review, we will highlight some of the pathways and molecular interactions leading to B-cell impairment prior to germinal center formation and B-cell activation mediated through the B-cell receptor in response to HIV-1 antigens. Recent studies indicate a regulatory role for B cells on T-cell biology and immune responses. We will discuss some of these novel findings and how these regulatory mechanisms could potentially be affected by the intrinsic defects of B cells taking place during HIV-1 infection.

  4. FcR-Like 2 Inhibition of B Cell Receptor-Mediated Activation of B Cells

    PubMed Central

    Jackson, Tanisha A.; Haga, Christopher L.; Ehrhardt, Götz R. A.; Davis, Randall S.; Cooper, Max D.

    2017-01-01

    FcR-like (FCRL) 2 is a transmembrane protein with immunomodulatory potential that is preferentially expressed by memory B cells in humans. It has two consensus ITIMs in addition to a putative ITAM sequence in its cytoplasmic domain. We have confirmed the cellular distribution of FCRL2 and analyzed its functional potential to show that coligation with the BCR leads to tyrosine phosphorylation of its ITIM motifs and subsequent Src homology region 2 domain-containing phosphatase-1 recruitment to facilitate inhibition of BCR signaling. Mutational analysis indicates that the tyrosine residues in both inhibitory motifs of FCRL2 are required for complete inhibition of BCR signaling, whereas tyrosines in the putative activation motif are dispensable for signal modulation. These findings suggest a negative immunomodulatory function for FCRL2 in the regulation of memory B cells. PMID:21068405

  5. Chronic active B-cell-receptor signalling in diffuse large B-cell lymphoma.

    PubMed

    Davis, R Eric; Ngo, Vu N; Lenz, Georg; Tolar, Pavel; Young, Ryan M; Romesser, Paul B; Kohlhammer, Holger; Lamy, Laurence; Zhao, Hong; Yang, Yandan; Xu, Weihong; Shaffer, Arthur L; Wright, George; Xiao, Wenming; Powell, John; Jiang, Jian-Kang; Thomas, Craig J; Rosenwald, Andreas; Ott, German; Muller-Hermelink, Hans Konrad; Gascoyne, Randy D; Connors, Joseph M; Johnson, Nathalie A; Rimsza, Lisa M; Campo, Elias; Jaffe, Elaine S; Wilson, Wyndham H; Delabie, Jan; Smeland, Erlend B; Fisher, Richard I; Braziel, Rita M; Tubbs, Raymond R; Cook, J R; Weisenburger, Dennis D; Chan, Wing C; Pierce, Susan K; Staudt, Louis M

    2010-01-07

    A role for B-cell-receptor (BCR) signalling in lymphomagenesis has been inferred by studying immunoglobulin genes in human lymphomas and by engineering mouse models, but genetic and functional evidence for its oncogenic role in human lymphomas is needed. Here we describe a form of 'chronic active' BCR signalling that is required for cell survival in the activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL). The signalling adaptor CARD11 is required for constitutive NF-kappaB pathway activity and survival in ABC DLBCL. Roughly 10% of ABC DLBCLs have mutant CARD11 isoforms that activate NF-kappaB, but the mechanism that engages wild-type CARD11 in other ABC DLBCLs was unknown. An RNA interference genetic screen revealed that a BCR signalling component, Bruton's tyrosine kinase, is essential for the survival of ABC DLBCLs with wild-type CARD11. In addition, knockdown of proximal BCR subunits (IgM, Ig-kappa, CD79A and CD79B) killed ABC DLBCLs with wild-type CARD11 but not other lymphomas. The BCRs in these ABC DLBCLs formed prominent clusters in the plasma membrane with low diffusion, similarly to BCRs in antigen-stimulated normal B cells. Somatic mutations affecting the immunoreceptor tyrosine-based activation motif (ITAM) signalling modules of CD79B and CD79A were detected frequently in ABC DLBCL biopsy samples but rarely in other DLBCLs and never in Burkitt's lymphoma or mucosa-associated lymphoid tissue lymphoma. In 18% of ABC DLBCLs, one functionally critical residue of CD79B, the first ITAM tyrosine, was mutated. These mutations increased surface BCR expression and attenuated Lyn kinase, a feedback inhibitor of BCR signalling. These findings establish chronic active BCR signalling as a new pathogenetic mechanism in ABC DLBCL, suggesting several therapeutic strategies.

  6. Transitional B cells: step by step towards immune competence.

    PubMed

    Chung, James B; Silverman, Michael; Monroe, John G

    2003-06-01

    Transitional B cells mark the crucial link between bone-marrow (BM) immature and peripheral mature B cells. Examination reveals unexpected heterogeneity, consisting of contiguous subsets with phenotypic and functional differences. Data point to the late transitional B-cell stage as a crucial juncture at which developing B cells gain access to splenic follicles, become responsive to T-cell help and lose sensitivity to negative selection, characterizing the immature B-cell response to B-cell antigen receptor (BCR) signaling in vitro and in vivo. The biological and molecular processes directing maturation through this stage are becoming clearer through biochemical studies and murine models deficient in various components of the BCR signaling pathway.

  7. Restoring balance to B cells in ADA deficiency.

    PubMed

    Luning Prak, Eline T

    2012-06-01

    It is paradoxical that immunodeficiency disorders are associated with autoimmunity. Adenosine deaminase (ADA) deficiency, a cause of X-linked severe combined immunodeficiency (SCID), is a case in point. In this issue of the JCI, Sauer and colleagues investigate the B cell defects in ADA-deficient patients. They demonstrate that ADA patients receiving enzyme replacement therapy had B cell tolerance checkpoint defects. Remarkably, gene therapy with a retrovirus that expresses ADA resulted in the apparent correction of these defects, with normalization of peripheral B cell autoantibody frequencies. In vitro, agents that either block ADA or overexpress adenosine resulted in altered B cell receptor and TLR signaling. Collectively, these data implicate a B cell-intrinsic mechanism for alterations in B cell tolerance in the setting of partial ADA deficiency that is corrected by gene therapy.

  8. RP105-Negative B Cells in Systemic Lupus Erythematosus

    PubMed Central

    Koarada, Syuichi; Tada, Yoshifumi

    2012-01-01

    Systemic lupus erythematosus (SLE) is a multisystem disease characterized by B cells producing autoantibodies against nuclear proteins and DNA, especially anti-double-strand DNA (dsDNA) antibodies. RP105 (CD180), the toll-like receptor- (TLR-) associated molecule, is expressed on normal B cells. However, RP105-negative B cells increase in peripheral blood from patients with active SLE. RP105 may regulate B-cell activation, and RP105-negative B cells produce autoantibodies and take part in pathophysiology of SLE. It is possible that targeting RP105-negative B cells is one of the treatments of SLE. In this paper, we discuss the RP105 biology and clinical significance in SLE. PMID:21941580

  9. The PI3K pathway in B cell metabolism.

    PubMed

    Jellusova, Julia; Rickert, Robert C

    2016-09-01

    B cell growth and proliferation is tightly regulated by signaling through the B cell receptor and by other membrane bound receptors responding to different cytokines. The PI3K signaling pathway has been shown to play a crucial role in B cell activation, differentiation and survival. Activated B cells undergo metabolic reprograming in response to changing energetic and biosynthetic demands. B cells also need to be able to coordinate metabolic activity and proliferation with nutrient availability. The PI3K signaling network has been implicated in regulating nutrient acquisition, utilization and biosynthesis, thus integrating receptor-mediated signaling with cell metabolism. In this review, we discuss the current knowledge about metabolic changes induced in activated B cells, strategies to adapt to metabolic stress and the role of PI3K signaling in these processes.

  10. Innate response activator B cells: origins and functions

    PubMed Central

    Swirski, Filip K.

    2015-01-01

    Innate response activator (IRA) B cells are a subset of B-1a derived B cells that produce the growth factors granulocyte macrophage colony stimulating factor and IL-3. In mouse models of sepsis and pneumonia, B-1a B cells residing in serosal sites recognize bacteria, migrate to the spleen or lung, and differentiate to IRA B cells that then contribute to the host response by amplifying inflammation and producing polyreactive IgM. In atherosclerosis, IRA B cells accumulate in the spleen, where they promote extramedullary hematopoiesis and activate classical dendritic cells. In this review, we focus on the ontogeny and function of IRA B cells in acute and chronic inflammation. PMID:25957266

  11. Distinct processing of the pre-B cell receptor and the B cell receptor.

    PubMed

    Cohen, Sharon; Haimovich, Joseph; Hollander, Nurit

    2013-06-01

    It has been recently demonstrated that while oligosaccharide moieties of μ heavy chains in the B-cell receptor (BCR) are of the complex type as expected, those of the pre-BCR on the surface of pre-B cells contain oligosaccharide moieties of the high-mannose type only. This is unique, because high-mannose glycans are generally restricted to the endoplasmic reticulum and not presented on the surface of mammalian cells. In the present study, we examined the processing of the unusually glycosylated μ heavy chains in pre-B cells. We demonstrate that the pre-BCR reaches the cell surface by a non-conventional brefeldin A-sensitive monensin-insensitive transport pathway. Although pre-BCR complexes consist of μ heavy chains with high-mannose oligosaccharide moieties, they are stably expressed in the plasma membrane and demonstrate turnover rates similar to those of the BCR. Thus, rapid internalization cannot account for their low surface expression, as previously postulated. Rather, we demonstrate that the low pre-BCR abundance in the plasma membrane results, at least in part, from insufficient production of surrogate light chains, which appears to be a limiting factor in pre-BCR expression.

  12. B-cell Non-Hodgkin Lymphomas with Plasmacytic Differentiation.

    PubMed

    Harmon, Charles M; Smith, Lauren B

    2016-03-01

    B-cell non-Hodgkin lymphomas with plasmacytic differentiation are a diverse group of entities with extremely variable morphologic features. Diagnostic challenges can arise in differentiating lymphoplasmacytic lymphoma from marginal zone lymphoma and other low-grade B-cell lymphomas. In addition, plasmablastic lymphomas can be difficult to distinguish from diffuse large B-cell lymphoma or other high-grade lymphomas. Judicious use of immunohistochemical studies and molecular testing can assist in appropriate classification.

  13. Utilization of a photoactivatable antigen system to examine B-cell probing termination and the B-cell receptor sorting mechanisms during B-cell activation.

    PubMed

    Wang, Jing; Tang, Shan; Wan, Zhengpeng; Gao, Yiren; Cao, Yiyun; Yi, Junyang; Si, Yanyan; Zhang, Haowen; Liu, Lei; Liu, Wanli

    2016-02-02

    Antigen binding to the B-cell receptor (BCR) induces several responses, resulting in B-cell activation, proliferation, and differentiation. However, it has been difficult to study these responses due to their dynamic, fast, and transient nature. Here, we attempted to solve this problem by developing a controllable trigger point for BCR and antigen recognition through the construction of a photoactivatable antigen, caged 4-hydroxy-3-nitrophenyl acetyl (caged-NP). This photoactivatable antigen system in combination with live cell and single molecule imaging techniques enabled us to illuminate the previously unidentified B-cell probing termination behaviors and the precise BCR sorting mechanisms during B-cell activation. B cells in contact with caged-NP exhibited probing behaviors as defined by the unceasing extension of membrane pseudopods in random directions. Further analyses showed that such probing behaviors are cell intrinsic with strict dependence on F-actin remodeling but not on tonic BCR signaling. B-cell probing behaviors were terminated within 4 s after photoactivation, suggesting that this response was sensitive and specific to BCR engagement. The termination of B-cell probing was concomitant with the accumulation response of the BCRs into the BCR microclusters. We also determined the Brownian diffusion coefficient of BCRs from the same B cells before and after BCR engagement. The analysis of temporally segregated single molecule images of both BCR and major histocompatibility complex class I (MHC-I) demonstrated that antigen binding induced trapping of BCRs into the BCR microclusters is a fundamental mechanism for B cells to acquire antigens.

  14. Relevant B Cell Epitopes in Allergic Disease

    PubMed Central

    Pomés, Anna

    2010-01-01

    The 3-dimensional structure of an allergen defines the accessible parts on the surface of the molecule or epitopes that interact with antibodies. Mapping the antigenic determinants for IgE antibody binding has been pursued through strategies based on the use of overlapping synthetic peptides, recombinant allergenic fragments or unfolded allergens. These approaches led to the identification of mostly linear epitopes and are useful for food allergens that undergo digestion or food processing. For inhaled allergens, conformational epitopes appear to be the primary targets of IgE responses. Knowledge of the molecular structure of allergens alone and in complex with antibodies that interfere with IgE antibody binding is important to understand the immune recognition of B cell-antigenic determinants on allergens and the design of recombinant allergens for immunotherapy. Starting with the molecular cloning and expression of allergens, and with the advent of X-ray crystallography and nuclear magnetic resonance techniques, we have been able to visualize conformational epitopes on allergens. PMID:19940500

  15. Auto-reactive B cells in transgenic mice.

    PubMed

    Pasquali, Jean-Louis; Soulas-Sprauel, Pauline; Korganow, Anne-Sophie; Martin, Thierry

    2007-12-01

    In order to understand how the natural occurrence of autoreactive B cells is controlled in normal individuals, and how self reactive B cells can escape this control during diverse clinical situations, many different transgenic mice have been generated expressing self reactive antibodies. In this review, we focus our attention on disease-associated self reactive transgenic models which show the variety of the tolerization mechanisms. The same transgenic lines are also used to analyse the effects of the autoimmune genetic background on the self reactive B cell fate, as well as to study the influence of infectious agents on the behaviour of the auto-reactive transgenic B cells.

  16. Transcriptional networks in developing and mature B cells.

    PubMed

    Matthias, Patrick; Rolink, Antonius G

    2005-06-01

    The development of B cells from haematopoietic stem cells proceeds along a highly ordered, yet flexible, pathway. At multiple steps along this pathway, cells are instructed by transcription factors on how to further differentiate, and several check-points have been identified. These check-points are initial commitment to lymphocytic progenitors, specification of pre-B cells, entry to the peripheral B-cell pool, maturation of B cells and differentiation into plasma cells. At each of these regulatory nodes, there are transcriptional networks that control the outcome, and much progress has recently been made in dissecting these networks. This article reviews our current understanding of this exciting field.

  17. CD23 can negatively regulate B-cell receptor signaling

    PubMed Central

    Liu, Chaohong; Richard, Katharina; Wiggins, Melvin; Zhu, Xiaoping; Conrad, Daniel H.; Song, Wenxia

    2016-01-01

    CD23 has been implicated as a negative regulator of IgE and IgG antibody responses. However, whether CD23 has any role in B-cell activation remains unclear. We examined the expression of CD23 in different subsets of peripheral B cells and the impact of CD23 expression on the early events of B-cell receptor (BCR) activation using CD23 knockout (KO) mice. We found that in addition to marginal zone B cells, mature follicular B cells significantly down regulate the surface expression level of CD23 after undergoing isotype switch and memory B-cell differentiation. Upon stimulation with membrane-associated antigen, CD23 KO causes significant increases in the area of B cells contacting the antigen-presenting membrane and the magnitude of BCR clustering. This enhanced cell spreading and BCR clustering is concurrent with increases in the levels of phosphorylation of tyrosine and Btk, as well as the levels of F-actin and phosphorylated Wiskott Aldrich syndrome protein, an actin nucleation promoting factor, in the contract zone of CD23 KO B cells. These results reveal a role of CD23 in the negative regulation of BCR signaling in the absence of IgE immune complex and suggest that CD23 down-regulates BCR signaling by influencing actin-mediated BCR clustering and B-cell morphological changes. PMID:27181049

  18. Age effects on B cells and humoral immunity in humans

    PubMed Central

    Frasca, Daniela; Diaz, Alain; Romero, Maria; Landin, Ana Marie; Blomberg, Bonnie B

    2010-01-01

    Both humoral and cellular immune responses are impaired in aged individuals, leading to decreased vaccine responses. Although T cell defects occur, defects in B cells play a significant role in age-related humoral immune changes. The ability to undergo class switch recombination (CSR), the enzyme for CSR, AID (activation-induced cytidine deaminase) and the transcription factor E47 are all decreased in aged stimulated B cells. We here present an overview of age-related changes in human B cell markers and functions, and also discuss some controversies in the field of B cell aging. PMID:20728581

  19. Involvement of B cells in non-infectious uveitis

    PubMed Central

    Smith, Justine R; Stempel, Andrew J; Bharadwaj, Arpita; Appukuttan, Binoy

    2016-01-01

    Non-infectious uveitis—or intraocular inflammatory disease—causes substantial visual morbidity and reduced quality of life amongst affected individuals. To date, research of pathogenic mechanisms has largely been focused on processes involving T lymphocyte and/or myeloid leukocyte populations. Involvement of B lymphocytes has received relatively little attention. In contrast, B-cell pathobiology is a major field within general immunological research, and large clinical trials have showed that treatments targeting B cells are highly effective for multiple systemic inflammatory diseases. B cells, including the terminally differentiated plasma cell that produces antibody, are found in the human eye in different forms of non-infectious uveitis; in some cases, these cells outnumber other leukocyte subsets. Recent case reports and small case series suggest that B-cell blockade may be therapeutic for patients with non-infectious uveitis. As well as secretion of antibody, B cells may promote intraocular inflammation by presentation of antigen to T cells, production of multiple inflammatory cytokines and support of T-cell survival. B cells may also perform various immunomodulatory activities within the eye. This translational review summarizes the evidence for B-cell involvement in non-infectious uveitis, and considers the potential contributions of B cells to the development and control of the disease. Manipulations of B cells and/or their products are promising new approaches to the treatment of non-infectious uveitis. PMID:26962453

  20. B cell receptor-mediated internalization of salmonella: a novel pathway for autonomous B cell activation and antibody production.

    PubMed

    Souwer, Yuri; Griekspoor, Alexander; Jorritsma, Tineke; de Wit, Jelle; Janssen, Hans; Neefjes, Jacques; van Ham, S Marieke

    2009-06-15

    The present paradigm is that primary B cells are nonphagocytosing cells. In this study, we demonstrate that human primary B cells are able to internalize bacteria when the bacteria are recognized by the BCR. BCR-mediated internalization of Salmonella typhimurium results in B cell differentiation and secretion of anti-Salmonella Ab by the Salmonella-specific B cells. In addition, BCR-mediated internalization leads to efficient Ag delivery to the MHC class II Ag-loading compartments, even though Salmonella remains vital intracellularly in primary B cells. Consequently, BCR-mediated bacterial uptake induces efficient CD4(+) T cell help, which boosts Salmonella-specific Ab production. BCR-mediated internalization of Salmonella by B cells is superior over extracellular Ag extraction to induce rapid and specific humoral immune responses and efficiently combat infection.

  1. B cell depletion therapy for new-onset opsoclonus-myoclonus.

    PubMed

    Pranzatelli, Michael R; Tate, Elizabeth D; Swan, Jennifer A; Travelstead, Anna L; Colliver, Jerry A; Verhulst, Steven J; Crosley, Carl J; Graf, William D; Joseph, Suja A; Kelfer, Howard M; Raju, G Praveen

    2010-01-30

    Twelve immunotherapy-naïve children with opsoclonus-myoclonus syndrome and CSF B cell expansion received rituximab, adrenocorticotropic hormone (ACTH), and IVIg. Motor severity lessened 73% by 6 mo and 81% at 1 yr (P < 0.0001). Opsoclonus and action myoclonus disappeared rapidly, whereas gait ataxia and some other motor components improved more slowly. ACTH dose was tapered by 87%. Reduction in total CSF B cells was profound at 6 mo (-93%). By study end, peripheral B cells returned to 53% of baseline and serum IgM levels to 63%. Overall clinical response trailed peripheral B cell and IgM depletion, but improvement continued after their levels recovered. All but one non-ambulatory subject became ambulatory without additional chemotherapy; two relapsed and remitted; four had rituximab-related or possibly related adverse events; and two had low-titer human anti-chimeric antibody. Combination of rituximab with conventional agents as initial therapy was effective and safe. A controlled trial with long-term safety monitoring is indicated.

  2. Molecular and cytogenetic characterization of expanded B-cell clones from multiclonal versus monoclonal B-cell chronic lymphoproliferative disorders

    PubMed Central

    Henriques, Ana; Rodríguez-Caballero, Arancha; Criado, Ignacio; Langerak, Anton W.; Nieto, Wendy G.; Lécrevisse, Quentin; González, Marcos; Cortesão, Emília; Paiva, Artur; Almeida, Julia; Orfao, Alberto

    2014-01-01

    Chronic antigen-stimulation has been recurrently involved in the earlier stages of monoclonal B-cell lymphocytosis, chronic lymphocytic leukemia and other B-cell chronic lymphoproliferative disorders. The expansion of two or more B-cell clones has frequently been reported in individuals with these conditions; potentially, such coexisting clones have a greater probability of interaction with common immunological determinants. Here, we analyzed the B-cell receptor repertoire and molecular profile, as well as the phenotypic, cytogenetic and hematologic features, of 228 chronic lymphocytic leukemia-like and non-chronic lymphocytic leukemia-like clones comparing multiclonal (n=85 clones from 41 cases) versus monoclonal (n=143 clones) monoclonal B-cell lymphocytosis, chronic lymphocytic leukemia and other B-cell chronic lymphoproliferative disorders. The B-cell receptor of B-cell clones from multiclonal cases showed a slightly higher degree of HCDR3 homology than B-cell clones from mono clonal cases, in association with unique hematologic (e.g. lower B-lymphocyte counts) and cytogenetic (e.g. lower frequency of cytogenetically altered clones) features usually related to earlier stages of the disease. Moreover, a subgroup of coexisting B-cell clones from individual multiclonal cases which were found to be phylogenetically related showed unique molecular and cytogenetic features: they more frequently shared IGHV3 gene usage, shorter HCDR3 sequences with a greater proportion of IGHV mutations and del(13q14.3), than other unrelated B-cell clones. These results would support the antigen-driven nature of such multiclonal B-cell expansions, with potential involvement of multiple antigens/epitopes. PMID:24488564

  3. Gata3 restrains B cell proliferation and cooperates with p18INK4c to repress B cell lymphomagenesis

    PubMed Central

    Liu, Shiqin; Chan, Ho Lam; Bai, Feng; Ma, Jinshan; Scott, Alexandria; Robbins, David J.; Capobianco, Anthony J.; Zhu, Ping; Pei, Xin-Hai

    2016-01-01

    GATA3, a lineage specifier, controls lymphoid cell differentiation and its function in T cell commitment and development has been extensively studied. GATA3 promotes T cell specification by repressing B cell potential in pro T cells and decreased GATA3 expression is essential for early B cell commitment. Inherited genetic variation in GATA3 has been associated with lymphoma susceptibility. However, it remains elusive how the loss of function of GATA3 promotes B cell development and induces B cell lymphomas. In this study, we found that haploid loss of Gata3 by heterozygous germline deletion increased B cell populations in the bone marrow (BM) and spleen, and decreased CD4 T cell populations in the thymus, confirming that Gata3 promotes T and suppresses B cell development. We discovered that haploid loss of Gata3 reduced thymocyte proliferation with induction of p18Ink4c (p18), an inhibitor of CDK4 and CDK6, but enhanced B cell proliferation in the BM and spleen independent of p18. Loss of p18 partially restored Gata3 deficient thymocyte proliferation, but further stimulated Gata3 deficient B cell proliferation in the BM and spleen. Furthermore, we discovered that haploid loss of Gata3 in p18 deficient mice led to the development of B cell lymphomas that were capable of rapidly regenerating tumors when transplanted into immunocompromised mice. These results indicate that Gata3 deficiency promotes B cell differentiation and proliferation, and cooperates with p18 loss to induce B cell lymphomas. This study, for the first time, reveals that Gata3 is a tumor suppressor specifically in B cell lymphomagenesis. PMID:27588406

  4. B-Cell-Mediated Strategies to Fight Chronic Allograft Rejection

    PubMed Central

    Dalloul, Ali

    2013-01-01

    Solid organs have been transplanted for decades. Since the improvement in graft selection and in medical and surgical procedures, the likelihood of graft function after 1 year is now close to 90%. Nonetheless even well-matched recipients continue to need medications for the rest of their lives hence adverse side effects and enhanced morbidity. Understanding Immune rejection mechanisms, is of increasing importance since the greater use of living-unrelated donors and genetically unmatched individuals. Chronic rejection is devoted to T-cells, however the role of B-cells in rejection has been appreciated recently by the observation that B-cell depletion improve graft survival. By contrast however, B-cells can be beneficial to the grafted tissue. This protective effect is secondary to either the secretion of protective antibodies or the induction of B-cells that restrain excessive inflammatory responses, chiefly by local provision of IL-10, or inhibit effector T-cells by direct cellular interactions. As a proof of concept B-cell-mediated infectious transplantation tolerance could be achieved in animal models, and evidence emerged that the presence of such B-cells in transplanted patients correlate with a favorable outcome. Among these populations, regulatory B-cells constitute a recently described population. These cells may develop as a feedback mechanism to prevent uncontrolled reactivity to antigens and inflammatory stimuli. The difficult task for the clinician, is to quantify the respective ratios and functions of “tolerant” vs. effector B-cells within a transplanted organ, at a given time point in order to modulate B-cell-directed therapy. Several receptors at the B-cell membrane as well as signaling molecules, can now be targeted for this purpose. Understanding the temporal expansion of regulatory B-cells in grafted patients and the stimuli that activate them will help in the future to implement specific strategies aimed at fighting chronic allograft

  5. Krüppel-Like Factor 4 Regulates B Cell Number and Activation-Induced B Cell Proliferation1

    PubMed Central

    Klaewsongkram, Jettanong; Yang, Yinhua; Golech, Susanne; Katz, Jonathan; Kaestner, Klaus H.; Weng, Nan-ping

    2008-01-01

    Krüppel-like factor 4 (Klf4) is a transcription factor and functions in regulating cell differentiation, cell growth, and cell cycle. Although Klf4 is expressed in lymphocytes, its function in lymphocytes is unknown. In this study, we report that the levels of Klf4 expression were low in pro-B cells and continuously increased in pre-B and in mature B cells. Upon activation, Klf4 was rapidly decreased in mature B cells after 2 h of activation. A modest decrease in numbers of pre-B cells in bone marrow and mature B cells in spleen was observed in Klf4-deficient mice. In the absence of Klf4, fewer B cells entered the S phase of the cell cycle and completed cell division in response to the engagement of BCR and/or CD40 in vitro. Furthermore, the delay in entering the cell cycle is associated with decreased expression of cyclin D2 in B cells that lack Klf4 expression. We then demonstrated that Klf4 directly bound to the promoter of cyclin D2 and regulated its expression. These findings demonstrate that Klf4 regulates B cell number and activation-induced B cell proliferation through directly acting on the promoter of cyclin D2. PMID:17878366

  6. DNA breaks early in replication in B cell cancers

    Cancer.gov

    Research by scientists at the NCI has identified a new class of DNA sites in cells that break early in the replication process. They found that these break sites correlate with damage often seen in B cell cancers, such as diffuse large B cell lymphoma.

  7. A fine romance: T follicular helper cells and B cells.

    PubMed

    King, Cecile

    2011-06-24

    T follicular helper (Tfh) cells help B cells to generate affinity-matured antibodies. Three papers in this issue of Immunity (Choi et al., 2011; Kerfoot et al., 2011; Kitano et al., 2011) provide information about the reciprocal relationship between B cells and Tfh cells.

  8. B Cells: The Old New Players in Reproductive Immunology

    PubMed Central

    Fettke, Franziska; Schumacher, Anne; Costa, Serban-Dan; Zenclussen, Ana Claudia

    2014-01-01

    Reproductive immunology research has long focused on T cell responses to paternal antigens and tolerance mechanisms supporting fetal well-being. The participation of B cells herein was not widely studied. Because of the fascinating immunological uniqueness of pregnancy, it is however to be expected that such pleiotropic cells play a considerable role. In fact, on the one hand B cells contribute toward pregnancy tolerance by secreting the immunomodulatory cytokine IL-10 but on the other hand can seriously harm pregnancy because of their capacity of producing autoantibodies. As for protective B cells, new evidences in mouse models arise suggesting that IL-10 producing B cells, the so-called B10 cells, help in maintaining tolerance toward semi-allogenic fetal antigens. They may be also important to fight danger signals at the fetal-maternal interface as, e.g., in the case of infections with the aim to restore the disrupted fetal tolerance. In human pregnancies, IL-10 producing B cells increase with pregnancy onset but not in the case of spontaneous abortions. In vitro, they are able to suppress TNF-α production by T cells from pregnant individuals. Their generation and functionality will be discussed throughout this review article. B cells can be deleterious to pregnancy as well. Aberrant B cell compartment is associated with obstetric pathologies. In particular, the capacity of B2 cells to produce specific autoantibodies or of B-1a B cells to secrete natural autoantibodies that can turn autoreactive will be discussed herein. PMID:25002862

  9. Comparison of EBV DNA viral load in whole blood, plasma, B-cells and B-cell culture supernatant.

    PubMed

    Ouedraogo, David Eric; Bollore, Karine; Viljoen, Johannes; Foulongne, Vincent; Reynes, Jacques; Cartron, Guillaume; Vendrell, Jean-Pierre; Van de Perre, Philippe; Tuaillon, Edouard

    2014-05-01

    Epstein-Barr virus (EBV) genome quantitation in whole blood is used widely for therapeutic monitoring of EBV-associated disorders in immunosuppressed individuals and in patients with EBV-associated lymphoma. However, the most appropriate biological material to be used for EBV DNA quantitation remains a subject of debate. This study compare the detection rate and levels of EBV DNA from whole blood, plasma, enriched B-cells, and B-cell short-term culture supernatant using quantitative real-time PCR. Samples were collected from 33 subjects with either HIV infection or B-cell lymphoma. Overall, EBV DNA was detected in 100% of enriched B-cell samples, in 82% of B-cell culture supernatants, in 57% of plasma, and 42% of whole blood samples. A significant correlation for EBV viral load was found between enriched B-cell and B-cell culture supernatant material (ρ = 0.92; P < 0.0001), but no significant correlation existed between EBV DNA levels in whole blood and enriched B-cells (ρ = -0.02; P = 0.89), whole blood and plasma (ρ = 0.24; P = 0.24), or enriched B-cells and plasma (ρ = 0.08; P = 0.77). Testing of enriched B-cells appeared to be the most sensitive method for detection of EBV DNA as well as for exploration of the cellular reservoir. Quantitation of EBV DNA in plasma and B-cell culture supernatant may be of interest to assess EBV reactivation dynamics and response to treatment as well as to decipher EBV host-pathogen interactions in various clinical scenarios.

  10. Essential role for B cells in transplantation tolerance

    PubMed Central

    Redfield, Robert R; Rodriguez, Eduardo; Parsons, Ronald; Vivek, Kumar; Mustafa, Moiz M; Noorchashm, Hooman; Naji, Ali

    2017-01-01

    T lymphocytes are the primary targets of immunotherapy in clinical transplantation. However, B lymphocytes are detrimental to graft survival by virtue of their capacity to present antigen to T cells via the indirect pathway of allorecognition and the generation of donor specific alloantibody. Furthermore, the long-term survival of organ allografts remains challenged by chronic rejection, a process in which activated B cells have been found to play a significant role. Therefore, the achievement of transplantation tolerance will likely require induction of both T and B cell tolerance to alloantigens. Moreover, human and animal investigations have shown that subsets of B cells, Transitional and Regulatory, are inherently tolerogenic. Developing therapeutic strategies that exploit these populations may be key to achieving transplantation tolerance. In this review we describe the current evidence for the essential role of B cells in transplant tolerance and discuss emerging B cell directed strategies to achieve allograft tolerance. PMID:21982511

  11. B cells and Autoantibodies: Complex Roles in CNS Injury

    PubMed Central

    Ankeny, Daniel P.; Popovich, Phillip G.

    2010-01-01

    Emerging data indicate that traumatic injury to the brain or spinal cord activates B lymphocytes, culminating in the production of antibodies specific for antigens found within and outside the central nervous system (CNS). In this article, we summarize what is known about the effects of CNS injury on B cells. We outline the potential mechanisms for CNS trauma-induced B cell activation and discuss the potential consequences of these injury-induced B cell responses. Based on recent data, we hypothesize that a subset of autoimmune B cell responses initiated by CNS injury are pathogenic and that targeted inhibition of B cells could improve recovery in brain and spinal cord injured patients. PMID:20691635

  12. The regulation and activation of lupus-associated B cells.

    PubMed

    Fields, Michele L; Hondowicz, Brian D; Wharton, Gina N; Adair, Brigette S; Metzgar, Michele H; Alexander, Shawn T; Caton, Andrew J; Erikson, Jan

    2005-04-01

    Anti-double-stranded DNA (anti-dsDNA) B cells are regulated in non-autoimmune mice. While some are deleted or undergo receptor editing, a population of anti-dsDNA (VH3H9/V lambda 1) B cells that emigrate into the periphery has also been identified. These cells have an altered phenotype relative to normal B cells in that they have a reduced lifespan, appear developmentally arrested, and localize primarily to the T/B-cell interface in the spleen. This phenotype may be the consequence of immature B cells encountering antigen in the absence of T-cell help. When provided with T-cell help, the anti-dsDNA B cells differentiate into antibody-forming cells. In the context of the autoimmune-prone lpr/lpr or gld/gld mutations, the VH3H9/V lambda 1 anti-dsDNA B cells populate the B-cell follicle and by 12 weeks of age produce serum autoantibodies. The early event of anti-dsDNA B-cell follicular entry, in the absence of autoantibody production, is dependent upon CD4(+) T cells. We hypothesize that control of autoantibody production in young autoimmune-prone mice may be regulated by the counterbalancing effect of T-regulatory (T(reg)) cells. Consistent with this model, we have demonstrated that T(reg) cells are able to prevent autoantibody production induced by T-cell help. Additional studies are aimed at investigating the mechanisms of this suppression as well as probing the impact of distinct forms of T-cell-dependent and -independent activation on anti-dsDNA B cells.

  13. Prolactin Rescues Immature B-Cells from Apoptosis Induced by B-Cell Receptor Cross-Linking

    PubMed Central

    Flores-Fernández, Rocio; Blanco-Favela, Francisco; Fuentes-Pananá, Ezequiel M.; Chávez-Sánchez, Luis; Gorocica-Rosete, Patricia; Pizaña-Venegas, Alberto; Chávez-Rueda, Adriana Karina

    2016-01-01

    Prolactin has an immunomodulatory effect and has been associated with B-cell-triggered autoimmune diseases, such as systemic lupus erythematosus (SLE). In mice that develop SLE, the PRL receptor is expressed in early bone marrow B-cells, and increased levels of PRL hasten disease manifestations, which are correlated with a reduction in the absolute number of immature B-cells. The aim of this work was to determine the effect of PRL in an in vitro system of B-cell tolerance using WEHI-231 cells and immature B-cells from lupus prone MRL/lpr mice. WEHI-231 cells express the long isoform of the PRL receptor, and PRL rescued the cells from cell death by decreasing the apoptosis induced by the cross-linking of the B-cell antigen receptor (BCR) as measured by Annexin V and active caspase-3. This decrease in apoptosis may have been due to the PRL and receptor interaction, which increased the relative expression of antiapoptotic Bcl-xL and decreased the relative expression of proapoptotic Bad. In immature B-cells from MRL/lpr mice, PRL increased the viability and decreased the apoptosis induced by the cross-linking of BCR, which may favor the maturation of self-reactive B-cells and contribute to the onset of disease. PMID:27314053

  14. The rap GTPases regulate B cell morphology, immune-synapse formation, and signaling by particulate B cell receptor ligands.

    PubMed

    Lin, Kevin B L; Freeman, Spencer A; Zabetian, Saba; Brugger, Hayley; Weber, Michele; Lei, Victor; Dang-Lawson, May; Tse, Kathy W K; Santamaria, Rene; Batista, Facundo D; Gold, Michael R

    2008-01-01

    B lymphocytes spread and extend membrane processes when searching for antigens and form immune synapses upon contacting cells that display antigens on their surface. Although these dynamic morphological changes facilitate B cell activation, the signaling pathways underlying these processes are not fully understood. We found that activation of the Rap GTPases was essential for these changes in B cell morphology. Rap activation was important for B cell receptor (BCR)- and lymphocyte-function-associated antigen-1 (LFA-1)-induced spreading, for BCR-induced immune-synapse formation, and for particulate BCR ligands to induce localized F-actin assembly and membrane-process extension. Rap activation and F-actin assembly were also required for optimal BCR signaling in response to particulate antigens but not soluble antigens. Thus by controlling B cell morphology and cytoskeletal organization, Rap might play a key role in the activation of B cells by particulate and cell-associated antigens.

  15. The growth of B cell receptor microcluster is a universal response of B cells encountering antigens with different motion features.

    PubMed

    Wan, Zhengpeng; Liu, Wanli

    2012-07-01

    B lymphocyte cell senses and acquires foreign antigens through clonal distributed B cell receptors (BCRs) expressed on the surface of plasma membrane. The presentation formats of antigens are quite diverse. Based on their Brownian diffusion mobility, there are three forms: free mobile soluble antigens, lateral mobile membrane bound antigens, and fixed immobile antigens. Here, using high resolution high speed live cell imaging approaches, we provide evidence that BCR microclusters are formed on the surface of B cells shortly after B cell's encountering of antigens with each format of motion features. Through high speed live cell imaging, we determine that these BCR microclusters show dynamic growth feature and by doing so function as the basic platforms for B cells to acquire the antigens. We propose that the formation and dynamic growth of BCR microcluster is a universal mechanism for B cell to response to antigens with diverse motion features.

  16. Integrin-mediated interactions between B cells and follicular dendritic cells influence germinal center B cell fitness1

    PubMed Central

    Wang, Xiaoming; Rodda, Lauren; Bannard, Oliver; Cyster, Jason G.

    2014-01-01

    Integrin-ligand interactions between germinal center (GC) B cells and antigen-presenting follicular dendritic cells (FDCs) have been suggested to play central roles during GC responses but their in vivo requirement has not been directly tested. Here we show that while integrins αLβ2 and α4β1 are highly expressed and functional on mouse GC B cells, removal of single integrins or their ligands had little effect on B cell participation in the GC response. Combined β2-integrin deficiency and α4-integrin blockade also did not affect the GC response against a particulate antigen. However, the combined integrin deficiency did cause B cells to be outcompeted in splenic GC responses against a soluble protein antigen and in mesenteric lymph node GC responses against gut-derived antigens. Similar findings were made for β2-deficient B cells in mice lacking VCAM1 on FDCs. The reduced fitness of the GC B cells did not appear to be due to decreased antigen acquisition, proliferation rates or pAKT levels. In summary, our findings provide evidence that αLβ2 and α4β1 play overlapping and context-dependent roles in supporting interactions with FDCs that can augment the fitness of responding GC B cells. We also find that mouse GC B cells upregulate αvβ3 and adhere to vitronectin and milk fat globule EGF-factor-8 protein. Integrin β3-deficient B cells contributed in a slightly exaggerated manner to GC responses suggesting this integrin has a regulatory function in GC B cells. PMID:24740506

  17. The Relationship between B-cell Epitope and Mimotope Sequences.

    PubMed

    Zhang, Chunhua; Li, Yunyun; Tang, Weina; Zhou, Zhiguo; Sun, Pingping; Ma, Zhiqiang

    2016-01-01

    B-cell epitope is a group of residues which is on the surface of an antigen. It invokes humoral responses. Locating B-cell epitope is important for effective vaccine design, and the development of diagnostic reagents. Mimotope-based B-cell epitope prediction method is a kind of conformational B-cell epitope prediction, and the core idea of the method is mapping the mimotope sequences which are obtained from a random phage display library. However, current mimotope-based B-cell epitope prediction methods cannot maintain a high degree of satisfaction in the circumstances of employing only mimotope sequences. In this study, we did a multi-perspective analysis on parameters for conformational B-cell epitopes and characteristics between epitope and mimotope on a benchmark datasets which contains 67 mimotope sets, corresponding to 40 unique complex structures. In these 67 cases, there are 25 antigen-antibody complexes and 42 protein-protein interactions. We analyzed the two parts separately. The results showed the mimotope sequences do have some epitope features, but there are also some epitope properties that mimotope sequences do not contain. In addition, the numbers of epitope segments with different lengths were obviously different between the antigen-antibody complexes and the protein-protein interactions. This study reflects how similar do mimotope sequence and genuine epitopes have; and evaluates existing mimotope-based B-cell epitope prediction methods from a novel viewpoint.

  18. YY1 Is Required for Germinal Center B Cell Development

    PubMed Central

    Vuyyuru, Raja; Jha, Vibha; Hodewadekar, Suchita; Manser, Tim; Atchison, Michael L.

    2016-01-01

    YY1 has been implicated as a master regulator of germinal center B cell development as YY1 binding sites are frequently present in promoters of germinal center-expressed genes. YY1 is known to be important for other stages of B cell development including the pro-B and pre-B cells stages. To determine if YY1 plays a critical role in germinal center development, we evaluated YY1 expression during B cell development, and used a YY1 conditional knock-out approach for deletion of YY1 in germinal center B cells (CRE driven by the immunoglobulin heavy chain γ1 switch region promoter; γ1-CRE). We found that YY1 is most highly expressed in germinal center B cells and is increased 3 fold in splenic B cells activated by treatment with anti-IgM and anti-CD40. In addition, deletion of the yy1 gene by action of γ1-CRE recombinase resulted in significant loss of GC cells in both un-immunized and immunized contexts with corresponding loss of serum IgG1. Our results show a crucial role for YY1 in the germinal center reaction. PMID:27167731

  19. Circulating clonotypic B cells in classic Hodgkin lymphoma.

    PubMed

    Jones, Richard J; Gocke, Christopher D; Kasamon, Yvette L; Miller, Carole B; Perkins, Brandy; Barber, James P; Vala, Milada S; Gerber, Jonathan M; Gellert, Lan L; Siedner, Mark; Lemas, M Victor; Brennan, Sarah; Ambinder, Richard F; Matsui, William

    2009-06-04

    Although Hodgkin and Reed-Sternberg (HRS) cells are B lymphoid cells, they are unlike any normal cells of that lineage. Moreover, the limited proliferative potential of HRS cells belies the clinical aggressiveness of Hodgkin lymphoma (HL). More than 20 years ago, the L428 HL cell line was reported to contain a small population of phenotypic B cells that appeared responsible for the continued generation of HRS cells. This observation, however, has never been corroborated, and such clonotypic B cells have never been documented in HL patients. We found that both the L428 and KM-H2 HL cell lines contained rare B-cell subpopulations responsible for the generation and maintenance of the predominant HRS cell population. The B cells within the HL cell lines expressed immunoglobulin light chain, the memory B-cell antigen CD27, and the stem cell marker aldehyde dehydrogenase (ALDH). Clonal CD27(+)ALDH(high) B cells, sharing immunoglobulin gene rearrangements with lymph node HRS cells, were also detected in the blood of most newly diagnosed HL patients regardless of stage. Although the clinical significance of circulating clonotypic B cells in HL remains unclear, these data suggest they may be the initiating cells for HL.

  20. YY1 Is Required for Germinal Center B Cell Development.

    PubMed

    Banerjee, Anupam; Sindhava, Vishal; Vuyyuru, Raja; Jha, Vibha; Hodewadekar, Suchita; Manser, Tim; Atchison, Michael L

    2016-01-01

    YY1 has been implicated as a master regulator of germinal center B cell development as YY1 binding sites are frequently present in promoters of germinal center-expressed genes. YY1 is known to be important for other stages of B cell development including the pro-B and pre-B cells stages. To determine if YY1 plays a critical role in germinal center development, we evaluated YY1 expression during B cell development, and used a YY1 conditional knock-out approach for deletion of YY1 in germinal center B cells (CRE driven by the immunoglobulin heavy chain γ1 switch region promoter; γ1-CRE). We found that YY1 is most highly expressed in germinal center B cells and is increased 3 fold in splenic B cells activated by treatment with anti-IgM and anti-CD40. In addition, deletion of the yy1 gene by action of γ1-CRE recombinase resulted in significant loss of GC cells in both un-immunized and immunized contexts with corresponding loss of serum IgG1. Our results show a crucial role for YY1 in the germinal center reaction.

  1. Gallium arsenide exposure impairs splenic B cell accessory function.

    PubMed

    Gondre-Lewis, Timothy A; Hartmann, Constance B; Caffrey, Rebecca E; McCoy, Kathleen L

    2003-03-01

    Gallium arsenide (GaAs) is utilized in industries for its semiconductor and optical properties. Chemical exposure of animals systemically suppresses several immune functions. The ability of splenic B cells to activate antigen-specific helper CD4(+) T cell hybridomas was assessed, and various aspects of antigen-presenting cell function were examined. GaAs-exposed murine B cells were impaired in processing intact soluble protein antigens, and the defect was antigen dependent. In contrast, B cells after exposure competently presented peptides to the T cells, which do not require processing. Cell surface expression of major histocompatibility complex (MHC) class II molecules and several costimulatory molecules on splenic B cells, which are critical for helper T cell activation, was not affected by chemical exposure. GaAs exposure also did not influence the stability of MHC class II heterodimers, suggesting that the defect may precede peptide exchange. GaAs-exposed B cells contained a normal level of aspartyl cathepsin activity; however, proteolytic activities of thiol cathepsins B and L were approximately half the control levels. Furthermore, two cleavage fragments of invariant chain, a molecular chaperone of MHC class II molecules, were increased in GaAs-exposed B cells, indicative of defective degradation. Thus, diminished thiol proteolytic activity in B cells may be responsible for their impaired antigen processing and invariant chain degradation, which may contribute to systemic immunosuppression caused by GaAs exposure.

  2. Phenotypic Approaches to Identify Inhibitors of B Cell Activation

    PubMed Central

    Kim, Suzie; Wiener, Jake; Rao, Navin L.; Milla, Marcos E.; DiSepio, Daniel

    2015-01-01

    An EPIC label-free phenotypic platform was developed to explore B cell receptor (BCR) and CD40R-mediated B cell activation. The phenotypic assay measured the association of RL non-Hodgkin’s lymphoma B cells expressing lymphocyte function-associated antigen 1 (LFA-1) to intercellular adhesion molecule 1 (ICAM-1)-coated EPIC plates. Anti-IgM (immunoglobulin M) mediated BCR activation elicited a response that was blocked by LFA-1/ICAM-1 specific inhibitors and a panel of Bruton’s tyrosine kinase (BTK) inhibitors. LFA-1/ICAM-1 association was further increased on coapplication of anti-IgM and mega CD40L when compared to individual application of either. Anti-IgM, mega CD40L, or the combination of both displayed distinct kinetic profiles that were inhibited by treatment with a BTK inhibitor. We also established a FLIPR-based assay to measure B cell activation in Ramos Burkitt’s lymphoma B cells and an RL cell line. Anti-IgM-mediated BCR activation elicited a robust calcium response that was inhibited by a panel of BTK inhibitors. Conversely, CD40R activation did not elicit a calcium response in the FLIPR assay. Compared to the FLIPR, the EPIC assay has the propensity to identify inhibitors of both BCR and CD40R-mediated B cell activation and may provide more pharmacological depth or novel mechanisms of action for inhibition of B cell activation. PMID:25948491

  3. Salmonella induces PD-L1 expression in B cells.

    PubMed

    Lopez-Medina, Marcela; Perez-Lopez, Araceli; Alpuche-Aranda, Celia; Ortiz-Navarrete, Vianney

    2015-10-01

    Salmonella persists for a long time in B cells; however, the mechanism(s) through which infected B cells avoid effector CD8 T cell responses has not been characterized. In this study, we show that Salmonella infects and survives within all B1 and B2 cell subpopulations. B cells are infected with a Salmonella typhimurium strain expressing an ovalbumin (OVA) peptide (SIINFEKL) to evaluate whether B cells process and present Salmonella antigens in the context of MHC-I molecules. Our data showed that OVA peptides are presented by MHC class I K(b)-restricted molecules and the presented antigen is generated through proteasomal degradation and vacuolar processing. In addition, Salmonella-infected B cells express co-stimulatory molecules such as CD40, CD80, and CD86 as well as inhibitory molecules such as PD-L1. Thus, the cross-presentation of Salmonella antigens and the expression of activation molecules suggest that infected B cells are able to prime and activate specific CD8(+) T cells. However, the Salmonella infection-stimulated expression of PD-L1 suggests that the PD-1/PD-L1 pathway may be involved in turning off the cytotoxic effector response during Salmonella persistent infection, thereby allowing B cells to become a reservoir for the bacteria.

  4. The emerging role of estrogen in B cell malignancies.

    PubMed

    Ladikou, Eleni-Eirini; Kassi, Eva

    2017-03-01

    Increasing evidence implicates a role of estrogens in hematological malignancies. We reviewed current knowledge on the emerging role of estrogens and estrogen receptors in normal B-cell function, chronic lymphocytic leukemia, and B-cell lymphoma. Data support that (1) normal human peripheral blood cells (mononuclear cells, total lymphocytes, T as well as B lymphocytes, and NK cells) express both estrogen receptor subtypes (ERα and ERβ), (2) B-cell malignancies express mainly ERβ while selective ERβ agonists inhibit cell growth and induce apoptosis, (3) estrogens regulate, via an ER-mediated pathway, gene expression of cyclins, kinases, bcl-2 proto-oncogene, activation-induced deaminase (AID), and transcription factors, associated with changes in BCR signaling and B cell tumorigenesis. In conclusion, estrogen receptors play an important role in normal B-cell function and B-cell tumorigenesis; however, further investigations are required to delineate the role of estrogens and estrogen receptors in the etiopathogenesis and therapy of B-cell malignancies.

  5. [The role of IRA B cells in selected inflammatory processes].

    PubMed

    Zasada, Magdalena; Rutkowska-Zapała, Magdalena; Lenart, Marzena; Kwinta, Przemko

    2016-03-16

    The first report about the discovery of new, previously unknown immune cells named IRA B cells (innate response activator B cells) appeared in 2012. So far, their presence has been verified in both mice and humans. However, IRA B cells belong to the family of B lymphocytes and have a number of characteristics unique to this group of cells. IRA B cells are formed from activated B1a lymphocytes after their contact with a pathogen. B1a lymphocytes mainly reside within body cavities. Activated by the pathogen, they move on into secondary lymphoid organs (spleen, lymph nodes) where they differentiate into IRA B cells. IRA B cells are a rich source of granulocyte-macrophage colony stimulating factor (GM-CSF). GM-CSF can stimulate IRA B cells in an autocrine manner for the secretion of intracellular stocks of immunoglobulin M (IgM), which can facilitate pathogens' phagocytosis by neutrophils. GM-CSF also stimulates neutrophils into active phagocytosis. Rapid eradication of the pathogen can prevent the development of an excessive inflammatory response, which can be dangerous for the organism. Until now the involvement of IRA B lymphocytes in the pathogenesis of sepsis and pneumonia has been proven, as well as their role in the progression of atherosclerotic lesions in mice. There is research in progress on the possibility of increasing the number of IRA B cells, for example by intravenous supply of modified immunoglobulins. It is necessary to characterize human IRA B cells and to determine their role in the functioning of the immune system.

  6. Human Memory B Cells in Healthy Gingiva, Gingivitis, and Periodontitis.

    PubMed

    Mahanonda, Rangsini; Champaiboon, Chantrakorn; Subbalekha, Keskanya; Sa-Ard-Iam, Noppadol; Rattanathammatada, Warattaya; Thawanaphong, Saranya; Rerkyen, Pimprapa; Yoshimura, Fuminobu; Nagano, Keiji; Lang, Niklaus P; Pichyangkul, Sathit

    2016-08-01

    The presence of inflammatory infiltrates with B cells, specifically plasma cells, is the hallmark of periodontitis lesions. The composition of these infiltrates in various stages of homeostasis and disease development is not well documented. Human tissue biopsies from sites with gingival health (n = 29), gingivitis (n = 8), and periodontitis (n = 21) as well as gingival tissue after treated periodontitis (n = 6) were obtained and analyzed for their composition of B cell subsets. Ag specificity, Ig secretion, and expression of receptor activator of NF-κB ligand and granzyme B were performed. Although most of the B cell subsets in healthy gingiva and gingivitis tissues were CD19(+)CD27(+)CD38(-) memory B cells, the major B cell component in periodontitis was CD19(+)CD27(+)CD38(+)CD138(+)HLA-DR(low) plasma cells, not plasmablasts. Plasma cell aggregates were observed at the base of the periodontal pocket and scattered throughout the gingiva, especially apically toward the advancing front of the lesion. High expression of CXCL12, a proliferation-inducing ligand, B cell-activating factor, IL-10, IL-6, and IL-21 molecules involved in local B cell responses was detected in both gingivitis and periodontitis tissues. Periodontitis tissue plasma cells mainly secreted IgG specific to periodontal pathogens and also expressed receptor activator of NF-κB ligand, a bone resorption cytokine. Memory B cells resided in the connective tissue subjacent to the junctional epithelium in healthy gingiva. This suggested a role of memory B cells in maintaining periodontal homeostasis.

  7. PDK1 regulates B cell differentiation and homeostasis.

    PubMed

    Baracho, Gisele V; Cato, Matthew H; Zhu, Zilu; Jaren, Olav R; Hobeika, Elias; Reth, Michael; Rickert, Robert C

    2014-07-01

    Successful B cell differentiation and prevention of cell transformation depends on balanced and fine-tuned activation of cellular signaling pathways. The phosphatidyl inositol-3 kinase (PI3K) signaling pathway has emerged as a major regulator of B lymphocyte homeostasis and function. Phosphoinositide-dependent protein kinase-1 (PDK1) is the pivotal node in the PI3K pathway, regulating the stability and activity of downstream AGC kinases (including Akt, RSK, S6K, SGK, and PKC). Although the importance of PI3K activity in B cell differentiation is well documented, the role of PDK1 and other downstream effectors is underexplored. Here we used inducible and stage-specific gene targeting approaches to elucidate the role of PDK1 in early and peripheral B cell differentiation. PDK1 ablation enhanced cell cycle entry and apoptosis of IL-7-dependent pro-B cells, blocking Ig synthesis and B cell maturation. PDK1 also was essential for the survival and activation of peripheral B cells via regulation of PKC and Akt-dependent downstream effectors, such as GSK3α/β and Foxo1. We found that PDK1 deletion strongly impaired B cell receptor (BCR) signaling, but IL-4 costimulation was sufficient to restore BCR-induced proliferation. IL-4 also normalized PKCβ activation and hexokinase II expression in BCR-stimulated cells, suggesting that this signaling pathway can act independent of PDK1 to support B cell growth. In summary, our results demonstrate that PDK1 is indispensable for B cell survival, proliferation, and growth regulation.

  8. Transitional B Cells in Early Human B Cell Development – Time to Revisit the Paradigm?

    PubMed Central

    Martin, Victoria G.; Wu, Yu-Chang Bryan; Townsend, Catherine L.; Lu, Grace H. C.; O’Hare, Joselli Silva; Mozeika, Alexander; Coolen, Anthonius C. C.; Kipling, David; Fraternali, Franca; Dunn-Walters, Deborah K.

    2016-01-01

    The B cell repertoire is generated in the adult bone marrow by an ordered series of gene rearrangement processes that result in massive diversity of immunoglobulin (Ig) genes and consequently an equally large number of potential specificities for antigen. As the process is essentially random, the cells exhibiting excess reactivity with self-antigens are generated and need to be removed from the repertoire before the cells are fully mature. Some of the cells are deleted, and some will undergo receptor editing to see if changing the light chain can rescue an autoreactive antibody. As a consequence, the binding properties of the B cell receptor are changed as development progresses through pre-B ≫ immature ≫ transitional ≫ naïve phenotypes. Using long-read, high-throughput, sequencing we have produced a unique set of sequences from these four cell types in human bone marrow and matched peripheral blood, and our results describe the effects of tolerance selection on the B cell repertoire at the Ig gene level. Most strong effects of selection are seen within the heavy chain repertoire and can be seen both in gene usage and in CDRH3 characteristics. Age-related changes are small, and only the size of the CDRH3 shows constant and significant change in these data. The paucity of significant changes in either kappa or lambda light chain repertoires implies that either the heavy chain has more influence over autoreactivity than light chain and/or that switching between kappa and lambda light chains, as opposed to switching within the light chain loci, may effect a more successful autoreactive rescue by receptor editing. Our results show that the transitional cell population contains cells other than those that are part of the pre-B ≫ immature ≫ transitional ≫ naïve development pathway, since the population often shows a repertoire that is outside the trajectory of gene loss/gain between pre-B and naïve stages. PMID:27994589

  9. Seeking help: B cells adapting to flu variability.

    PubMed

    van der Most, Robbert G; Roman, François P; Innis, Bruce; Hanon, Emmanuel; Vaughn, David W; Gillard, Paul; Walravens, Karl; Wettendorff, Martine

    2014-07-23

    The study of influenza vaccines has revealed potential interactions between preexisting immunological memory and antigenic context and/or adjuvantation. In the face of antigenic diversity, the process of generating B cell adaptability is driven by cross-reactive CD4 memory cells, such as T follicular helper cells from previous infections or vaccinations. Although such "helped" B cells are capable of adapting to variant antigens, lack of CD4 help could lead to a suboptimal antibody response. Collectively, this indicates an interplay between CD4 T cells, adjuvant, and B cell adaptability.

  10. B cell-helping functions of gut microbial metabolites.

    PubMed

    Kim, Chang H

    2016-09-23

    Commensal microflora profoundly affects the host immune system. It has long been observed that commensal bacteria enhance antibody production in the host by producing antigens for B cell receptors (BCR) and ligands for Toll-like receptors (TLR). We recently reported that the microbial metabolites short-chain fatty acids (SCFAs) regulate the metabolism and gene expression in B cells to promote antibody production (Kim et al. Gut Microbial Metabolites Fuel Host Antibody Responses. Cell Host & Microbe. 2016; 20(2):202-14). The B-cell helping function of SCFAs and its implication in the host immune system are discussed in this article.

  11. B cell-helping functions of gut microbial metabolites

    PubMed Central

    Kim, Chang H.

    2016-01-01

    Commensal microflora profoundly affects the host immune system. It has long been observed that commensal bacteria enhance antibody production in the host by producing antigens for B cell receptors (BCR) and ligands for Toll-like receptors (TLR). We recently reported that the microbial metabolites short-chain fatty acids (SCFAs) regulate the metabolism and gene expression in B cells to promote antibody production (Kim et al. Gut Microbial Metabolites Fuel Host Antibody Responses. Cell Host & Microbe. 2016; 20(2):202-14). The B-cell helping function of SCFAs and its implication in the host immune system are discussed in this article. PMID:28357321

  12. ATM deficiency promotes development of murine B-cell lymphomas that resemble diffuse large B-cell lymphoma in humans

    PubMed Central

    Hathcock, Karen S.; Padilla-Nash, Hesed M.; Camps, Jordi; Shin, Dong-Mi; Triner, Daniel; Shaffer, Arthur L.; Maul, Robert W.; Steinberg, Seth M.; Gearhart, Patricia J.; Staudt, Louis M.; Morse, Herbert C.; Ried, Thomas

    2015-01-01

    The serine-threonine kinase ataxia-telangiectasia mutated (ATM) plays a central role in maintaining genomic integrity. In mice, ATM deficiency is exclusively associated with T-cell lymphoma development, whereas B-cell tumors predominate in human ataxia-telangiectasia patients. We demonstrate in this study that when T cells are removed as targets for lymphomagenesis and as mediators of immune surveillance, ATM-deficient mice exclusively develop early-onset immunoglobulin M+ B-cell lymphomas that do not transplant to immunocompetent mice and that histologically and genetically resemble the activated B cell–like (ABC) subset of human diffuse large B-cell lymphoma (DLBCL). These B-cell lymphomas show considerable chromosomal instability and a recurrent genomic amplification of a 4.48-Mb region on chromosome 18 that contains Malt1 and is orthologous to a region similarly amplified in human ABC DLBCL. Of importance, amplification of Malt1 in these lymphomas correlates with their dependence on nuclear factor (NF)-κB, MALT1, and B-cell receptor (BCR) signaling for survival, paralleling human ABC DLBCL. Further, like some human ABC DLBCLs, these mouse B-cell lymphomas also exhibit constitutive BCR-dependent NF-κB activation. This study reveals that ATM protects against development of B-cell lymphomas that model human ABC DLBCL and identifies a potential role for T cells in preventing the emergence of these tumors. PMID:26400962

  13. B Cell Development in the Bone Marrow Is Regulated by Homeostatic Feedback Exerted by Mature B Cells.

    PubMed

    Shahaf, Gitit; Zisman-Rozen, Simona; Benhamou, David; Melamed, Doron; Mehr, Ramit

    2016-01-01

    Cellular homeostasis in the B cell compartment is strictly imposed to balance cell production and cell loss. However, it is not clear whether B cell development in the bone marrow is an autonomous process or subjected to regulation by the peripheral B cell compartment. To specifically address this question, we used mice transgenic for human CD20, where effective depletion of B lineage cells is obtained upon administration of mouse anti-human CD20 antibodies, in the absence of any effect on other cell lineages and/or tissues. We followed the kinetics of B cell return to equilibrium by BrdU labeling and flow cytometry and analyzed the resulting data by mathematical modeling. Labeling was much faster in depleted mice. Compared to control mice, B cell-depleted mice exhibited a higher proliferation rate in the pro-/pre-B compartment, and higher cell death and lower differentiation in the immature B cell compartment. We validated the first result by analysis of the expression of Ki67, the nuclear protein expressed in proliferating cells, and the second using Annexin V staining. Collectively, our results suggest that B lymphopoiesis is subjected to homeostatic feedback mechanisms imposed by mature B cells in the peripheral compartment.

  14. Transgelin-2 in B-Cells Controls T-Cell Activation by Stabilizing T Cell - B Cell Conjugates

    PubMed Central

    Chae, Myoung-Won; Kim, Hye-Ran; Kim, Chang-Hyun; Jun, Chang-Duk; Park, Zee-Yong

    2016-01-01

    The immunological synapse (IS), a dynamic and organized junction between T-cells and antigen presenting cells (APCs), is critical for initiating adaptive immunity. The actin cytoskeleton plays a major role in T-cell reorganization during IS formation, and we previously reported that transgelin-2, an actin-binding protein expressed in T-cells, stabilizes cortical F-actin, promoting T-cell activation in response to antigen stimulation. Transgelin-2 is also highly expressed in B-cells, although no specific function has been reported. In this study, we found that deficiency in transgelin-2 (TAGLN2-/-) in B-cells had little effect on B-cell development and activation, as measured by the expression of CD69, MHC class II molecules, and CD80/86. Nevertheless, in B-cells, transgelin-2 accumulated in the IS during the interaction with T-cells. These results led us to hypothesize that transgelin-2 may also be involved in IS stability in B-cells, thereby influencing T-cell function. Notably, we found that transgelin-2 deficiency in B-cells reduced T-cell activation, as determined by the release of IL-2 and interferon-γ and the expression of CD69. Furthermore, the reduced T-cell activation was correlated with reduced B-cell–T-cell conjugate formation. Collectively, these results suggest that actin stability in B-cells during IS formation is critical for the initiation of adaptive T-cell immunity. PMID:27232882

  15. How Follicular Dendritic Cells Shape the B-Cell Antigenome

    PubMed Central

    Kranich, Jan; Krautler, Nike Julia

    2016-01-01

    Follicular dendritic cells (FDCs) are stromal cells residing in primary follicles and in germinal centers of secondary and tertiary lymphoid organs (SLOs and TLOs). There, they play a crucial role in B-cell activation and affinity maturation of antibodies. FDCs have the unique capacity to bind and retain native antigen in B-cell follicles for long periods of time. Therefore, FDCs shape the B-cell antigenome (the sum of all B-cell antigens) in SLOs and TLOs. In this review, we discuss recent findings that explain how this stromal cell type can arise in almost any tissue during TLO formation and, furthermore, focus on the mechanisms of antigen capture and retention involved in the generation of long-lasting antigen depots displayed on FDCs. PMID:27446069

  16. COMPUTATION MODELING OF TCDD DISRUPTION OF B CELL TERMINAL DIFFERENTIATION

    EPA Science Inventory

    In this study, we established a computational model describing the molecular circuit underlying B cell terminal differentiation and how TCDD may affect this process by impinging upon various molecular targets.

  17. B cell epitope spreading: mechanisms and contribution to autoimmune diseases.

    PubMed

    Cornaby, Caleb; Gibbons, Lauren; Mayhew, Vera; Sloan, Chad S; Welling, Andrew; Poole, Brian D

    2015-01-01

    While a variety of factors act to trigger or initiate autoimmune diseases, the process of epitope spreading is an important contributor in their development. Epitope spreading is a diversification of the epitopes recognized by the immune system. This process happens to both T and B cells, with this review focusing on B cells. Such spreading can progress among multiple epitopes on a single antigen, or from one antigenic molecule to another. Systemic lupus erythematosus, multiple sclerosis, pemphigus, bullous pemphigoid and other autoimmune diseases, are all influenced by intermolecular and intramolecular B cell epitope spreading. Endocytic processing, antigen presentation, and somatic hypermutation act as molecular mechanisms that assist in driving epitope spreading and broadening the immune response in autoimmune diseases. The purpose of this review is to summarize our current understanding of B cell epitope spreading with regard to autoimmunity, how it contributes during the progression of various autoimmune diseases, and treatment options available.

  18. Chronic B-Cell Leukemias and Agent Orange

    MedlinePlus

    ... survivors' benefits . Research on B-cell leukemias and herbicides The Health and Medicine Division (HMD) (formally known ... sufficient evidence of an association between exposure to herbicides and chronic lymphocytic leukemia. In 2003, VA recognized ...

  19. Long Noncoding RNA Expression during Human B-Cell Development

    PubMed Central

    Petri, Andreas; Dybkær, Karen; Bøgsted, Martin; Thrue, Charlotte Albæk; Hagedorn, Peter H.; Schmitz, Alexander; Bødker, Julie Støve; Johnsen, Hans Erik; Kauppinen, Sakari

    2015-01-01

    Long noncoding RNAs (lncRNAs) have emerged as important regulators of diverse cellular processes, but their roles in the developing immune system are poorly understood. In this study, we analysed lncRNA expression during human B-cell development by array-based expression profiling of eleven distinct flow-sorted B-cell subsets, comprising pre-B1, pre-B2, immature, naive, memory, and plasma cells from bone marrow biopsies (n = 7), and naive, centroblast, centrocyte, memory, and plasmablast cells from tonsil tissue samples (n = 6), respectively. A remapping strategy was used to assign the array probes to 37630 gene-level probe sets, reflecting recent updates in genomic and transcriptomic databases, which enabled expression profiling of 19579 long noncoding RNAs, comprising 3947 antisense RNAs, 5277 lincRNAs, 7625 pseudogenes, and 2730 additional lncRNAs. As a first step towards inferring the functions of the identified lncRNAs in developing B-cells, we analysed their co-expression with well-characterized protein-coding genes, a method known as “guilt by association”. By using weighted gene co-expression network analysis, we identified 272 lincRNAs, 471 antisense RNAs, 376 pseudogene RNAs, and 64 lncRNAs within seven sub-networks associated with distinct stages of B-cell development, such as early B-cell development, B-cell proliferation, affinity maturation of antibody, and terminal differentiation. These data provide an important resource for future studies on the functions of lncRNAs in development of the adaptive immune response, and the pathogenesis of B-cell malignancies that originate from distinct B-cell subpopulations. PMID:26394393

  20. Memory B Cells and Pneumococcal Antibody After Splenectomy1

    PubMed Central

    Wasserstrom, Heather; Bussel, James; Lim, Lony C.-L.; Cunningham-Rundles, Charlotte

    2010-01-01

    Splenectomized patients are susceptible to bloodstream infections with encapsulated bacteria, potentially due to loss of blood filtering but also defective production of anticarbohydrate Ab. Recent studies propose that a lack of Ab is related to reduced numbers of IgM+ CD27+ memory B cells found after splenectomy. To test this, we analyzed CD27+ memory B cell subsets, IgG, and IgM pneumococcal Ab responses in 26 vaccinated splenectomized subjects in comparison to memory B cell subsets and Ab responses in healthy controls. As shown previously, the splenectomized autoimmune subjects had fewer total, isotype switched, and IgM+ CD27+ memory B cells as compared with controls, but there was no difference in memory B cells subsets between controls and splenectomized subjects with spherocytosis. There was no difference between the geometric mean IgG Ab response between normal controls and splenectomized subjects (p = 0.51; p = 0.81). Control subjects produced more IgM Ab than splenectomized autoimmune subjects (p = 0.01) but the same levels as subjects with spherocytosis (p = 0.15.) There was no correlation between memory B cell subsets and IgG or IgM Ab responses for controls or splenectomized subjects. These data suggest that splenectomy alone may not be the sole reason for loss of memory B cells and reduced IgM antipneumococcal Ab. Because subjects with autoimmunity had splenectomy at a significantly older age than participants with spherocytosis, these data suggest that an age-related loss of extra splenic sites necessary for the maintenance or function of memory B cells may lead to impaired immunity in these subjects. PMID:18714044

  1. Identification of autoreactive B cells with labeled nucleosomes.

    PubMed

    Gies, Vincent; Wagner, Alain; Seifert, Cécile; Guffroy, Aurélien; Fauny, Jean-D; Knapp, Anne-M; Pasquali, Jean-L; Martin, Thierry; Dumortier, Hélène; Korganow, Anne-S; Soulas-Sprauel, Pauline

    2017-04-04

    The pathogenesis of autoimmune diseases has not been completely elucidated yet, and only a few specific treatments have been developed so far. In autoimmune diseases mediated by pathogenic autoantibodies, such as systemic lupus erythematosus, the specific detection and analysis of autoreactive B cells is crucial for a better understanding of the physiopathology. Biological characterization of these cells may help to define new therapeutic targets. Very few techniques allowing the precise detection of autoreactive B cells have been described so far. Herein we propose a new flow cytometry technique for specific detection of anti-nucleosome B cells, which secrete autoantibodies in systemic lupus erythematosus, using labeled nucleosomes. We produced different fluorochrome-labeled nucleosomes, characterized them, and finally tested them in flow cytometry. Nucleosomes labeled via the cysteines present in H3 histone specifically bind to autoreactive B cells in the anti-DNA transgenic B6.56R mice model. The present work validates the use of fluorochrome-labeled nucleosomes via cysteines to identify anti-nucleosome B cells and offers new opportunities for the description of autoreactive B cell phenotype.

  2. The role of B cells in systemic sclerosis

    PubMed Central

    Kraaij, Marina D; van Laar, Jacob M

    2008-01-01

    Systemic sclerosis (SSc) is a connective disease characterized by features of autoimmunity, vasculopathy, inflammation, and fibrosis. The disease typically starts with Raynaud’s phenomenon, followed by skin thickening in the extremities due to inflammation and fibrosis. Fibrosis results from excessive collagen production by fibroblasts, which constitutes the final common pathway of complex cellular interactions including B cells. Several studies have indicated that B cells may play a role in SSc. Lesional skin infiltrates from SSc patients consist of a variety of cells, including eosinophils, neutrophils, lymphocytes, plasma cells, and macrophages. Autoantibodies of several specificities are present in the serum of SSc patients of which antitopoisomerase 1 is the most common, and evidence has been gathered for a potential pathogenic role of some autoantibodies, eg, anti-PDGF antibodies. The blood of SSc patients contains an increased proportion of naïve B cells but a decreased proportion of memory B cells. Furthermore, serum levels of interleukin-6, an important pro-inflammatory cytokine, have been shown to correlate with skin fibrosis. Animal models of SSc have provided more in-depth information on the role of B lymphocytes, eg, through disruption of B cell function. In this review we will discuss the evidence that B cells are involved in the pathogenesis of SSc. PMID:19707370

  3. Transcriptional analysis of the B cell germinal center reaction

    PubMed Central

    Klein, Ulf; Tu, Yuhai; Stolovitzky, Gustavo A.; Keller, Jeffrey L.; Haddad, Joseph; Miljkovic, Vladan; Cattoretti, Giorgio; Califano, Andrea; Dalla-Favera, Riccardo

    2003-01-01

    The germinal center (GC) reaction is crucial for T cell-dependent immune responses and is targeted by B cell lymphomagenesis. Here we analyzed the transcriptional changes that occur in B cells during GC transit (naïve B cells → centroblasts → centrocytes → memory B cells) by gene expression profiling. Naïve B cells, characterized by the expression of cell cycle-inhibitory and antiapoptotic genes, become centroblasts by inducing an atypical proliferation program lacking c-Myc expression, switching to a proapoptotic program, and down-regulating cytokine, chemokine, and adhesion receptors. The transition from GC to memory cells is characterized by a return to a phenotype similar to that of naïve cells except for an apoptotic program primed for both death and survival and for changes in the expression of cell surface receptors including IL-2 receptor β. These results provide insights into the dynamics of the GC reaction and represent the basis for the analysis of B cell malignancies. PMID:12604779

  4. B cells enhance early innate immune responses during bacterial sepsis

    PubMed Central

    Kelly-Scumpia, Kindra M.; Scumpia, Philip O.; Weinstein, Jason S.; Delano, Matthew J.; Cuenca, Alex G.; Nacionales, Dina C.; Wynn, James L.; Lee, Pui Y.; Kumagai, Yutaro; Efron, Philip A.; Akira, Shizuo; Wasserfall, Clive; Atkinson, Mark A.

    2011-01-01

    Microbes activate pattern recognition receptors to initiate adaptive immunity. T cells affect early innate inflammatory responses to viral infection, but both activation and suppression have been demonstrated. We identify a novel role for B cells in the early innate immune response during bacterial sepsis. We demonstrate that Rag1−/− mice display deficient early inflammatory responses and reduced survival during sepsis. Interestingly, B cell–deficient or anti-CD20 B cell–depleted mice, but not α/β T cell–deficient mice, display decreased inflammatory cytokine and chemokine production and reduced survival after sepsis. Both treatment of B cell–deficient mice with serum from wild-type (WT) mice and repletion of Rag1−/− mice with B cells improves sepsis survival, suggesting antibody-independent and antibody-dependent roles for B cells in the outcome to sepsis. During sepsis, marginal zone and follicular B cells are activated through type I interferon (IFN-I) receptor (IFN-α/β receptor [IFNAR]), and repleting Rag1−/− mice with WT, but not IFNAR−/−, B cells improves IFN-I–dependent and –independent early cytokine responses. Repleting B cell–deficient mice with the IFN-I–dependent chemokine, CXCL10 was also sufficient to improve sepsis survival. This study identifies a novel role for IFN-I–activated B cells in protective early innate immune responses during bacterial sepsis. PMID:21746813

  5. Gsk3 is a metabolic checkpoint regulator in B cells.

    PubMed

    Jellusova, Julia; Cato, Matthew H; Apgar, John R; Ramezani-Rad, Parham; Leung, Charlotte R; Chen, Cindi; Richardson, Adam D; Conner, Elaine M; Benschop, Robert J; Woodgett, James R; Rickert, Robert C

    2017-03-01

    B cells predominate in a quiescent state until an antigen is encountered, which results in rapid growth, proliferation and differentiation of the B cells. These distinct cell states are probably accompanied by differing metabolic needs, yet little is known about the metabolic control of B cell fate. Here we show that glycogen synthase kinase 3 (Gsk3) is a metabolic sensor that promotes the survival of naive recirculating B cells by restricting cell mass accumulation. In antigen-driven responses, Gsk3 was selectively required for regulation of B cell size, mitochondrial biogenesis, glycolysis and production of reactive oxygen species (ROS), in a manner mediated by the co-stimulatory receptor CD40. Gsk3 was required to prevent metabolic collapse and ROS-induced apoptosis after glucose became limiting, functioning in part by repressing growth dependent on the myelocytomatosis oncoprotein c-Myc. Notably, we found that Gsk3 was required for the generation and maintenance of germinal center B cells, which require high glycolytic activity to support growth and proliferation in a hypoxic microenvironment.

  6. B cells with regulatory properties in transplantation tolerance

    PubMed Central

    Durand, Justine; Chiffoleau, Elise

    2015-01-01

    Induction of tolerance remains a major goal in transplantation. Indeed, despite potent immunosuppression, chronic rejection is still a real problem in transplantation. The humoral response is an important mediator of chronic rejection, and numerous strategies have been developed to target either B cells or plasma cells. However, the use of anti-CD20 therapy has highlighted the beneficial role of subpopulation of B cells, termed regulatory B cells. These cells have been characterized mainly in mice models of auto-immune diseases but emerging literature suggests their role in graft tolerance in transplantation. Regulatory B cells seem to be induced following inflammation to restrain excessive response. Different phenotypes of regulatory B cells have been described and are functional at various differentiation steps from immature to plasma cells. These cells act by multiple mechanisms such as secretion of immuno-suppressive cytokines interleukin-10 (IL-10) or IL-35, cytotoxicity, expression of inhibitory receptors or by secretion of non-inflammatory antibodies. Better characterization of the development, phenotype and mode of action of these cells seems urgent to develop novel approaches to manipulate the different B cell subsets and the response to the graft in a clinical setting. PMID:26722647

  7. Cutaneous primary B-cell lymphomas: from diagnosis to treatment*

    PubMed Central

    Lima, Margarida

    2015-01-01

    Primary cutaneous B-cell lymphomas are a heterogeneous group of mature B-cells neoplasms with tropism for the skin, whose biology and clinical course differ significantly from the equivalent nodal lymphomas. The most indolent forms comprise the primary cutaneous marginal zone and follicle center B-cell lymphomas that despite the excellent prognosis have cutaneous recurrences very commonly. The most aggressive forms include the primary cutaneous large B-cell lymphomas, consisting in two major groups: the leg type, with poor prognosis, and others, the latter representing a heterogeneous group of lymphomas from which specific entities are supposed to be individualized over time, such as intravascular large B-cell lymphomas. Treatment may include surgical excision, radiotherapy, antibiotics, corticosteroids, interferon, monoclonal antibodies and chemotherapy, depending on the type of lymphoma and on the type and location of the skin lesions. In subtypes with good prognosis is contraindicated overtreatment and in those associated with a worse prognosis the recommended therapy relies on CHOP-like regimens associated with rituximab, assisted or not with local radiotherapy. We review the primary cutaneous B-cell lymphomas, remembering the diagnostic criteria, differential diagnosis, classification, and prognostic factors and presenting the available therapies. PMID:26560215

  8. CCR 20th anniversary commentary: Radioactive Drones for B-cell lymphoma.

    PubMed

    Knox, Susan J; Levy, Ronald

    2015-02-01

    In a study published in the March 1, 1996, issue of Clinical Cancer Research, Knox and colleagues (1) demonstrated the safety and efficacy of Yttirium-90 ((90)Y)-anti-CD20 monoclonal antibody therapy, as well as the benefit of preinfusion of unlabeled antibody on radiolabeled antibody biodistribution. Subsequent clinical trials with this radiolabeled antibody led to regulatory approval of this treatment for B-cell lymphoma. See related article by Knox et al., Clin Cancer Res 1996;2(3) Mar 1996; 457-70.

  9. Malaria-associated atypical memory B cells exhibit markedly reduced B cell receptor signaling and effector function.

    PubMed

    Portugal, Silvia; Tipton, Christopher M; Sohn, Haewon; Kone, Younoussou; Wang, Jing; Li, Shanping; Skinner, Jeff; Virtaneva, Kimmo; Sturdevant, Daniel E; Porcella, Stephen F; Doumbo, Ogobara K; Doumbo, Safiatou; Kayentao, Kassoum; Ongoiba, Aissata; Traore, Boubacar; Sanz, Inaki; Pierce, Susan K; Crompton, Peter D

    2015-05-08

    Protective antibodies in Plasmodium falciparum malaria are only acquired after years of repeated infections. Chronic malaria exposure is associated with a large increase in atypical memory B cells (MBCs) that resemble B cells expanded in a variety of persistent viral infections. Understanding the function of atypical MBCs and their relationship to classical MBCs will be critical to developing effective vaccines for malaria and other chronic infections. We show that VH gene repertoires and somatic hypermutation rates of atypical and classical MBCs are indistinguishable indicating a common developmental history. Atypical MBCs express an array of inhibitory receptors and B cell receptor (BCR) signaling is stunted in atypical MBCs resulting in impaired B cell responses including proliferation, cytokine production and antibody secretion. Thus, in response to chronic malaria exposure, atypical MBCs appear to differentiate from classical MBCs becoming refractory to BCR-mediated activation and potentially interfering with the acquisition of malaria immunity.

  10. Clinical use of blinatumomab for B-cell acute lymphoblastic leukemia in adults

    PubMed Central

    Lee, Kum Ja; Chow, Vivian; Weissman, Ashley; Tulpule, Sunil; Aldoss, Ibrahim; Akhtari, Mojtaba

    2016-01-01

    Adults with relapsed or refractory B-cell acute lymphoblastic leukemia have a dismal prognosis with a short median overall survival that can be measured in months. Because most patients will have chemotherapy-resistant disease, allogeneic hematopoietic stem cell transplantation remains the only potentially curative treatment. Despite advances in current management, patients continue to have poor outcomes and lack of durable responses. Thus, new therapies with alternative modes of actions are currently being investigated. Blinatumomab is a novel bispecific T-cell engager that simultaneously binds CD3-positive cytotoxic T-cells and CD19-positive B-cells, resulting in selective lysis of tumor cells. It has shown promising results in patients with relapsed or refractory acute lymphoblastic leukemia or those achieving hematologic response with persistent minimum residual disease. Future clinical trials will answer questions regarding its optimal place in the treatment paradigm. Dose-limiting toxicities include immunological toxicities and cytokine release syndrome. However, most patients tolerate the therapy relatively well. This review will focus on the pharmacology, clinical efficacy, and safety of blinatumomab in the treatment of adult B-cell acute lymphoblastic leukemia while highlighting its unique drug warnings and toxicity management. PMID:27601914

  11. Culture medium type affects endocytosis of multi-walled carbon nanotubes in BEAS-2B cells and subsequent biological response.

    PubMed

    Haniu, Hisao; Saito, Naoto; Matsuda, Yoshikazu; Tsukahara, Tamotsu; Maruyama, Kayo; Usui, Yuki; Aoki, Kaoru; Takanashi, Seiji; Kobayashi, Shinsuke; Nomura, Hiroki; Okamoto, Masanori; Shimizu, Masayuki; Kato, Hiroyuki

    2013-09-01

    We examined the cytotoxicity of multi-walled carbon nanotubes (MWCNTs) and the resulting cytokine secretion in BEAS-2B cells or normal human bronchial epithelial cells (HBEpCs) in two types of culture media (Ham's F12 containing 10% FBS [Ham's F12] and serum-free growth medium [SFGM]). Cellular uptake of MWCNT was observed by fluorescent microscopy and analyzed using flow cytometry. Moreover, we evaluated whether MWCNT uptake was suppressed by 2 types of endocytosis inhibitors. We found that BEAS-2B cells cultured in Ham's F12 and HBEpCs cultured in SFGM showed similar biological responses, but BEAS-2B cells cultured in SFGM did not internalize MWCNTs, and the 50% inhibitory concentration value, i.e., the cytotoxicity, was increased by more than 10-fold. MWCNT uptake was suppressed by a clathrin-mediated endocytosis inhibitor and a caveolae-mediated endocytosis inhibitor in BEAS-2B cells cultured in Ham's F12 and HBEpCs cultured in SFGM. In conclusion, we suggest that BEAS-2B cells cultured in a medium containing serum should be used for the safety evaluation of nanomaterials as a model of normal human bronchial epithelial cells. However, the culture medium composition may affect the proteins that are expressed on the cytoplasmic membrane, which may influence the biological response to MWCNTs.

  12. New B-cell Lymphomas in the Setting of a Previous Rare Breast Implant–Associated B-cell Lymphoma

    PubMed Central

    Messer, Alison; Wang, Wei; Duvic, Madeleine

    2016-01-01

    Summary: We present a follow-up of a patient who underwent right-sided subtotal mastectomy and placement of right-sided saline implant in 1968 for a phyllodes tumor and then in 2012 was diagnosed with a rare B-cell type lymphoma of the right breast. In 2015, she was diagnosed with diffuse large B-cell lymphoma involvement of the left breast and left leg and experienced subsequent self-regression of leg lesions without therapy. PMID:27975038

  13. Kidins220/ARMS binds to the B cell antigen receptor and regulates B cell development and activation

    PubMed Central

    Fiala, Gina J.; Janowska, Iga; Prutek, Fabiola; Hobeika, Elias; Satapathy, Annyesha; Sprenger, Adrian; Plum, Thomas; Seidl, Maximilian; Dengjel, Jörn; Reth, Michael; Cesca, Fabrizia; Brummer, Tilman

    2015-01-01

    B cell antigen receptor (BCR) signaling is critical for B cell development and activation. Using mass spectrometry, we identified a protein kinase D–interacting substrate of 220 kD (Kidins220)/ankyrin repeat–rich membrane-spanning protein (ARMS) as a novel interaction partner of resting and stimulated BCR. Upon BCR stimulation, the interaction increases in a Src kinase–independent manner. By knocking down Kidins220 in a B cell line and generating a conditional B cell–specific Kidins220 knockout (B-KO) mouse strain, we show that Kidins220 couples the BCR to PLCγ2, Ca2+, and extracellular signal-regulated kinase (Erk) signaling. Consequently, BCR-mediated B cell activation was reduced in vitro and in vivo upon Kidins220 deletion. Furthermore, B cell development was impaired at stages where pre-BCR or BCR signaling is required. Most strikingly, λ light chain–positive B cells were reduced sixfold in the B-KO mice, genetically placing Kidins220 in the PLCγ2 pathway. Thus, our data indicate that Kidins220 positively regulates pre-BCR and BCR functioning. PMID:26324445

  14. Ibrutinib Before and After Stem Cell Transplant in Treating Patients With Relapsed or Refractory Diffuse Large B-cell Lymphoma

    ClinicalTrials.gov

    2017-04-11

    Activated B-Cell-Like Diffuse Large B-Cell Lymphoma; B-Cell Lymphoma, Unclassifiable, With Features Intermediate Between Diffuse Large B-Cell Lymphoma and Burkitt Lymphoma; Diffuse Large B-Cell Lymphoma, Not Otherwise Specified; Recurrent Diffuse Large B-Cell Lymphoma; Refractory Diffuse Large B-Cell Lymphoma

  15. TIM-1 signaling in B cells regulates antibody production

    SciTech Connect

    Ma, Juan; Usui, Yoshihiko; Takeda, Kazuyoshi; Harada, Norihiro; Yagita, Hideo; Okumura, Ko; Akiba, Hisaya

    2011-03-11

    Highlights: {yields} TIM-1 is highly expressed on anti-IgM + anti-CD40-stimulated B cells. {yields} Anti-TIM-1 mAb enhanced proliferation and Ig production on activated B cell in vitro. {yields} TIM-1 signaling regulates Ab production by response to TI-2 and TD antigens in vivo. -- Abstract: Members of the T cell Ig and mucin (TIM) family have recently been implicated in the control of T cell-mediated immune responses. In this study, we found TIM-1 expression on anti-IgM- or anti-CD40-stimulated splenic B cells, which was further up-regulated by the combination of anti-IgM and anti-CD40 Abs. On the other hand, TIM-1 ligand was constitutively expressed on B cells and inducible on anti-CD3{sup +} anti-CD28-stimulated CD4{sup +} T cells. In vitro stimulation of activated B cells by anti-TIM-1 mAb enhanced proliferation and expression of a plasma cell marker syndecan-1 (CD138). We further examined the effect of TIM-1 signaling on antibody production in vitro and in vivo. Higher levels of IgG2b and IgG3 secretion were detected in the culture supernatants of the anti-TIM-1-stimulated B cells as compared with the control IgG-stimulated B cells. When immunized with T-independent antigen TNP-Ficoll, TNP-specific IgG1, IgG2b, and IgG3 Abs were slightly increased in the anti-TIM-1-treated mice. When immunized with T-dependent antigen OVA, serum levels of OVA-specific IgG2b, IgG3, and IgE Abs were significantly increased in the anti-TIM-1-treated mice as compared with the control IgG-treated mice. These results suggest that TIM-1 signaling in B cells augments antibody production by enhancing B cell proliferation and differentiation.

  16. Building Classifier Ensembles for B-Cell Epitope Prediction

    PubMed Central

    EL-Manzalawy, Yasser; Honavar, Vasant

    2015-01-01

    Identification of B-cell epitopes in target antigens is a critical step in epitope-driven vaccine design, immunodiagnostic tests, and antibody production. B-cell epitopes could be linear, i.e., a contiguous amino acid sequence fragment of an antigen, or conformational, i.e., amino acids that are often not contiguous in the primary sequence but appear in close proximity within the folded 3D antigen structure. Numerous computational methods have been proposed for predicting both types of B-cell epitopes. However, the development of tools for reliably predicting B-cell epitopes remains a major challenge in immunoinformatics. Classifier ensembles a promising approach for combining a set of classifiers such that the overall performance of the resulting ensemble is better than the predictive performance of the best individual classifier. In this chapter, we show how to build a classifier ensemble for improved prediction of linear B-cell epitopes. The method can be easily adapted to build classifier ensembles for predicting conformational epitopes. PMID:25048130

  17. Regulation of germinal center B-cell differentiation.

    PubMed

    Zhang, Yang; Garcia-Ibanez, Laura; Toellner, Kai-Michael

    2016-03-01

    Germinal centers (GC) are the main sites where antigen-activated B-cell clones expand and undergo immunoglobulin gene hypermutation and selection. Iterations of this process will lead to affinity maturation, replicating Darwinian evolution on the cellular level. GC B-cell selection can lead to four different outcomes: further expansion and evolution, apoptosis (non-selection), or output from the GC with differentiation into memory B cells or plasma cells. T-helper cells in GC have been shown to have a central role in regulating B-cell selection by sensing the density of major histocompatibility complex (MHC):peptide antigen complexes. Antigen is provided on follicular dendritic cells in the form of immune complex. Antibody on these immune complexes regulates antigen accessibility by shielding antigen from B-cell receptor access. Replacement of antibody on immune complexes by antibody generated from GC-derived plasma cell output will gradually reduce the availability of antigen. This antibody feedback can lead to a situation where a slow rise in selection stringency caused by a changing environment leads to directional evolution toward higher affinity antibody.

  18. TRAF3 deficiency promotes metabolic reprogramming in B cells

    PubMed Central

    Mambetsariev, Nurbek; Lin, Wai W.; Wallis, Alicia M.; Stunz, Laura L.; Bishop, Gail A.

    2016-01-01

    The adaptor protein TNF receptor-associated factor 3 (TRAF3) is a critical regulator of B lymphocyte survival. B cell-specific TRAF3 deficiency results in enhanced viability and is associated with development of lymphoma and multiple myeloma. We show that TRAF3 deficiency led to induction of two proteins important for glucose metabolism, Glut1 and Hexokinase 2 (HXK2). This was associated with increased glucose uptake. In the absence of TRAF3, anaerobic glycolysis and oxidative phosphorylation were increased in B cells without changes in mitochondrial mass or reactive oxygen species. Chemical inhibition of glucose metabolism or glucose deprivation substantially attenuated the enhanced survival of TRAF3-deficient B cells, with a decrease in the pro-survival protein Mcl-1. Changes in Glut1 and Mcl-1 levels, glucose uptake and B cell number in the absence of TRAF3 were all dependent upon NF-κB inducing kinase (NIK). These results indicate that TRAF3 deficiency suffices to metabolically reprogram B cells, a finding that improves our understanding of the role of TRAF3 as a tumor suppressor, and suggests potential therapeutic strategies. PMID:27752131

  19. The Role of Latently Infected B Cells in CNS Autoimmunity

    PubMed Central

    Márquez, Ana Citlali; Horwitz, Marc Steven

    2015-01-01

    The onset of multiple sclerosis (MS) is caused by both genetic and environmental factors. Among the environmental factors, it is believed that previous infection with Epstein–Barr virus (EBV) may contribute in the development of MS. EBV has been associated with other autoimmune diseases, such as systemic lupus erythematous, and cancers like Burkitt’s lymphoma. EBV establishes a life-long latency in B cells with occasional reactivation of the virus throughout the individual’s life. The role played by B cells in MS pathology has been largely studied, yet is not clearly understood. In MS patients, Rituximab, a novel treatment that targets CD20+ B cells, has proven to have successful results in diminishing the number of relapses in remitting relapsing MS; however, the mechanism of how this drug acts has not been clearly established. In this review, we analyze the evidence of how B cells latently infected with EBV might be altering the immune system response and helping in the development of MS. We will also discuss how animal models, such as experimental autoimmune encephalomyelitis (EAE) and murine gammaherpesvirus-68 (γHV-68), can be used as powerful tools in the study of the relationship between EBV, MS, and B cells. PMID:26579121

  20. Transcriptional Control of Early T and B Cell Developmental Choices

    PubMed Central

    Rothenberg, Ellen V.

    2014-01-01

    T and B cells share a common somatic gene rearrangement mechanism for assembling the genes that code for their antigen receptors and developmental pathways with many parallels. Shared usage of basic helix-loop-helix E proteins as transcriptional drivers underlies these common features. However, the transcription factor networks in which these E proteins are embedded are different both in membership and in architecture for T and B cell gene regulatory programs. These differences permit lineage commitment decisions to be made in different hierarchical orders. Furthermore, in a contrast to B-cell gene networks, the T-cell gene network architecture for effector differentiation is sufficiently modular so that E protein inputs can be removed. Complete “T-cell-like” effector differentiation can proceed without T-cell receptor rearrangement or selection when E proteins are neutralized, yielding natural killer and other innate lymphoid cells. PMID:24471430

  1. How do viruses trick B-cells into becoming lymphomas?

    PubMed Central

    Cesarman, Ethel

    2014-01-01

    Purpose of review Since the discovery of EBV in Burkitt lymphoma 50 years ago, only one other virus, namely KSHV/HHV-8, has been confirmed to be a direct cause of B cell lymphoma. Here we will review the evidence for EBV and KSHV as causal lymphoma agents. Recent findings A deeper understanding of specific mechanisms by which EBV and KSHV cause B cell lymphomas has been acquired over the past years, in particular with respect to viral protein interactions with host cell pathways, microRNA functions. Specific therapies based on knowledge of viral functions are beginning to be evaluated, mostly in pre-clinical models. Summary Understanding the causal associations of specific infections agents with certain B cell lymphomas has allowed more accurate diagnosis and classification. A deeper knowledge of the specific mechanisms of transformation is essential to begin assessing whether virus-targeted treatment modalities may be used in the future. PMID:24886824

  2. Transcription factors regulating B cell fate in the germinal centre.

    PubMed

    Recaldin, T; Fear, D J

    2016-01-01

    Diversification of the antibody repertoire is essential for the normal operation of the vertebrate adaptive immune system. Following antigen encounter, B cells are activated, proliferate rapidly and undergo two diversification events; somatic hypermutation (followed by selection), which enhances the affinity of the antibody for its cognate antigen, and class-switch recombination, which alters the effector functions of the antibody to adapt the response to the challenge faced. B cells must then differentiate into antibody-secreting plasma cells or long-lived memory B cells. These activities take place in specialized immunological environments called germinal centres, usually located in the secondary lymphoid organs. To complete the germinal centre activities successfully, a B cell adopts a transcriptional programme that allows it to migrate to specific sites within the germinal centre, proliferate, modify its DNA recombination and repair pathways, alter its apoptotic potential and finally undergo terminal differentiation. To co-ordinate these processes, B cells employ a number of 'master regulator' transcription factors which mediate wholesale transcriptomic changes. These master transcription factors are mutually antagonistic and form a complex regulatory network to maintain distinct gene expression programs. Within this network, multiple points of positive and negative feedback ensure the expression of the 'master regulators', augmented by a number of 'secondary' factors that reinforce these networks and sense the progress of the immune response. In this review we will discuss the different activities B cells must undertake to mount a successful T cell-dependent immune response and describe how a regulatory network of transcription factors controls these processes.

  3. A perspective on B-cell-targeting therapy for SLE

    PubMed Central

    Looney, R. John; Anolik, Jennifer; Sanz, Inaki

    2014-01-01

    In recent years, large controlled trials have tested several new agents for systemic lupus erythematosus (SLE). Unfortunately, none of these trials has met its primary outcome. This does not mean progress has not been made. In fact, a great deal has been learned about doing clinical trials in lupus and about the biological and clinical effects of the drugs being tested. Many of these drugs were designed to target B cells directly, e.g., rituximab, belimumab, epratuzumab, and transmembrane activator and calcium modulator and cyclophilin ligand interactor–immunoglobulin (TACI–Ig). The enthusiasm for targeting B cells derives from substantial evidence showing the critical role of B cells in murine models of SLE, as well promising results from multiple open trials with rituximab, a chimeric anti-CD20 monoclonal antibody that specifically depletes B cells (Martin and Chan in Immunity 20(5):517–527, 2004; Sobel et al. in J Exp Med 173:1441–1449, 1991; Silverman and Weisman in Arthritis Rheum 48:1484–1492, 2003; Silverman in Arthritis Rheum 52(4):1342, 2005; Shlomchik et al. in Nat Rev Immunol 1:147–153, 2001; Looney et al. in Arthritis Rheum 50:2580–2589, 2004; Lu et al. in Arthritis Rheum 61(4):482–487, 2009; Saito et al. in Lupus 12(10):798–800, 2003; van Vollenhoven et al. in Scand J Rheumatol 33(6):423–427, 2004; Sfikakis et al. Arthritis Rheum 52(2):501–513, 2005). Why have the controlled trials of B-cell-targeting therapies failed to demonstrate efficacy? Were there flaws in design or execution of these trials? Or, were promising animal studies and open trials misleading, as so often happens? This perspective discusses the current state of B-cell-targeting therapies for human lupus and the future development of these therapies. PMID:19669389

  4. The nanoscale spatial organization of B-cell receptors on immunoglobulin M- and G-expressing human B-cells.

    PubMed

    Lee, Jinmin; Sengupta, Prabuddha; Brzostowski, Joseph; Lippincott-Schwartz, Jennifer; Pierce, Susan K

    2017-02-15

    B-cell activation is initiated by the binding of antigen to the B-cell receptor (BCR). Here we used dSTORM superresolution imaging to characterize the nanoscale spatial organization of immunoglobulin M (IgM) and IgG BCRs on the surfaces of resting and antigen--activated human peripheral blood B-cells. We provide insights into both the fundamental process of antigen-driven BCR clustering and differences in the spatial organization of IgM and IgG BCRs that may contribute to the characteristic differences in the responses of naive and memory B-cells to antigen. We provide evidence that although both IgM and IgG BCRs reside in highly heterogeneous protein islands that vary in size and number of BCR single-molecule localizations, both resting and activated B-cells intrinsically maintain a high -frequency of single isolated BCR localizations, which likely represent BCR monomers. IgG BCRs are more clustered than IgM BCRs on resting cells and form larger protein islands after antigen activation. Small, dense BCR clusters likely formed via protein-protein interactions are present on the surface of resting cells, and antigen activation induces these to come together to form less dense, larger islands, a process likely governed, at least in part, by protein-lipid interactions.

  5. BCA-1, A B-cell chemoattractant signal, is constantly expressed in cutaneous lymphoproliferative B-cell disorders.

    PubMed

    Mori, M; Manuelli, C; Pimpinelli, N; Bianchi, B; Orlando, C; Mavilia, C; Cappugi, P; Maggi, E; Giannotti, B; Santucci, M

    2003-07-01

    We analysed the immunophenotypic and molecular expression of BCA-1 (B-cell-specific chemokine) and CXCR5 (BCA-1 receptor) in normal skin and different cutaneous lymphoproliferative disorders (cutaneous T-cell lymphoma (CTCL); cutaneous B-cell lymphoma (CBCL); cutaneous B-cell pseudolymphoma (PCBCL)), with the aim of investigating their possible involvement in the pathogenesis of cutaneous B-cell disorders. BCA-1 and CXCR5 were constantly expressed in CBCL and PCBCL, but not in normal skin and CTCL. BCA-1 and CXCR5 were constantly coexpressed by CD22+ B-cells, while CD35+ follicular dendritic cells coexpressed BCA-1 in PCBCL cells only. In low grade CBCL, as compared with high grade CBCL, the intensity of CXCR5 expression on neoplastic CD22+ cells was lower than that of BCA-1. The image analysis of reverse transcriptase-polymerase chain reaction (RT-PCR) products showed a significant quantitative difference between PCBCL/low grade CBCL and high grade CBCL. The above findings, although only observed in a small series of patients, are in keeping with findings in MALT gastric and gastric MALT lymphomas, adding further evidence of the close similarities between CBCL and MALT lymphomas.

  6. Primary B-cell malignant lymphoma of the lung.

    PubMed

    Canver, C C

    1993-10-01

    A 52-year-old asymptomatic man was evaluated for two right lung lesions discovered on a chest roentgenogram during a routine physical examination. A computed tomographic scan revealed the absence of mediastinal nodal involvement. Guided-needle aspiration cytology was inconclusive. A subsequent right thoracotomy was necessary to perform biopsy of these masses, which proved to be B-cell malignant lymphomas of the lung. This case represents a rare example of a primary low-grade B-cell pulmonary lymphoma of mucosa-associated lymphoid tissue, with its distinct clinicopathologic features.

  7. Activation of B cells by non-canonical helper signals.

    PubMed

    Cerutti, Andrea; Cols, Montserrat; Puga, Irene

    2012-09-01

    Cognate interaction between T and B lymphocytes of the adaptive immune system is essential for the production of high-affinity antibodies against microbes, and for the establishment of long-term immunological memory. Growing evidence shows that--in addition to presenting antigens to T and B cells--macrophages, dendritic cells and other cells of the innate immune system provide activating signals to B cells, as well as survival signals to antibody-secreting plasma cells. Here, we discuss how these innate immune cells contribute to the induction of highly diversified and temporally sustained antibody responses, both systemically and at mucosal sites of antigen entry.

  8. Membrane phenotypic studies in B cell lymphoproliferative disorders.

    PubMed Central

    Scott, C S; Limbert, H J; MacKarill, I D; Roberts, B E

    1985-01-01

    A total of 398 cases of B cell lymphoproliferative disease were phenotypically characterised by membrane mouse red blood cell (MRBC) receptor, surface immunoglobulin, common acute lymphoblastic leukaemia (CALLA), and FMC7 and T1 monoclonal antibody studies. Relations between chronic lymphocytic leukaemia (CLL), prolymphocytic leukaemia (PLL), and "prolymphocytoid" CLL variants were examined with particular reference to the expression of FMC7. In addition, the reactivity of TU1 monoclonal antibody with B cell disorders was established. The results suggest that despite some heterogeneity most cases may be characterised by their phenotypic patterns and that these investigations provide a reproducible basis for classification. PMID:2413082

  9. A Literature Revision in Primary Cutaneous B-cell Lymphoma

    PubMed Central

    Selva, R La; Violetti, S Alberti; Delfino, C; Grandi, V; Cicchelli, S; Tomasini, C; Fierro, M T; Berti, E; Pimpinelli, N; Quaglino, P

    2017-01-01

    The term “Primary Cutaneous B-Cell Lymphoma” (PCBCL) comprehends a variety of lymphoproliferative disorders characterized by a clonal proliferation of B-cells primarily involving the skin. The absence of evident extra-cutaneous disease must be confirmed after six-month follow-up in order to exclude a nodal non-Hodgkin's lymphoma (NHL) with secondary cutaneous involvement, which may have a completely different clinical behavior and prognosis. In this article, we have summarized the clinico-pathological features of main types of PCBCL and we outline the guidelines for management based on a review of the available literature.

  10. S1P3 confers differential S1P migration by autoreactive and non-autoreactive immature B cells and is required for normal B cell development

    PubMed Central

    Donovan, Erin E.; Pelanda, Roberta; Torres, Raul M.

    2010-01-01

    SUMMARY During B cell development, immature B cell fate is determined by whether the B cell antigen receptor is engaged in the bone marrow. Immature B cells that are non-autoreactive continue maturation and emigrate from the marrow whereas autoreactive immature B cells remain and are tolerized. However, the microenvironment where these events occur and the chemoattractants responsible for immature B cell trafficking within and out of the bone marrow remain largely undefined. Sphingosine 1-phosphate (S1P) is a chemoattractant that directs lymphocyte trafficking and thymocyte egress and in this study we investigated whether S1P contributed to B cell development, egress and positioning within the bone marrow. Our findings show that immature B cells are chemotactic towards S1P but that this response is dependent on antigen receptor specificity: non-autoreactive, but not autoreactive, immature B cells migrate towards S1P and are shown to require S1P3 receptor for this response. Despite this response, S1P3 is shown not to facilitate immature B cell egress but is required for normal B cell development including the positioning of transitional B cells within bone marrow sinusoids. These data indicate that S1P3 signaling directs immature B cells to a bone marrow microenvironment important for both tolerance induction and maturation. PMID:20039302

  11. Primary central nervous system B cell lymphoma with features intermediate between diffuse large B cell lymphoma and Burkitt lymphoma

    PubMed Central

    Jiang, Liuyan; Li, Zhimin; Finn, Laura E; Personnet, David A; Edenfield, Brandy; Foran, James M; Jaeckle, Kurt A; Reimer, Ronald; Menke, David M; Ketterling, Rhett P; Tun, Han W

    2012-01-01

    B cell lymphoma with features intermediate between diffuse large B cell lymphoma and Burkitt lymphoma (DLBCL/BL) is a new lymphoma entity which is recognized in the current World Health Organization (WHO) classification (2008). We report a case of a primary central nervous system lymphoma (PCNSL) with findings consistent with DLBCL/BL. It is characterized by a very aggressive clinical course, and a widespread multifocal involvement of the CNS. Our case shows that a DLBCL/BL can manifest in the CNS alone without any systemic involvement. PMID:22295149

  12. Activation-induced cytidine deaminase (AID) expression in human B-cell precursors is essential for central B-cell tolerance

    PubMed Central

    Cantaert, Tineke; Schickel, Jean-Nicolas; Bannock, Jason M.; Ng, Yen-Shing; Massad, Christopher; Oe, Tyler; Wu, Renee; Lavoie, Aubert; Walter, Jolan E.; Notarangelo, Luigi D.; Al-Herz, Waleed; Kilic, Sara Sebnem; Ochs, Hans D.; Nonoyama, Shigeaki; Durandy, Anne; Meffre, Eric

    2015-01-01

    SUMMARY Activation-induced cytidine deaminase (AID), the enzyme mediating class switch recombination (CSR) and somatic hypermutation (SHM) of immunoglobulin genes, is essential for the removal of developing autoreactive B cells. How AID mediates central B-cell tolerance remains unknown. We report that AID enzymes were produced in a discrete population of immature B cells that expressed recombination-activating gene 2 (RAG2), suggesting that they undergo secondary recombination to edit autoreactive antibodies. However, most AID+ immature B cells lacked anti-apoptotic MCL-1 and were deleted by apoptosis. AID inhibition using lentiviral-encoded short hairpin (sh)RNA in B cells developing in humanized mice resulted in a failure to remove autoreactive clones. Hence, B-cell intrinsic AID expression mediates central B-cell tolerance potentially through its RAG-coupled genotoxic activity in self-reactive immature B cells. PMID:26546282

  13. New Insights into Monoclonal B-Cell Lymphocytosis

    PubMed Central

    Kalpadakis, Christina; Pangalis, Gerassimos A.; Sachanas, Sotirios; Vassilakopoulos, Theodoros P.; Kyriakaki, Stavroula; Korkolopoulou, Penelope; Koulieris, Efstathios; Moschogiannis, Maria; Yiakoumis, Xanthi; Tsirkinidis, Pantelis; Kyrtsonis, Marie-Christine; Levidou, Georgia; Papadaki, Helen A.; Panayiotidis, Panayiotis; Angelopoulou, Maria K.

    2014-01-01

    Monoclonal B-cell lymphocytosis (MBL) is a premalignant condition characterized by the presence of less than 5000/μL circulating clonal B cells in otherwise healthy individuals. Three subcategories have been identified according to the immunophenotypic features: CLL-like, CD5(+) atypical, and CD5(−) MBL. CLL-like MBL is by far the most frequent and best studied category and further divided in low-count [LC] and high-count [HC] MBL, based on a cutoff value of 500/μL clonal B cells. LC-MBL typically remains stable and probably does not represent a truly premalignant condition, but rather an age-related immune senescence. On the other hand, HC-MBL is closely related to CLL-Rai0, bearing similar immunogenetic profile, and is associated with an annual risk of progression to CLL requiring therapy at a rate of 1.1%. Currently there are no reproducible factors for evaluating the risk of progression to CLL. CD5(−) MBL is characterized by an immunophenotype consistent with marginal zone origin and displays many similarities with marginal zone lymphomas (MZL), mainly the splenic MZL. The cutoff value of 5000/μL clonal B cells cannot probably be applied in CD5(−) MBL, requiring a new definition to describe those cases. PMID:25295254

  14. Cord blood transplants for SCID: better B-cell engraftment?

    PubMed

    Chan, Wan-Yin; Roberts, Robert Lloyd; Moore, Theodore B; Stiehm, E Richard

    2013-01-01

    Hematopoietic stem-cell transplantation is the treatment of choice for severe combined immunodeficiency (SCID). Despite successful T-cell engraftment in transplanted patients, B-cell function is not always achieved; up to 58% of patients require immunoglobulin therapy after receiving haploidentical transplants. We report 2 half-sibling males with X-linked γ-chain SCID treated with different sources of stem cells. Sibling 1 was transplanted with T-cell-depleted haploidentical maternal bone marrow and sibling 2 was transplanted with 7/8 human leukocyte antigen-matched unrelated umbilical cord blood. Both patients received pretransplant conditioning and posttransplant graft-versus-host-disease prophylaxis. B-cell engraftment and function was achieved in sibling 1 but not in sibling 2. This disparate result is consistent with a review of 19 other SCID children who received cord blood transplants. B-cell function, as indicated by no need for immunoglobulin therapy, was restored in 42% of patients given haploidentical transplants and in 68% of patients given matched unrelated donor transplants compared with 80% of patients given cord blood transplants. Cord blood is an alternative source of stem cells for transplantation in children with SCID and has a higher likelihood of B-cell reconstitution.

  15. The Memory Function of the B Cell Antigen Receptor.

    PubMed

    Wienands, Jürgen; Engels, Niklas

    2016-01-01

    Activated B lymphocytes preserve their antigen experience by differentiating into long-lived pools of antibody-secreting plasma cells or various types of memory B cells (MBCs). The former population constantly produces serum immunoglobulins with sufficient specificity and affinity to thwart infections with recurrent pathogens. By contrast, memory B cell populations retain their antigen receptors on the cell surface and hence need pathogen-induced differentiation steps before they can actively contribute to host defense. The terminal differentiation of MBCs into antibody-secreting plasma cells is hallmarked by the absence of the lag phase characteristic for primary antibody responses. Moreover, secondary antibody responses are predominantly driven by MBCs that bear an antigen receptor of the IgG class on their surface although IgM-positive memory populations exist as well. These fundamental principles of B cell memory were enigmatic for decades. Only recently, we have begun to understand the underlying mechanisms. This review summarizes our current understanding of how different subpopulations of MBCs are generated during primary immune responses and how their functional heterogeneity on antigen recall is controlled by different signaling capabilities of B cell antigen receptor (BCR) isotypes and by the nature of the antigen.

  16. Likelihood-Based Inference of B Cell Clonal Families

    PubMed Central

    Ralph, Duncan K.

    2016-01-01

    The human immune system depends on a highly diverse collection of antibody-making B cells. B cell receptor sequence diversity is generated by a random recombination process called “rearrangement” forming progenitor B cells, then a Darwinian process of lineage diversification and selection called “affinity maturation.” The resulting receptors can be sequenced in high throughput for research and diagnostics. Such a collection of sequences contains a mixture of various lineages, each of which may be quite numerous, or may consist of only a single member. As a step to understanding the process and result of this diversification, one may wish to reconstruct lineage membership, i.e. to cluster sampled sequences according to which came from the same rearrangement events. We call this clustering problem “clonal family inference.” In this paper we describe and validate a likelihood-based framework for clonal family inference based on a multi-hidden Markov Model (multi-HMM) framework for B cell receptor sequences. We describe an agglomerative algorithm to find a maximum likelihood clustering, two approximate algorithms with various trade-offs of speed versus accuracy, and a third, fast algorithm for finding specific lineages. We show that under simulation these algorithms greatly improve upon existing clonal family inference methods, and that they also give significantly different clusters than previous methods when applied to two real data sets. PMID:27749910

  17. Unraveling the warp and weft of B cell fate.

    PubMed

    Stadanlick, Jason E; Cancro, Michael P

    2006-09-01

    Two recent Immunity articles (Enzler et al., 2006; Sasaki et al., 2006) probe the roles of Nuclear Factor kappa-B (NF-kappaB) pathways in survival and differentiation mediated by B cell activation factor of the TNF family (BAFF).

  18. Diffuse Large B Cell Lymphoma Mimicking Granulomatosis with Polyangiitis

    PubMed Central

    Horowitz, Netanel; Ben-Itzhak, Ofer; Braun-Moscovici, Yolanda

    2016-01-01

    In a patient with systemic multiorgan disease with overlapping features, the differential diagnosis included infectious diseases, malignancies, and systemic autoimmune or inflammatory diseases. We present an unusual case of a young male with B cell lymphoma who presented with symptoms mimicking systemic vasculitis and review the existing literature. PMID:27293945

  19. Control of Viremia Enables Acquisition of Resting Memory B Cells with Age and Normalization of Activated B Cell Phenotypes in HIV-Infected Children

    PubMed Central

    Muema, Daniel M.; Macharia, Gladys N.; Hassan, Amin S.; Mwaringa, Shalton M.; Fegan, Greg W.; Berkley, James A.; Urban, Britta C.

    2015-01-01

    HIV affects the function of all lymphocyte populations, including B cells. Phenotypic and functional defects of B cells in HIV-infected adults have been well characterized, but defects in children have not been studied to the same extent. We determined the proportion of B cell subsets and frequencies of Ag-specific memory B cells in peripheral blood from HIV-infected children and healthy controls, using flow cytometry and B cell ELISPOT, respectively. In addition, we measured the quantities and avidities of plasma Abs against various Ags by ELISA. We also determined plasma levels of BAFF and expression of BAFF receptors on B cells. Children with high HIV viremia had increased proportions of activated mature B cells, tissue-like memory B cells and plasmablasts, and low proportions of naive B cells when compared with community controls and children with low HIV viremia, similar to adults infected with HIV. HIV-infected groups had lower proportions of resting memory B cells than did community controls. Notably, high HIV viremia prevented the age-dependent accumulation of class-switched resting memory B cells. HIV-infected children, regardless of the level of viremia, showed lower quantities and avidities of IgG and lower frequencies of memory B cells against Expanded Program on Immunization vaccines. The HIV-infected children had an altered BAFF profile that could have affected their B cell compartment. Therefore, B cell defects in HIV-infected children are similar to those seen in HIV-infected adults. However, control of HIV viremia is associated with normalization of activated B cell subsets and allows age-dependent accumulation of resting memory B cells. PMID:26116511

  20. B cell autophagy mediates TLR7-dependent autoimmunity and inflammation.

    PubMed

    Weindel, Chi G; Richey, Lauren J; Bolland, Silvia; Mehta, Abhiruchi J; Kearney, John F; Huber, Brigitte T

    2015-01-01

    Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease, defined by loss of B cell self-tolerance that results in production of antinuclear antibodies (ANA) and chronic inflammation. While the initiating events in lupus development are not well defined, overexpression of the RNA-recognizing toll-like receptor (TLR)7 has been linked to SLE in humans and mice. We postulated that autophagy plays an essential role in TLR7 activation of B cells for the induction of SLE by delivering RNA ligands to the endosomes, where this innate immune receptor resides. To test this hypothesis, we compared SLE development in Tlr7 transgenic (Tg) mice with or without B cell-specific ablation of autophagy (Cd19-Cre Atg5(f/f)). We observed that in the absence of B cell autophagy the 2 hallmarks of SLE, ANA and inflammation, were eliminated, thus curing these mice of lupus. This was also evident in the significantly extended survival of the autophagy-deficient mice compared to Tlr7.1 Tg mice. Furthermore, glomerulonephritis was ameliorated, and the serum levels of inflammatory cytokines in the knockout (KO) mice were indistinguishable from those of control mice. These data provide direct evidence that B cells require TLR7-dependent priming through an autophagy-dependent mechanism before autoimmunity is induced, thereafter involving many cell types. Surprisingly, hyper-IgM production persisted in Tlr7.1 Tg mice in the absence of autophagy, likely involving a different activation pathway than the production of autoantibodies. Furthermore, these mice still presented with anemia, but responded with a striking increase in extramedullary hematopoiesis (EMH), possibly due to the absence of pro-inflammatory cytokines.

  1. Ectopic germinal centers, BAFF and anti-B-cell therapy in myasthenia gravis.

    PubMed

    Berrih-Aknin, Sonia; Ragheb, Samia; Le Panse, Rozen; Lisak, Robert P

    2013-07-01

    Myasthenia gravis (MG) is an autoimmune disease mediated by antibodies directed to molecules of the endplate of the neuromuscular junction. B cells play a major role in MG disease since they produce the pathogenic antibodies and therapies targeting B cells are effective. The aim of this article was to review the role of B cells in myasthenia gravis. We will first describe what we know about B cells in this disease and examine the involvement of the B cells in the thymus of MG patients. We will detail the role of factors associated with B-cell function such as BAFF. Finally, we will discuss the effects of therapy targeting B cells.

  2. Germinal center B cells recognize antigen through a specialized immune synapse architecture

    PubMed Central

    Nowosad, Carla R.; Spillane, Katelyn M.; Tolar, Pavel

    2016-01-01

    B cell activation is regulated by B cell antigen receptor (BCR) signaling and antigen internalization in immune synapses. Using large-scale imaging across B cell subsets, we show that in contrast to naive and memory B cells, which gathered antigen towards the synapse center before internalization, germinal center (GC) B cells extracted antigen by a distinct pathway using small peripheral clusters. Both naive and GC B cell synapses required proximal BCR signaling, but GC cells signaled less through the protein kinase C-β (PKC-β)–NF-κB pathway and produced stronger tugging forces on the BCR, thereby more stringently regulating antigen binding. Consequently, GC B cells extracted antigen with better affinity discrimination than naive B cells, suggesting that specialized biomechanical patterns in B cell synapses regulate T-cell dependent selection of high-affinity B cells in GCs. PMID:27183103

  3. Targeted antibody-mediated depletion of murine CD19 CAR T cells permanently reverses B cell aplasia.

    PubMed

    Paszkiewicz, Paulina J; Fräßle, Simon P; Srivastava, Shivani; Sommermeyer, Daniel; Hudecek, Michael; Drexler, Ingo; Sadelain, Michel; Liu, Lingfeng; Jensen, Michael C; Riddell, Stanley R; Busch, Dirk H

    2016-11-01

    The adoptive transfer of T cells that have been genetically modified to express a CD19-specific chimeric antigen receptor (CAR) is effective for treating human B cell malignancies. However, the persistence of functional CD19 CAR T cells causes sustained depletion of endogenous CD19+ B cells and hypogammaglobulinemia. Thus, there is a need for a mechanism to ablate transferred T cells after tumor eradication is complete to allow recovery of normal B cells. Previously, we developed a truncated version of the epidermal growth factor receptor (EGFRt) that is coexpressed with the CAR on the T cell surface. Here, we show that targeting EGFRt with the IgG1 monoclonal antibody cetuximab eliminates CD19 CAR T cells both early and late after adoptive transfer in mice, resulting in complete and permanent recovery of normal functional B cells, without tumor relapse. EGFRt can be incorporated into many clinical applications to regulate the survival of gene-engineered cells. These results support the concept that EGFRt represents a promising approach to improve safety of cell-based therapies.

  4. Targeted antibody-mediated depletion of murine CD19 CAR T cells permanently reverses B cell aplasia

    PubMed Central

    Paszkiewicz, Paulina J.; Fräßle, Simon P.; Srivastava, Shivani; Sommermeyer, Daniel; Hudecek, Michael; Sadelain, Michel; Liu, Lingfeng; Jensen, Michael C.; Riddell, Stanley R.; Busch, Dirk H.

    2016-01-01

    The adoptive transfer of T cells that have been genetically modified to express a CD19-specific chimeric antigen receptor (CAR) is effective for treating human B cell malignancies. However, the persistence of functional CD19 CAR T cells causes sustained depletion of endogenous CD19+ B cells and hypogammaglobulinemia. Thus, there is a need for a mechanism to ablate transferred T cells after tumor eradication is complete to allow recovery of normal B cells. Previously, we developed a truncated version of the epidermal growth factor receptor (EGFRt) that is coexpressed with the CAR on the T cell surface. Here, we show that targeting EGFRt with the IgG1 monoclonal antibody cetuximab eliminates CD19 CAR T cells both early and late after adoptive transfer in mice, resulting in complete and permanent recovery of normal functional B cells, without tumor relapse. EGFRt can be incorporated into many clinical applications to regulate the survival of gene-engineered cells. These results support the concept that EGFRt represents a promising approach to improve safety of cell-based therapies. PMID:27760047

  5. Germinal Center B-Cell-Associated Nuclear Protein (GANP) Involved in RNA Metabolism for B Cell Maturation.

    PubMed

    Sakaguchi, N; Maeda, K

    2016-01-01

    Germinal center B-cell-associated nuclear protein (GANP) is upregulated in germinal center B cells against T-cell-dependent antigens in mice and humans. In mice, GANP depletion in B cells impairs antibody affinity maturation. Conversely, its transgenic overexpression augments the generation of high-affinity antigen-specific B cells. GANP associates with AID in the cytoplasm, shepherds AID into the nucleus, and augments its access to the rearranged immunoglobulin (Ig) variable (V) region of the genome in B cells, thereby precipitating the somatic hypermutation of V region genes. GANP is also upregulated in human CD4(+) T cells and is associated with APOBEC3G (A3G). GANP interacts with A3G and escorts it to the virion cores to potentiate its antiretroviral activity by inactivating HIV-1 genomic cDNA. Thus, GANP is characterized as a cofactor associated with AID/APOBEC cytidine deaminase family molecules in generating diversity of the IgV region of the genome and genetic alterations of exogenously introduced viral targets. GANP, encoded by human chromosome 21, as well as its mouse equivalent on chromosome 10, contains a region homologous to Saccharomyces Sac3 that was characterized as a component of the transcription/export 2 (TREX-2) complex and was predicted to be involved in RNA export and metabolism in mammalian cells. The metabolism of RNA during its maturation, from the transcription site at the chromosome within the nucleus to the cytoplasmic translation apparatus, needs to be elaborated with regard to acquired and innate immunity. In this review, we summarize the current knowledge on GANP as a component of TREX-2 in mammalian cells.

  6. Hand Safety

    MedlinePlus

    ... Hand Safety Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening Safety Turkey Carving Removing a Ring ... Hand Safety Fireworks Safety Lawnmower Safety Snowblower safety Pumpkin Carving Gardening Safety Turkey Carving Removing a Ring ...

  7. Molecular footprints of a germinal center derivation of human IgM+(IgD+)CD27+ B cells and the dynamics of memory B cell generation.

    PubMed

    Seifert, Marc; Küppers, Ralf

    2009-11-23

    The origin of IgM(+)CD27(+) B lymphocytes with mutated IgV genes, which account for approximately 20% of human peripheral blood (PB) B cells, is controversially discussed. A generation in a primary diversification pathway, in T cell-independent immune responses, or in T cell-dependent germinal center (GC) reactions has been proposed. We show here that IgM(+)IgD(+)CD27(+) and IgM(+)IgD(-/low)CD27(+) B cell subsets carry, like class-switched memory B cells, mutations in the Bcl6 gene as a genetic trait of a GC experience. Moreover, the identification of PB IgM(+)IgD(+)CD27(+) B cells clonally related to GC-derived IgG(+) memory B cells with shared and distinct IgV gene mutations demonstrates the GC origin also of the former subset. These findings provide genetic evidence for a GC derivation of somatically mutated IgM(+) B cells and indicate that adult humans harbor a large population of IgM(+)IgD(+) post-GC memory B cells. Furthermore, the analysis revealed that a highly diverse and often very large population of memory B cells is generated from a given GC B cell clone, and that (preferentially IgM) memory B cells are generated already early in the GC reaction. This provides novel insights into the dynamics of GC reactions and the generation of a memory B cell repertoire.

  8. The Epigenetic basis of diffuse large B-cell lymphoma

    PubMed Central

    Jiang, Yanwen; Melnick, Ari

    2015-01-01

    The pathogenesis of DLBCL is strongly linked to perturbation of epigenetic mechanisms. The germinal center (GC) B-cells from which DLBCLs arise are prone to instability in their cytosine methylation patterns. DLBCLs inherit this epigenetic instability and display variable degrees of epigenetic heterogeneity. Greater epigenetic heterogeneity is linked with poor clinical outcome. Somatic mutations of histone modifying proteins have also emerged as a hallmark of DLBCL. The effect of these somatic mutations may be to disrupt epigenetic switches that control the GC phenotype and “lock in” certain oncogenic features of GC B-cells resulting in malignant transformation. DNA methyltransferase and histone methyltransferase inhibitors are emerging as viable therapeutic approaches to erase aberrant epigenetic programming, suppress DLBCL growth and overcome chemotherapy resistance. This review will discuss these recent advances and their therapeutic implications. PMID:25805588

  9. Primary Mediastinal Large B-cell Lymphoma Exhibiting Endobronchial Involvement

    PubMed Central

    Shimada, Midori; Fukuda, Minoru; Horio, Kensuke; Suyama, Takayuki; Kitazaki, Takeshi; Hashiguchi, Kohji; Fukuda, Masaaki; Shigematsu, Kazuto; Nakamura, Yoichi; Honda, Takuya; Ashizawa, Kazuto; Mukae, Hiroshi

    2016-01-01

    Primary mediastinal large B-cell lymphoma (PMLBCL) is one of the subtypes of diffuse large B-cell lymphoma. We experienced a rare case of PMLBCL that exhibited endobronchial involvement. A 33-year-old Japanese female with the chief complaints of epigastralgia, back pain, and nausea visited a primary care hospital. Computed tomography of the chest and abdomen demonstrated a bulky mass in the left anterior mediastinum, multiple pulmonary nodules, axillary lymph node swelling, and a pancreatic tumor. Fiberoptic bronchoscopy showed a white-tinged irregularly shaped endobronchial tumor accompanied by capillary vessel dilation in the left upper lobar bronchus. Taken together, these findings resulted in a diagnosis of PMLBCL. PMID:27803409

  10. 324 Facility B-cell quality process plan

    SciTech Connect

    Carlson, J.L.

    1998-07-29

    B-Cell is currently being cleaned out (i.e., removal of equipment, fixtures and residual radioactive materials) and deactivated. TPA Milestone M-89-02 dictates that all mixed waste and equipment be removed from B-Cell by 5/31/99. The following sections describe the major activities that remain for completion of the TPA milestone. These include: Size Reduce Tank 119 and Miscellaneous Equipment; Load and Ship Low-Level Waste; Remove and Size Reduce the 1B Rack; Collect Dispersible Material from Cell Floor; Remove and Size Reduce the 2A Rack; Size Reduce the 1A Rack; Load and Ship Mixed Waste to PUREX Tunnels; and Move Spent Fuel to A-Cell;

  11. Epigenetic Impact on EBV Associated B-Cell Lymphomagenesis

    PubMed Central

    Ghosh Roy, Shatadru; Robertson, Erle S.; Saha, Abhik

    2016-01-01

    Epigenetic modifications leading to either transcriptional repression or activation, play an indispensable role in the development of human cancers. Epidemiological study revealed that approximately 20% of all human cancers are associated with tumor viruses. Epstein-Barr virus (EBV), the first human tumor virus, demonstrates frequent epigenetic alterations on both viral and host genomes in associated cancers—both of epithelial and lymphoid origin. The cell type-dependent different EBV latent gene expression patterns appear to be determined by the cellular epigenetic machinery and similarly viral oncoproteins recruit epigenetic regulators in order to deregulate the cellular gene expression profile resulting in several human cancers. This review elucidates the epigenetic consequences of EBV–host interactions during development of multiple EBV-induced B-cell lymphomas, which may lead to the discovery of novel therapeutic interventions against EBV-associated B-cell lymphomas by alteration of reversible patho-epigenetic markings. PMID:27886133

  12. Rheumatic autoimmune diseases: proposed elimination of autoreactive B-cells with magnetic nanoparticle-linked antigens.

    PubMed

    Bollmann, F Mathias

    2012-04-01

    Although the pathogenesis of rheumatoid arthritis and other rheumatic diseases is still not fully understood, it has become clear that in many cases autoimmune responses with production of autoantibodies against physiological targets play a significant and causal role. Current immunosuppressive and immunomodulatory approaches such as bone marrow transplantation or the therapeutic antibody rituximab are effective, but unspecific and have serious side effects. Here, a method for targeted elimination of specific autoreactive B-cells which are essential for autoantibody production and maintenance of the autoimmune response is proposed. By binding to their receptive antigens linked to magnetic nanoparticles, the autoreactive B-cells can be separated from the rest of the blood in an extracorporeal filtration process, reducing the number of autoimmune cells and autoantibodies in the blood. The method can be adapted for use in different autoimmune diseases provided some key aspects of pathogenesis are known, and can be repeated if necessary. Evidence for feasibility and safety of this method is briefly reviewed, and potential limitations and hurdles to overcome are discussed.

  13. B-Cell Lymphoma in the Tricuspid Valve

    PubMed Central

    Agha, Ali C; Limback, Joseph; Loya, Raul; Ramirez, Ashley; Valente, Michael

    2016-01-01

    Lymphoma can involve any organ or tissue that contains lymphoid tissue and the heart is no exception. A few prior case reports have described lymphoma encasing a coronary artery or involving one or more cardiac valves. We present a rare case of diffuse large B-cell lymphoma (DLBCL) involving the tricuspid valve and right coronary artery diagnosed on coronary CT angiography. The clinical and imaging characteristics of cardiac lymphoma are discussed. PMID:28097081

  14. B-Cell Lymphoma in the Tricuspid Valve.

    PubMed

    Agha, Ali C; Limback, Joseph; Loya, Raul; Ramirez, Ashley; Valente, Michael; Burt, Jeremy

    2016-12-16

    Lymphoma can involve any organ or tissue that contains lymphoid tissue and the heart is no exception. A few prior case reports have described lymphoma encasing a coronary artery or involving one or more cardiac valves. We present a rare case of diffuse large B-cell lymphoma (DLBCL) involving the tricuspid valve and right coronary artery diagnosed on coronary CT angiography. The clinical and imaging characteristics of cardiac lymphoma are discussed.

  15. How B cells shape the immune response against Mycobacterium tuberculosis.

    PubMed

    Maglione, Paul J; Chan, John

    2009-03-01

    Extensive work illustrating the importance of cellular immune mechanisms for protection against Mycobacterium tuberculosis has largely relegated B-cell biology to an afterthought within the tuberculosis (TB) field. However, recent studies have illustrated that B lymphocytes, through a variety of interactions with the cellular immune response, play previously underappreciated roles in shaping host defense against non-viral intracellular pathogens, including M. tuberculosis. Work in our laboratory has recently shown that, by considering these lymphocytes more broadly within their variety of interactions with cellular immunity, B cells have a significant impact on the outcome of airborne challenge with M. tuberculosis as well as the resultant inflammatory response. In this review, we advocate for a revised view of TB immunology in which roles of cellular and humoral immunity are not mutually exclusive. In the context of our current understanding of host defense against non-viral intracellular infections, we review recent data supporting a more significant role of B cells during M. tuberculosis infection than previously thought.

  16. Bcipep: A database of B-cell epitopes

    PubMed Central

    Saha, Sudipto; Bhasin, Manoj; Raghava, Gajendra PS

    2005-01-01

    Background Bcipep is a database of experimentally determined linear B-cell epitopes of varying immunogenicity collected from literature and other publicly available databases. Results The current version of Bcipep database contains 3031 entries that include 763 immunodominant, 1797 immunogenic and 471 null-immunogenic epitopes. It covers a wide range of pathogenic organisms like viruses, bacteria, protozoa, and fungi. The database provides a set of tools for the analysis and extraction of data that includes keyword search, peptide mapping and BLAST search. It also provides hyperlinks to various databases such as GenBank, PDB, SWISS-PROT and MHCBN. Conclusion A comprehensive database of B-cell epitopes called Bcipep has been developed that covers information on epitopes from a wide range of pathogens. The Bcipep will be source of information for investigators involved in peptide-based vaccine design, disease diagnosis and research in allergy. It should also be a promising data source for the development and evaluation of methods for prediction of B-cell epitopes. The database is available at . PMID:15921533

  17. Interleukin 7 independent development of human B cells.

    PubMed Central

    Prieyl, J A; LeBien, T W

    1996-01-01

    Mammalian hematopoietic stem cell (HSC) commitment and differentiation into lymphoid lineage cells proceed through a series of developmentally restricted progenitor compartments. A complete understanding of this process, and how it differs from HSC commitment and differentiation into cells of the myeloid/erythroid lineages, requires the development of model systems that support HSC commitment to the lymphoid lineages. We now describe a human bone marrow stromal cell culture that preferentially supports commitment and differentiation of human HSC to CD19+ B-lineage cells. Fluorescence activated cell sorterpurified CD34++/lineage-cells were isolated from fetal bone marrow and cultured on human fetal bone marrow stromal cells in serum-free conditions containing no exogenous cytokines. Over a period of 3 weeks, CD34++/lineage- cells underwent commitment, differentiation, and expansion into the B lineage. Progressive changes included: loss of CD34, acquisition of and graded increases in the level of cell surface CD19, and appearance of immature B cells expressing mu/kappa or mu/lambda cell surface Ig receptors. The tempo and phenotype of B-cell development was not influenced by the addition of IL-7 (10 ng/ml), or by the addition of goat anti-IL-7 neutralizing antibody. These results indicate a profound difference between mouse and human in the requirement for IL-7 in normal B-cell development, and provide an experimental system to identify and characterize human bone marrow stromal cell-derived molecules crucial for human B lymphopoiesis. PMID:8816803

  18. Akt and mTOR in B Cell Activation and Differentiation.

    PubMed

    Limon, Jose J; Fruman, David A

    2012-01-01

    Activation of phosphoinositide 3-kinase (PI3K) is required for B cell proliferation and survival. PI3K signaling also controls key aspects of B cell differentiation. Upon engagement of the B cell receptor (BCR), PI3K activation promotes Ca(2+) mobilization and activation of NFκB-dependent transcription, events which are essential for B cell proliferation. PI3K also initiates a distinct signaling pathway involving the Akt and mTOR serine/threonine kinases. It has been generally assumed that activation of Akt and mTOR downstream of PI3K is essential for B cell function. However, Akt and mTOR have complex roles in B cell fate decisions and suppression of this pathway can enhance certain B cell responses while repressing others. In this review we will discuss genetic and pharmacological studies of Akt and mTOR function in normal B cells, and in malignancies of B cell origin.

  19. A methyl-deficient diet modifies early B cell development.

    PubMed

    Kurogi, Toshiaki; Inoue, Hiroko; Guo, Yun; Nobukiyo, Asako; Nohara, Keiko; Kanno, Masamoto

    2012-01-01

    A functional methyl group donor is essential for the epigenetic regulation of all biological events due to the importance of DNA methylation and histone methylation as an epigenetic marker. However, the epigenetic alterations in the immune system due to methyl donor deficiency are not well known. In this study, we tried to address this question by studying the lymphocyte development and DNA methylation changes caused by a methyl-deficient diet (MDD). We fed one group of C57BL/6J mice with a methyl-sufficient diet (MSD) and the other group with an MDD for 5 months. Flow cytometry analyses of their immune systems showed a decrease in B220+ IgM+ (immature B) cells and an increase in B220+ IgM- (pro/pre-B) cells in the bone marrow of mice fed an MDD. By means of an in vitro OP9 coculture system, we recognized that this B220+ IgM- cell fraction from the MDD has an intrinsic developmental defect. When we quantitatively measured the mRNA expression levels of transcription factors and recombination machinery related to B cell development in the B220+ IgM- cell fraction of their bone marrow, we found that ADA, EBF1, DNTT and Pax5 mRNA expression levels were significantly downregulated in mice fed with an MDD. In addition, there was a drastic decrease in histone methylation profile H3K4me3 in the Pax5 and EBF1 promoters in these B220+ IgM- B cells. However, CpG-DNA methylation profiles had not changed and this revealed that these two promoters are demethylated even under an MSD condition. We also found changed expression levels of the Polycomb group genes (mel18, bmi1, Pc1, Pc2, Ring1A, Ring1B, Ph1) on semi-quantitative RT-PCR. These results indicate that under an MDD condition, early B cell development in bone marrow is easily affected by epigenetic alterations.

  20. T cell-derived B cell growth and differentiation factors. Dichotomy between the responsiveness of B cells from adult and neonatal mice

    PubMed Central

    1983-01-01

    In these studies we have determined the molecular weights of B cell growth factor (BCGF) (less than 20,000), and B cell differentiation factors (BCDF) that induce immunoglobulin M (IgM) secretion (BCDF mu) (30-60,000) and IgG secretion (BCDF gamma) (less than 20,000). Thus, the molecular weight of BCDF mu is distinct from that of BCGF and BCDF gamma; BCGF and BCDF gamma cannot be distinguished. In addition, BCGF, BCDF mu, and BCDF gamma are distinguishable by their presence or absence in different supernatants from a panel of mitogen-induced T cell clones. These results suggest that the three lymphokines are different. This conclusion is supported by their differential biological effect on B cells from adult and neonatal mice. Thus, treatment with anti-Ig induces B cells from adult mice to proliferate and this proliferation is sustained by BCGF. In contrast, even in the presence of BCGF, anti-Ig does not induce B cells from neonatal mice to proliferate. However, BCDF mu and BCDF gamma induce IgM and IgG secretion in B cells, respectively, from both adult and neonatal mice. Thus, mature B cells can both clonally expand and differentiate in response to anti-Ig, BCGF, and BCDF, whereas immature B cells can only differentiate. The poor response of neonatal B cells to anti-Ig and BCGF may partially explain the relative immunoincompetence of immature B cells. PMID:6600488

  1. B-cell activation with CD40L or CpG measures the function of B-cell subsets and identifies specific defects in immunodeficient patients.

    PubMed

    Marasco, Emiliano; Farroni, Chiara; Cascioli, Simona; Marcellini, Valentina; Scarsella, Marco; Giorda, Ezio; Piano Mortari, Eva; Leonardi, Lucia; Scarselli, Alessia; Valentini, Diletta; Cancrini, Caterina; Duse, Marzia; Grimsholm, Ola; Carsetti, Rita

    2017-01-01

    Around 65% of primary immunodeficiencies are antibody deficiencies. Functional tests are useful tools to study B-cell functions in vitro. However, no accepted guidelines for performing and evaluating functional tests have been issued yet. Here, we report our experience on the study of B-cell functions in infancy and throughout childhood. We show that T-independent stimulation with CpG measures proliferation and differentiation potential of memory B cells. Switched memory B cells respond better than IgM memory B cells. On the other hand, CD40L, a T-dependent stimulus, does not induce plasma cell differentiation, but causes proliferation of naïve and memory B cells. During childhood, the production of plasmablasts in response to CpG increases with age mirroring the development of memory B cells. The response to CD40L does not change with age. In patients with selective IgA deficiency (SIgAD), we observed that switched memory B cells are reduced due to the absence of IgA memory B cells. In agreement, IgA plasma cells are not generated in response to CpG. Unexpectedly, B cells from SIgAD patients show a reduced proliferative response to CD40L. Our results demonstrate that functional tests are an important tool to assess the functions of the humoral immune system.

  2. Monoclonal B-cell lymphocytosis (MBL) with normal lymphocyte counts is associated with decreased numbers of normal circulating B-cell subsets.

    PubMed

    Hauswirth, Alexander W; Almeida, Julia; Nieto, Wendy G; Teodosio, Cristina; Rodriguez-Caballero, Arancha; Romero, Alfonso; López, Antonio; Fernandez-Navarro, Paulino; Vega, Tomas; Perez-Andres, Martin; Valent, Peter; Jäger, Ulrich; Orfao, Alberto

    2012-07-01

    Monoclonal B-cell lymphocytosis (MBL) with normal lymphocyte counts is associated with decreased numbers of normal circulating B-cell subsets.Little is known about the distribution of normal lymphoid cells and their subsets in the peripheral blood (PB) of subjects with monoclonal B-cell lymphocytosis (MBL). In our study, we compared the absolute number of PB lymphoid cells and their subpopulations in 95 MBL cases with normal lymphocyte counts vs. 617 age-/sex-matched non-MBL healthy subjects (controls), using highly sensitive flow cytometry. MBL cases showed significantly reduced numbers of normal circulating B-cells, at the expense of immature and naive B-cells; in addition, CD4+CD8+ double-positive T-cells and CD8+ T-cells were significantly lower and higher vs. controls, respectively. Moreover, most normal B-cell subsets were significantly decreased in PB at >1% MBL-counts, vs. "low-count" MBL cases, and lower amounts of immature/naive B-cells were detected in biclonal (particularly in cases with coexisting CLL-like- and non-CLL-like B-cell clones) vs. monoclonal MBL subjects. In summary, our results show imbalanced (reduced) absolute numbers of recently produced normal circulating B-cells (e.g., immature and naıve B-cells) in MBL, which becomes more pronounced as the MBL cell count increases.

  3. Splenic B cells and antigen-specific B cells process anti-Ig in a similar manner

    SciTech Connect

    Myers, C.D.; Vitetta, E.S.

    1989-06-01

    B lymphocytes can process and present antigen to T cells. However, the fate of native antigen after its binding to specific B cells, i.e., the intracellular events involved in the processing and recycling of the antigenic fragments to the cell surface for antigen presentation, are not well understood. In the present study, we demonstrate that murine B cells degrade anti-Ig molecules bound to their surface and release acid soluble fragments into the supernatant. We also demonstrate that the kinetics of this process are identical for anti-mu, anti-delta, and anti-light chain antibodies, indicating that both surface IgM and surface IgD are equally effective in binding antigen and directing its processing. We also describe the effects of azide, chloroquine, and irradiation on this process. To extend these studies to the processing of specifically bound antigen, we demonstrate that highly purified trinitrophenyl antigen-binding cells degrade anti-Ig molecules with the same kinetics as unpurified splenic B cells. Thus, this purified population provides a suitable model system for the analysis of antigen degradation by antigen-specific cells.

  4. Clonal B cells in Waldenström's macroglobulinemia exhibit functional features of chronic active B-cell receptor signaling

    PubMed Central

    Argyropoulos, K V; Vogel, R; Ziegler, C; Altan-Bonnet, G; Velardi, E; Calafiore, M; Dogan, A; Arcila, M; Patel, M; Knapp, K; Mallek, C; Hunter, Z R; Treon, S P; van den Brink, M R M; Palomba, M L

    2016-01-01

    Waldenström's macroglobulinemia (WM) is a B-cell non-Hodgkin's lymphoma (B-NHL) characterized by immunoglobulin M (IgM) monoclonal gammopathy and the medullary expansion of clonal lymphoplasmacytic cells. Neoplastic transformation has been partially attributed to hyperactive MYD88 signaling, secondary to the MYD88 L265P mutation, occurring in the majority of WM patients. Nevertheless, the presence of chronic active B-cell receptor (BCR) signaling, a feature of multiple IgM+ B-NHL, remains a subject of speculation in WM. Here, we interrogated the BCR signaling capacity of primary WM cells by utilizing multiparametric phosphoflow cytometry and found heightened basal phosphorylation of BCR-related signaling proteins, and augmented phosphoresponses on surface IgM (sIgM) crosslinking, compared with normal B cells. In support of those findings we observed high sIgM expression and loss of phosphatase activity in WM cells, which could both lead to signaling potentiation in clonal cells. Finally, led by the high-signaling heterogeneity among WM samples, we generated patient-specific phosphosignatures, which subclassified patients into a ‘high' and a ‘healthy-like' signaling group, with the second corresponding to patients with a more indolent clinical phenotype. These findings support the presence of chronic active BCR signaling in WM while providing a link between differential BCR signaling utilization and distinct clinical WM subgroups. PMID:26867669

  5. Addition of an Indoleamine-2,3,-dioxygenase Inhibitor to B cell Depletion Therapy Blocks Autoreactive B Cell Activation and Recurrence of Arthritis

    PubMed Central

    Pigott, Elizabeth; Mandik-Nayak, Laura

    2012-01-01

    Objective Define the role indoleamine-2,3-dioxygenase (IDO) plays in driving pathogenic B cells responses leading to arthritis and determine if inhibitors of the IDO pathway can be used in conjunction with B cell depletion therapy to prevent the re-emergence of autoantibodies and arthritis following reconstitution of the B cell repertoire. Methods Immunoglobulin transgenic mice were treated with the IDO inhibitor 1-methyl-tryptophan (1MT) and followed for the extent of autoreactive B cell activation. Arthritic mice (K/BxN) were treated with B cell depletion therapy alone or in combination with 1MT. Mice were followed for the presence of autoantibody secreting cells, inflammatory cytokines, and joint inflammation. Results 1MT did not affect the initial activation or survival of autoreactive B cells, but did inhibit their ability to differentiate into autoantibody secreting cells. Treatment with anti-CD20 depleted the B cell repertoire and attenuated arthritis symptoms; however, arthritis symptoms rapidly returned as B cells repopulated the repertoire. Administration of 1MT prior to B cell repopulation prevented the production of autoantibodies, inflammatory cytokines, and flare in arthritis symptoms. Conclusion IDO activity is essential for the differentiation of autoreactive B cells into antibody secreting cells, but is not necessary for their initial stages of activation. Addition of 1MT to B cell depletion therapy prevents the differentiation of autoantibody secreting cells and recurrence of autoimmune arthritis following reconstitution of the B cell repertoire. These data suggest that IDO inhibitors could be used in conjunction with B cell depletion as an effective co-therapeutic strategy in the treatment of rheumatoid arthritis. PMID:22294267

  6. Optimization of a human IgG B-cell ELISpot assay for the analysis of vaccine-induced B-cell responses.

    PubMed

    Jahnmatz, Maja; Kesa, Gun; Netterlid, Eva; Buisman, Anne-Marie; Thorstensson, Rigmor; Ahlborg, Niklas

    2013-05-31

    B-cell responses after infection or vaccination are often measured as serum titers of antigen-specific antibodies. Since this does not address the aspect of memory B-cell activity, it may not give a complete picture of the B-cell response. Analysis of memory B cells by ELISpot is therefore an important complement to conventional serology. B-cell ELISpot was developed more than 25 years ago and many assay protocols/reagents would benefit from optimization. We therefore aimed at developing an optimized B-cell ELISpot for the analysis of vaccine-induced human IgG-secreting memory B cells. A protocol was developed based on new monoclonal antibodies to human IgG and biotin-avidin amplification to increase the sensitivity. After comparison of various compounds commonly used to in vitro-activate memory B cells for ELISpot analysis, the TLR agonist R848 plus interleukin (IL)-2 was selected as the most efficient activator combination. The new protocol was subsequently compared to an established protocol, previously used in vaccine studies, based on polyclonal antibodies without biotin avidin amplification and activation of memory B-cells using a mix of antigen, CpG, IL-2 and IL-10. The new protocol displayed significantly better detection sensitivity, shortened the incubation time needed for the activation of memory B cells and reduced the amount of antigen required for the assay. The functionality of the new protocol was confirmed by analyzing specific memory B cells to five different antigens, induced in a limited number of subjects vaccinated against tetanus, diphtheria and pertussis. The limited number of subjects did not allow for a direct comparison with other vaccine studies. Optimization of the B-cell ELISpot will facilitate an improved analysis of IgG-secreting B cells in vaccine studies.

  7. Regulatory B cells in human inflammatory and autoimmune diseases: from mouse models to clinical research.

    PubMed

    Miyagaki, Tomomitsu; Fujimoto, Manabu; Sato, Shinichi

    2015-10-01

    B cells have been generally considered to be positive regulators of immune responses because of their ability to produce antigen-specific antibodies and to activate T cells through antigen presentation. Impairment of B cell development and function may cause inflammatory and autoimmune diseases. Recently, specific B cell subsets that can negatively regulate immune responses have been described in mouse models of a wide variety of inflammatory and autoimmune diseases. The concept of those B cells, termed regulatory B cells, is now recognized as important in the murine immune system. Among several regulatory B cell subsets, IL-10-producing regulatory B cells are the most widely investigated. On the basis of discoveries from studies of such mice, human regulatory B cells that produce IL-10 in most cases are becoming an active area of research. There have been emerging data suggesting the importance of human regulatory B cells in various diseases. Revealing the immune regulation mechanisms of human regulatory B cells in human inflammatory and autoimmune diseases could lead to the development of novel B cell targeted therapies. This review highlights the current knowledge on regulatory B cells, mainly IL-10-producing regulatory B cells, in animal models of inflammatory and autoimmune diseases and in clinical research using human samples.

  8. Unraveling Effector Functions of B Cells During Infection: The Hidden World Beyond Antibody Production

    PubMed Central

    León, Beatriz; Ballesteros-Tato, André; Misra, Ravi S.; Wojciechowski, Wojciech; Lund, Frances E.

    2015-01-01

    Antibodies made by B cells are critically important for immune protection to a variety of infectious agents. However, it is becoming increasingly clear that B cells do more than make antibodies and that B cells can both enhance and suppress immune responses. Furthermore, there is growing evidence that B cells modulate cellular immune responses by antibody dependent and independent mechanisms. Although we have a good understanding of the roles played by antibody-secreting effector B cells during immune responses, we know very little about the Ab independent “effector” functions of B cells in either health or disease. Given the recent data suggesting that B cells may contribute to autoimmune disease pathogenesis via an antibody independent mechanism and the increasing use of B cell depletion therapy in autoimmune patients, investigators are beginning to reassess the multiple roles for B cells during immune responses. In this article, we review data describing how B cells mediate protection to pathogens independently of antibody production. In particular, we will focus on the role that B cells play in facilitating dendritic cell and T cell interactions in lymph nodes, the importance of antigen-presenting B cells in sustaining effector T cell and T follicular helper responses to pathogens and the relevance of cytokine-producing effector and regulatory B cells in immune responses. PMID:22394173

  9. CD47 limits antibody dependent phagocytosis against non-malignant B cells.

    PubMed

    Gallagher, Sandra; Turman, Sean; Lekstrom, Kristen; Wilson, Susan; Herbst, Ronald; Wang, Yue

    2017-05-01

    Recent studies have demonstrated the importance of CD47 in protecting malignant B cells from antibody dependent cellular phagocytosis (ADCP). Combined treatment of anti-CD47 and -CD20 antibodies synergistically augment elimination of tumor B cells in xenograft mouse models. This has led to the development of novel reagents that can potentially enhance killing of malignant B cells in patients. B cell depleting therapy is also a promising treatment for autoimmune patients. In the current study, we aimed to investigate whether or not CD47 protects non-malignant B cells from ADCP. We show that CD47 is expressed on all B cells in mice, with the highest level on plasma cells in bone marrow and spleen. Although its expression is dispensable for B cell development in mice, CD47 on B cells limits antibody mediated phagocytosis. B cell depletion following in vivo anti-CD19 treatment is more efficient in CD47-/- mice than in wild type mice. In vitro, both naïve and activated B cells from CD47-/- mice are more sensitive to ADCP than wild type B cells. Lastly, we show in an ADCP assay that blocking CD47 can enhance anti-CD19 antibody mediated phagocytosis of wild type B cells. These results suggest that in addition to its already demonstrated benefit in cancer, targeting CD47 may be used as an adjunct in combination with B cell depletion antibodies for treatment of autoimmune diseases.

  10. CD22 is required for formation of memory B cell precursors within germinal centers

    PubMed Central

    Chappell, Craig P.; Draves, Kevin E.

    2017-01-01

    CD22 is a BCR co-receptor that regulates B cell signaling, proliferation and survival and is required for T cell-independent Ab responses. To investigate the role of CD22 during T cell-dependent (TD) Ab responses and memory B cell formation, we analyzed Ag-specific B cell responses generated by wild-type (WT) or CD22-/- B cells following immunization with a TD Ag. CD22-/- B cells mounted normal early Ab responses yet failed to generate either memory B cells or long-lived plasma cells, whereas WT B cells formed both populations. Surprisingly, B cell expansion and germinal center (GC) differentiation were comparable between WT and CD22-/- B cells. CD22-/- B cells, however, were significantly less capable of generating a population of CXCR4hiCD38hi GC B cells, which we propose represent memory B cell precursors within GCs. These results demonstrate a novel role for CD22 during TD humoral responses evident during primary GC formation and underscore that CD22 functions not only during B cell maturation but also during responses to both TD and T cell-independent antigens. PMID:28346517

  11. Nivolumab With or Without Varlilumab in Treating Patients With Relapsed or Refractory Aggressive B-cell Lymphomas

    ClinicalTrials.gov

    2017-03-13

    Activated B-Cell-Like Diffuse Large B-Cell Lymphoma; ALK-Positive Large B-Cell Lymphoma; Atypical Burkitt/Burkitt-Like Lymphoma; Diffuse Large B-Cell Lymphoma Associated With Chronic Inflammation; Diffuse Large B-Cell Lymphoma, Not Otherwise Specified; Epstein-Barr Virus Positive Diffuse Large B-Cell Lymphoma of the Elderly; Epstein-Barr Virus-Positive Mucocutaneous Ulcer; Germinal Center B-Cell-Like Diffuse Large B-Cell Lymphoma; High-Grade B-Cell Lymphoma With MYC and BCL2 and/or BCL6 Rearrangements; Human Herpesvirus-8-Positive Neoplastic Cells Present; Intravascular Large B-Cell Lymphoma; MYC-Negative B-Cell Lymphoma With 11q Aberration Resembling Burkitt Lymphoma; Plasmablastic Lymphoma; Primary Cutaneous Diffuse Large B-Cell Lymphoma; Primary Cutaneous Diffuse Large B-Cell Lymphoma, Leg Type; Primary Diffuse Large B-Cell Lymphoma of the Central Nervous System; Primary Effusion Lymphoma; Recurrent Adult Burkitt Lymphoma; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Lymphomatoid Granulomatosis; Recurrent Mediastinal (Thymic) Large B-Cell Cell Lymphoma; Refractory Burkitt Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Refractory Mediastinal (Thymic) Large B-Cell Cell Lymphoma; Skin Ulcer; Small Intestinal B-Cell Lymphoma, Unclassifiable, With Features Intermediate Between Diffuse Large B-Cell Lymphoma and Burkitt Lymphoma; T-Cell/Histiocyte-Rich Large B-Cell Lymphoma

  12. Lung B cells promote early pathogen dissemination and hasten death from inhalation anthrax.

    PubMed

    Rayamajhi, M; Delgado, C; Condon, T V; Riches, D W; Lenz, L L

    2012-07-01

    Sampling of mucosal antigens regulates immune responses but may also promote dissemination of mucosal pathogens. Lung dendritic cells (LDCs) capture antigens and traffic them to lung-draining lymph nodes (LDLNs) dependent on the chemokine receptor CCR7 (chemokine (C-C motif) receptor 7). LDCs also capture lung pathogens such as Bacillus anthracis (BA). However, we show here that the initial traffic of BA spores from lungs to LDLNs is largely independent of LDCs and CCR7, occurring instead in association with B cells. BA spores rapidly bound B cells in lungs and cultured mouse and human B cells. Binding was independent of the B-cell receptor (BCR). B cells instilled in the lungs trafficked to LDLNs and BA spore traffic to LDLNs was impaired by B-cell deficiency. Depletion of B cells also delayed death of mice receiving a lethal BA infection. These results suggest that mucosal B cells traffic BA, and possibly other antigens, from lungs to LDLNs.

  13. Distinct functions for the transcription factor Foxo1 at various stages of B cell differentiation.

    PubMed

    Dengler, Hart S; Baracho, Gisele V; Omori, Sidne A; Bruckner, Shane; Arden, Karen C; Castrillon, Diego H; DePinho, Ronald A; Rickert, Robert C

    2008-12-01

    The transcription factors Foxo1, Foxo3 and Foxo4 modulate cell fate 'decisions' in diverse systems. Here we show that Foxo1-dependent gene expression was critical at many stages of B cell differentiation. Early deletion of Foxo1 caused a substantial block at the pro-B cell stage due to a failure to express interleukin 7 receptor-alpha. Foxo1 inactivation in late pro-B cells resulted in an arrest at the pre-B cell stage due to lower expression of the recombination-activating genes Rag1 and Rag2. Deletion of Foxo1 in peripheral B cells led to fewer lymph node B cells due to lower expression of L-selectin and failed class-switch recombination due to impaired upregulation of the gene encoding activation-induced cytidine deaminase. Thus, Foxo1 regulates a transcriptional program that is essential for early B cell development and peripheral B cell function.

  14. Essential Role for Survivin in the Proliferative Expansion of Progenitor and Mature B Cells.

    PubMed

    Miletic, Ana V; Jellusova, Julia; Cato, Matthew H; Lee, Charlotte R; Baracho, Gisele V; Conway, Edward M; Rickert, Robert C

    2016-03-01

    Survivin is a member of the inhibitor of apoptosis family of proteins and a biomarker of poor prognosis in aggressive B cell non-Hodgkin's lymphoma. In addition to its role in inhibition of apoptosis, survivin also regulates mitosis. In this article, we show that deletion of survivin during early B cell development results in a complete block at the cycling pre-B stage. In the periphery, B cell homeostasis is not affected, but survivin-deficient B cells are unable to mount humoral responses. Correspondingly, we show that survivin is required for cell division in response to mitogenic stimulation. Thus, survivin is essential for proliferation of B cell progenitors and activated mature B cells, but is dispensable for B cell survival. Moreover, a small-molecule inhibitor of survivin strongly impaired the growth of representative B lymphoma lines in vitro, supporting the validity of survivin as an attractive therapeutic target for high-grade B cell non-Hodgkin's lymphoma.

  15. MicroRNAs, Major Players in B Cells Homeostasis and Function

    PubMed Central

    Danger, Richard; Braza, Faouzi; Giral, Magali; Soulillou, Jean-Paul; Brouard, Sophie

    2014-01-01

    As a main actor in humoral immunity, B cells participate in various antibody-related disorders. However, a deeper understanding of B-cell differentiation and function is needed in order to decipher their immune-modulatory roles, notably with the recent highlighting of regulatory B cells. microRNAs (miRNAs), key factors in various biological and pathological processes, have been shown to be essential for B-cell homeostasis, and therefore understanding their participation in B-cell biology could help identify biomarkers and contribute toward curing B-cell-related immune disorders. This review aims to report studies casting light on the roles played by miRNAs in B-cell lineage and function and B-cell-related immune pathologies. PMID:24653724

  16. Mucosal immunoglobulins and B cells of teleost fish.

    PubMed

    Salinas, Irene; Zhang, Yong-An; Sunyer, J Oriol

    2011-12-01

    As physical barriers that separate teleost fish from the external environment, mucosae are also active immunological sites that protect them against exposure to microbes and stressors. In mammals, the sites where antigens are sampled from mucosal surfaces and where stimulation of naïve T and B lymphocytes occurs are known as inductive sites and are constituted by mucosa-associated lymphoid tissue (MALT). According to anatomical location, the MALT in teleost fish is subdivided into gut-associated lymphoid tissue (GALT), skin-associated lymphoid tissue (SALT), and gill-associated lymphoid tissue (GIALT). All MALT contain a variety of leukocytes, including, but not limited to, T cells, B cells, plasma cells, macrophages and granulocytes. Secretory immunoglobulins are produced mainly by plasmablasts and plasma cells, and play key roles in the maintenance of mucosal homeostasis. Until recently, teleost fish B cells were thought to express only two classes of immunoglobulins, IgM and IgD, in which IgM was thought to be the only one responding to pathogens both in systemic and mucosal compartments. However, a third teleost immunoglobulin class, IgT/IgZ, was discovered in 2005, and it has recently been shown to behave as the prevalent immunoglobulin in gut mucosal immune responses. The purpose of this review is to summarise the current knowledge of mucosal immunoglobulins and B cells of fish MALT. Moreover, we attempt to integrate the existing knowledge on both basic and applied research findings on fish mucosal immune responses, with the goal to provide new directions that may facilitate the development of novel vaccination strategies that stimulate not only systemic, but also mucosal immunity.

  17. Mucosal immunoglobulins and B cells of Teleost fish

    PubMed Central

    Salinas, Irene; Zhang, Yong-An; Sunyer, J. Oriol

    2012-01-01

    As physical barriers that separate teleost fish from the external environment, mucosae are also active immunological sites that protect them against exposure to microbes and stressors. In mammals, the sites where antigens are sampled from mucosal surfaces and where stimulation of naive T and B lymphocytes occurs are known as inductive sites and are constituted by mucosa-associated lymphoid tissue (MALT). According to anatomical location, the MALT in teleost fish is subdivided into gut-associated lymphoid tissue (GALT), skin-associated lymphoid tissue (SALT), and gill-associated lymphoid tissue (GIALT). All MALT contain a variety of leukocytes, including, but not limited to, T cells, B cells, plasma cells, macrophages and granulocytes. Secretory immunoglobulins are produced mainly by plasmablasts and plasma cells, and play key roles in the maintenance of mucosal homeostasis. Until recently, teleost fish B cells were thought to express only two classes of immunoglobulins, IgM and IgD, in which IgM was thought to be the only one responding to pathogens both in systemic and mucosal compartments. However, a third teleost immunoglobulin class, IgT/IgZ, was discovered in 2005, and it has recently been shown to behave as the prevalent immunoglobulin in gut mucosal immune responses. The purpose of this review is to summarise the current knowledge of mucosal immunoglobulins and B cells of fish MALT. Moreover, we attempt to integrate the existing knowledge on both basic and applied research findings on fish mucosal immune responses, with the goal to provide new directions that may facilitate the development of novel vaccination strategies that stimulate not only systemic, but also mucosal immunity. PMID:22133710

  18. Primary non-hodgkin B cell lymphoma in a man.

    PubMed

    Alhabshi, Sh M I; Ismail, Z; Arasaratnam, Sh A

    2011-03-01

    Malignant breast lymphoma is a rare condition and primary breast lymphoma is extremely rare in the male population. We present a case of a 26-year-old man (transgender) who presented with a large palpable mass in the right breast. This mass was rapidly growing in size associated with right axillary lymphadenopathy. Ultrasound and MRI findings were consistent with BIRADS IV lesion which was suspicious of malignancy. Core biopsy was performed and histopathology confirmed the diagnosis of primary non Hodgkin B cell lymphoma of the breast.

  19. Hepatitis C virus - associated B cell non-Hodgkin's lymphoma

    PubMed Central

    Mihăilă, Romeo-Gabriel

    2016-01-01

    The hepatitis C virus (HCV) infected patients are prone to develop bone marrow or various tissue infiltrates with monoclonal B cells, monoclonal B lymphocytosis or different types of B cell non-Hodgkin’s lymphoma (BCNHL), of which the most common are splenic marginal zone BCNHL, diffuse large BCNHL and follicular lymphoma. The association between chronic HCV infection and non Hodgkin’s lymphoma has been observed especially in areas with high prevalence of this viral infection. Outside the limitations of some studies that have been conducted, there are also geographic, environmental, and genetic factors that contribute to the epidemiological differences. Various microenvironmental signals, such as cytokines, viral antigenic external stimulation of lymphocyte receptors by HCV antigens, and intercellular interactions contribute to B cell proliferation. HCV lymphotropism and chronic antigenic stimulation are involved in B-lymphocyte expansion, as mixted cryoglobulinemia or monoclonal gammopathy of undetermined significance, which can progress to BCNHL. HCV replication in B lymphocytes has oncogenic effect mediated by intracellular HCV proteins. It is also involved in an important induction of reactive oxygen species that can lead to permanent B lymphocyte damage, as DNA mutations, after binding to surface B-cell receptors. Post-transplant lymphoproliferative disorder could appear and it has a multiclonal potentiality that may develop into different types of lymphomas. The hematopoietic stem cell transplant made for lymphoma in HCV-infected patients can increase the risk of earlier progression to liver fibrosis and cirrhosis. HCV infected patients with indolent BCNHL who receive antiviral therapy can be potentially cured. Viral clearance was related to lymphoma response, fact that highlights the probable involvement of HCV in lymphomagenesis. Direct acting antiviral drugs could be a solution for the patients who did not tolerate or respond to interferon, as they

  20. [Effect of Ikaros in B Cell Acute Lymphoblastic Leukemia].

    PubMed

    Zhang, Hai-Ying; Bai, Hai

    2015-08-01

    The Ikaros - a DNA-binding zinc finger protein, acting as a regulator of chromatin remodeling and gene transcription, is crucial for regulating the development and function of the immune system and acting as a master regulator of hematopoietic differentiation. Function-loss mutations of IKZF1, gene encoding Ikaros are frequent in B cell acute lymphoblastic leukemia (B-ALL) and are associated with a poor prognosis. This review briefly summarizes the available data regarding the structure and function of Ikaros, the role of Ikaros as a tumor suppressor in B-ALL, and its regulation mechanism.

  1. [Intravascular large B-cell lymphoma with massive pulmonary lesions].

    PubMed

    Higashiyama, Asumi; Hashino, Satoshi; Onozawa, Masahiro; Takahata, Mutsumi; Okada, Kohei; Kahata, Kaoru; Taniguchi, Natsuko; Nasuhara, Yasuyuki; Kubota, Kanako; Fujimoto, Nozomu; Matsuno, Yoshihiro; Nishimura, Masahiro; Asaka, Masahiro

    2010-05-01

    A 61-year-old man was admitted to our hospital with dyspnea on effort. Neither computed tomography scan nor chest X-ray film detected any specific findings that could explain hypoxemia. Since (67)Ga scintigraphy showed abnormal uptake in the bilateral lungs, transbronchial lung biopsy (TBLB) was performed. The TBLB specimen was diagnosed as intravascular large B-cell lymphoma (IVLBCL). There was no involvement of any other organ considered typical of IVLBCL. In cases showing clinical findings such as hypoxia despite mild pulmonary radiographic changes, a definitive diagnosis should be made using methods such as TBLB with consideration given to the possibility of IVLBCL.

  2. Anti-CDR3 Therapy for B-Cell Malignancies

    DTIC Science & Technology

    2013-10-01

    MONITORING AGENCY NAME(S) AND ADDRESS(ES) US Army Medical Material Ft Detrick, MD 21702-5012 10. SPONSOR/MONITOR’S ACRONYM(S) USAMRAA 11...1-5 in the report). The "Tomlinson" human antibody phage library will be used to pan for antibodies that bind these target CDR3s and not the parent...Supporting Data……………………………………………………………………… 16 3 INTRODUCTION: In the US the incidence of newly diagnosed B-cell leukemias

  3. Subepithelial B cells in the human palatine tonsil. II. Functional characterization.

    PubMed

    Dono, M; Zupo, S; Augliera, A; Burgio, V L; Massara, R; Melagrana, A; Costa, M; Grossi, C E; Chiorazzi, N; Ferrarini, M

    1996-09-01

    This study investigates the main functional features of subepithelial (SE) B cells and compares them with those of purified germinal center (GC) and follicular mantle (FM) B cells isolated from the same tonsils. Unlike FM B cells, SE B cells failed to produce polyspecific antibodies in vitro; unlike GC B cells, SE B cells expressed high levels of Bcl-2 and failed to undergo spontaneous apoptosis in vitro. The most striking function of SE B cells was their ability to produce IgM antibodies to T cell-independent type-2 (TI-2) (but not to TI-1) antigens (Ag). These antibodies could not be detected when both FM and GC B cells were stimulated with TI-2 Ag in vitro. Moreover, B cells isolated from peripheral blood were unable to mount a response to TI-2 Ag. The latter finding is consistent with the observation that B cells with the phenotypic features of SE B cells were virtually absent in the peripheral blood and emphasizes the notion that SE B cells belong to a subset of non-recirculating B cells. SE B cells were by far superior to FM B cells in mixed lymphocyte reaction (MLR) stimulation of allogeneic T cells in vitro, although they were not as efficient as dendritic cells (DC). In order to stimulate T cells efficiently, SE B cells had to be exposed to anti-mu antibody, a treatment which induced expression of activation markers such as CD80, CD86, CD69 and CD39, usually absent in resting SE B cells. CD80 and CD86 molecules expressed by SE B cells participated in the chain of events required to promote the proliferation of allogeneic T cells as demonstrated by inhibition tests with the appropriate mAb. The expression of CD80 and CD86 by anti-mu-treated SE B cells was not, however, the sole explanation for their good antigen presenting capacities since the exposure of FM B cells to anti-mu antibody also induced expression of these surface structures. Nevertheless, these cells failed to become good MLR stimulators. Collectively, the above data contribute further to the

  4. B-cell activation in cats with feline infectious peritonitis (FIP) by FIP-virus-induced B-cell differentiation/survival factors.

    PubMed

    Takano, Tomomi; Azuma, Natsuko; Hashida, Yoshikiyo; Satoh, Ryoichi; Hohdatsu, Tsutomu

    2009-01-01

    It has been suggested that antibody overproduction plays a role in the pathogenesis of feline infectious peritonitis (FIP). However, only a few studies on the B-cell activation mechanism after FIP virus (FIPV) infection have been reported. The present study shows that: (1) the ratio of peripheral blood sIg(+) CD21(-) B-cells was higher in cats with FIP than in SPF cats, (2) the albumin-to-globulin ratio has negative correlation with the ratio of peripheral blood sIg(+) CD21(-) B-cell, (3) cells strongly expressing mRNA of the plasma cell master gene, B-lymphocyte-induced maturation protein 1 (Blimp-1), were increased in peripheral blood in cats with FIP, (4) mRNA expression of B-cell differentiation/survival factors, IL-6, CD40 ligand, and B-cell-activating factor belonging to the tumor necrosis factor family (BAFF), was enhanced in macrophages in cats with FIP, and (5) mRNAs of these B-cell differentiation/survival factors were overexpressed in antibody-dependent enhancement (ADE)-induced macrophages. These data suggest that virus-infected macrophages overproduce B-cell differentiation/survival factors, and these factors act on B-cells and promote B-cell differentiation into plasma cells in FIPV-infected cats.

  5. Spontaneous follicular exclusion of SHP1-deficient B cells is conditional on the presence of competitor wild-type B cells.

    PubMed

    Schmidt, K N; Hsu, C W; Griffin, C T; Goodnow, C C; Cyster, J G

    1998-03-16

    Engagement of antigen receptors on mature B lymphocytes is known to block cell entry into lymphoid follicles and promote accumulation in T cell zones, yet the molecular basis for this change in cell distribution is not understood. Previous studies have shown that follicular exclusion requires a threshold level of antigen receptor engagement combined with occupancy of follicles by B cells without equivalent receptor engagement. The possibility has been raised that follicular composition affects B cell positioning by altering the amount of available antigen and the degree of receptor occupancy. Here we show that follicular composition affects migration of mature B cells under conditions that are independent of antigen receptor occupancy. B cells deficient in the negative regulatory protein tyrosine phosphatase, SHP1, which have elevated intracellular signaling by the B cell receptor, are shown to accumulate in the T zone in the absence of their specific antigen. Follicular exclusion of SHP1-deficient B cells was found to be conditional on the presence of excess B cells that lack elevated intracellular signaling, and was not due to a failure of SHP-1-deficient cells to mature and express the follicle-homing chemokine receptor Burkitt's lymphoma receptor 1. These findings strongly suggest that signals that are negatively regulated by SHP1 promote B cell localization in T cell zones by reducing competitiveness for follicular entry, and provide further evidence that follicular composition influences the positioning of antigen-engaged B cells.

  6. Isolation and characterization of HIV-1 envelope glycoprotein specific B cell from immortalized human naïve B cell library.

    PubMed

    Sun, Zehua; Lu, Shiqiang; Yang, Zheng; Li, Jingjing; Zhang, Meiyun

    2017-01-10

    With the recent development of single B cell cloning techniques, an increasing number of HIV-1-specific broadly neutralizing antibodies (bNAbs) have been isolated since 2009. However, knowledge regarding HIV-1-specific B cells in vivo is limited. In this study, an HIV-1-specific B cell line has been established using healthy PBMC donors by the highly efficient EBV transformation method to generate immortalized human naïve B cell libraries. The enrichment of HIV-1 envelope-specific B cells was observed after four rounds of cell panning with the HIV-1 envelope glycoprotein. An HIV-1 envelope-specific stable B cell line (LCL-P4) was generated. Although this cell line acquired a lymphoblastic phenotype, no expression was observed for activation-induced cytidine deaminase (AID), an enzyme responsible for initiating somatic hypermutation and class switch recombination in B cells. This study describes a method that enables fast isolation of HIV-1-specific B cells, and this approach may extend to isolating other B cell-specific antigens for further experiments.

  7. Hepatitis C virus upregulates B-cell receptor signaling: a novel mechanism for HCV-associated B-cell lymphoproliferative disorders

    PubMed Central

    Dai, B; Chen, A Y; Corkum, C P; Peroutka, R J; Landon, A; Houng, S; Muniandy, P A; Zhang, Y; Lehrmann, E; Mazan-Mamczarz, K; Steinhardt, J; Shlyak, M; Chen, Q C; Becker, K G; Livak, F; Michalak, T I; Talwani, R; Gartenhaus, R B

    2016-01-01

    B-cell receptor (BCR) signaling is essential for the development of B cells and has a critical role in B-cell neoplasia. Increasing evidence indicates an association between chronic hepatitis C virus (HCV) infection and B-cell lymphoma, however, the mechanisms by which HCV causes B-cell lymphoproliferative disorder are still unclear. Herein, we demonstrate the expression of HCV viral proteins in B cells of HCV-infected patients and show that HCV upregulates BCR signaling in human primary B cells. HCV nonstructural protein NS3/4A interacts with CHK2 and downregulates its activity, modulating HuR posttranscriptional regulation of a network of target mRNAs associated with B-cell lymphoproliferative disorders. Interestingly, the BCR signaling pathway was found to have the largest number of transcripts with increased association with HuR and was upregulated by NS3/4A. Our study reveals a previously unidentified role of NS3/4A in regulation of host BCR signaling during HCV infection, contributing to a better understanding of the molecular mechanisms underlying HCV-associated B-cell lymphoproliferative disorders. PMID:26434584

  8. Requirement for three signals in B cell responses. II. Analysis of antigen- and Ia-restricted T helper cell-B cell interaction

    PubMed Central

    1982-01-01

    We have recently reported that resting B cells must receive at least three different signals in a T helper cell (TH)-dependent as well as in a lipopolysaccharide (LPS)-induced B cell response (3), i.e., a specific TH signal (that can be bypassed by LPS), a nonspecific TH signal (mediated by Ia or antigen-nonspecific B cell helper factor), and an antigen (hapten) signal. In a system using male (H-Y) antigen- specific cloned TH of C57BL/6 origin and male (or female) B cells, we now confirm and extend these findings by demonstrating that H-Y- specific TH must see both H-Y and Ia determinants on the B cells (and not only on macrophages) to provide the first specific TH signal required for a plaque-forming cell (PFC) response. This signal was interfered with by a monoclonal anti-I-Ab antibody at the B cell level, was not mediated by detectable soluble factors (in contrast to the nonspecific signal also provided by the TH), and could be bypassed by LPS, in which case anti-I-Ab antibody had no effect. However, although the H-Y-specific TH induced a polyclonal PFC response (B cell differentiation) in the apparent absence of an antigen seen by the B cells, significant clonal expansion of PFC precursors occurred only when the B cells also recognized an antigen (hapten). PMID:6980255

  9. Regulatory B cells preferentially accumulate in tumor-draining lymph nodes and promote tumor growth.

    PubMed

    Ganti, Sheila N; Albershardt, Tina C; Iritani, Brian M; Ruddell, Alanna

    2015-07-20

    Our previous studies found that B16-F10 melanoma growth in the rear footpad of immunocompetent mice induces marked B cell accumulation within tumor-draining popliteal lymph nodes (TDLN). This B cell accumulation drives TDLN remodeling that precedes and promotes metastasis, indicating a tumor-promoting role for TDLN B cells. Here we show that phenotypic characterization of lymphocytes in mice bearing B16-F10 melanomas identifies preferential accumulation of T2-MZP B cells in the TDLN. Comparison of non-draining LNs and spleens of tumor-bearing mice with LNs and spleens from naïve mice determined that this pattern of B cell accumulation was restricted to the TDLN. B cell-deficient and immunocompetent mice reconstituted with T2-MZP B cells but not with other B cell subsets displayed accelerated tumor growth, demonstrating that T2-MZP B cells possess regulatory activity in tumor-bearing mice. Unlike splenic regulatory B cells, however, these TDLN B cells did not exhibit increased IL-10 production, nor did they promote Treg generation in the TDLN. These findings demonstrate that tumors initially signal via the lymphatic drainage to stimulate the preferential accumulation of T2-MZP regulatory B cells. This local response may be an early and critical step in generating an immunosuppressive environment to permit tumor growth and metastasis.

  10. Germinal center B cells regulate their capability to present antigen by modulation of HLA-DO.

    PubMed

    Glazier, Kim S; Hake, Sandra B; Tobin, Helen M; Chadburn, Amy; Schattner, Elaine J; Denzin, Lisa K

    2002-04-15

    Peptide acquisition by MHC class II molecules is catalyzed by HLA-DM (DM). In B cells, HLA-DO (DO) inhibits or modifies the peptide exchange activity of DM. We show here that DO protein levels are modulated during B cell differentiation. Remarkably, germinal center (GC) B cells, which have low levels of DO relative to naive and memory B cells, are shown to have enhanced antigen presentation capabilities. DM protein levels also were somewhat reduced in GC B cells; however, the ratio of DM to DO in GC B cells was substantially increased, resulting in more free DM in GC B cells. We conclude that modulation of DM and DO in distinct stages of B cell differentiation represents a mechanism by which B cells regulate their capacity to function as antigen-presenting cells. Efficient antigen presentation in GC B cells would promote GC B cell-T cell interactions that are essential for B cells to survive positive selection in the GC.

  11. Downregulation of FOXP1 is required during germinal center B-cell function

    PubMed Central

    Sagardoy, Ainara; Martinez-Ferrandis, Jose I.; Roa, Sergio; Bunting, Karen L.; Aznar, María Angela; Elemento, Olivier; Shaknovich, Rita; Fontán, Lorena; Fresquet, Vicente; Perez-Roger, Ignacio; Robles, Eloy F.; De Smedt, Linde; Sagaert, Xavier

    2013-01-01

    B-cell maturation and germinal center (GC) formation are dependent on the interplay between BCL6 and other transcriptional regulators. FOXP1 is a transcription factor that regulates early B-cell development, but whether it plays a role in mature B cells is unknown. Analysis of human tonsillar B-cell subpopulations revealed that FOXP1 shows the opposite expression pattern to BCL6, suggesting that FOXP1 regulates the transition from resting follicular B cell to activated GC B cell. Chromatin immunoprecipitation-on-chip and gene expression assays on B cells indicated that FOXP1 acts as a transcriptional activator and repressor of genes involved in the GC reaction, half of which are also BCL6 targets. To study FOXP1 function in vivo, we developed transgenic mice expressing human FOXP1 in lymphoid cells. These mice exhibited irregular formation of splenic GCs, showing a modest increase in naïve and marginal-zone B cells and a significant decrease in GC B cells. Furthermore, aberrant expression of FOXP1 impaired transcription of noncoding γ1 germline transcripts and inhibited efficient class switching to the immunoglobulin G1 isotype. These studies show that FOXP1 is physiologically downregulated in GC B cells and that aberrant expression of FOXP1 impairs mechanisms triggered by B-cell activation, potentially contributing to B-cell lymphomagenesis. PMID:23580662

  12. B cells have distinct roles in host protection against different nematode parasites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    B cells may mediate protective responses against nematode parasites by supporting Th2 cell development and/or by producing antibodies. To examine this, B cell-deficient mice were inoculated with Nippostrongylus brasiliensis (Nb) or Heligmosomoides polygyrus (Hp). B cell-deficient and wild type (WT...

  13. Decoupling activation and exhaustion of B cells in spontaneous controllers of HIV infection

    PubMed Central

    Sciaranghella, Gaia; Tong, Neath; Mahan, Alison E.; Suscovich, Todd J.; Alter, Galit

    2013-01-01

    Objective To define the impact of chronic viremia and associated immune activation on B-cell exhaustion in HIV infection. Design Progressive HIV infection is marked by B-cell anergy and exhaustion coupled with dramatic hypergammaglobulinemia. Although both upregulation of CD95 and loss of CD21 have been used as markers of infection-associated B-cell dysfunction, little is known regarding the specific profiles of dysfunctional B cells and whether persistent viral replication and its associated immune activation play a central role in driving B-cell dysfunction. Methods Multiparameter flow cytometry was used to define the profile of dysfunctional B cells. The changes in the expression of CD21 and CD95 were tracked on B-cell subpopulations in patients with differential control of viral replication. Results Although the emergence of exhausted, CD21low tissue-like memory B cells followed similar patterns in both progressors and controllers, the frequency of CD21low activated memory B cells was lower in spontaneous controllers. Conclusion Our results suggest that the loss of CD21 and the upregulation of CD95 occur as separate events during the development of B-cell dysfunction. The loss of CD21 is a marker of B-cell exhaustion induced in the absence of appreciable viral replication, whereas the upregulation of CD95 is tightly linked to persistent viral replication and its associated immune activation. Thus, these dysfunctional profiles potentially represent two functionally distinct states within the B-cell compartment. PMID:23135171

  14. Inhibition of demethylase KDM6B sensitizes diffuse large B-cell lymphoma to chemotherapeutic drugs

    PubMed Central

    Mathur, Rohit; Sehgal, Lalit; Havranek, Ondrej; Köhrer, Stefan; Khashab, Tamer; Jain, Neeraj; Burger, Jan A.; Neelapu, Sattva S.; Davis, R. Eric; Samaniego, Felipe

    2017-01-01

    Histone methylation and demethylation regulate B-cell development, and their deregulation correlates with tumor chemoresistance in diffuse large B-cell lymphoma, limiting cure rates. Since histone methylation status correlates with disease aggressiveness and relapse, we investigated the therapeutic potential of inhibiting histone 3 Lys27 demethylase KDM6B, in vitro, using the small molecule inhibitor GSK-J4. KDM6B is overexpressed in the germinal center B-cell subtype of diffuse large B-cell lymphoma, and higher KDM6B levels are associated with worse survival in patients with diffuse large B-cell lymphoma treated with R-CHOP. GSK-J4-induced apoptosis was observed in five (SU-DHL-6, OCI-Ly1, Toledo, OCI-Ly8, SU-DHL-8) out of nine germinal center B-cell diffuse large B-cell lymphoma cell lines. Treatment with GSK-J4 predominantly resulted in downregulation of B-cell receptor signaling and BCL6. Cell lines expressing high BCL6 levels or CREBBP/EP300 mutations were sensitive to GSK-J4. Our results suggest that B-cell receptor-dependent downregulation of BCL6 is responsible for GSK-J4-induced cytotoxicity. Furthermore, GSK-J4-mediated inhibition of KDM6B sensitizes germinal center B-cell diffuse large B-cell lymphoma cells to chemotherapy agents that are currently utilized in treatment regimens for diffuse large B-cell lymphoma. PMID:27742770

  15. B cells as under-appreciated mediators of non-auto-immune inflammatory disease.

    PubMed

    Nikolajczyk, Barbara S

    2010-06-01

    B lymphocytes play roles in many auto-immune diseases characterized by unresolved inflammation, and B cell ablation is proving to be a relatively safe, effective treatment for such diseases. B cells function, in part, as important sources of regulatory cytokines in auto-immune disease, but B cell cytokines also play roles in other non-auto-immune inflammatory diseases. B cell ablation may therefore benefit inflammatory disease patients in addition to its demonstrated efficacy in auto-immune disease. Current ablation drugs clear both pro- and anti-inflammatory B cell subsets, which may unexpectedly exacerbate some pathologies. This possibility argues that a more thorough understanding of B cell function in human inflammatory disease is required to safely harness the clinical promise of B cell ablation. Type 2 diabetes (T2D) and periodontal disease (PD) are two inflammatory diseases characterized by little autoimmunity. These diseases are linked by coincident presentation and alterations in toll-like receptor (TLR)-dependent B cell cytokine production, which may identify B cell ablation as a new therapy for co-affected individuals. Further analysis of the role B cells and B cell cytokines play in T2D, PD and other inflammatory diseases is required to justify testing B cell depletion therapies on a broader range of patients.

  16. R-ICE and Lenalidomide in Treating Patients With First-Relapse/Primary Refractory Diffuse Large B-Cell Lymphoma

    ClinicalTrials.gov

    2017-03-03

    Diffuse Large B-Cell Lymphoma; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Mediastinal (Thymic) Large B-Cell Cell Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Refractory Mediastinal (Thymic) Large B-Cell Cell Lymphoma; Transformed Recurrent Non-Hodgkin Lymphoma

  17. JCAR014 and Durvalumab in Treating Patients With Relapsed or Refractory B-cell Non-Hodgkin Lymphoma

    ClinicalTrials.gov

    2017-01-05

    Diffuse Large B-Cell Lymphoma, Not Otherwise Specified; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Mediastinal (Thymic) Large B-Cell Cell Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Refractory Mediastinal (Thymic) Large B-Cell Cell Lymphoma

  18. Mercury Alters B-Cell Protein Phosphorylation Profiles

    PubMed Central

    Carruthers, Nicholas J.; Stemmer, Paul M.; Shin, Namhee; Dombkowski, Alan; Caruso, Joseph A.; Gill, Randal; Rosenspire, Allen

    2014-01-01

    Environmental exposure to mercury is suggested to contribute to human immune dysfunction. To shed light on the mechanism we identified changes in the phosphoproteomic profile of the WEHI-231 B cell line after intoxication with Hg2+. These changes were compared to changes in the phosphoproteome that were induced by pervanadate or okadaic acid exposure. Both 250 μM HgCl2 and pervanadate, a known phosphotyrosine phosphatase inhibitor, caused an increase in the number of proteins identified after TiO2 affinity selection and LC-MS/MS analysis. Pervanadate treatment had a larger effect than Hg2+ on the number of Scansite motifs which were tyrosine-phosphorylated, 17, and Ingenuity canonical signaling pathways activated, 4 with score > 5.0. However, Hg2+ had a more focused effect, primarily causing tyrosine-phosphorylation in SH2 domains in proteins that are in the B cell receptor signaling pathway. The finding that many of the changes induced by Hg2+ overlap with those of pervanadate, indicates that at high concentrations Hg2+ inhibits protein tyrosine phosphatases. PMID:24224561

  19. Immunoglobulin variable region structure and B-cell malignancies.

    PubMed

    Kiyoi, H; Naoe, T

    2001-01-01

    The enormous diversity of immunoglobulin (Ig) variable (V) gene sequences encoding the antibody repertoire are formed by the somatic recombination of relatively few genetic elements. In B-lineage malignancies, Ig gene rearrangements have been widely used for determining clonality and cell origin. The recent development of rapid cloning and sequencing techniques has resulted in a substantial accumulation of IgV region sequences at various stages of B-cell development and has revealed stage-specific trends in the use of V, diversity, joining genes, the degree of noncoding nucleotide addition, and the rate of somatic mutations. Furthermore, sequences from B-lineage malignant cells nearly reflect the characteristics of the normal counterpart at each respective stage of development. Alternatively, from the IgV region structure of the malignant cells, it is possible to speculate at which stage of B-cell development the cells were transformed. As the complete nucleotide sequences of the human Ig heavy and Ig light V region loci have now been determined, the study of Ig genetics has entered into the super-information era.

  20. Anti-CD20 monoclonal antibodies: beyond B-cells.

    PubMed

    Avivi, Irit; Stroopinsky, Dina; Katz, Tamar

    2013-09-01

    Anti-CD20 monoclonal antibodies (MoAbs), employed in treating CD20⁺ lymphomas and autoimmune diseases, appear to have broader functions than just eradicating malignant B-cells and decreasing autoantibody production. Rituximab-induced T-cell inactivation, reported both in-vitro and in-vivo, may contribute to the increased risk of T-cell-dependent infections, observed in patients receiving this therapy. T-cell polarization into a suppressive phenotype, often observed in patients receiving rituximab for autoimmune disorders, was reported to be associated with prolonged remissions. Elimination of B-cells serving as antigen-presenting cells, thereby causing impaired T-cell activation, could play a significant role in induction of these changes. Direct binding of rituximab to a CD20dim T-cell population, inducing its depletion, may contribute to the decreased T-cell activation following rituximab therapy. Further investigation of the complex network through which rituximab and new anti-CD20 MoAbs act, would advance the employment of these agents in different clinical settings.

  1. Childhood B cell lymphomas arising in the mediastinum.

    PubMed Central

    Carr, T F; Lockwood, L; Stevens, R F; Morris-Jones, P H; Lewis, I; DaCosta, P E; Kelsey, A M

    1993-01-01

    AIMS--To report the clinical features and pathology of four childhood cases of primary mediastinal non-Hodgkin's lymphoma of non-lymphoblastic pathology. METHODS--Biopsy material was fixed in formol-saline and routinely processed and stained. Immunohistochemical staining was performed on paraffin wax embedded sections using the alkaline phosphatase anti-alkaline phosphatase method. RESULTS--The four patients presented with a large mediastinal mass and symptoms consistent with superior vena cava syndrome secondary to lymphoma. None of the patients had any clinically important disease outside the mediastinum. The four tumours had a histological appearance similar to diffuse large cell non-Hodgkin's lymphoma with sclerosis. Immunohistochemical staining showed that these tumours were of B cell origin. One patient died from infection during treatment and two patients died with progressive disease. The remaining patient remained well 43 months off all treatment. CONCLUSIONS--These four cases further illustrate the heterogeneity of paediatric large cell lymphomas. Clinically, they seem to be equivalent to the B cell lymphoma of the mediastinum, sclerosing type, that is seen in young (predominantly female) adults. The clinical and biological features of this type of tumour in childhood are largely unknown. Using standard treatment protocols, this tumour seems to have a poor prognosis and its optimal treatment therefore requires further clarification. Images PMID:8331171

  2. Identifying Novel B Cell Epitopes within Toxoplasma gondii GRA6

    PubMed Central

    Wang, Yanhua; Wang, Guangxiang; Cai, Jian Ping

    2016-01-01

    The study of antigenic epitopes from Toxoplasma gondii has not only enhanced our understanding of the structure and function of antigens, the reactions between antigens and antibodies, and many other aspects of immunology, but it also plays a significant role in the development of new diagnostic reagents and vaccines. In the present study, T. gondii GRA6 epitopes were identified using bioinformatics tools and a synthetic peptide technique. The potential B cell epitopes of GRA6 predicted by bioinformatics tools concentrated upon 3 regions of GRA6, 1-20 aa, 44-103 aa, and 172-221 aa. Ten shorter peptides from the 3 regions were synthesized and assessed by ELISA using pig sera from different time points after infection. Three of the 10 peptides (amino acids 44-63, 172-191, and 192-211) tested were recognized by all sera and determined to be immunodominant B-cell epitopes of GRA6. The results indicated that we precisely and accurately located the T. gondii GRA6 epitopes using pig sera collected at different time points after infection. The identified epitopes may be very useful for further studies of epitope-based vaccines and diagnostic reagents. PMID:27658594

  3. B cell repertoire expansion occurs in meningeal ectopic lymphoid tissue

    PubMed Central

    Lehmann-Horn, Klaus; Wang, Sheng-zhi; Sagan, Sharon A.; Zamvil, Scott S.

    2016-01-01

    Ectopic lymphoid tissues (ELT) can be found in multiple sclerosis (MS) and other organ-specific inflammatory conditions. Whether ELT in the meninges of central nervous system (CNS) autoimmune disease exhibit local germinal center (GC) activity remains unknown. In an experimental autoimmune encephalomyelitis model of CNS autoimmunity, we found activation-induced cytidine deaminase, a GC-defining enzyme, in meningeal ELT (mELT) densely populated by B and T cells. To determine GC activity in mELT, we excised meningeal lymphoid aggregates using laser capture microscopy and evaluated B cell repertoires in mELT and secondary lymphoid organs by next-generation immune repertoire sequencing. We found immunoglobulin heavy chain variable region sequences that were unique to mELT and had accumulated functionally relevant somatic mutations, together indicating localized antigen-driven affinity maturation. Our results suggest that B cells in mELT actively participate in CNS autoimmunity, which may be relevant to mELT in MS and ELT in other chronic inflammatory conditions. PMID:27942581

  4. Quantifying evolutionary constraints on B-cell affinity maturation

    PubMed Central

    McCoy, Connor O.; Bedford, Trevor; Minin, Vladimir N.; Bradley, Philip; Robins, Harlan; Matsen, Frederick A.

    2015-01-01

    The antibody repertoire of each individual is continuously updated by the evolutionary process of B-cell receptor (BCR) mutation and selection. It has recently become possible to gain detailed information concerning this process through high-throughput sequencing. Here, we develop modern statistical molecular evolution methods for the analysis of B-cell sequence data, and then apply them to a very deep short-read dataset of BCRs. We find that the substitution process is conserved across individuals but varies significantly across gene segments. We investigate selection on BCRs using a novel method that side-steps the difficulties encountered by previous work in differentiating between selection and motif-driven mutation; this is done through stochastic mapping and empirical Bayes estimators that compare the evolution of in-frame and out-of-frame rearrangements. We use this new method to derive a per-residue map of selection, which provides a more nuanced view of the constraints on framework and variable regions. PMID:26194758

  5. Design and pre-clinical development of epitope-based DNA vaccines against B-cell lymphoma.

    PubMed

    Iurescia, Sandra; Fioretti, Daniela; Fazio, Vito Michele; Rinaldi, Monica

    2011-10-01

    Optimally designed cancer vaccines should combine the best tumor antigens with the most effective immunotherapy agents and delivery strategies to achieve positive clinical results. The unique immunoglobulin (Ig) idiotype on the surface of each B-cell lymphoma represents an ideal tumor-specific antigen for use as a cancer vaccine. It has been theorized that effective cancer vaccines can be developed using the minimum essential subset of T cell and B cell epitopes that comprise the 'immunome', the universe of neoplasm-derived peptides that interface with B and T cells of the host immune system. Idiotypic antigenic determinants of a B-cell lymphoma lie within the hypervariable regions and mainly within the complementarity-determining regions (CDR)s 3. Thus, the CDR3s are considered a "hot spot" of particular interest for construction of subunit vaccines. DNA vaccines, whose safety and tolerability are substantiated in completed and ongoing clinical trials, have emerged as a novel lymphoma vaccine formulation for antigen-specific immunotherapy. The molecular precision tools offered by gene-based vaccines allow to explore the use of CDR3 sequence as an anti-lymphoma vaccine.

  6. Chemotherapy-Refractory Diffuse Large B-Cell Lymphoma and Indolent B-Cell Malignancies Can Be Effectively Treated With Autologous T Cells Expressing an Anti-CD19 Chimeric Antigen Receptor

    PubMed Central

    Kochenderfer, James N.; Dudley, Mark E.; Kassim, Sadik H.; Somerville, Robert P.T.; Carpenter, Robert O.; Stetler-Stevenson, Maryalice; Yang, James C.; Phan, Giao Q.; Hughes, Marybeth S.; Sherry, Richard M.; Raffeld, Mark; Feldman, Steven; Lu, Lily; Li, Yong F.; Ngo, Lien T.; Goy, Andre; Feldman, Tatyana; Spaner, David E.; Wang, Michael L.; Chen, Clara C.; Kranick, Sarah M.; Nath, Avindra; Nathan, Debbie-Ann N.; Morton, Kathleen E.; Toomey, Mary Ann; Rosenberg, Steven A.

    2015-01-01

    Purpose T cells can be genetically modified to express an anti-CD19 chimeric antigen receptor (CAR). We assessed the safety and efficacy of administering autologous anti-CD19 CAR T cells to patients with advanced CD19+ B-cell malignancies. Patients and Methods We treated 15 patients with advanced B-cell malignancies. Nine patients had diffuse large B-cell lymphoma (DLBCL), two had indolent lymphomas, and four had chronic lymphocytic leukemia. Patients received a conditioning chemotherapy regimen of cyclophosphamide and fludarabine followed by a single infusion of anti-CD19 CAR T cells. Results Of 15 patients, eight achieved complete remissions (CRs), four achieved partial remissions, one had stable lymphoma, and two were not evaluable for response. CRs were obtained by four of seven evaluable patients with chemotherapy-refractory DLBCL; three of these four CRs are ongoing, with durations ranging from 9 to 22 months. Acute toxicities including fever, hypotension, delirium, and other neurologic toxicities occurred in some patients after infusion of anti-CD19 CAR T cells; these toxicities resolved within 3 weeks after cell infusion. One patient died suddenly as a result of an unknown cause 16 days after cell infusion. CAR T cells were detected in the blood of patients at peak levels, ranging from nine to 777 CAR-positive T cells/μL. Conclusion This is the first report to our knowledge of successful treatment of DLBCL with anti-CD19 CAR T cells. These results demonstrate the feasibility and effectiveness of treating chemotherapy-refractory B-cell malignancies with anti-CD19 CAR T cells. The numerous remissions obtained provide strong support for further development of this approach. PMID:25154820

  7. Change you can B(cell)eive in: recent progress confirms a critical role for B cells in type 1 diabetes

    PubMed Central

    O’Neill, Shannon K.; Liu, Edwin; Cambier, John C.

    2010-01-01

    Purpose of review Here we review extant recent findings regarding the multiple roles of B cells in type 1 diabetes (T1D) and discuss how autoreactive B cells may become activated by a breach in B cell tolerance, and thereby initiate disease. Finally, we discuss the use of B cell-targeted therapies for treatment of autoimmunity. Recent findings Anti-CD20-specific depletion of B cells prevents and reverses diabetes in humanCD20/non-obese diabetic (NOD) mice. Correspondingly, in nontransgenic NOD mice B cells are effectively depleted with high dose antimouse CD20 mAbs of varying isotypes, and this also prevents diabetes in more than 60% of the mice when administered early, and significantly delays disease in 15-week-old animals. A separate study revealed that targeting B cells with anti-CD22/cal monoclonal antibody therapy delays diabetes onset in prediabetic NOD mice and restores normoglycemia in new-onset hyperglycemic NOD mice. In humans, a clinical trial of rituximab in new onset type 1 diabetics has yielded promising preliminary findings. Summary B cells are major players in T1D in humans, and clearly essential for disease development in the NOD mouse model of T1D. In this review, we discuss the silencing of autoreactive B cells and how failure of this process may contribute to autoimmunity. Further, we describe the most recent advances in studies of therapeutic effects of B cell depletion in T1D, and provide recent data indicating the diverse functions by which B cells may mediate disease. PMID:19502979

  8. Characterization of tumor-associated B-cell subsets in patients with colorectal cancer

    PubMed Central

    Gryschok, Luise; Malcher, Joke; Wennhold, Kerstin; Garcia-Marquez, Maria; Herbold, Till; Neuhaus, Laura S.; Becker, Hans J.; Fiedler, Anne; Scherwitz, Pascal; Koslowsky, Thomas; Hake, Roland; Stippel, Dirk L.; Hölscher, Arnulf H.; Eidt, Sebastian; Hallek, Michael; Theurich, Sebastian; von Bergwelt-Baildon, Michael S.

    2014-01-01

    Purpose: A precise understanding of the mechanisms by which human immune cell subsets affect tumor biology will be critical for successful treatment of cancer using immunotherapeutic approaches. Recent evidence suggests that B cells can both promote and inhibit the development and progression of tumors. The aim of this study was to characterize the composition of the B-cell infiltrates in colorectal cancers (CRC) in order to gain further insight into the role of B cells in CRC. Experimental Design: In this study we characterized B-cell subsets in primary tumors (n=38), metastases (n=6) and blood (n=46) of 51 patients with a diagnosis of CRC and blood of 10 healthy controls. B-cell subsets were analyzed by flow cytometry or immunohistochemistry. Results: Peripheral blood of CRC patients contained a higher percentage of memory B cells than that of age-matched healthy controls. Furthermore, the percentage of B cells within tumors was higher than that in the peripheral blood of CRC patients while metastases were typically devoid of tumor-infiltrating B cells. Tumor-associated B cells were enriched for activated and terminally differentiated B cells. Relevant proportions of regulatory B cells could only be detected in advanced cancer and metastases. Conclusion: B cells constitute a significant proportion of the immune infiltrate in CRC. The B-cell infiltrate of primary CRC is characterized by an accumulation of terminally differentiated memory B cells or plasma cells suggestive of a specific immune response against the tumor. However advanced tumors and metastases are also infiltrated by a considerable number of regulatory B cells. PMID:25026291

  9. A Role for TLR Signaling During B Cell Activation in Antiretroviral-Treated HIV Individuals

    PubMed Central

    Keshavarzian, Ali; French, Audrey; Demarais, Patricia; Landay, Alan

    2013-01-01

    Abstract The mechanisms underlying B cell activation that persists during antiretroviral therapy (ART) are unknown. Toll-like receptor (TLR) signaling is a critical mediator of innate cell activation and though B cells express TLRs, few studies have investigated a role for TLR signaling in B cell activation during HIV infection. We addressed this question by assessing the activated phenotype and TLR expression/responsiveness of B cells from ART-treated HIV-infected subjects (HIVART+). We evaluated activation markers implicated in B cell-mediated T cell trans infection during HIV pathogenesis. We found no significant difference in TLR expression between B cells of HIVART+ and HIV− subjects. However, B cells of HIVART+ subjects exhibited heightened endogenous expression levels of IL-6 (p=0.0051), T cell cognate ligands CD40 (p=0.0475), CD54 (p=0.0229), and phosphorylated p38 (p<0.0001), a marker of TLR signaling. In vitro, B cells of HIVART+ individuals were less responsive to TLR stimulation compared to B cells of HIV− subjects. The activated phenotype of in vitro TLR-stimulated B cells of HIV− subjects was similar to ex vivo B cells from HIVART+ individuals. TLR2 stimulation was a potent mediator of B cell activation, whereas B cells were least responsive to TLR4 stimulation. Compared to HIV− subjects, the serum level of lipoteichoic acid (TLR2 ligand) in HIVART+ subjects was significantly higher (p=0.0207), correlating positively with viral load (p=0.0127, r=0.6453). Our data suggest that during HIV infection TLR-activated B cells may exert a pathogenic role and B cells from HIVART+ subjects respond to in vitro TLR stimulation, yet exhibit a TLR tolerant phenotype suggesting prior in vivo TLR stimulation. PMID:23763346

  10. Human innate B cells: a link between host defense and autoimmunity?

    PubMed

    Milner, Eric C B; Anolik, Jennifer; Cappione, Amedeo; Sanz, Iñaki

    2005-03-01

    B cells play a variety of immunoregulatory roles through their antigen-presentation ability and through cytokine and chemokine production. Innate immune activation of B cells may play a beneficial role through the generation of natural cross-reactive antibodies, by maintaining B cell memory and by exercising immunomodulatory functions that may provide protection against autoimmunity. In this article, we review human B cell populations and their functional properties, with a particular focus on a population of inherently autoreactive B cells, which seem to play an important physiological role in innate immunity, but which, if selected into adaptive immune responses, appear to become pathogenic agents in systemic lupus erythematosus.

  11. Role of B cells in systemic lupus erythematosus and rheumatoid arthritis.

    PubMed

    Mandik-Nayak, Laura; Ridge, Natalie; Fields, Michele; Park, Audrey Y; Erikson, Jan

    2008-12-01

    B cell tolerance to many self-proteins is actively maintained by either purging self-reactive B receptors through clonal deletion and receptor editing, or by functional silencing known as anergy. However, these processes are clearly incomplete as B cell driven autoimmune diseases still occur. The significance of B cells in two such diseases, rheumatoid arthritis and systemic lupus erythematosus, is highlighted by the ameliorative effects of B cell depletion. It remains to be determined, however, whether the key role of the B cell in autoimmune disease is autoantibody production or another antibody-independent function.

  12. Identification of a unique B-cell-stimulating factor produced by a cloned dendritic cell.

    PubMed Central

    Clayberger, C; DeKruyff, R H; Fay, R; Cantor, H

    1985-01-01

    We describe a cloned dendritic cell, clone Den-1, which is a potent accessory cell for some B-cell responses. Clone Den-1 produces a unique lymphokine that induces polyclonal B-cell proliferation in the absence of other costimulators. This clone or factors produced by it also stimulate purified B cells to develop plaque-forming cell responses to type 2 antigens. The effect of this factor(s) on various B-cell populations and its relationship to previously described B-cell-stimulating factors is discussed. Images PMID:3871522

  13. Essential role of MALT1 protease activity in activated B cell-like diffuse large B-cell lymphoma.

    PubMed

    Hailfinger, Stephan; Lenz, Georg; Ngo, Vu; Posvitz-Fejfar, Anita; Rebeaud, Fabien; Guzzardi, Montserrat; Penas, Eva-Maria Murga; Dierlamm, Judith; Chan, Wing C; Staudt, Louis M; Thome, Margot

    2009-11-24

    A key element for the development of suitable anti-cancer drugs is the identification of cancer-specific enzymatic activities that can be therapeutically targeted. Mucosa-associated lymphoid tissue transformation protein 1 (MALT1) is a proto-oncogene that contributes to tumorigenesis in diffuse large B-cell lymphoma (DLBCL) of the activated B-cell (ABC) subtype, the least curable subtype of DLBCL. Recent data suggest that MALT1 has proteolytic activity, but it is unknown whether this activity is relevant for tumor growth. Here we report that MALT1 is constitutively active in DLBCL lines of the ABC but not the GCB subtype. Inhibition of the MALT1 proteolytic activity led to reduced expression of growth factors and apoptosis inhibitors, and specifically affected the growth and survival of ABC DLBCL lines. These results demonstrate a key role for the proteolytic activity of MALT1 in DLBCL of the ABC subtype, and provide a rationale for the development of pharmacological inhibitors of MALT1 in DLBCL therapy.

  14. The regulatory network of B-cell differentiation: a focused view of early B-cell factor 1 function

    PubMed Central

    Boller, Sören; Grosschedl, Rudolf

    2014-01-01

    During the last decades, many studies have investigated the transcriptional and epigenetic regulation of lineage decision in the hematopoietic system. These efforts led to a model in which extrinsic signals and intrinsic cues establish a permissive chromatin context upon which a regulatory network of transcription factors and epigenetic modifiers act to guide the differentiation of hematopoietic lineages. These networks include lineage-specific factors that further modify the epigenetic landscape and promote the generation of specific cell types. The process of B lymphopoiesis requires a set of transcription factors, including Ikaros, PU.1, E2A, and FoxO1 to ‘prime’ cis-regulatory regions for subsequent activation by the B-lineage-specific transcription factors EBF1 and Pax-5. The expression of EBF1 is initiated by the combined action of E2A and FoxO1, and it is further enhanced and maintained by several positive feedback loops that include Pax-5 and IL-7 signaling. EBF1 acts in concert with Ikaros, PU.1, Runx1, E2A, FoxO1, and Pax-5 to establish the B cell-specific transcription profile. EBF1 and Pax-5 also collaborate to repress alternative cell fates and lock cells into the B-lineage fate. In addition to the functions of EBF1 in establishing and maintaining B-cell identity, EBF1 is required to coordinate differentiation with cell proliferation and survival. PMID:25123279

  15. Early B-cell-specific inactivation of ATM synergizes with ectopic CyclinD1 expression to promote pre-germinal center B-cell lymphomas in mice.

    PubMed

    Yamamoto, K; Lee, B J; Li, C; Dubois, R L; Hobeika, E; Bhagat, G; Zha, S

    2015-06-01

    Ataxia telangiectasia-mutated (ATM) kinase is a master regulator of the DNA damage response. ATM is frequently inactivated in human B-cell non-Hodgkin lymphomas, including ~50% of mantle cell lymphomas (MCLs) characterized by ectopic expression of CyclinD1. Here we report that early and robust deletion of ATM in precursor/progenitor B cells causes cell autonomous, clonal mature B-cell lymphomas of both pre- and post-germinal center (GC) origins. Unexpectedly, naive B-cell-specific deletion of ATM is not sufficient to induce lymphomas in mice, highlighting the important tumor suppressor function of ATM in immature B cells. Although EμCyclinD1 is not sufficient to induce lymphomas, EμCyclinD1 accelerates the kinetics and increases the incidence of clonal lymphomas in ATM-deficient B-cells and skews the lymphomas toward pre-GC-derived small lymphocytic neoplasms, sharing morphological features of human MCL. This is in part due to CyclinD1-driven expansion of ATM-deficient naive B cells with genomic instability, which promotes the deletions of additional tumor suppressor genes (i.e. Trp53, Mll2, Rb1 and Cdkn2a). Together these findings define a synergistic function of ATM and CyclinD1 in pre-GC B-cell proliferation and lymphomagenesis and provide a prototypic animal model to study the pathogenesis of human MCL.

  16. Intravascular Large B-Cell Lymphoma: A Difficult Diagnostic Challenge.

    PubMed

    Khan, Maria S; McCubbin, Mark; Nand, Sucha

    2014-01-01

    Case Presentation. A 69-year-old Hispanic male, with a past history of diabetes and coronary disease, was admitted for fever, diarrhea, and confusion of 4 weeks duration. Physical examination showed a disoriented patient with multiple ecchymoses, possible ascites, and bilateral scrotal swelling. Hemoglobin was 6.7, prothrombin time (PT) 21.4 seconds with international normalized ratio 2.1, partial thromboplastin time (PTT) 55.6 seconds, fibrin split 10 µg/L, and lactate dehydrogenase (LDH) 1231 IU/L. Except for a positive DNA test for Epstein-Barr virus (EBV) infection, extensive diagnostic workup for infections, malignancy, or a neurological cause was negative. Mixing studies revealed a nonspecific inhibitor of PT and PTT but Factor VIII levels were normal. The patient was empirically treated with antibiotics but developed hypotension and died on day 27 of admission. At autopsy, patient was found to have intravascular diffuse large B-cell lymphoma involving skin, testes, lung, and muscles. The malignant cells were positive for CD20, CD791, Mum-1, and Pax-5 and negative for CD3, CD5, CD10, CD30, and Bcl-6. The malignant cells were 100% positive for Ki-67. Discussion. Intravascular large cell B-cell lymphoma (IVLBCL) is rare form of diffuse large B-cell lymphoma and tends to proliferate within small blood vessels, particularly capillaries and postcapillary venules. The cause of its affinity for vascular bed remains unknown. In many reports, IVLBCL was associated with HIV, HHV8, and EBV infections. The fact that our case showed evidence of EBV infection lends support to the association of this diagnosis to viral illness. The available literature on this subject is scant, and in many cases, the diagnosis was made only at autopsy. The typical presentation of this disorder is with B symptoms, progressive neurologic deficits, and skin findings. Bone marrow, spleen, and liver are involved in a minority of patients. Nearly all patients have elevated LDH, and about 65% are

  17. The role of BLyS/BLyS receptors in anti-chromatin B cell regulation.

    PubMed

    Hondowicz, Brian D; Alexander, Shawn T; Quinn, William J; Pagán, Antonio J; Metzgar, Michele H; Cancro, Michael P; Erikson, Jan

    2007-04-01

    B lymphocyte stimulator (BLyS), also known as B cell-activating factor, is a key positive regulator of B cell homeostasis, and elevated levels of BLyS have been observed in systemic lupus erythematosus (SLE) patients. Given that anti-chromatin auto-antibodies are one of the hallmarks of SLE, we examined the role of BLyS and its receptors in the regulation of anti-chromatin B cells. We demonstrate that exogenous BLyS treatment leads to an increase in B cell numbers, particularly anti-chromatin B cells; yet, their localization in the spleen and auto-antibody production remain unaffected. We also examined transmembrane activator and CAML interactor (TACI), BLyS receptor 3 (BR3) and B cell maturation antigen expression on anti-chromatin B cells before and after receiving T cell help. Interestingly, in the absence of T cell help, TACI expression is greater on immature anti-chromatin B cells compared with immature Tg(-) B cells, whereas BR3 levels are comparable. After receiving T cell help, the anti-chromatin B cells that have differentiated into short-lived plasma cells no longer express BR3 but retain TACI. These data suggest a novel role for TACI in anti-chromatin B cell homeostasis and differentiation.

  18. Regulation and Maintenance of an Adoptive T-Cell Dependent Memory B Cell Pool

    PubMed Central

    Anson, Marie; Amado, Inês; Mailhé, Marie-Pierre; Donnadieu, Emmanuel; Garcia, Sylvie; Huetz, François; Freitas, Antonio A.

    2016-01-01

    We investigated the ability of monoclonal B cells to restore primary and secondary T-cell dependent antibody responses in adoptive immune-deficient hosts. Priming induced B cell activation and expansion, AID expression, antibody production and the generation of IgM+IgG- and IgM-IgG+ antigen-experienced B-cell subsets that persisted in the lymphopenic environment by cell division. Upon secondary transfer and recall the IgM-IgG+ cells responded by the production of antigen-specific IgG while the IgM+ memory cells secreted mainly IgM and little IgG, but generated new B cells expressing germinal center markers. The recall responses were more efficient if the antigenic boost was delayed suggesting that a period of adaptation is necessary before the transferred cells are able to respond. Overall these findings indicate that reconstitution of a functional and complete memory pool requires transfer of all different antigen-experienced B cell subsets. We also found that the size of the memory B cell pool did not rely on the number of the responding naïve B cells, suggesting autonomous homeostatic controls for naïve and memory B cells. By reconstituting a stable memory B cell pool in immune-deficient hosts using a monoclonal high-affinity B cell population we demonstrate the potential value of B cell adoptive immunotherapy. PMID:27880797

  19. Distinct T helper cell dependence of memory B-cell proliferation versus plasma cell differentiation.

    PubMed

    Zabel, Franziska; Fettelschoss, Antonia; Vogel, Monique; Johansen, Pål; Kündig, Thomas M; Bachmann, Martin F

    2017-03-01

    Several memory B-cell subclasses with distinct functions have been described, of which the most effective is the class-switched (CS) memory B-cell population. We have previously shown, using virus-like particles (VLPs), that the proliferative potential of these CS memory B cells is limited and they fail to re-enter germinal centres (GCs). However, VLP-specific memory B cells quickly differentiated into secondary plasma cells (PCs) with the virtue of elevated antibody production compared with primary PCs. Whereas the induction of VLP(+) memory B cells was strongly dependent on T helper cells, we were wondering whether re-stimulation of VLP(+) memory B cells and their differentiation into secondary PCs would also require T helper cells. Global absence of T helper cells led to strongly impaired memory B cell proliferation and PC differentiation. In contrast, lack of interleukin-21 receptor-dependent follicular T helper cells or CD40 ligand signalling strongly affected proliferation of memory B cells, but differentiation into mature secondary PCs exhibiting increased antibody production was essentially normal. This contrasts with primary B-cell responses, where a strong dependence on CD40 ligand but limited importance of interleukin-21 receptor was seen. Hence, T helper cell dependence differs between primary and secondary B-cell responses as well as between memory B-cell proliferation and PC differentiation.

  20. Mechanisms of Regulatory B cell Function in Autoimmune and Inflammatory Diseases beyond IL-10

    PubMed Central

    Ray, Avijit; Dittel, Bonnie N.

    2017-01-01

    In the past two decades it has become clear that in addition to antigen presentation and antibody production B cells play prominent roles in immune regulation. While B cell-derived IL-10 has garnered much attention, B cells also effectively regulate inflammation by a variety of IL-10-independent mechanisms. B cell regulation has been studied in both autoimmune and inflammatory diseases. While collectively called regulatory B cells (Breg), no definitive phenotype has emerged for B cells with regulatory potential. This has made their study challenging and thus unique B cell regulatory mechanisms have emerged in a disease-dependent manner. Thus to harness the therapeutic potential of Breg, further studies are needed to understand how they emerge and are induced to evoke their regulatory activities. PMID:28124981

  1. The Multifaceted Roles of B Cells in Solid Tumors: Emerging Treatment Opportunities.

    PubMed

    Flynn, Nicole J; Somasundaram, Rajasekharan; Arnold, Kimberly M; Sims-Mourtada, Jennifer

    2017-04-01

    The influence of tumor infiltrating lymphocytes on tumor growth and response to therapy is becoming increasingly apparent. While much work has focused on the role of T cell responses in anti-tumor immunity, the role of B cells in solid tumors is much less understood. Tumor infiltrating B cells have been found in a variety of solid tumors, including breast, ovarian, prostate, melanoma, and colorectal cancer. The function of B cells in solid tumors is controversial, with many studies reporting a pro-tumor effect, while other studies demonstrate a role for B cells in the anti-tumor immune response. In this review, we discuss the prognostic ability of B cells in solid tumors as well as the mechanisms by which B cells can either promote or suppress anti-tumor immunity. Additionally, we review current therapeutic strategies that may target both pro- and anti-tumor B cells.

  2. Plasmodium Infection Promotes Genomic Instability and AID Dependent B Cell Lymphoma

    PubMed Central

    Robbiani, Davide F.; Deroubaix, Stephanie; Feldhahn, Niklas; Oliveira, Thiago Y.; Callen, Elsa; Wang, Qiao; Jankovic, Mila; Silva, Israel T.; Rommel, Philipp C.; Bosque, David; Eisenreich, Tom; Nussenzweig, André; Nussenzweig, Michel C.

    2015-01-01

    Summary Chronic infection with Plasmodium falciparum was epidemiologically associated with endemic Burkitt’s lymphoma, a mature B cell cancer characterized by chromosome translocation between the c-myc oncogene and Igh, over 50 years ago. Whether infection promotes B cell lymphoma, and if so by what mechanism remains unknown. To investigate the relationship between parasitic disease and lymphomagenesis we used Plasmodium chabaudi (Pc) to produce chronic malaria infection in mice. Pc induces prolonged expansion of germinal centers (GCs), unique compartments where B cells undergo rapid clonal expansion and express activation-induced cytidine deaminase (AID), a DNA mutator. GC B cells elicited during Pc infection suffer widespread DNA damage leading to chromosome translocations. Although infection does not change the overall rate, it modifies lymphomagenesis to favor mature B cell lymphomas that are AID dependent and show chromosome translocations. Thus, malaria infection favors mature B cell cancers by eliciting protracted AID expression in GC B cells. PMID:26276629

  3. Switch-mediated activation and retargeting of CAR-T cells for B-cell malignancies.

    PubMed

    Rodgers, David T; Mazagova, Magdalena; Hampton, Eric N; Cao, Yu; Ramadoss, Nitya S; Hardy, Ian R; Schulman, Andrew; Du, Juanjuan; Wang, Feng; Singer, Oded; Ma, Jennifer; Nunez, Vanessa; Shen, Jiayin; Woods, Ashley K; Wright, Timothy M; Schultz, Peter G; Kim, Chan Hyuk; Young, Travis S

    2016-01-26

    Chimeric antigen receptor T (CAR-T) cell therapy has produced impressive results in clinical trials for B-cell malignancies. However, safety concerns related to the inability to control CAR-T cells once infused into the patient remain a significant challenge. Here we report the engineering of recombinant antibody-based bifunctional switches that consist of a tumor antigen-specific Fab molecule engrafted with a peptide neo-epitope, which is bound exclusively by a peptide-specific switchable CAR-T cell (sCAR-T). The switch redirects the activity of the bio-orthogonal sCAR-T cells through the selective formation of immunological synapses, in which the sCAR-T cell, switch, and target cell interact in a structurally defined and temporally controlled manner. Optimized switches specific for CD19 controlled the activity, tissue-homing, cytokine release, and phenotype of sCAR-T cells in a dose-titratable manner in a Nalm-6 xenograft rodent model of B-cell leukemia. The sCAR-T-cell dosing regimen could be tuned to provide efficacy comparable to the corresponding conventional CART-19, but with lower cytokine levels, thereby offering a method of mitigating cytokine release syndrome in clinical translation. Furthermore, we demonstrate that this methodology is readily adaptable to targeting CD20 on cancer cells using the same sCAR-T cell, suggesting that this approach may be broadly applicable to heterogeneous and resistant tumor populations, as well as other liquid and solid tumor antigens.

  4. [Posterior uveitis caused by highly malignant B cell lymphoma].

    PubMed

    Held, R; Eckardt, C; Brix, F; Feller, A C

    1989-01-01

    A diagnostic vitrectomy was performed on three patients with posterior uveitis of unknown origin and whose vitrous body was markedly affected. In all cases, cells of high-grade B-cell lymphoma (earlier referred to as reticulum cell sarcoma) were identified by cytological analysis of the specimen. In addition to the ocular findings, one of the three patients showed clinical and radiological evidence of a tumorous mass in the area of the right thalamus at the time of diagnosis. This was interpreted as a cerebral manifestation of the lymphoma. Initially, the other two patients did not show any cerebral involvement. One of them, however, developed clinical symptoms 9 months after diagnosis, which were radiologically verified as tumor infiltration of the cerebellum and the diencephalon. Under radiation therapy, the ocular findings disappeared within a few weeks.

  5. Antiviral B cell and T cell immunity in the lungs.

    PubMed

    Chiu, Christopher; Openshaw, Peter J

    2015-01-01

    Respiratory viruses are frequent causes of repeated common colds, bronchitis and pneumonia, which often occur unpredictably as epidemics and pandemics. Despite those decimating effects on health and decades of intensive research, treatments remain largely supportive. The only commonly available vaccines are against influenza virus, and even these need improvement. The lung shares some features with other mucosal sites, but preservation of its especially delicate anatomical structures necessitates a fine balance of pro- and anti-inflammatory responses; well-timed, appropriately placed and tightly regulated T cell and B cell responses are essential for protection from infection and limitation of symptoms, whereas poorly regulated inflammation contributes to tissue damage and disease. Recent advances in understanding adaptive immunity should facilitate vaccine development and reduce the global effect of respiratory viruses.

  6. B-Cell Lymphoma of the Mandible: A Case Report

    PubMed Central

    Adouani, Ali; Bouguila, Jed; Jeblaoui, Yassine; Ben Aicha, Mehdi; Abdelali, Mouhamed Ali; Hellali, Mouna; Zitouni, Karima; Amani, Landolsi; Issam, Zairi

    2008-01-01

    Summary Introduction The mandible is an infrequent localisation of primary osseous non-Hodgkin’s lymphomas. Few cases of mandibular non-Hodgkin’s lymphomas (NHL) have been reported. Case report A rare condition of primary malignant non-Hodgkin’s lymphoma of the mandible in 53-year-old man, was reported at the Department of Maxillofacial and Plastic Surgery in Charles Nicolle Hospital (Tunis, Tunisia). Histologic and Immunohistochemical (IHC) examination Confirmed a B-Cell lymphoma. Discussion The purpose of this report is to describe this rare case of NHL of the mandible, explore the diagnosis and workup, and discuss treatment strategies. In this localisation, neither the clinical features nor the radiologic appearances are often pathognomonic. Conclusion Particular care must be taken to consider lymphoma in the differential diagnosis because this uncommon lesion can pose significant diagnostic problems and is frequently misdiagnosed. PMID:21892315

  7. B-cell receptor pathway modulators in NHL

    PubMed Central

    Blum, Kristie A.

    2016-01-01

    With the recent success of the Bruton's tyrosine kinase (BTK) inhibitor, ibrutinib, and the phosphoinositide-3-kinase (PI3K) inhibitor, idelalisib, in the treatment of patients with relapsed or refractory non-Hodgkin's lymphoma (NHL), a number of new agents targeting the B-cell receptor (BCR) pathway are in clinical development. In addition, multiple trials combining these agents with conventional cytotoxic chemotherapy, immunomodulatory agents, monoclonal antibodies, or other kinase inhibitors are underway. This review will summarize the current data with the use of single agent and combination therapy with BCR inhibitors in NHL. In addition, commonly encountered as well as serious toxicities and hypothesized resistance mechanisms will be discussed. Lastly, this review will examine the future of these agents and opportunities to maneuver them into the front-line setting in selected NHL subtypes. PMID:26637705

  8. Naturally occurring B-cell autoreactivity: a critical overview.

    PubMed

    Avrameas, Stratis; Ternynck, Therese; Tsonis, Ioannis A; Lymberi, Peggy

    2007-12-01

    In over one century of research in immunology marked progress in the scientific knowledge and the implications derived from it has been made. At the same time several contradictory and seemingly opposing results have been obtained. The term autoimmunity is still conceived by many as a term directly related to an immunopathological state. However, strong evidence exist that not only the immune system is able to recognize self-constituents, but it appears also that this property is essential for homeostasis. Direct or indirect alterations of such self-recognition properties of the immune system may contribute to pathology. In this review, the most recent advances in the field of naturally occurring B-cell autoreactivity in health as well as in disease are presented and discussed.

  9. Lenalidomide in diffuse large B-cell lymphoma.

    PubMed

    Thieblemont, Catherine; Delfau-Larue, Marie-Hélène; Coiffier, Bertrand

    2012-01-01

    Diffuse large B-cell lymphoma (DLBCL) is the most common form of non-Hodgkin's lymphoma (NHL) in adults. Even if the natural history of DLBCL has been improved with the advent of immunochemotherapy, the survival results obtained with current treatment options clearly indicate that new agents or novel approaches are needed. Lenalidomide (Revlimid, Celgene Corporation, Summit, NJ, USA), an analogue of thalidomide, is an immunomodulatory drug with pleiotropic mechanisms of action potentially adding to immunochemotherapy. We present here the biological rational for the use of lenalidomide in DLBCL in light of recent advances in the pathophysiology of the disease and the therapeutic results of the most recent trials published in literature or reported in meetings in relapsed/refractory situations as well as in first-line treatment.

  10. [Presence of B cell clones in acute myelomonocytic leukemia].

    PubMed

    Novoa, Viviana; Nuñez, Neri; Cervellini, Mirta; Starosta, Aida; Carballo, Orlando G

    2010-01-01

    The coexistence of acute myeloid leukemia and chronic lymphocytic leukemia in the same patient is rare. The majority of the cases correspond to patients that developed acute leukemia during the evolutionary course of a chronic lymphatic leukemia following treatment with chemotherapy drugs. We report a case of acute myelomonocytic leukemia concurrent with untreated B-cell chronic lymphocytic leukemia in which the use of flow cytometry analysis with a large panel of monoclonal antibodies, allowed the demonstration of different pathological populations and determine immunophenotyping patterns. Published cases of simultaneous chronic lymphocytic leukemia and acute leukemia are reviewed. The use of multiparametric flow cytometry to differentiate the populations demonstrates the utility of this technology in the diagnosis of these hematological malignancies.

  11. A primitive cell origin for B-cell precursor ALL?

    PubMed

    Cox, C V; Blair, A

    2005-01-01

    A stem cell origin has been described for both acute and chronic myelogenous leukemias. In contrast, childhood B-cell precursor acute lymphoblastic leukemia (ALL) is thought to arise in committed B-lineage cells. Recently described in vitro and in vivo model systems that support the proliferation and expansion of ALL cells have provided new tools to investigate the cellular targets for the origin of this malignancy. Evidence suggests that some subtypes of childhood ALL have a primitive cell origin and share many immunophenotypic characteristics with normal progenitor cells. These leukemic stem cells may be resistant to current therapeutic strategies designed to kill the bulk ALL cell population and subsequent relapses may arise from this population. More precise definition of these ALL stem cells through combined analyses of antigen expression, genetic lesions, and functionality is essential for the development of more effective, targeted therapeutic strategies.

  12. Asian-variant intravascular large B-cell lymphoma

    PubMed Central

    Pasch, Whitney; Costales, Cristina; Siddiqi, Imran; Mohrbacher, Ann

    2017-01-01

    Intravascular large B-cell lymphoma (IVLBCL) is a rare and deadly malignancy involving the growth of lymphoma cells within vessel lumina of all organ types. IVLBCL is further divided into the hemophagocytic Asian variant and a classical Western variant. Both variants are difficult to diagnose by imaging, and although diagnostic criteria have been developed to guide workup, histopathological examination remains imperative. Treatment of IVLBCL remains difficult given the high mortality of the disease, but rituximab has emerged as a promising therapeutic option when combined with various cytotoxic regimens. The two main variants of IVLBCL generally manifest in their respective Asian or Western populations, and crossover between ethnicities is rare. We present the second described case of Asian-variant IVLBCL in an African American individual.

  13. TP53 dysfunction in diffuse large B-cell lymphoma.

    PubMed

    Lu, Ting-Xun; Young, Ken H; Xu, Wei; Li, Jian-Yong

    2016-01-01

    The aberrations of TP53 gene and dysregulation of the TP53 pathway are important in the pathogenesis of many human cancers, including malignant lymphomas, especially for diffuse large B cell lymphoma (DLBCL). By regulating many downstream target genes or molecules, TP53 governs major defenses against tumor growth and promotes cellular DNA repair, apoptosis, autophagy, cell cycle arrest, signaling, transcription, immune or inflammatory responses and metabolism. Dysfunction of TP53, including microRNA regulations, copy number alterations of TP53 pathway and TP53 itself, dysregulation of TP53 regulators, and somatic mutations by abnormal TP53 function modes, play an important role in lymphoma generation, progression and invasion. The role of TP53 in DLBCL has been widely explored recently. In this review, we summarized recent advances on different mechanisms of TP53 in DLBCL and new therapeutic approaches to overcome TP53 inactivation.

  14. Signals from activation of B-cell receptor with anti-IgD can override the stimulatory effects of excess BAFF on mature B cells in vivo.

    PubMed

    Nguyen, Tue G; Morris, Jonathan M

    2014-09-01

    The selection and maturation of B-cell clones are critically determined by tonic signals from activated B cell receptors (BCR) and survival signals from BAFF cytokine. These finely tuned and coordinated signals provide a net positive signal that can promote the selection, maturation, proliferation and differentiation of a developing B cell. Stimulation with an anti-IgD antibody can also activate BCR but can lead to depletion and an arrest of mature B-cell development in vivo. It is not known whether survival signals from excess BAFF can override the suppressive effects of treatment with anti-IgD on mature B cells in vivo. Herein, we examined the effects of co-treatment of BAFF and anti-IgD on the mature B-cell compartment and antibody production in vivo by treating mice with either 1mg/kg BAFF or anti-IgD alone or in combination for 3 consecutive days. We found that co-treatment with anti-IgD significantly abrogated these stimulatory effects of BAFF treatment on splenic CD19+ B cells as well as mature CD19+IgD(hi)IgM+ B cells in vivo. Anti-IgD down-regulated the expression of the BCR complex (mIgM, mIgD and CD19) and the BAFF receptor TACI without regard to the presence of BAFF. Anti-IgD treatment also significantly negated BAFF-induced IgM production in vivo. Both BAFF and anti-IgD could individually stimulate IL-10 synthesis in B cells but did not affect one another. Taken together, our data suggest that activation of BCR with an anti-IgD antibody can override the stimulatory effects from excess BAFF on B cell proliferation and antibody production by down-regulating the expression of BCR complex and BAFF receptors.

  15. Cerebral toxoplasmosis in a diffuse large B cell lymphoma patient

    PubMed Central

    Savsek, Lina; Opaskar, Tanja Ros

    2016-01-01

    Background Toxoplasmosis is an opportunistic protozoal infection that has, until now, probably been an underestimated cause of encephalitis in patients with hematological malignancies, independent of stem cell or bone marrow transplant. T and B cell depleting regimens are probably an important risk factor for reactivation of a latent toxoplasma infection in these patients. Case report We describe a 62-year-old HIV-negative right-handed Caucasian female with systemic diffuse large B cell lymphoma who presented with sudden onset of high fever, headache, altered mental status, ataxia and findings of pancytopenia, a few days after receiving her final, 8th cycle of rituximab, cyclophosphamide, vincristine, doxorubicin, prednisolone (R-CHOP) chemotherapy regimen. A progression of lymphoma to the central nervous system was suspected. MRI of the head revealed multiple on T2 and fluid attenuated inversion recovery (FLAIR) hyperintense parenchymal lesions with mild surrounding edema, located in both cerebral and cerebellar hemispheres that demonstrated moderate gadolinium enhancement. The polymerase chain reaction on cerebrospinal fluid (CSF PCR) was positive for Toxoplasma gondii. The patient was diagnosed with toxoplasmic encephalitis and successfully treated with sulfadiazine, pyrimethamine and folic acid. Due to the need for maintenance therapy with rituximab for lymphoma remission, the patient now continues with secondary prophylaxis of toxoplasmosis. Conclusions With this case report, we wish to emphasize the need to consider cerebral toxoplasmosis in patients with hematological malignancies on immunosuppressive therapy when presenting with new neurologic deficits. In such patients, there are numerous differential diagnoses for cerebral toxoplasmosis, and the CNS lymphoma is the most difficult among all to distinguish it from. If left untreated, cerebral toxoplasmosis has a high mortality rate; therefore early recognition and treatment are of essential importance. PMID

  16. A two-scale model for correlation between B cell VDJ usage in zebrafish

    NASA Astrophysics Data System (ADS)

    Pan, Keyao; Deem, Michael

    2011-03-01

    The zebrafish (Danio rerio) is one of the model animals for study of immunology. The dynamics of the adaptive immune system in zebrafish is similar to that in higher animals. In this work, we built a two-scale model to simulate the dynamics of B cells in primary and secondary immune reactions in zebrafish and to explain the reported correlation between VDJ usage of B cell repertoires in distinct zebrafish. The first scale of the model consists of a generalized NK model to simulate the B cell maturation process in the 10-day primary immune response. The second scale uses a delay ordinary differential equation system to model the immune responses in the 6-month lifespan of zebrafish. The generalized NK model shows that mature B cells specific to one antigen mostly possess a single VDJ recombination. The probability that mature B cells in two zebrafish have the same VDJ recombination increases with the B cell population size or the B cell selection intensity and decreases with the B cell hypermutation rate. The ODE model shows a distribution of correlation in the VDJ usage of the B cell repertoires in two six-month-old zebrafish that is highly similar to that from experiment. This work presents a simple theory to explain the experimentally observed correlation in VDJ usage of distinct zebrafish B cell repertoires after an immune response.

  17. Induction of polyclonal B cell activation and differentiation by the AIDS retrovirus (HTLV-III/LAV)

    SciTech Connect

    Higgins, S.E.; Schnittman, S.M.; Lane, H.C.; Folks, T.; Koenig, S.; Fauci, A.S.

    1986-03-05

    The immune systems of individuals infected with HTLV-III/LAV are characterized by a profound defect in cellular immunity together with paradoxical polyclonal B cell activation. The present study examined the direct effects of HTLV-III/LAV on B lymphocytes. Peripheral blood B cells from healthy donors were incubated with a variety of HTLV-III/LAV isolates for 1 h and /sup 3/H-thymidine incorporation was measured at multiple time points. Responses ranged from 9000-28,000 cpm and peaked on day 4. This B cell activation was not enhanced by the addition of interleukin-2 to culture, was not synergistic with Staphylococcus aureus Cowan I, was not modulated by the addition of T lymphocytes to culture, and was not associated with B cell transformation. Supernatant Ig could first be detected in virus-activated cultures at day 4, plateaued by day 8, and yielded a mean of 12,500 ng IgG+IgM/ml/50,000 B cells. Thus, HTLV-III/LAV is a potent T cell independent B cell mitogen capable of inducing B cell activation, proliferation, and differentiation comparable in magnitude to that of the most potent B cell activators. This biological property of HTLV-III/LAV may help explain the profound polyclonal B cell activation observed in patients with AIDS and may provide investigators with another probe for investigating the mechanisms of B cell activation.

  18. Regulatory B cells contribute to the impaired antitumor immunity in ovarian cancer patients.

    PubMed

    Wei, Xin; Jin, Yangqiu; Tian, Yinpu; Zhang, Huiyuan; Wu, Jie; Lu, Wei; Lu, Xiaofen

    2016-05-01

    Multiple factors in the tumor microenvironment were found to inhibit antitumor adaptive immune responses, allowing tumor persistence and growth. In this study, ascites from ovarian cancer patients were collected. We observed that a population of interleukin-10(+) B (IL-10(+) B) cells was preferentially enriched in the ascites. This population was associated with naive B cell phenotype or IgM or class-switched memory B cell phenotypes. The frequencies of IL-10(+) B cells were negatively correlated with the frequencies of interferon gamma-producing (IFN-g(+)) CD8(+) T cells and were positively correlated with the frequencies of Foxp3(+) CD4(+) T cells. To examine whether increased IL-10(+) B cells in ascites could directly result in increased suppression of IFN-g production by CD8(+) T cells, we cocultured CD8(+) T cells with autologous blood B cells or ascitic B cells and found that CD8(+) T cells cocultured with ascitic B cells demonstrated significantly suppressed IFN-g production. This suppression was in part mediated by IL-10 as well as low CD80/CD86 expression, since depletion of IL-10 and stimulation of CD28 partially reverted IL-10(+) B cell-mediated suppression. Together, these data demonstrated an additional regulatory mechanism in the tumor microenvironment, which utilizes IL-10(+) B cells.

  19. Increased STAT3 phosphorylation on CD27(+) B-cells from common variable immunodeficiency disease patients.

    PubMed

    Clemente, Antonio; Pons, Jaume; Lanio, Nallibe; Cunill, Vanesa; Frontera, Guillem; Crespí, Catalina; Matamoros, Núria; Ferrer, Joana M

    2015-12-01

    Maturation and differentiation of B-cells are driven by T-cells' help through IL-21/STAT3 axis in GC centers or through extrafollicular pathways, in a T-independent manner. B-cell differentiation is defective in common variable immunodeficiency disease (CVID) patients. We investigated if IL-21/STAT3 axis alterations could influence B-cell fate. We activated purified CVID B-cells with surrogate T-dependent (anti-CD40), T-independent (TLR-9 ligand) stimuli or through B-cell receptor engagement (anti-IgM) with or without IL-21. IL-21 mediated STAT3 activation was greater on CD27(-) than CD27(+) B-cells depending on the stimulus. IL-21 alone induced STAT3 phosphorylation (pSTAT3) only on CD27(-) B-cells and IL-21 induced higher pSTAT3 levels on CD27(-) than CD27(+) B-cells after anti-IgM or anti-CD40 activation. CVID CD27(+) B-cells showed selective STAT3 hyperphosphorylation after activation with anti-IgM or anti-CD40 alone and anti-IgM, anti-CD40 or ODN combined with IL-21. Increased STAT3 activation during immune responses could result in B-cell differentiation defects in CVID.

  20. IL-4Rα-Associated Antigen Processing by B Cells Promotes Immunity in Nippostrongylus brasiliensis Infection

    PubMed Central

    Hoving, Jennifer C.; Nieuwenhuizen, Natalie; McSorley, Henry J.; Ndlovu, Hlumani; Bobat, Saeeda; Kimberg, Matti; Kirstein, Frank; Cutler, Anthony J.; DeWals, Benjamin; Cunningham, Adam F.; Brombacher, Frank

    2013-01-01

    In this study, B cell function in protective TH2 immunity against N. brasiliensis infection was investigated. Protection against secondary infection depended on IL-4Rα and IL-13; but not IL-4. Protection did not associate with parasite specific antibody responses. Re-infection of B cell-specific IL-4Rα−/− mice resulted in increased worm burdens compared to control mice, despite their equivalent capacity to control primary infection. Impaired protection correlated with reduced lymphocyte IL-13 production and B cell MHC class II and CD86 surface expression. Adoptive transfer of in vivo N. brasiliensis primed IL-4Rα expressing B cells into naïve BALB/c mice, but not IL-4Rα or IL-13 deficient B cells, conferred protection against primary N. brasiliensis infection. This protection required MHC class II compatibility on B cells suggesting cognate interactions by B cells with CD4+ T cells were important to co-ordinate immunity. Furthermore, the rapid nature of these protective effects by B cells suggested non-BCR mediated mechanisms, such as via Toll Like Receptors, was involved, and this was supported by transfer experiments using antigen pulsed Myd88−/− B cells. These data suggest TLR dependent antigen processing by IL-4Rα-responsive B cells producing IL-13 contribute significantly to CD4+ T cell-mediated protective immunity against N. brasiliensis infection. PMID:24204255

  1. IL-6 contributes to an immune tolerance checkpoint in post germinal center B cells.

    PubMed

    Yan, Yi; Wang, Ying-Hua; Diamond, Betty

    2012-02-01

    The generation of a B cell repertoire involves producing and subsequently purging autoreactive B cells. Receptor editing, clonal deletion and anergy are key mechanisms of central B cell tolerance. Somatic mutation of antigen-activated B cells within the germinal center produces a second wave of autoreactivity; but the regulatory mechanisms that operate at this phase of B cell activation are poorly understood. We recently identified a post germinal center tolerance checkpoint, where receptor editing is re-induced to extinguish autoreactivity that is generated by somatic hypermutation. Re-induction of the recombinase genes RAG1 and RAG2 in antigen-activated B cells requires antigen to engage the B cell receptor and IL-7 to signal through the IL-7 receptor. We demonstrate that this process requires IL-6 to upregulate IL-7 receptor expression on post germinal center B cells. Diminishing IL-6 by blocking antibody or haplo-insufficiency leads to reduced expression of the IL-7 receptor and RAG and increased titers of anti-DNA antibodies following immunization with a peptide mimetope of DNA. The dependence on IL-6 to initiate receptor editing is B cell intrinsic. Interestingly, estradiol decreases IL-6 expression thereby increasing the anti-DNA response. Our data reveal a novel regulatory cascade to control post germinal center B cell autoreactivity.

  2. B cells responses and cytokine production are regulated by their immune microenvironment.

    PubMed

    Vazquez, Monica I; Catalan-Dibene, Jovani; Zlotnik, Albert

    2015-08-01

    The adaptive immune system consists of two types of lymphocytes: T and B cells. These two lymphocytes originate from a common precursor, yet are fundamentally different with B cells mediating humoral immunity while T cells mediate cell mediated immunity. In cytokine production, naïve T cells produce multiple cytokines upon activation while naïve activated B cells do not. B cells are capable of producing cytokines, but their cytokine production depends on their differentiation state and activation conditions. Hence, unlike T cells that can produce a large amount of cytokines upon activation, B cells require specific differentiation and activation conditions to produce cytokines. Many cytokines act on B cells as well. Here, we discuss several cytokines and their effects on B cells including: Interleukins, IL-7, IL-4, IL-6, IL-10, and Interferons, IFN-α, IFN-β, IFN-γ. These cytokines play important roles in the development, survival, differentiation and/or proliferation of B cells. Certain chemokines also play important roles in B cell function, namely antibody production. As an example, we discuss CCL28, a chemokine that directs the migration of plasma cells to mucosal sites. We conclude with a brief overview of B cells as cytokine producers and their likely functional consequences on the immune response.

  3. Defective B cell tolerance in adenosine deaminase deficiency is corrected by gene therapy.

    PubMed

    Sauer, Aisha V; Morbach, Henner; Brigida, Immacolata; Ng, Yen-Shing; Aiuti, Alessandro; Meffre, Eric

    2012-06-01

    Adenosine deaminase (ADA) gene defects are among the most common causes of SCID. Restoration of purine metabolism and immune functions can be achieved by enzyme replacement therapy, or more effectively by bone marrow transplant or HSC gene therapy (HSC-GT). However, autoimmune complications and autoantibody production, including anti-nuclear antibodies (ANAs), frequently occur in ADA-SCID patients after treatment. To assess whether ADA deficiency affects the establishment of B cell tolerance, we tested the reactivity of recombinant antibodies isolated from single B cells of ADA-SCID patients before and after HSC-GT. We found that before HSC-GT, new emigrant/transitional and mature naive B cells from ADA-SCID patients contained more autoreactive and ANA-expressing clones, indicative of defective central and peripheral B cell tolerance checkpoints. We further observed impaired B cell receptor (BCR) and TLR functions in B cells after ADA inhibition, which may underlie the defects in B cell tolerance. Strikingly, after HSC-GT, ADA-SCID patients displayed quasi-normal early B cell tolerance checkpoints, as evidenced by restored removal of developing autoreactive and ANA-expressing B cells. Hence, ADA plays an essential role in controlling autoreactive B cell counterselection by regulating BCR and TLR functions.

  4. B cell antigen presentation is sufficient to drive neuroinflammation in an animal model of multiple sclerosis.

    PubMed

    Parker Harp, Chelsea R; Archambault, Angela S; Sim, Julia; Ferris, Stephen T; Mikesell, Robert J; Koni, Pandelakis A; Shimoda, Michiko; Linington, Christopher; Russell, John H; Wu, Gregory F

    2015-06-01

    B cells are increasingly regarded as integral to the pathogenesis of multiple sclerosis, in part as a result of the success of B cell-depletion therapy. Multiple B cell-dependent mechanisms contributing to inflammatory demyelination of the CNS have been explored using experimental autoimmune encephalomyelitis (EAE), a CD4 T cell-dependent animal model for multiple sclerosis. Although B cell Ag presentation was suggested to regulate CNS inflammation during EAE, direct evidence that B cells can independently support Ag-specific autoimmune responses by CD4 T cells in EAE is lacking. Using a newly developed murine model of in vivo conditional expression of MHC class II, we reported previously that encephalitogenic CD4 T cells are incapable of inducing EAE when B cells are the sole APC. In this study, we find that B cells cooperate with dendritic cells to enhance EAE severity resulting from myelin oligodendrocyte glycoprotein (MOG) immunization. Further, increasing the precursor frequency of MOG-specific B cells, but not the addition of soluble MOG-specific Ab, is sufficient to drive EAE in mice expressing MHCII by B cells alone. These data support a model in which expansion of Ag-specific B cells during CNS autoimmunity amplifies cognate interactions between B and CD4 T cells and have the capacity to independently drive neuroinflammation at later stages of disease.

  5. SAP modulates B cell functions in a genetic background-dependent manner.

    PubMed

    Detre, Cynthia; Yigit, Burcu; Keszei, Marton; Castro, Wilson; Magelky, Erica M; Terhorst, Cox

    2013-06-01

    Mutations affecting the SLAM-associated protein (SAP) are responsible for the X-linked lympho-proliferative syndrome (XLP), a severe primary immunodeficiency syndrome with disease manifestations that include fatal mononucleosis, B cell lymphoma and dysgammaglobulinemia. It is well accepted that insufficient help by SAP-/- CD4+ T cells, in particular during the germinal center reaction, is a component of dysgammaglobulinemia in XLP patients and SAP-/- animals. It is however not well understood whether in XLP patients and SAP-/- mice B cell functions are affected, even though B cells themselves do not express SAP. Here we report that B cell intrinsic responses to haptenated protein antigens are impaired in SAP-/- mice and in Rag-/- mice into which B cells derived from SAP-/- mice together with wt CD4+ T cells had been transferred. This impaired B cells functions are in part depending on the genetic background of the SAP-/- mouse, which affects B cell homeostasis. Surprisingly, stimulation with an agonistic anti-CD40 causes strong in vivo and in vitro B cell responses in SAP-/- mice. Taken together, the data demonstrate that genetic factors play an important role in the SAP-related B cell functions. The finding that anti-CD40 can in part restore impaired B cell responses in SAP-/- mice, suggests potentially novel therapeutic interventions in subsets of XLP patients.

  6. The Functional Response of B Cells to Antigenic Stimulation: A Preliminary Report of Latent Tuberculosis

    PubMed Central

    du Plessis, Willem J.; Kleynhans, Léanie; du Plessis, Nelita; Stanley, Kim; Malherbe, Stephanus T.; Maasdorp, Elizna; Ronacher, Katharina; Chegou, Novel N.; Walzl, Gerhard; Loxton, Andre G.

    2016-01-01

    Mycobacterium tuberculosis (M.tb) remains a successful pathogen, causing tuberculosis disease numbers to constantly increase. Although great progress has been made in delineating the disease, the host-pathogen interaction is incompletely described. B cells have shown to function as both effectors and regulators of immunity via non-humoral methods in both innate and adaptive immune settings. Here we assessed specific B cell functional interaction following stimulation with a broad range of antigens within the LTBI milieu. Our results indicate that B cells readily produce pro- and anti-inflammatory cytokines (including IL-1β, IL-10, IL-17, IL-21 and TNF-α) in response to stimulation. TLR4 and TLR9 based stimulations achieved the greatest secreted cytokine-production response and BCG stimulation displayed a clear preference for inducing IL-1β production. We also show that the cytokines produced by B cells are implicated strongly in cell-mediated communication and that plasma (memory) B cells (CD19+CD27+CD138+) is the subset with the greatest contribution to cytokine production. Collectively our data provides insight into B cell responses, where they are implicated in and quantifies responses from specific B cell phenotypes. These findings warrant further functional B cell research with a focus on specific B cell phenotypes under conditions of active TB disease to further our knowledge about the contribution of various cell subsets which could have implications for future vaccine development or refined B cell orientated treatment in the health setting. PMID:27050308

  7. B cells populating the multiple sclerosis brain mature in the draining cervical lymph nodes

    PubMed Central

    Stern, Joel N. H.; Yaari, Gur; Vander Heiden, Jason A.; Church, George; Donahue, William F.; Hintzen, Rogier Q.; Huttner, Anita J.; Laman, Jon D.; Nagra, Rashed M.; Nylander, Alyssa; Pitt, David; Ramanan, Sriram; Siddiqui, Bilal A.; Vigneault, Francois; Kleinstein, Steven H.; Hafler, David A.; O’Connor, Kevin C.

    2015-01-01

    Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS) characterized by autoimmune mediated demyelination and neurodegeneration. The CNS of patients with MS harbors expanded clones of antigen-experienced B cells that reside in distinct compartments including the meninges, cerebrospinal fluid (CSF) and parenchyma. It is not understood whether this immune infiltrate initiates its development in the CNS or in peripheral tissues. B cells in the CSF can exchange with those in peripheral blood, implying that CNS B cells may have access to lymphoid tissue that may be the specific compartment(s) in which CNS resident B cells encounter antigen and experience affinity maturation. In this study, paired tissues were used to determine whether the B cells that populate the CNS mature in the draining cervical lymph nodes (CLNs). High-throughput sequencing of the antibody repertoire demonstrated that clonally expanded B cells were present in both compartments. Founding members of clonal families were more often found in the draining CLNs. More mature clonal family members derived from these founders were observed in the draining CLNs and also in the CNS, including lesions. These data provide new evidence that B cells traffic freely across the tissue barrier with the majority of B cell maturation occurring outside of the CNS in the secondary lymphoid tissue. Our study may aid in further defining the mechanisms of immunomodulatory therapies that either deplete circulating B cells or impact the intrathecal B cell compartment by inhibiting lymphocyte transmigration into the CNS. PMID:25100741

  8. Interleukin 4 induces membrane Thy-1 expression on normal murine B cells.

    PubMed Central

    Snapper, C M; Hornbeck, P V; Atasoy, U; Pereira, G M; Paul, W E

    1988-01-01

    Thy-1, a cell-surface glycoprotein of undetermined function, is expressed in relatively large amounts on mouse thymocytes, peripheral T cells, and neurons. It is widely used as a marker to distinguish peripheral T cells from B cells in mice. We show here that, in five distinct mouse strains, recombinant interleukin 4 (IL-4/B-cell stimulatory factor 1) strikingly induces membrane expression of Thy-1 on the vast majority of lipopolysaccharide (LPS)-stimulated normal murine B cells. Thy-1+ B cells are precursors for immunoglobulin-secreting cells. RNA blot analysis indicates that B cells express a Thy-1 mRNA of 1.8 kilobases, the same size as that found in T cells. Cell mixing experiments show that only cells derived from Thy-1.2+ donors express Thy-1.2, indicating that B cells expressing Thy-1 have not passively absorbed the glycoprotein from another cell source. Recombinant interferon-gamma inhibits Thy-1 induction by B cells stimulated with LPS and IL-4. Thy-1 is also induced on B cells that have been stimulated as a result of the specific activation of an IL-4-producing T-helper clone. Anti-IL-4 monoclonal antibody inhibits the induction of B-cell Thy-1 in this T-cell-B-cell interaction. Images PMID:2901096

  9. B cells moderate inflammatory progression and enhance bacterial containment upon pulmonary challenge with Mycobacterium tuberculosis.

    PubMed

    Maglione, Paul J; Xu, Jiayong; Chan, John

    2007-06-01

    Though much is known about the function of T lymphocytes in the adaptive immune response against Mycobacterium tuberculosis, comparably little is understood regarding the corresponding role of B lymphocytes. Indicating B cells as components of lymphoid neogenesis during pulmonary tuberculosis, we have identified ectopic germinal centers (GCs) in the lungs of infected mice. B cells in these pulmonary lymphoid aggregates express peanut agglutinin and GL7, two markers of GC B cells, as well as CXCR5, and migrate in response to the lymphoid-associated chemokine CXCL13 ex vivo. CXCL13 is negatively regulated by the presence of B cells, as its production is elevated in lungs of B cell-deficient (B cell(-/-)) mice. Upon aerosol with 100 CFU of M. tuberculosis Erdman, B cell(-/-) mice have exacerbated immunopathology corresponding with elevated pulmonary recruitment of neutrophils. Infected B cell(-/-) mice show increased production of IL-10 in the lungs, whereas IFN-gamma, TNF-alpha, and IL-10R remain unchanged from wild type. B cell(-/-) mice have enhanced susceptibility to infection when aerogenically challenged with 300 CFU of M. tuberculosis corresponding with elevated bacterial burden in the lungs but not in the spleen or liver. Adoptive transfer of B cells complements the phenotypes of B cell(-/-) mice, confirming a role for B cells in both modulation of the host response and optimal containment of the tubercle bacillus. As components of ectopic GCs, moderators of inflammatory progression, and enhancers of local immunity against bacterial challenge, B cells may have a greater role in the host defense against M. tuberculosis than previously thought.

  10. Major histocompatibility complex class II expression distinguishes two distinct B cell developmental pathways during ontogeny

    PubMed Central

    1994-01-01

    All mature B cells coexpress major histocompatibility complex (MHC) class II molecules, I-A and I-E, which are restriction elements required for antigen presentation to CD4+ T cells. However, the expression of class II during the early stages of B cell development has been unclear. We demonstrate here that there is a difference in the expression of class II during murine B cell development in the fetal liver and adult bone marrow (BM). These differences define two distinct B cell developmental pathways. The Fetal-type (FT) pathway is characterized by pre-B and immature IgM+ B cells generated in the fetal liver which initially lack all class II expression. In contrast, the Adult-type (AT) pathway is typified by B cells developing in the adult BM which express class II molecules from the pre-B cell stage. In vitro stromal cell cultures of sorted fetal liver and adult BM pro-B cells indicated that the difference in I-A expression during B cell development is intrinsic to the progenitors. In addition, we show that FT B cell development is not restricted to the fetal liver but occurs in the peritoneal cavities, spleens, liver, and BM of young mice up to at least 1 mo of age. The AT B cell development begins to emerge after birth but is, however, restricted to the BM environment. These findings indicate that there are two distinct B cell developmental pathways during ontogeny, each of which could contribute differentially to the immune repertoire and thus the functions of B cell subsets and lineages. PMID:7913950

  11. Nuclear TRAF3 is a negative regulator of CREB in B cells.

    PubMed

    Mambetsariev, Nurbek; Lin, Wai W; Stunz, Laura L; Hanson, Brett M; Hildebrand, Joanne M; Bishop, Gail A

    2016-01-26

    The adaptor protein TNF receptor-associated factor 3 (TRAF3) regulates signaling through B-lymphocyte receptors, including CD40, BAFF receptor, and Toll-like receptors, and also plays a critical role inhibiting B-cell homoeostatic survival. Consistent with these findings, loss-of-function human TRAF3 mutations are common in B-cell cancers, particularly multiple myeloma and B-cell lymphoma. B cells of B-cell-specific TRAF3(-/-) mice (B-Traf3(-/-)) display remarkably enhanced survival compared with littermate control (WT) B cells. The mechanism for this abnormal homeostatic survival is poorly understood, a key knowledge gap in selecting optimal treatments for human B-cell cancers with TRAF3 deficiency. We show here for the first time to our knowledge that TRAF3 is a resident nuclear protein that associates with the transcriptional regulator cAMP response element binding protein (CREB) in both mouse and human B cells. The TRAF-C domain of TRAF3 was necessary and sufficient to localize TRAF3 to the nucleus via a functional nuclear localization signal. CREB protein was elevated in TRAF3(-/-) B cells, without change in mRNA, but with a decrease in CREB ubiquitination. CREB-mediated transcriptional activity was increased in TRAF3-deficient B cells. Consistent with these findings, Mcl-1, an antiapoptotic target of CREB-mediated transcription, was increased in the absence of TRAF3 and enhanced Mcl-1 was suppressed with CREB inhibition. TRAF3-deficient B cells were also preferentially sensitive to survival inhibition with pharmacologic CREB inhibitor. Our results identify a new mechanism by which nuclear TRAF3 regulates B-cell survival via inhibition of CREB stability, information highly relevant to the role of TRAF3 in B-cell malignancies.

  12. Derailed B cell homeostasis in patients with mixed connective tissue disease.

    PubMed

    Hajas, A; Barath, S; Szodoray, P; Nakken, B; Gogolak, P; Szekanecz, Z; Zold, E; Zeher, M; Szegedi, G; Bodolay, E

    2013-07-01

    Mixed connective tissue disease (MCTD) is a systemic autoimmune disorder, characterized by the presence of antibodies to U1-RNP protein. We aimed to determine phenotypic abnormalities of peripheral B cell subsets in MCTD. Blood samples were obtained from 46 MCTD patients, and 20 controls. Using anti-CD19, anti-CD27, anti-IgD and anti-CD38 monoclonal antibodies, the following B cell subsets were identified by flow cytometry: (1) transitional B cells (CD19+CD27-IgD+CD38(high)); (2) naive B cells (CD19+CD27-IgD+CD38(low)); (3) non-switched memory B cells (CD19+CD27+IgD+); (4) switched memory B cells (CD19+CD27+IgD-); (5) double negative (DN) memory B cells (CD19+CD27-IgD-) and (6) plasma cells (CD19+CD27(high)IgD-). The proportion of transitional B cells, naive B cells and DN B lymphocytes was higher in MCTD than in controls. The DN B cells were positive for CD95 surface marker. This memory B cells population showed a close correlation with disease activity. The number of plasma cells was also increased, and there was an association between the number of plasma cells and the anti-U1RNP levels. Cyclophosphamide, methotrexate, and corticosteroid treatment decreased the number of DN and CD27(high) B cells. In conclusion, several abnormalities were found in the peripheral B-cell subsets in MCTD, which reinforces the role of derailed humoral autoimmune processes in the pathogenesis.

  13. Antibody-Independent Function of Human B Cells Contributes to Antifungal T Cell Responses.

    PubMed

    Li, Rui; Rezk, Ayman; Li, Hulun; Gommerman, Jennifer L; Prat, Alexandre; Bar-Or, Amit

    2017-04-15

    Fungal infections (e.g., Candida albicans) can manifest as serious medical illnesses, especially in the elderly and immune-compromised hosts. T cells are important for Candida control. Whether and how B cells are involved in antifungal immunity has been less clear. Although patients with agammaglobulinemia exhibit normal antifungal immunity, increased fungal infections are reported following B cell-depleting therapy, together pointing to Ab-independent roles of B cells in controlling such infections. To test how human B cells may contribute to fungal-associated human T cell responses, we developed a novel Ag-specific human T cell/B cell in vitro coculture system and found that human B cells could induce C. albicans-associated, MHC class II-restricted responses of naive T cells. Activated B cells significantly enhanced C. albicans-mediated Th1 and Th17 T cell responses, which were both strongly induced by CD80/CD86 costimulation. IL-6(+)GM-CSF(+) B cells were the major responding B cell subpopulation to C. albicans and provided efficient costimulatory signals to the T cells. In vivo B cell depletion in humans resulted in reduced C. albicans-associated T responses. Of note, the decreased Th17, but not Th1, responses could be reversed by soluble factors from B cells prior to depletion, in an IL-6-dependent manner. Taken together, our results implicate an Ab-independent cytokine-defined B cell role in human antifungal T cell responses. These findings may be particularly relevant given the prospects of chronic B cell depletion therapy use in lymphoma and autoimmune disease, as patients age and are exposed to serial combination therapies.

  14. CD19 CAR-targeted T cells induce long-term remission and B Cell Aplasia in an immunocompetent mouse model of B cell acute lymphoblastic leukemia.

    PubMed

    Davila, Marco L; Kloss, Christopher C; Gunset, Gertrude; Sadelain, Michel

    2013-01-01

    Although many adults with B cell acute lymphoblastic leukemia (B-ALL) are induced into remission, most will relapse, underscoring the dire need for novel therapies for this disease. We developed murine CD19-specific chimeric antigen receptors (CARs) and an immunocompetent mouse model of B-ALL that recapitulates the disease at genetic, cellular, and pathologic levels. Mouse T cells transduced with an all-murine CD3ζ/CD28-based CAR that is equivalent to the one being used in our clinical trials, eradicate B-ALL in mice and mediate long-term B cell aplasias. In this model, we find that increasing conditioning chemotherapy increases tumor eradication, B cell aplasia, and CAR-modified T cell persistence. Quantification of recipient B lineage cells allowed us to estimate an in vivo effector to endogenous target ratio for B cell aplasia maintenance. In mice exhibiting a dramatic B cell reduction we identified a small population of progenitor B cells in the bone marrow that may serve as a reservoir for long-term CAR-modified T cell stimulation. Lastly, we determine that infusion of CD8+ CAR-modified T cells alone is sufficient to maintain long-term B cell eradication. The mouse model we report here should prove valuable for investigating CAR-based and other therapies for adult B-ALL.

  15. Physiology of B cells in mice with X-linked immunodeficiency. II. Influence of the thymus and mature T cells on B cell differentiation

    SciTech Connect

    Sprent, J.; Bruce, J.

    1984-07-01

    Evidence is presented that the in vivo differentiation of B cells expressing X-linked immunodeficiency (xid) is controlled by mature T cells. Normal (C57BL/6 X CBA/J)F1 mice were thymectomized (ATx), heavily irradiated, and reconstituted with CBA/N (xid) or CBA/Ca (nondefective) marrow. In contrast to sham-operated mice, ATx recipients of xid marrow showed an almost total absence of Ig+ B cells in lymph nodes (LN) and thoracic duct lymph at 2 mo post-reconstitution; B cells were markedly reduced in the spleen in some mice but only moderately in others. Addition of mature T cells soon after marrow reconstitution substantially abrogated the B cell depletion. In control experiments with nondefective B cells, the number of B cells developing in ATx irradiated recipients of normal (xid-) marrow cells was not detectably lower than in sham-operated recipients. These data imply that a subset of T-dependent B cells is either missing in normal mice or present in only very small numbers.

  16. Physiology of B cells in mice with X-linked immunodeficiency (xid). III. Disappearance of xid B cells in double bone marrow chimeras

    SciTech Connect

    Sprent, J.; Bruce, J.

    1984-09-01

    Evidence is presented that B cells from mice with X-linked immunodeficiency (xid) differentiate at a slower rate than normal B cells. This conclusion stems from studies in which (B6 X CBA/J)F1 mice were heavily irradiated (1,000 rads) and reconstituted with a mixture of T-depleted marrow cells taken from (a) nondefective B6 mice (H-2b) and (b) xid CBA/N or nondefective CBA/Ca mice (both H-2k). With transfer of CBA/Ca plus B6 marrow cells, the irradiated recipients become repopulated with B cells derived from both parental marrow sources; except for an early imbalance (probably reflecting Hh resistance), the degree of chimerism remained relatively stable over a period of more than 6 months. Very different results occurred with transfer of a mixture of xid CBA/N and normal B6 marrow. Within the first 2 months after marrow reconstitution, a low but significant proportion of the B cells in both spleen and lymph nodes were of CBA/N origin. Thereafter the proportion of these cells fell progressively, and by 6-9 months virtually all of the B cells were of B6 origin. This gradual decline in CBA/N-derived cells did not apply to other cell types, i.e., T cells or pluripotential stem cells. Analogous results were obtained with transfer of CBA/N vs. CBA/Ca marrow cells into sublethally irradiated (750 rads) (CBA/N X DBA/2)F1 male vs. female mice. For example, CBA/N-marrow derived B cells differentiated effectively and survived for long periods in F1 male mice (xid----xid) but not in F1 female mice (xid----normal). The finding that xid B cells eventually disappear in the presence of normal B cells strengthens the view that xid B cells are an abnormal population not represented in normal mice.

  17. Selective inhibitors of phosphoinositide 3-kinase delta: modulators of B-cell function with potential for treating autoimmune inflammatory diseases and B-cell malignancies

    PubMed Central

    Puri, Kamal D.; Gold, Michael R.

    2012-01-01

    The delta isoform of the p110 catalytic subunit (p110δ) of phosphoinositide 3-kinase is expressed primarily in hematopoietic cells and plays an essential role in B-cell development and function. Studies employing mice lacking a functional p110δ protein, as well as the use of highly-selective chemical inhibitors of p110δ, have revealed that signaling via p110δ-containing PI3K complexes (PI3Kδ) is critical for B-cell survival, migration, and activation, functioning downstream of key receptors on B cells including the B-cell antigen receptor, chemokine receptors, pro-survival receptors such as BAFF-R and the IL-4 receptor, and co-stimulatory receptors such as CD40 and Toll-like receptors (TLRs). Similarly, this PI3K isoform plays a key role in the survival, proliferation, and dissemination of B-cell lymphomas. Herein we summarize studies showing that these processes can be inhibited in vitro and in vivo by small molecule inhibitors of p110δ enzymatic activity, and that these p110δ inhibitors have shown efficacy in clinical trials for the treatment of several types of B-cell malignancies including chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL). PI3Kδ also plays a critical role in the activation, proliferation, and tissue homing of self-reactive B cells that contribute to autoimmune diseases, in particular innate-like B-cell populations such as marginal zone (MZ) B cells and B-1 cells that have been strongly linked to autoimmunity. We discuss the potential utility of p110δ inhibitors, either alone or in combination with B-cell depletion, for treating autoimmune diseases such as lupus, rheumatoid arthritis, and type 1 diabetes. Because PI3Kδ plays a major role in both B-cell-mediated autoimmune inflammation and B-cell malignancies, PI3Kδ inhibitors may represent a promising therapeutic approach for treating these diseases. PMID:22936933

  18. Changes in B Cell Populations and Merozoite Surface Protein-1-Specific Memory B Cell Responses after Prolonged Absence of Detectable P. falciparum Infection.

    PubMed

    Ayieko, Cyrus; Maue, Alexander C; Jura, Walter G Z O; Noland, Gregory S; Ayodo, George; Rochford, Rosemary; John, Chandy C

    2013-01-01

    Clinical immunity to malaria declines in the absence of repeated parasite exposure. However, little is known about how B cell populations and antigen-specific memory B cells change in the absence of P. falciparum infection. A successful indoor residual insecticide spraying campaign in a highland area of western Kenya, led to an absence of blood-stage P. falciparum infection between March 2007 and April 2008. We assessed memory B cell responses in 45 adults at the beginning (April 2008) and end (April 2009) of a subsequent 12-month period during which none of the adults had evidence of asymptomatic parasitemia or clinical disease. Antibodies and memory B cells to the 42-kDa portion of the merozoite surface protein-1 (MSP-142) were measured using ELISA and ELISPOT assays, respectively. B cell populations were characterized by flow cytometry. From 2008 to 2009, the prevalence of MSP-142-specific memory B cells (45% vs. 55%, respectively, P = 0.32) or antibodies (91% vs. 82%, respectively, P = 0.32) did not differ significantly, although specific individuals did change from positive to negative and vice versa, particularly for memory B cells, suggesting possible low-level undetected parasitemia may have occurred in some individuals. The magnitude of MSP-142-specific memory B cells and levels of antibodies to MSP-142 also did not differ from 2008 to 2009 (P>0.10 for both). However, from 2008 to 2009 the proportions of both class-switched atypical (CD19+IgD-CD27-CD21-IgM-) and class-switched activated (CD19+IgD-CD27+CD21-IgM-) memory B cells decreased (both P<0.001). In contrast, class-switched resting classical memory B cells (CD19+IgD-CD27+CD21+IgM-) increased (P<0.001). In this area of seasonal malaria transmission, a one- year absence of detectable P. falciparum infection was not associated with changes in the prevalence or level of MSP-142 specific memory B cells, but was associated with major changes in overall memory B cell subsets.

  19. Aggressive B-cell lymphomas: how many categories do we need?

    PubMed Central

    Said, Jonathan W

    2015-01-01

    Aggressive B-cell lymphomas are diverse group of neoplasms that arise at different stages of B-cell development and by various mechanisms of neoplastic transformation. The aggressive B-cell lymphomas include many types, subtypes and variants of diffuse large B-cell lymphoma (DLBCL), Burkitt lymphoma (BL), mantle cell lymphoma and its blastoid variant, and B lymphoblastic lymphoma. Differences in histology, cytogenetic and molecular abnormalities, as well as the relationship with the tumor microenvironment, help define characteristic signatures for these neoplasms, and in turn dictate potential therapeutic targets. Rather than survey the entire spectrum of aggressive B-cell lymphomas, this report aims to identify and characterize important clinically aggressive subtypes of DLBCL, and explore the relationship of DLBCL to BL and the gray zone between them (B-cell lymphoma unclassifiable with features intermediate between DLBCL and BL). PMID:23154748

  20. Signaling Proteins and Transcription Factors in Normal and Malignant Early B Cell Development

    PubMed Central

    Pérez-Vera, Patricia; Reyes-León, Adriana; Fuentes-Pananá, Ezequiel M.

    2011-01-01

    B cell development starts in bone marrow with the commitment of hematopoietic progenitors to the B cell lineage. In murine models, the IL-7 and preBCR receptors, and the signaling pathways and transcription factors that they regulate, control commitment and maintenance along the B cell pathway. E2A, EBF1, PAX5, and Ikaros are among the most important transcription factors controlling early development and thereby conditioning mice homeostatic B cell lymphopoiesis. Importantly, their gain or loss of function often results in malignant development in humans, supporting conserved roles for these transcription factors. B cell acute lymphoblastic leukemia is the most common cause of pediatric cancer, and it is characterized by unpaired early B cell development resulting from genetic lesions in these critical signaling pathways and transcription factors. Fine mapping of these genetic abnormalities is allowing more specific treatments, more accurately predicting risk profiles for this disease, and improving survival rates. PMID:22046564

  1. Signaling proteins and transcription factors in normal and malignant early B cell development.

    PubMed

    Pérez-Vera, Patricia; Reyes-León, Adriana; Fuentes-Pananá, Ezequiel M

    2011-01-01

    B cell development starts in bone marrow with the commitment of hematopoietic progenitors to the B cell lineage. In murine models, the IL-7 and preBCR receptors, and the signaling pathways and transcription factors that they regulate, control commitment and maintenance along the B cell pathway. E2A, EBF1, PAX5, and Ikaros are among the most important transcription factors controlling early development and thereby conditioning mice homeostatic B cell lymphopoiesis. Importantly, their gain or loss of function often results in malignant development in humans, supporting conserved roles for these transcription factors. B cell acute lymphoblastic leukemia is the most common cause of pediatric cancer, and it is characterized by unpaired early B cell development resulting from genetic lesions in these critical signaling pathways and transcription factors. Fine mapping of these genetic abnormalities is allowing more specific treatments, more accurately predicting risk profiles for this disease, and improving survival rates.

  2. Mechanisms of action of BCL6 during germinal center B cell development.

    PubMed

    Huang, ChuanXin; Melnick, Ari

    2015-12-01

    The transcriptional repressor B cell lymphoma 6 (BCL6) controls a large transcriptional network that is required for the formation and maintenance of germinal centers (GC). GC B cells represent the normal counterpart of most human B-cell lymphomas, which are often characterized by deregulated BCL6 expression or BCL6-mediated pathways. BCL6 suppresses gene transcription largely through recruitment of its co-repressors through its distinct repression domain. Understanding the precise biological roles of each repression domain in normal and malignant B cells is helpful for development of targeted inhibition of BCL6 functions that is emerging as the basis for design of anti-lymphoma therapies. This review focuses on recent progress in the molecular mechanisms of action of BCL6 in B cells and discusses remaining unresolved questions related to how these mechanisms are linked to normal and malignant B cell development.

  3. [B-cell targeted therapy for children and adolescents with rheumatic diseases].

    PubMed

    Morbach, H; Girschick, H J

    2013-05-01

    The introduction of cytokine-targeted therapies has significantly improved the treatment options of rheumatic diseases; however, some patients are also refractory to these treatment measures. The B cells play a central role in the pathogenesis of many rheumatic diseases and B-cell targeted therapies are a promising option as second-line medication for treating patients with a refractory disease course. Randomized controlled trials analyzing the efficacy of B-cell directed therapies for childhood rheumatic diseases have not yet been performed. The use of the B-cell depleting antibody rituximab showed positive results in non-controlled case series of juvenile systemic lupus erythematosus (SLE) patients. Patients with a refractory disease course of oligoarticular or polyarticular juvenile idiopathic arthritis might also benefit from B-cell depletion using rituximab. The B cell-targeting therapies for the treatment of childhood rheumatic diseases should be initiated and closely supervised by a pediatric rheumatologist.

  4. Pediatric human immunodeficiency virus infection and circulating IgD+ memory B cells.

    PubMed

    Jacobsen, Marianne C; Thiébaut, Rodolphe; Fisher, Christopher; Sefe, Delali; Clapson, Margaret; Klein, Nigel; Baxendale, Helen E

    2008-08-15

    Levels of circulating naive and memory B cells were measured in human immunodeficiency virus (HIV)-infected children and control subjects to determine whether the irreversible depletion of memory B cells described in HIV-infected adults occurs in children with HIV infection. Depletion of circulating IgD+ memory B cells was seen in HIV-infected children despite control of the HIV load with highly active antiretroviral therapy (HAART) (P =. 04). IgD+ memory B cell percentages did not correlate with CD4+ cell percentages (P =. 027) or disease duration (P =. 026). Naive/transitional and IgD- memory B cell numbers were not affected. Pediatric HIV infection is associated with selective depletion of circulating IgD+ memory B cells despite control of the HIV load with HAART.

  5. Subepithelial B cells in the human palatine tonsil. I. Morphologic, cytochemical and phenotypic characterization.

    PubMed

    Dono, M; Burgio, V L; Tacchetti, C; Favre, A; Augliera, A; Zupo, S; Taborelli, G; Chiorazzi, N; Grossi, C E; Ferrarini, M

    1996-09-01

    This study describes the purification of a subset of tonsillar B cells which share phenotypic, morphologic and cytochemical features with subepithelial (SE) B cells. These cells, which represented the 5-10% of the total tonsillar B cells, were found in the Percoll gradient fraction of highest density, together with resting follicular mantle (FM) B cells. The latter B cells, however, expressed surface CD5 and could be removed by an immune rosetting procedure. The remaining small CD5- B cells had a surface phenotype (IgM+, IgD+, CD23-, CD38+/-, CD10-, CD44+) that was different from that of FM (IgM+, IgD+, CD23+, CD39+, CD38-, CD10-, CD44+2) and of germinal center (GC) (CD23-, CD39-, CD38+, CD10+, CD44+/-, IgG+) B cells isolated from the same cell suspensions. Furthermore, the absence of surface activation markers (CD71 and CD69) and of surface IgG allowed us to distinguish small CD5- B cells from activated and memory cells migrating within Percoll fractions of lower density. In situ immunohistochemical studies revealed that B cells with an identical phenotype as that of small CD5- B cells could be detected predominantly in the SE region (lamina propria) of the tonsil, and also within the epithelium lining the cryptae. This area was also comprised of a relatively minor proportion of activated B cells, not found in the small CD5- B cell fraction owing to the separation procedure used. Consistent with the notion that the SE area could be a site of B cell activation was also the presence of activated macrophages and of plasma cells. Thirty to forty percent of small CD5- B cells isolated in suspension were positive for the endogeneous alkaline phosphatase (ALP) activity. In contrast, only a few FM B cells were ALP+, while GC cells were consistently ALP-. In situ studies also demonstrated a prevalent expression of ALP activity by the B cells in the SE area. At the ultrastructural level, small CD5- B cells were clearly different from both FM and GC B cells. They displayed a

  6. Perspectives on fetal-derived CD5+ B1 B cells

    PubMed Central

    Hardy, Richard R.; Hayakawa, Kyoko

    2015-01-01

    CD5+ B cell origins and their pre-disposition to lymphoma are long-standing issues. Transfer of fetal and adult liver bone marrow Pro-B cells generates B cells with distinct phenotypes: fetal cells generate IgMhighIgDlowCD5+, whereas adult cells IgMlowIgDhighCD5−. This suggests a developmental switch in B lymphopoiesis, similar to the switch in erythropoiesis. Comparison of mRNA and miRNA expression in fetal and adult Pro-B cells revealed differential expression of Lin28b mRNA and Let-7 miRNA, providing evidence that this regulatory axis functions in the switch. Recent work has shown that Arid3a is a key transcription factor mediating fetal-type B-cell development. Lin28b-promoted fetal development generates CD5+ B cells as a consequence of positively selected self-reactivity. CD5+ B cells play important roles in clearance of apoptotic cells and in protective immune responses, but also pose a risk of progression to leukemia/lymphoma. Differential Lin28b expression in fetal and adult human B-cell precursors showed that human B-cell development may resemble mouse, with self-reactive “innate-like” B cells generated early in life. It remains to be determined whether such human B cells have a higher propensity to leukemic progression. This review describes our recent research with CD5+ B cells and presents our perspective on their role in disease. PMID:26339791

  7. Determination of the Role of Estrogen Receptors and Estrogen Regulated Genes in B Cell Autoreactivity

    DTIC Science & Technology

    2010-07-01

    14. ABSTRACT Systemic lupus erythematosus (SLE) is an autoimmune disease that occurs preferentially in women. In murine models of SLE, it is... Systemic Lupus , Estrogen, BCR Signaling, B Cell Maturation, B Cell Selection 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF...therefore, be important to test ERα antagonists in murine studies of B cell development and in murine models of lupus . This approach to therapy might

  8. Quorum Sensing Contributes to Activated IgM-Secreting B Cell Homeostasis

    PubMed Central

    Montaudouin, Caroline; Anson, Marie; Hao, Yi; Duncker, Susanne V.; Fernandez, Tahia; Gaudin, Emmanuelle; Ehrenstein, Michael; Kerr, William G.; Colle, Jean-Hervé; Bruhns, Pierre; Daëron, Marc; Freitas, António A.

    2013-01-01

    Maintenance of plasma IgM levels is critical for immune system function and homeostasis in humans and mice. However, the mechanisms that control homeostasis of the activated IgM-secreting B cells are unknown. After adoptive transfer into immune-deficient hosts, B lymphocytes expand poorly, but fully reconstitute the pool of natural IgM-secreting cells and circulating IgM levels. By using sequential cell transfers and B cell populations from several mutant mice, we were able to identify novel mechanisms regulating the size of the IgM-secreting B cell pool. Contrary to previous mechanisms described regulating homeostasis, which involve competition for the same niche by cells having overlapping survival requirements, homeostasis of the innate IgM-secreting B cell pool is also achieved when B cell populations are able to monitor the number of activated B cells by detecting their secreted products. Notably, B cell populations are able to assess the density of activated B cells by sensing their secreted IgG. This process involves the FcγRIIB, a low-affinity IgG receptor that is expressed on B cells and acts as a negative regulator of B cell activation, and its intracellular effector the inositol phosphatase SHIP. As a result of the engagement of this inhibitory pathway, the number of activated IgM-secreting B cells is kept under control. We hypothesize that malfunction of this quorum-sensing mechanism may lead to uncontrolled B cell activation and autoimmunity. PMID:23209322

  9. Age-related differences in human palatine tonsillar B cell subsets and immunoglobulin isotypes.

    PubMed

    Lee, Jino; Chang, Dong-Yeop; Kim, Sang-Wook; Choi, Yoon Seok; Jeon, Sea-Yuong; Racanelli, Vito; Kim, Dae Woo; Shin, Eui-Cheol

    2016-02-01

    The tonsils provide defense of the upper aerodigestive tract against pathogens. Although long known to undergo functional changes with age, the precise changes occurring within tonsillar B cell populations remain undefined. In the present study, we investigated age-related changes in palatine tonsillar B cell subsets and immunoglobulin (Ig) isotypes. Palatine tonsils were obtained from forty-two tonsillectomy patients without tonsillitis who were divided into three groups: young children (4-9 years), adolescents (10-19 years), and adults (20-60 years). Tonsillar B cells were then analyzed by flow cytometry. Using expression of CD38 and IgD to define B cell subsets, we found that the frequency of germinal center (GC) B cells in the tonsils was significantly higher, and the frequency of memory B cells lower, in young children as compared to adolescents and adults. Within the GC B cell subsets, adults had a higher frequency of IgA(+) cells and a lower frequency of IgM(+) cells as compared to individuals in the younger age groups. Moreover, young children had a higher frequency of IgG(+) cells in the GC B cell subsets than did individuals in the older age groups. We also observed an abundance of IgM(+) cells among memory B cells and plasmablasts in young children and IgA(+) cells in adults. In summary, the proportion of GC B cells in palatine tonsillar B cells decreases with age, while the proportion of memory B cells increases with age. In addition, Ig isotypes in tonsils preferentially switch from IgM to IgA as individuals age.

  10. Translating transitions – how to decipher peripheral human B cell development

    PubMed Central

    Bemark, Mats

    2015-01-01

    Abstract During the last two decades our understanding of human B cell differentiation has developed considerably. Our understanding of the human B cell compartment has advanced from a point where essentially all assays were based on the presence or not of class-switched antibodies to a level where a substantial diversity is appreciated among the cells involved. Several consecutive transitional stages that newly formed IgM expressing B cells go through after they leave the bone marrow, but before they are fully mature, have been described, and a significant complexity is also acknowledged within the IgM expressing and class-switched memory B cell compartments. It is possible to isolate plasma blasts in blood to follow the formation of plasma cells during immune responses, and the importance and uniqueness of the mucosal IgA system is now much more appreciated. Current data suggest the presence of at least one lineage of human innate-like B cells akin to B1 and/or marginal zone B cells in mice. In addition, regulatory B cells with the ability to produce IL-10 have been identified. Clinically, B cell depletion therapy is used for a broad range of conditions. The ability to define different human B cell subtypes using flow cytometry has therefore started to come into clinical use, but as our understanding of human B cell development further progresses, B cell subtype analysis will be of increasing importance in diagnosis, to measure the effect of immune therapy and to understand the underlying causes for diseases. In this review the diversity of human B cells will be discussed, with special focus on current data regarding their phenotypes and functions. PMID:26243514

  11. B cells as multi-functional players during Mycobacterium tuberculosis infection and disease.

    PubMed

    du Plessis, Willem J; Walzl, Gerhard; Loxton, André G

    2016-03-01

    Immunity to tuberculosis is still understood to be driven and maintained by T-cell derived immune responses. With a steady influx of data, it is becoming clear that B cells, the mediators of humoral immunity, have the capacity to function in roles not previously appreciated within the traditional B cell dogma. In this review we aim to discuss B cells, from its generation through to its functioning as effectors in both the innate and adaptive immune response, within the tuberculosis domain.

  12. B-cell homeostasis requires complementary CD22 and BLyS/BR3 survival signals

    PubMed Central

    Smith, Susan H.; Haas, Karen M.; Poe, Jonathan C.; Yanaba, Koichi; Ward, Christopher D.; Migone, Thi-Sau

    2010-01-01

    Peripheral B-cell numbers are tightly regulated by homeostatic mechanisms that influence the transitional and mature B-cell compartments and dictate the size and clonotypic diversity of the B-cell repertoire. B-lymphocyte stimulator (BLyS, a trademark of Human Genome Sciences, Inc.) plays a key role in regulating peripheral B-cell homeostasis. CD22 also promotes peripheral B-cell survival through ligand-dependent mechanisms. The B-cell subsets affected by the absence of BLyS and CD22 signals overlap, suggesting that BLyS- and CD22-mediated survival are intertwined. To examine this, the effects of BLyS insufficiency following neutralizing BLyS mAb treatment in mice also treated with CD22 ligand-blocking mAb were examined. Combined targeting of the BLyS and CD22 survival pathways led to significantly greater clearance of recirculating bone marrow, blood, marginal zone and follicular B cells than either treatment alone. Likewise, BLyS blockade further reduced bone marrow, blood and spleen B-cell numbers in CD22−/− mice. Notably, BLyS receptor expression and downstream signaling were normal in CD22−/− B cells, suggesting that CD22 does not directly alter BLyS responsiveness. CD22 survival signals were likewise intact in the absence of BLyS, as CD22 mAb treatment depleted blood B cells from mice with impaired BLyS receptor 3 (BR3) signaling. Finally, enforced BclxL expression, which rescues BR3 impairment, did not affect B-cell depletion following CD22 mAb treatment. Thus, the current studies support a model whereby CD22 and BLyS promote the survival of overlapping B-cell subsets but contribute to their maintenance through independent and complementary signaling pathways. PMID:20513733

  13. Targeted Therapies in Adult B-Cell Malignancies

    PubMed Central

    Rossi, Jean-François

    2015-01-01

    B-lymphocytes are programmed for the production of immunoglobulin (Ig) after antigen presentation, in the context of T-lymphocyte control within lymphoid organs. During this differentiation/activation process, B-lymphocytes exhibit different restricted or common surface markers, activation of cellular pathways that regulate cell cycle, metabolism, proteasome activity, and protein synthesis. All molecules involved in these different cellular mechanisms are potent therapeutic targets. Nowadays, due to the progress of the biology, more and more targeted drugs are identified, a situation that is correlated with an extended field of the targeted therapy. The full knowledge of the cellular machinery and cell-cell communication allows making the best choice to treat patients, in the context of personalized medicine. Also, focus should not be restricted to the immediate effects observed as clinical endpoints, that is, response rate, survival markers with conventional statistical methods, but it should consider the prediction of different clinical consequences due to other collateral drug targets, based on new methodologies. This means that new reflection and new bioclinical follow-up have to be monitored, particularly with the new drugs used with success in B-cell malignancies. This review discussed the principal aspects of such evident bioclinical progress. PMID:26425544

  14. Epigenetic Heterogeneity of B-Cell Lymphoma: Chromatin Modifiers

    PubMed Central

    Hopp, Lydia; Nersisyan, Lilit; Löffler-Wirth, Henry; Arakelyan, Arsen; Binder, Hans

    2015-01-01

    We systematically studied the expression of more than fifty histone and DNA (de)methylating enzymes in lymphoma and healthy controls. As a main result, we found that the expression levels of nearly all enzymes become markedly disturbed in lymphoma, suggesting deregulation of large parts of the epigenetic machinery. We discuss the effect of DNA promoter methylation and of transcriptional activity in the context of mutated epigenetic modifiers such as EZH2 and MLL2. As another mechanism, we studied the coupling between the energy metabolism and epigenetics via metabolites that act as cofactors of JmjC-type demethylases. Our study results suggest that Burkitt’s lymphoma and diffuse large B-cell Lymphoma differ by an imbalance of repressive and poised promoters, which is governed predominantly by the activity of methyltransferases and the underrepresentation of demethylases in this regulation. The data further suggest that coupling of epigenetics with the energy metabolism can also be an important factor in lymphomagenesis in the absence of direct mutations of genes in metabolic pathways. Understanding of epigenetic deregulation in lymphoma and possibly in cancers in general must go beyond simple schemes using only a few modes of regulation. PMID:26506391

  15. B cells and their role in the teleost gut

    PubMed Central

    Korytář, Tomáš; Takizawa, Fumio

    2016-01-01

    Mucosal surfaces are the main route of entry for pathogens in all living organisms. In the case of teleost fish, mucosal surfaces cover the vast majority of the animal. As these surfaces are in constant contact with the environment, fish are perpetually exposed to a vast number of pathogens. Despite the potential prevalence and variety of pathogens, mucosal surfaces are primarily populated by commensal non-pathogenic bacteria. Indeed, a fine balance between these two populations of microorganisms is crucial for animal survival. This equilibrium, controlled by the mucosal immune system, maintains homeostasis at mucosal tissues. Teleost fish possess a diffuse mucosa-associated immune system in the intestine, with B cells being one of the main responders. Immunoglobulins produced by these lymphocytes are a critical line of defense against pathogens and also prevent the entrance of commensal bacteria into the epithelium. In this review we will summarize recent literature regarding the role of B-lymphocytes and immunoglobulins in gut immunity in teleost fish, with specific focus on immunoglobulin isotypes and the microorganisms, pathogenic and non-pathogenic that interact with the immune system. PMID:26995768

  16. A rare case of primary cardiac B cell lymphoma

    PubMed Central

    2014-01-01

    Primary cardiac lymphomas represent an extremely rare entity of extranodal lymphomas and should be distinguished from secondary cardiac involvement of disseminated lymphomas belonging to the non-Hodgkin’s classification of blood cancers. Only 90 cases have been reported in literature. Presentation of cardiac lymphomas on imaging studies may not be unambiguous since they potentially mimic other cardiac neoplasms including myxomas, angiosarcoma or rhadomyomas and therefore require multimodality cardiac imaging, endomyocardial biopsy, excisional intraoperative biopsy and pericardial fluid cytological evaluation to establish final diagnosis. Herein we report the case of a 70 y/o immunocompetent Caucasian female with a rapidly progressing superior vena cava syndrome secondary to a large primary cardiac diffuse large B cell lymphoma (NHL lymphoma) almost completely obstructing the right atrium, right ventricle and affecting both mitral and tricuspid valve. The patient had no clinical evidence of disseminated disease and was successfully treated with extensive debulking during open-heart surgery on cardiopulmonary bypass and 6 cycles of rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone chemotherapy (R-CHOP). PMID:24422789

  17. Relapsed/refractory diffuse large B-cell lymphoma.

    PubMed

    Friedberg, Jonathan W

    2011-01-01

    Despite overall improvements in outcomes of diffuse large B-cell lymphoma (DLBCL), approximately one-third of patients will develop relapsed/refractory disease that remains a major cause of morbidity and mortality. Novel insights from gene-expression analyses have increased our understanding of chemotherapy resistance and yielded rational targets for therapeutic intervention to both prevent and treat relapsed/refractory DLBCL. The clinical approach to relapsed/refractory DLBCL should include high-dose therapy and autologous stem cell transplantation (HD-ASCT) with curative intent in patients without comorbidities. Results from the recently reported CORAL study suggest that patients refractory to rituximab-containing regimens have inferior outcomes with HD-ASCT. Ongoing efforts to improve ASCT include novel conditioning regimens and evaluation of maintenance approaches after ASCT. Unfortunately, because the majority of patients are not eligible for ASCT due to refractory disease or age/comorbidities, these approaches have limited impact. The large group of patients not eligible for ASCT have incurable disease and should be referred for clinical trials of rationally targeted agents.

  18. B Cell-Based Seamless Engineering of Antibody Fc Domains

    PubMed Central

    Murayama, Akiho; Ohta, Kunihiro

    2016-01-01

    Engineering of monoclonal antibodies (mAbs) enables us to obtain mAbs with additional functions. In particular, modifications in antibody’s Fc (fragment, crystallizable) region can provide multiple benefits such as added toxicity by drug conjugation, higher affinity to Fc receptors on immunocytes, or the addition of functional modules. However, the generation of recombinant antibodies requires multiple laborious bioengineering steps. We previously developed a technology that enables rapid in vitro screening and isolation of specific mAb-expressing cells from the libraries constructed with chicken B-cell line DT40 (referred to as the ‘ADLib system’). To upgrade this ADLib system with the ability to generate customized mAbs, we developed a novel and rapid engineering technology that enables seamless exchanges of mAbs’ Fc domains after initial selections of mAb-producing clones by the ADLib system, using a gene-replacement unit for recombinase-mediated cassette exchange (RMCE). In this system, Cre-recombinase recognition sites were inserted into the Fc region of the active DT40 IgM allele, allowing the replacement of the Fc domain by the sequences of interest upon co-transfection of a Cre recombinase and a donor DNA, enabling the rapid exchange of Fc regions. Combining this method with the ADLib system, we demonstrate rapid Fc engineering to generate fluorescent antibodies and to enhance affinity to Fc receptors. PMID:27907066

  19. The human fetal lymphocyte lineage: identification by CD27 and LIN28B expression in B cell progenitors

    PubMed Central

    McWilliams, Laurie; Su, Kuei-Ying; Liang, Xiaoe; Liao, Dongmei; Floyd, Serina; Amos, Joshua; Moody, M. Anthony; Kelsoe, Garnett; Kuraoka, Masayuki

    2013-01-01

    CD27, a member of the TNFR superfamily, is used to identify human memory B cells. Nonetheless, CD27+ B cells are present in patients with HIGM1 syndrome who are unable to generate GCs or memory B cells. CD27+IgD+ fetal B cells are present in umbilical cord blood, and CD27 may also be a marker of the human B1-like B cells. To define the origin of naïve CD27+IgD+ human B cells, we studied B cell development in both fetal and adult tissues. In human FL, most CD19+ cells coexpressed CD10, a marker of human developing B cells. Some CD19+CD10+ B cells expressed CD27, and these fetal CD27+ cells were present in the pro-B, pre-B, and immature/transitional B cell compartments. Lower frequencies of phenotypically identical cells were also identified in adult BM. CD27+ pro-B, pre-B, and immature/transitional B cells expressed recombination activating gene-1, terminal deoxynucleotidyl transferase and Vpre-B mRNA comparably to their CD27− counterparts. CD27+ and CD27− developing B cells showed similar Ig heavy chain gene usage with low levels of mutations, suggesting that CD27+ developing B cells are distinct from mutated memory B cells. Despite these similarities, CD27+ developing B cells differed from CD27− developing B cells by their increased expression of LIN28B, a transcription factor associated with the fetal lymphoid lineages of mice. Furthermore, CD27+ pro-B cells efficiently generated IgM+IgD+ immature/transitional B cells in vitro. Our observations suggest that CD27 expression during B cell development identifies a physiologic state or lineage for human B cell development distinct from the memory B cell compartment. PMID:23901121

  20. PI3K Signaling in Normal B Cells and Chronic Lymphocytic Leukemia (CLL)

    PubMed Central

    Okkenhaug, Klaus; Burger, Jan A.

    2016-01-01

    B cells provide immunity to extracellular pathogens by secreting a diverse repertoire of antibodies with high affinity and specificity for exposed antigens. The B cell receptor (BCR) is a transmembrane antibody, which facilitates the clonal selection of B cells producing secreted antibodies of the same specificity. The diverse antibody repertoire is generated by V(D)J recombination of heavy and light chain genes, whereas affinity maturation is mediated by activation-induced cytidine deaminase (AID)-mediated mutagenesis. These processes, which are essential for the generation of adaptive humoral immunity, also render B cells susceptible to chromosomal rearrangements and point mutations that in some cases lead to cancer. In this chapter, we will review the central role of PI3Ks in mediating signals from the B cell receptor that not only facilitate the development of functional B cell repertoire, but also support the growth and survival of neoplastic B cells, focusing on chronic lymphocytic leukemia (CLL) B cells. Perhaps because of the central role played by PI3K in BCR signaling, B cell leukemia and lymphomas are the first diseases for which a PI3K inhibitor has been approved for clinical use. PMID:26350103

  1. Mediation of transitional B cell maturation in the absence of functional Bruton's tyrosine kinase.

    PubMed

    Tanwar, Shalini; Dhar, Atika; Varanasi, Vineeth; Mukherjee, Tapas; Boppana, Ramanamurthy; Basak, Soumen; Bal, Vineeta; George, Anna; Rath, Satyajit

    2017-04-05

    X-linked immune-deficient (Xid) mice, carrying a mutation in Bruton's tyrosine kinase (Btk), have multiple B cell lineage differentiation defects. We now show that, while Xid mice showed only mild reduction in the frequency of the late transitional (T2) stage of peripheral B cells, the defect became severe when the Xid genotype was combined with either a CD40-null, a TCRbeta-null or an MHC class II (MHCII)-null genotype. Purified Xid T1 and T2 B cells survived poorly in vitro compared to wild-type (WT) cells. BAFF rescued WT but not Xid T1 and T2 B cells from death in culture, while CD40 ligation equivalently rescued both. Xid transitional B cells ex vivo showed low levels of the p100 protein substrate for non-canonical NF-kappaB signalling. In vitro, CD40 ligation induced equivalent activation of the canonical but not of the non-canonical NF-kappaB pathway in Xid and WT T1 and T2 B cells. CD40 ligation efficiently rescued p100-null T1 B cells from neglect-induced death in vitro. These data indicate that CD40-mediated signals, likely from CD4 T cells, can mediate peripheral transitional B cell maturation independent of Btk and the non-canonical NF-kappaB pathway, and thus contribute to the understanding of the complexities of peripheral B cell maturation.

  2. CD22 Regulates Adaptive and Innate Immune Responses of B Cells

    PubMed Central

    Kawasaki, Norihito; Rademacher, Christoph; Paulson, James C.

    2011-01-01

    B cells sense microenvironments through the B cell receptor (BCR) and Toll-like receptors (TLRs). While signals from BCR and TLRs synergize to distinguish self from nonself, inappropriate regulation can result in development of autoimmune disease. Here we show that CD22, an inhibitory co-receptor of BCR, also negatively regulates TLR signaling in B cells. CD22-deficient (Cd22–/–) B cells exhibit hyperactivation in response to ligands of TLRs 3, 4 and 9. Evidence suggests that this results from impaired induction of suppressors of cytokine signaling 1 and 3, well-known suppressors of TLR signaling. Antibody-mediated sequestration of CD22 on wild-type (WT) B cells augments proliferation by TLR ligands. Conversely, expression of CD22 in a Cd22–/– B cell line blunts responses to TLR ligands. We also show that lipopolysaccharide-induced transcription by nuclear factor-κB is inhibited by ectopic expression of CD22 in a TLR4 reporter cell line. Taken together, these results suggest that negative regulation of TLR signaling is an intrinsic property of CD22. Since TLRs and BCR activate B cells through different signaling pathways, and are differentially localized in B cells, CD22 exhibits a broader regulation of receptors that mediate adaptive and innate immune responses of B cells than previously recognized. PMID:21178327

  3. Decreased somatic hypermutation induces an impaired peripheral B cell tolerance checkpoint

    PubMed Central

    Cantaert, Tineke; Schickel, Jean-Nicolas; Bannock, Jason M.; Ng, Yen-Shing; Massad, Christopher; Delmotte, Fabien R.; Yamakawa, Natsuko; Glauzy, Salome; Chamberlain, Nicolas; Kinnunen, Tuure; Menard, Laurence; Lavoie, Aubert; Walter, Jolan E.; Notarangelo, Luigi D.; Bruneau, Julie; Al-Herz, Waleed; Kilic, Sara Sebnem; Ochs, Hans D.; Cunningham-Rundles, Charlotte; Kuijpers, Taco W.; Kracker, Sven; Kaneko, Hideo; Nonoyama, Shigeaki; Durandy, Anne

    2016-01-01

    Patients with mutations in AICDA, which encodes activation-induced cytidine deaminase (AID), display an impaired peripheral B cell tolerance. AID mediates class-switch recombination (CSR) and somatic hypermutation (SHM) in B cells, but the mechanism by which AID prevents the accumulation of autoreactive B cells in blood is unclear. Here, we analyzed B cell tolerance in AID-deficient patients, patients with autosomal dominant AID mutations (AD-AID), asymptomatic AICDA heterozygotes (AID+/–), and patients with uracil N-glycosylase (UNG) deficiency, which impairs CSR but not SHM. The low frequency of autoreactive mature naive B cells in UNG-deficient patients resembled that of healthy subjects, revealing that impaired CSR does not interfere with the peripheral B cell tolerance checkpoint. In contrast, we observed decreased frequencies of SHM in memory B cells from AD-AID patients and AID+/– subjects, who were unable to prevent the accumulation of autoreactive mature naive B cells. In addition, the individuals with AICDA mutations, but not UNG-deficient patients, displayed Tregs with defective suppressive capacity that correlated with increases in circulating T follicular helper cells and enhanced cytokine production. We conclude that SHM, but not CSR, regulates peripheral B cell tolerance through the production of mutated antibodies that clear antigens and prevent sustained interleukin secretions that interfere with Treg function. PMID:27701145

  4. Adhesion of Human B Cells to Germinal Centers in Vitro Involves VLA-4 and INCAM-110

    NASA Astrophysics Data System (ADS)

    Freedman, Arnold S.; Munro, J. Michael; Rice, G. Edgar; Bevilacqua, Michael P.; Morimoto, Chikao; McIntyre, Bradley W.; Rhynhart, Kurt; Pober, Jordan S.; Nadler, Lee M.

    1990-08-01

    Human B lymphocytes localize and differentiate within the microenvironment of lymphoid germinal centers. A frozen section binding assay was developed for the identification of those molecules involved in the adhesive interactions between B cells and lymphoid follicles. Activated human B cells and B cell lines were found to selectively adhere to germinal centers. The VLA-4 molecule on the lymphocyte and the adhesion molecule INCAM-110, expressed on follicular dendritic cells, supported this interaction. This cellular interaction model can be used for the study of how B cells differentiate.

  5. Signaling and Dynamic Actin Responses of B Cells on Topographical Substrates

    NASA Astrophysics Data System (ADS)

    Ketchum, Christina; Sun, Xiaoyu; Fourkas, John; Song, Wenxia; Upadhyaya, Arpita

    B cells become activated upon physical contact with antigen on the surface of antigen presenting cells, such as dendritic cells. Binding of the B cell receptor with antigen initiates actin-mediated spreading of B cells, signaling cascades and eventually infection fighting antibodies. Lymphocytes, including B cells and T cells, have been shown to be responsive to the physical parameters of the contact surface, such as antigen mobility and substrate stiffness. However the roll of surface topography on lymphocyte function is unknown. Here we investigate the degree to which substrate topography controls actin-mediated spreading and B cell activation using nano-fabricated surfaces and live cell imaging. The model topographical system consists of 600 nanometer tall ridges with spacing varying between 800 nanometers and 5 micrometers. Using TIRF imaging we observe actin dynamics, B cell receptor motion and calcium signaling of B cells as they spread on the ridged substrates. We show that the spacing between ridges had a strong effect on the dynamics of actin and calcium influx on B cells. Our results indicate that B cells are highly sensitive to surface topography during cell spreading and signaling activation.

  6. Decreased somatic hypermutation induces an impaired peripheral B cell tolerance checkpoint.

    PubMed

    Cantaert, Tineke; Schickel, Jean-Nicolas; Bannock, Jason M; Ng, Yen-Shing; Massad, Christopher; Delmotte, Fabien R; Yamakawa, Natsuko; Glauzy, Salome; Chamberlain, Nicolas; Kinnunen, Tuure; Menard, Laurence; Lavoie, Aubert; Walter, Jolan E; Notarangelo, Luigi D; Bruneau, Julie; Al-Herz, Waleed; Kilic, Sara Sebnem; Ochs, Hans D; Cunningham-Rundles, Charlotte; van der Burg, Mirjam; Kuijpers, Taco W; Kracker, Sven; Kaneko, Hideo; Sekinaka, Yujin; Nonoyama, Shigeaki; Durandy, Anne; Meffre, Eric

    2016-11-01

    Patients with mutations in AICDA, which encodes activation-induced cytidine deaminase (AID), display an impaired peripheral B cell tolerance. AID mediates class-switch recombination (CSR) and somatic hypermutation (SHM) in B cells, but the mechanism by which AID prevents the accumulation of autoreactive B cells in blood is unclear. Here, we analyzed B cell tolerance in AID-deficient patients, patients with autosomal dominant AID mutations (AD-AID), asymptomatic AICDA heterozygotes (AID+/-), and patients with uracil N-glycosylase (UNG) deficiency, which impairs CSR but not SHM. The low frequency of autoreactive mature naive B cells in UNG-deficient patients resembled that of healthy subjects, revealing that impaired CSR does not interfere with the peripheral B cell tolerance checkpoint. In contrast, we observed decreased frequencies of SHM in memory B cells from AD-AID patients and AID+/- subjects, who were unable to prevent the accumulation of autoreactive mature naive B cells. In addition, the individuals with AICDA mutations, but not UNG-deficient patients, displayed Tregs with defective suppressive capacity that correlated with increases in circulating T follicular helper cells and enhanced cytokine production. We conclude that SHM, but not CSR, regulates peripheral B cell tolerance through the production of mutated antibodies that clear antigens and prevent sustained interleukin secretions that interfere with Treg function.

  7. Accumulation of peripheral autoreactive B cells in the absence of functional human regulatory T cells

    PubMed Central

    Kinnunen, Tuure; Chamberlain, Nicolas; Morbach, Henner; Choi, Jinyoung; Kim, Sangtaek; Craft, Joseph; Mayer, Lloyd; Cancrini, Caterina; Passerini, Laura; Bacchetta, Rosa; Ochs, Hans D.; Torgerson, Troy R.

    2013-01-01

    Regulatory T cells (Tregs) play an essential role in preventing autoimmunity. Mutations in the forkhead box protein 3 (FOXP3) gene, which encodes a transcription factor critical for Treg function, result in a severe autoimmune disorder and the production of various autoantibodies in mice and in IPEX (immune dysregulation, polyendocrinopathy, enteropathy, X-linked) patients. However, it is unknown whether Tregs normally suppress autoreactive B cells. To investigate a role for Tregs in maintaining human B-cell tolerance, we tested the reactivity of recombinant antibodies isolated from single B cells isolated from IPEX patients. Characteristics and reactivity of antibodies expressed by new emigrant/transitional B cells from IPEX patients were similar to those from healthy donors, demonstrating that defective Treg function does not impact central B-cell tolerance. In contrast, mature naive B cells from IPEX patients often expressed autoreactive antibodies, suggesting an important role for Tregs in maintaining peripheral B-cell tolerance. T cells displayed an activated phenotype in IPEX patients, including their Treg-like cells, and showed up-regulation of CD40L, PD-1, and inducibl T-cell costimulator (ICOS), which may favor the accumulation of autoreactive mature naive B cells in these patients. Hence, our data demonstrate an essential role for Tregs in the establishment and the maintenance of peripheral B-cell tolerance in humans. PMID:23223361

  8. MicroRNA-155 influences B-cell function through PU.1 in rheumatoid arthritis

    PubMed Central

    Alivernini, Stefano; Kurowska-Stolarska, Mariola; Tolusso, Barbara; Benvenuto, Roberta; Elmesmari, Aziza; Canestri, Silvia; Petricca, Luca; Mangoni, Antonella; Fedele, Anna Laura; Di Mario, Clara; Gigante, Maria Rita; Gremese, Elisa; McInnes, Iain B.; Ferraccioli, Gianfranco

    2016-01-01

    MicroRNA-155 (miR-155) is an important regulator of B cells in mice. B cells have a critical role in the pathogenesis of rheumatoid arthritis (RA). Here we show that miR-155 is highly expressed in peripheral blood B cells from RA patients compared with healthy individuals, particularly in the IgD-CD27- memory B-cell population in ACPA+ RA. MiR-155 is highly expressed in RA B cells from patients with synovial tissue containing ectopic germinal centres compared with diffuse synovial tissue. MiR-155 expression is associated reciprocally with lower expression of PU.1 at B-cell level in the synovial compartment. Stimulation of healthy donor B cells with CD40L, anti-IgM, IL-21, CpG, IFN-α, IL-6 or BAFF induces miR-155 and decreases PU.1 expression. Finally, inhibition of endogenous miR-155 in B cells of RA patients restores PU.1 and reduces production of antibodies. Our data suggest that miR-155 is an important regulator of B-cell activation in RA. PMID:27671860

  9. Coordinate suppression of B cell lymphoma by PTEN and SHIP phosphatases.

    PubMed

    Miletic, Ana V; Anzelon-Mills, Amy N; Mills, David M; Omori, Sidne A; Pedersen, Irene M; Shin, Dong-Mi; Ravetch, Jeffrey V; Bolland, Silvia; Morse, Herbert C; Rickert, Robert C

    2010-10-25

    The inositol phosphatases phosphatase and tensin homologue (PTEN) and Src homology 2 domain-containing inositol phosphatase (SHIP) negatively regulate phosphatidylinositol-3-kinase (PI3K)-mediated growth, survival, and proliferation of hematopoietic cells. Although deletion of PTEN in mouse T cells results in lethal T cell lymphomas, we find that animals lacking PTEN or SHIP in B cells show no evidence of malignancy. However, concomitant deletion of PTEN and SHIP (bPTEN/SHIP(-/-)) results in spontaneous and lethal mature B cell neoplasms consistent with marginal zone lymphoma or, less frequently, follicular or centroblastic lymphoma. bPTEN/SHIP(-/-) B cells exhibit enhanced survival and express more MCL1 and less Bim. These cells also express low amounts of p27(kip1) and high amounts of cyclin D3 and thus appear poised to undergo proliferative expansion. Unlike normal B cells, bPTEN/SHIP(-/-) B cells proliferate to the prosurvival factor B cell activating factor (BAFF). Interestingly, although BAFF availability may promote lymphoma progression, we demonstrate that BAFF is not required for the expansion of transferred bPTEN/SHIP(-/-) B cells. This study reveals that PTEN and SHIP act cooperatively to suppress B cell lymphoma and provides the first direct evidence that SHIP is a tumor suppressor. As such, assessment of both PTEN and SHIP function are relevant to understanding the etiology of human B cell malignancies that exhibit augmented activation of the PI3K pathway.

  10. MicroRNA-155 influences B-cell function through PU.1 in rheumatoid arthritis.

    PubMed

    Alivernini, Stefano; Kurowska-Stolarska, Mariola; Tolusso, Barbara; Benvenuto, Roberta; Elmesmari, Aziza; Canestri, Silvia; Petricca, Luca; Mangoni, Antonella; Fedele, Anna Laura; Di Mario, Clara; Gigante, Maria Rita; Gremese, Elisa; McInnes, Iain B; Ferraccioli, Gianfranco

    2016-09-27

    MicroRNA-155 (miR-155) is an important regulator of B cells in mice. B cells have a critical role in the pathogenesis of rheumatoid arthritis (RA). Here we show that miR-155 is highly expressed in peripheral blood B cells from RA patients compared with healthy individuals, particularly in the IgD(-)CD27(-) memory B-cell population in ACPA(+) RA. MiR-155 is highly expressed in RA B cells from patients with synovial tissue containing ectopic germinal centres compared with diffuse synovial tissue. MiR-155 expression is associated reciprocally with lower expression of PU.1 at B-cell level in the synovial compartment. Stimulation of healthy donor B cells with CD40L, anti-IgM, IL-21, CpG, IFN-α, IL-6 or BAFF induces miR-155 and decreases PU.1 expression. Finally, inhibition of endogenous miR-155 in B cells of RA patients restores PU.1 and reduces production of antibodies. Our data suggest that miR-155 is an important regulator of B-cell activation in RA.

  11. Interferon-driven deletion of antiviral B cells at the onset of chronic infection

    PubMed Central

    Ertuna, Yusuf I.; Remy, Melissa; Sommerstein, Rami; Cornille, Karen; Kreutzfeldt, Mario; Page, Nicolas; Zimmer, Gert; Geier, Florian; Straub, Tobias; Pircher, Hanspeter; Larimore, Kevin; Greenberg, Philip D.; Merkler, Doron; Pinschewer, Daniel D.

    2016-01-01

    Inadequate antibody responses and perturbed B cell compartments represent hallmarks of persistent microbial infections, but the mechanisms whereby persisting pathogens suppress humoral immunity remain poorly defined. Using adoptive transfer experiments in the context of a chronic lymphocytic choriomeningitis virus (LCMV) infection of mice, we have documented rapid depletion of virus-specific B cells that coincided with the early type I interferon response to infection. We found that the loss of activated B cells was driven by type I interferon (IFN-I) signaling to several cell types including dendritic cells, T cells and myeloid cells. Intriguingly, this process was independent of B cell-intrinsic IFN-I sensing and resulted from biased differentiation of naïve B cells into short-lived antibody-secreting cells. The ability to generate robust B cell responses was restored upon IFN-I receptor blockade or, partially, when experimentally depleting myeloid cells or the IFN-I-induced cytokines interleukin 10 and tumor necrosis factor alpha. We have termed this IFN-I-driven depletion of B cellsB cell decimation”. Strategies to counter “B cell decimation” should thus help us better leverage humoral immunity in the combat against persistent microbial diseases. PMID:27872905

  12. EndoU is a novel regulator of AICD during peripheral B cell selection

    PubMed Central

    Poe, Jonathan C.; Kountikov, Evgueni I.; Lykken, Jacquelyn M.; Natarajan, Abirami; Marchuk, Douglas A.

    2014-01-01

    Balanced transmembrane signals maintain a competent peripheral B cell pool limited in self-reactive B cells that may produce pathogenic autoantibodies. To identify molecules regulating peripheral B cell survival and tolerance to self-antigens (Ags), a gene modifier screen was performed with B cells from CD22-deficient C57BL/6 (CD22−/−[B6]) mice that undergo activation-induced cell death (AICD) and fail to up-regulate c-Myc expression after B cell Ag receptor ligation. Likewise, lysozyme auto-Ag–specific B cells in IgTg hen egg lysozyme (HEL) transgenic mice inhabit the spleen but undergo AICD after auto-Ag encounter. This gene modifier screen identified EndoU, a single-stranded RNA-binding protein of ancient origin, as a major regulator of B cell survival in both models. EndoU gene disruption prevents AICD and normalizes c-Myc expression. These findings reveal that EndoU is a critical regulator of an unexpected and novel RNA-dependent pathway controlling peripheral B cell survival and Ag responsiveness that may contribute to peripheral B cell tolerance. PMID:24344237

  13. Critical roles for Rac1 and Rac2 GTPases in B cell development and signaling.

    PubMed

    Walmsley, Marita J; Ooi, Steen K T; Reynolds, Lucinda F; Smith, Susan Harless; Ruf, Sandra; Mathiot, Anne; Vanes, Lesley; Williams, David A; Cancro, Michael P; Tybulewicz, Victor L J

    2003-10-17

    The Rac1 guanosine triphosphatase (GTPase) has been implicated in multiple cellular functions, including actin dynamics, proliferation, apoptosis, adhesion, and migration resulting from signaling by multiple receptors, including the B cell antigen receptor (BCR). We used conditional gene targeting to generate mice with specific Rac1 deficiency in the B cell lineage. In the absence of both Rac1 and the highly related Rac2, B cell development was almost completely blocked. Both GTPases were required to transduce BCR signals leading to proliferation, survival and up-regulation of BAFF-R, a receptor for BAFF, a key survival molecule required for B cell development and maintenance.

  14. Mediation of transitional B cell maturation in the absence of functional Bruton’s tyrosine kinase

    PubMed Central

    Tanwar, Shalini; Dhar, Atika; Varanasi, Vineeth; Mukherjee, Tapas; Boppana, Ramanamurthy; Basak, Soumen; Bal, Vineeta; George, Anna; Rath, Satyajit

    2017-01-01

    X-linked immune-deficient (Xid) mice, carrying a mutation in Bruton’s tyrosine kinase (Btk), have multiple B cell lineage differentiation defects. We now show that, while Xid mice showed only mild reduction in the frequency of the late transitional (T2) stage of peripheral B cells, the defect became severe when the Xid genotype was combined with either a CD40-null, a TCRbeta-null or an MHC class II (MHCII)-null genotype. Purified Xid T1 and T2 B cells survived poorly in vitro compared to wild-type (WT) cells. BAFF rescued WT but not Xid T1 and T2 B cells from death in culture, while CD40 ligation equivalently rescued both. Xid transitional B cells ex vivo showed low levels of the p100 protein substrate for non-canonical NF-kappaB signalling. In vitro, CD40 ligation induced equivalent activation of the canonical but not of the non-canonical NF-kappaB pathway in Xid and WT T1 and T2 B cells. CD40 ligation efficiently rescued p100-null T1 B cells from neglect-induced death in vitro. These data indicate that CD40-mediated signals, likely from CD4 T cells, can mediate peripheral transitional B cell maturation independent of Btk and the non-canonical NF-kappaB pathway, and thus contribute to the understanding of the complexities of peripheral B cell maturation. PMID:28378771

  15. Phosphatidylserine Outer Layer Translocation Is Implicated in IL-10 Secretion by Human Regulatory B Cells.

    PubMed

    Audo, Rachel; Hua, Charlotte; Hahne, Michael; Combe, Bernard; Morel, Jacques; Daien, Claire I

    2017-01-01

    B cells can have a regulatory role, mainly mediated by interleukin 10 (IL-10). IL-10 producing B cells (B10 cells) cells remain to be better characterized. Annexin V binds phosphatidylserine (PS), which is externalized during apoptosis. Previous works suggested that B10 cells are apoptotic cells since they bind Annexin V. Others showed that Annexin V binding could also be expressed on viable B cells. We aimed to explore if PS exposure can be a marker of B10 cells and if PS exposure has a functional role on B cell IL-10 production in healthy subjects. We found that B10 cells were significantly more often Annexin V+ than IL-10 non-producing B cells. After CpG activation, Annexin V+ B cells differentiated more often into B10 cells than Annexin Vneg B cells. Cell death and early apoptosis were similar between Annexin V+ and Annexin Vneg B cells. PS blockage, using biotinylated AnV and glyburide, decreased B10 cell differentiation. This study showed that B10 cells have an increased PS exposure independently of any apoptotic state. B cells exposing PS differentiate more into B10 cells whereas PS blockage inhibits B10 cells generation. These results strongly suggest a link between PS exposure and B10 cells.

  16. B cells produce less IL-10, IL-6 and TNF-α in myasthenia gravis.

    PubMed

    Yilmaz, Vuslat; Oflazer, Piraye; Aysal, Fikret; Parman, Yeşim G; Direskeneli, Haner; Deymeer, Feza; Saruhan-Direskeneli, Güher

    2015-06-01

    B cells from myasthenia gravis (MG) patients with autoantibodies (Aab) against acetylcholine receptor (AChR), muscle-specific kinase (MuSK) or with no detectable Aab were investigated as cytokine producing cells in this study. B cells were evaluated for memory phenotypes and expressions of IL-10, IL-6 and IL-12A. Induced productions of IL-10, IL-6, IL-12p40, TNF-α and LT from isolated B cells in vitro were measured by immunoassays. MG patients receiving immunosuppressive treatment had higher proportions of memory B cells compared with healthy controls and untreated patients. With CD40 stimulation MG patients produced significantly lower levels of IL-10, IL-6. With CD40 and B cell receptor stimulation of B cells, TNF-α production also decreased in addition to these cytokines. The lower levels of these cytokine productions were not related to treatment. Our results confirm a disturbance of B cell subpopulations in MG subgroups on immunosuppressive treatment. B cell derived IL-10, IL-6 and TNF-α are down-regulated in MG, irrespective of different antibody productions. Ineffective cytokine production by B cells may be a susceptibility factor in dysregulation of autoimmune Aab production.

  17. CEACAM1 mediates B cell aggregation in central nervous system autoimmunity

    PubMed Central

    Rovituso, Damiano M.; Scheffler, Laura; Wunsch, Marie; Dörck, Sebastian; Ulzheimer, Jochen; Bayas, Antonios; Steinman, Lawrence; Ergün, Süleyman; Kuerten, Stefanie

    2016-01-01

    B cell aggregates in the central nervous system (CNS) have been associated with rapid disease progression in patients with multiple sclerosis (MS). Here we demonstrate a key role of carcinoembryogenic antigen-related cell adhesion molecule1 (CEACAM1) in B cell aggregate formation in MS patients and a B cell-dependent mouse model of MS. CEACAM1 expression was increased on peripheral blood B cells and CEACAM1+ B cells were present in brain infiltrates of MS patients. Administration of the anti-CEACAM1 antibody T84.1 was efficient in blocking aggregation of B cells derived from MS patients. Along these lines, application of the monoclonal anti-CEACAM1 antibody mCC1 was able to inhibit CNS B cell aggregate formation and significantly attenuated established MS-like disease in mice in the absence of any adverse effects. CEACAM1 was co-expressed with the regulator molecule T cell immunoglobulin and mucin domain −3 (TIM-3) on B cells, a novel molecule that has recently been described to induce anergy in T cells. Interestingly, elevated coexpression on B cells coincided with an autoreactive T helper cell phenotype in MS patients. Overall, these data identify CEACAM1 as a clinically highly interesting target in MS pathogenesis and open new therapeutic avenues for the treatment of the disease. PMID:27435215

  18. Post-transcriptional regulation of interleukin-10 in peripheral B cells of airway allergy patients

    PubMed Central

    Luo, Xiang-Qian; Yang, Shao-Bo; Qiu, Shu-Qi; Xie, Rui-Di; Yang, Li-Tao; Ke, Yu-Xing; Zhao, Hong-Xia; Geng, Xiao-Rui; Yang, Gui; Liu, Zhi-Qiang; Liu, Jiang-Qi; Wang, Shuai; Liu, Da-Bo; Liu, Jun

    2016-01-01

    The dysfunction of peripheral immune tolerance plays an important role in the pathogenesis of allergic diseases. Recent reports indicate that micro RNA (miR)-98 is associated with the process of aberrant immune responses. This study aims to test a hypothesis that miR-98 is associated with the pathogenesis of airway allergy via interfering with the development of regulatory B cells (Breg). In this study, patients with airway allergy were recruited into this study. The frequency of Bregs was assessed by flow cytometry. The levels of miR-98 in peripheral B cells were determined by RT-qPCR. A cell-culture model of B cells was developed to test the role of miR-98 in the repressing of interleukin (IL)-10 in B cells. The results showed that the levels of IL-10 in peripheral B cells were significantly lower in patients with airway allergy as compared with healthy subjects. High levels of miR-98 (one of the miR-98 members) were detected in peripheral B cells of patients with airway allergy, which was mimicked by stimulating B cells with IL-4. Histone acetyltransferase p300 was involved in the IL-4-induced miR-98 expression. miR-98 mediated the IL-4-inhibited IL-10 expression in B cells. In conclusion, miR-98 affects the expression of IL-10 in B cells and may be a novel therapeutic target for the treatment of allergic diseases. PMID:28078048

  19. B cell maturation antigen deficiency exacerbates lymphoproliferation and autoimmunity in murine lupus.

    PubMed

    Jiang, Chao; Loo, William M; Greenley, Erin J; Tung, Kenneth S; Erickson, Loren D

    2011-06-01

    Systemic lupus erythematosus and its preclinical lupus-prone mouse models are autoimmune disorders involving the production of pathogenic autoantibodies. Genetic predisposition to systemic lupus erythematosus results in B cell hyperactivity, survival of self-reactive B cells, and differentiation to autoantibody-secreting plasma cells (PCs). These corrupt B cell responses are, in part, controlled by excess levels of the cytokine BAFF that normally maintains B cell homeostasis and self-tolerance through limited production. B cell maturation Ag (BCMA) is a receptor for BAFF that, under nonautoimmune conditions, is important for sustaining enduring Ab protection by mediating survival of long-lived PCs but is not required for B cell maturation and homeostasis. Through analysis of two different lupus-prone mouse models deficient in BCMA, we identify BCMA as an important factor in regulating peripheral B cell expansion, differentiation, and survival. We demonstrate that a BCMA deficiency combined with the lpr mutation or the murine lupus susceptibility locus Nba2 causes dramatic B cell and PC lymphoproliferation, accelerated autoantibody production, and early lethality. This study unexpectedly reveals that BCMA works to control B cell homeostasis and self-tolerance in systemic autoimmunity.

  20. Plasmodium chabaudi infection induces AID expression in transitional and marginal zone B cells

    PubMed Central

    Wilmore, Joel R.; Maue, Alexander C.

    2016-01-01

    Abstract Introduction Endemic Burkitt's lymphoma (eBL) is associated with Epstein–Barr virus and repeated malaria infections. A defining feature of eBL is the translocation of the c‐myc oncogene to the control of the immunoglobulin promoter. Activation‐induced cytidine deaminase (AID) has been shown to be critical for this translocation. Malaria infection induces AID in germinal center B cells, but whether malaria infection more broadly affects AID activation in extrafollicular B cells is unknown. Methods We either stimulated purified B cells from AID‐green fluorescence protein (GFP) reporter mice or infected AID‐GFP mice with Plasmodium chabaudi, AID fluorescence was monitored in B cell subsets by flow cytometry. Results In vitro analysis of B cells from these mice revealed that CpG (a Toll‐like receptor 9 ligand) was a potent inducer of AID in both mature and immature B cell subsets. Infection of AID‐GFP mice with Plasmodium chabaudi demonstrated that AID expression occurs in transitional and marginal zone B cells during acute malaria infection. Transitional B cells were also capable of differentiating into antibody secreting cells when stimulated in vitro with CpG when isolated from a P. chabaudi‐infected mouse. Conclusions These data suggest that P. chabaudi is capable of inducing AID expression in B cell subsets that do not participate in the germinal center reaction, suggesting an alternative role for malaria in the etiology of eBL. PMID:27980783

  1. Phosphatidylserine Outer Layer Translocation Is Implicated in IL-10 Secretion by Human Regulatory B Cells

    PubMed Central

    Hahne, Michael; Combe, Bernard; Morel, Jacques; Daien, Claire I.

    2017-01-01

    B cells can have a regulatory role, mainly mediated by interleukin 10 (IL-10). IL-10 producing B cells (B10 cells) cells remain to be better characterized. Annexin V binds phosphatidylserine (PS), which is externalized during apoptosis. Previous works suggested that B10 cells are apoptotic cells since they bind Annexin V. Others showed that Annexin V binding could also be expressed on viable B cells. We aimed to explore if PS exposure can be a marker of B10 cells and if PS exposure has a functional role on B cell IL-10 production in healthy subjects. We found that B10 cells were significantly more often Annexin V+ than IL-10 non-producing B cells. After CpG activation, Annexin V+ B cells differentiated more often into B10 cells than Annexin Vneg B cells. Cell death and early apoptosis were similar between Annexin V+ and Annexin Vneg B cells. PS blockage, using biotinylated AnV and glyburide, decreased B10 cell differentiation. This study showed that B10 cells have an increased PS exposure independently of any apoptotic state. B cells exposing PS differentiate more into B10 cells whereas PS blockage inhibits B10 cells generation. These results strongly suggest a link between PS exposure and B10 cells. PMID:28072868

  2. Reduced numbers of switched memory B cells with high terminal differentiation potential in Down syndrome.

    PubMed

    Carsetti, Rita; Valentini, Diletta; Marcellini, Valentina; Scarsella, Marco; Marasco, Emiliano; Giustini, Ferruccio; Bartuli, Andrea; Villani, Alberto; Ugazio, Alberto G

    2015-03-01

    Children with Down syndrome (DS) have increased susceptibility to infections and a high frequency of leukemia and autoimmune disorders, suggesting that immunodeficiency and immune dysfunction are integral parts of the syndrome. A reduction in B-cell numbers has been reported, associated with moderate immunodeficiency and normal immunoglobulin levels. Here, we compared B-cell populations of 19 children with DS with those in healthy age-matched controls. We found that all steps of peripheral B-cell development are altered in DS, with a more severe defect during the later stages of B-cell development. Transitional and mature-naïve B-cell numbers are reduced by 50% whereas switched memory B cells represent 10-15% of the numbers in age-matched controls. Serum IgM levels were slightly reduced, but all other immunoglobulin isotypes were in the normal range. The frequency of switched memory B cells specific for vaccine antigens was significantly lower in affected children than in their equivalently vaccinated siblings. In vitro switched memory B cells of patients with DS have an increased ability to differentiate into antibody-forming cells in response to TLR9 signals. Tailored vaccination schedules increasing the number of switched memory B cells may improve protection and reduce the risk of death from infection in DS.

  3. Increased RP105-Negative B Cells in IgG4-Related Disease.

    PubMed

    Koarada, S; Tashiro, S; Nagao, N; Suematsu, R; Ohta, A; Tada, Y

    2013-01-01

    Four patients with IgG4-related disease (IgG4-RD) showed increased percentages of RP105-negative B cells in the peripheral blood. Case 1: A 66-year-old man having retroperitoneal fibrosis had 18.8% of RP105-negative B cells. Oral prednisolone improved the affected lesions and the percentage of RP105-negative B cells decreased (3.2%) after the treatment. Case 2: A 53-year-old man with retroperitoneal fibrosis had 27.9% of RP105-negative B cells. Case 3: A 38-year-old man with follicular hyperplasia showed increased percentage of RP105-negative B cells (8.3%). Case 4: A 60-year-old man with interstitial nephritis had 27.5% of RP105-negative B cells. The treatment decreased the numbers of RP105-negative B cells. Increased numbers of RP105-negatvie B cells is possibly associated with disease activity of IgG4-RD. Analysis of expression of RP105 on B cells may be helpful in evaluation of disease activity of IgG4-RD.

  4. Suppression of human B cell activation by 2,3,7,8-tetrachlorodibenzo-p-dioxin involves altered regulation of B cell lymphoma-6.

    PubMed

    Phadnis-Moghe, Ashwini S; Crawford, Robert B; Kaminski, Norbert E

    2015-03-01

    The environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces marked suppression of the primary humoral immune response in virtually every animal species evaluated thus far. In addition, epidemiological studies performed in areas of dioxin contamination have identified an association between TCDD exposure and an increased incidence of non-Hodgkin's lymphoma (NHL). Recent studies using an in vitro CD40 ligand model of human B cell differentiation have shown that TCDD impairs both B cell activation and differentiation. The present study extends these findings by identifying B cell lymphoma-6 [BCL-6] as a putative cellular target for deregulation by TCDD, which may contribute to suppression of B cell function as well as NHL. BCL-6 is a multifunctional transcriptional repressor frequently mutated in NHLs and known to regulate critical events of B cell activation and differentiation. In the presence of TCDD, BCL-6 protein levels were elevated and concurrently the same population of cells with high BCL-6 levels showed decreased CD80 and CD69 expression indicative of impaired cellular activation. The elevated BCL-6 levels resulted in a concomitant increase in BCL-6 DNA binding activity at its cognate binding site within an enhancer region for CD80. Furthermore, a small molecule inhibitor of BCL-6 activity reversed TCDD-mediated suppression of CD80 expression in human B cells. In the presence of a low-affinity ligand of the aryl hydrocarbon receptor (AHR), suppression of B cell activation and altered BCL-6 regulation were not observed. These results provide new mechanistic insights into the role of BCL-6 in the suppression of human B cell activation by TCDD.

  5. Engagement of CD22 on B cells with the monoclonal antibody epratuzumab stimulates the phosphorylation of upstream inhibitory signals of the B cell receptor.

    PubMed

    Lumb, Simon; Fleischer, Sarah J; Wiedemann, Annika; Daridon, Capucine; Maloney, Alison; Shock, Anthony; Dörner, Thomas

    2016-06-01

    The binding of antigen to the B cell receptor (BCR) results in a cascade of signalling events that ultimately drive B cell activation. Uncontrolled B cell activation is regulated by negative feedback loops that involve inhibitory co-receptors such as CD22 and CD32B that exert their functions following phosphorylation of immunoreceptor tyrosine-based inhibition motifs (ITIMs). The CD22-targeted antibody epratuzumab has previously been shown to inhibit BCR-driven signalling events, but its effects on ITIM phosphorylation of CD22 and CD32B have not been properly evaluated. The present study therefore employed both immunoprecipitation and flow cytometry approaches to elucidate the effects of epratuzumab on direct phosphorylation of key tyrosine (Tyr) residues on both these proteins, using both transformed B cell lines and primary human B cells. Epratuzumab induced the phosphorylation of Tyr(822) on CD22 and enhanced its co-localisation with SHP-1. Additionally, in spite of high basal phosphorylation of other key ITIMs on CD22, in primary human B cells epratuzumab also enhanced phosphorylation of Tyr(807), a residue involved in the recruitment of Grb2. Such initiation events could explain the effects of epratuzumab on downstream signalling in B cells. Finally, we were able to demonstrate that epratuzumab stimulated the phosphorylation of Tyr(292) on the low affinity inhibitory Fc receptor CD32B which would further attenuate BCR-induced signalling. Together, these data demonstrate that engagement of CD22 with epratuzumab leads to the direct phosphorylation of key upstream inhibitory receptors of BCR signalling and may help to explain how this antibody modulates B cell function.

  6. Activation of resting human B cells by helper T-cell clone supernatant: characterization of a human B-cell-activating factor.

    PubMed Central

    Diu, A; Gougeon, M L; Moreau, J L; Reinherz, E L; Thèze, J

    1987-01-01

    The effects of helper T-cell clone supernatants on resting human B cells were investigated. Four different helper T-cell clones (two T4+ and two T8+) were stimulated by anti-T3 monoclonal antibodies on Sepharose beads or anti-T11(2) plus anti-T11(3) monoclonal antibodies. The supernatants from these activated clones induced the proliferation of highly purified resting B lymphocytes from the peripheral blood. The B cells exhibited a cell size and a surface-antigen pattern (4F2 antigen and transferrin receptor) of phase G0 B cells, and they were functionally resting. In response to T-cell supernatants a large fraction of the B cells enlarged and expressed 4F2 antigens and transferrin receptors. In gel filtration, the corresponding activity migrated with an apparent Mr of 12,000-15,000. Our findings strongly support the existence of a human B-cell-activating factor acting on resting B cells and causing them to enter phase G1 of the cell cycle. PMID:2962196

  7. A cyclin D1-positive diffuse large B-cell lymphoma of germinal center B-cell-like subtype in the right tonsil

    PubMed Central

    Jiang, Changrui; Shi, Xiuying; Fan, Chuifeng

    2017-01-01

    Abstract Introduction: Cyclin D1-positive tumor cells are commonly found in mantle cell lymphoma but they are very rare in diffuse large B-cell lymphoma. Clinical findings/Patient concerns: Here we present a rare case of cyclin D1-positive diffuse large B-cell lymphoma in the right tonsil of a 50-year-old man. Computed tomographic imaging detected a mass, about 2.5 cm × 1.8 cm in size, in the left side of the oropharynx. Diagnoses: Microscopically, the tumor cells were located under the pharyngeal mucosa and diffusely arranged. The tumor cells were large, with marked nuclear atypia. On performing immunohistochemistry, the tumor cells showed diffuse positive staining for CD10, CD20, cyclin D1, and Pax-5, and negative staining for CD3, CD15, CD30, CD56, and CK. Bcl-6 and Mum-1 expression were observed in 60% and 80% of tumor cells, respectively. The tumor Ki67 index was about 60%. Based on these findings, The tumor was diagnosed as a rare cyclin D1-positive diffuse large B-cell lymphoma rather than a mantle cell lymphoma. Conclusion: Cyclin D1-positive large B-cell lymphoma is rare, but as large B-cell lymphoma is a common type of lymphoma, cyclin D1-positive large B-cell lymphoma should be considered a major possibility during differential diagnosis, including in the tonsils. PMID:28296741

  8. Obinutuzumab (GA101) for the treatment of chronic lymphocytic leukemia and other B-cell non-hodgkin's lymphomas: a glycoengineered type II CD20 antibody.

    PubMed

    Goede, Valentin; Klein, Christian; Stilgenbauer, Stephan

    2015-01-01

    Obinutuzumab (GA101) is a humanized, monoclonal type II CD20 antibody modified by glycoengineering. The glycoengineered Fc portion enhances the binding affinity to the FcγRIII receptor on immune effector cells, resulting in increased antibody-dependent cellular cytotoxicity and phagocytosis. In addition, the type II antibody binding characteristics of obinutuzumab to CD20 lead to an efficient induction of direct non-apoptotic cell death. Preclinical data demonstrated more efficient B-cell depletion in whole blood and superior antitumor activity in xenograft models of obinutuzumab as compared to the type I CD20 antibody rituximab. In previously untreated patients with chronic lymphocytic leukemia (CLL) and comorbidities, obinutuzumab plus chlorambucil increased response rates and prolonged progression-free survival compared with rituximab plus chlorambucil. Obinutuzumab had an acceptable and manageable safety profile, with infusion-related reactions during the first infusion as the most common adverse event. Further phase I/II clinical trials have also shown promising activity in other CD20-positive B-cell non-Hodgkin's lymphomas (NHL). Therefore, several clinical studies are planned or ongoing to investigate obinutuzumab with different combination partners in both untreated and relapsed/refractory patients with different B-cell NHL entities, which in addition to CLL include diffuse large B-cell lymphoma and follicular lymphoma. © 2015 S. Karger GmbH, Freiburg.

  9. Translational Mini-Review Series on B Cell-Directed Therapies: The pathogenic role of B cells in autoantibody-associated autoimmune diseases – lessons from B cell-depletion therapy

    PubMed Central

    Leandro, M J; de la Torre, I

    2009-01-01

    B cell depletion therapy with rituximab (BCDT) is a licensed treatment for rheumatoid arthritis and has shown promising results in the treatment of severe, refractory patients with other autoantibody-associated autoimmune diseases (AAID). The exact role that B cells play in the pathogenesis of AAID and consequently the mechanisms by which BCDT is effective are not known. The two more widely discussed hypotheses are that BCDT is effective because it removes the precursors of plasma cells producing pathogenic autoantibody species, or because it depletes a critical mass of autoreactive B cell clones that present antigen to pathogenic autoreactive T cells. This review will focus on the effects of BCDT and whether the response of patients with AAID to BCDT could be due ultimately to its effects on autoantibodies. A better knowledge of the main role that B cells play in the pathogenesis of the different diseases and a better understanding of the most likely mechanism of relapse following an earlier response to BCDT would help to guide further developments of B cell targeting therapies and potentially increase the chance of designing a protocol that could induce a long-term remission. PMID:19604258

  10. IL-15 Expression on RA Synovial Fibroblasts Promotes B Cell Survival

    PubMed Central

    Benito-Miguel, Marta; García-Carmona, Yolanda; Balsa, Alejandro; Bautista-Caro, María-Belén; Arroyo-Villa, Irene; Cobo-Ibáñez, Tatiana; Bonilla-Hernán, María Gema; de Ayala, Carlos Pérez; Sánchez-Mateos, Paloma; Martín-Mola, Emilio; Miranda-Carús, María-Eugenia

    2012-01-01

    Introduction The purpose of this study was to examine the role of RA Synovial Fibroblast (RASFib) IL-15 expression on B cell survival. Methods Magnetically sorted peripheral blood memory B cells from 15 healthy subjects were cocultured with RASFib. Results RASFib constitutively expressed membrane IL-15. Survival of isolated B cells cultured for 6 days, below 5%, was extended in coculture with RASFib to 52+/−8% (p<0.001). IL-15 neutralizing agents but not isotype controls, reduced this rate to 31+/−6% (p<0.05). Interestingly, rhIL-15 had no effect on isolated B cells but significantly increased their survival in coculture with RASFib. In parallel, B cell IL-15R chains were upregulated in cocultures. BAFF and VCAM-1, that are expressed on RASFib, were tested as potential candidates involved in upregulating B cell IL-15R. Culture of B cells in the presence of rhBAFF or rhVCAM-1 resulted in significantly increased survival, together with upregulation of all three IL-15R chains; in parallel, rhIL-15 potentiated the anti-apoptotic effect of BAFF and VCAM-1. Both BAFF and VCAM-1 neutralizing agents downmodulated the effect of RASFib on B cell survival and IL-15R expression. In parallel, rhIL-15 had a lower effect on the survival of B cells cocultured with RASFib in the presence of BAFF or VCAM-1 neutralizing agents. Peripheral blood B cells from 15 early RA patients demonstrated an upregulated IL-15R and increased survival in cocultures. Conclusion IL-15 expression on RASFib significantly contributes to the anti-apoptotic effect of RASFib on B cells. IL-15 action is facilitated by BAFF and VCAM-1 expressed on RASFib, through an upregulation of IL-15R chains. PMID:22792388

  11. Pax5: a master regulator of B cell development and leukemogenesis.

    PubMed

    Medvedovic, Jasna; Ebert, Anja; Tagoh, Hiromi; Busslinger, Meinrad

    2011-01-01

    The B cell lineage of the hematopoietic system is responsible for the generation of high-affinity antibodies, which provide humoral immunity for protection against foreign pathogens. B cell commitment and development depend on many transcription factors including Pax5. Here, we review the different functions of Pax5 in regulating various aspects of B lymphopoiesis. At B cell commitment, Pax5 restricts the developmental potential of lymphoid progenitors to the B cell pathway by repressing B-lineage-inappropriate genes, while it simultaneously promotes B cell development by activating B-lymphoid-specific genes. Pax5 thereby controls gene transcription by recruiting chromatin-remodeling, histone-modifying, and basal transcription factor complexes to its target genes. Moreover, Pax5 contributes to the diversity of the antibody repertoire by controlling V(H)-DJ(H) recombination by inducing contraction of the immunoglobulin heavy-chain locus in pro-B cells, which is likely mediated by PAIR elements in the 5' region of the V(H) gene cluster. Importantly, all mature B cell types depend on Pax5 for their differentiation and function. Pax5 thus controls the identity of B lymphocytes throughout B cell development. Consequently, conditional loss of Pax5 allows mature B cells from peripheral lymphoid organs to develop into functional T cells in the thymus via dedifferentiation to uncommitted progenitors in the bone marrow. Pax5 has also been implicated in human B cell malignancies because it can function as a haploinsufficient tumor suppressor or oncogenic translocation fusion protein in B cell precursor acute lymphoblastic leukemia.

  12. TGF-β3 Inhibits Antibody Production by Human B Cells

    PubMed Central

    Tsuchida, Yumi; Sumitomo, Shuji; Ishigaki, Kazuyoshi; Suzuki, Akari; Kochi, Yuta; Tsuchiya, Haruka; Ota, Mineto; Komai, Toshihiko; Inoue, Mariko; Morita, Kaoru; Okamura, Tomohisa; Yamamoto, Kazuhiko; Fujio, Keishi

    2017-01-01

    TGF-β is a pleotropic cytokine involved in various biological processes. Of the three isoforms of TGF-β, TGF-β1 has long been recognized as an important inhibitory cytokine in the immune system and has been reported to inhibit B cell function in both mice and humans. Recently, it has been suggested that TGF-β3 may play an important role in the regulation of immune system in mice. Murine CD4+CD25-LAG3+ regulatory T cells suppress B cell function through the production of TGF-β3, and it has been reported that TGF-β3 is therapeutic in a mouse model of systemic lupus erythematosus. The effect of TGF-β3 on human B cells has not been reported, and we herein examined the effect of TGF-β3 on human B cells. TGF-β3 suppressed B cell survival, proliferation, differentiation into plasmablasts, and antibody secretion. Although the suppression of human B cells by TGF-β1 has long been recognized, the precise mechanism for the suppression of B cell function by TGF-β1 remains elusive; therefore, we examined the effect of TGF-β1 and β3 on pathways important in B cell activation and differentiation. TGF-β1 and TGF-β3 inhibited some of the key molecules of the cell cycle, as well as transcription factors important in B cell differentiation into antibody secreting cells such as IRF4, Blimp-1, and XBP1. TGF-β1 and β3 also inhibited B cell receptor signaling. Our results suggest that TGF-β3 modifying therapy might be therapeutic in autoimmune diseases with B cell dysregulation in humans. PMID:28052118

  13. Synergistic activation of cells by Epstein-Barr virus and B-cell growth factor.

    PubMed Central

    Hutt-Fletcher, L M

    1987-01-01

    Infection with Epstein-Barr virus (EBV) is initiated by virus binding to the C3dg-C3d receptor CR2. Several workers have implicated this receptor in the control of B-cell activation by examining the effects of antibodies to CR2 and isolated C3d on B-cell proliferation and differentiation. We report here on the activating effects of irradiated EBV, which retains its capacity to bind to CR2 but loses its ability to function as a T-independent B-cell activator. EBV synergized with B-cell growth factor in the induction of uptake of tritiated thymidine by T cell-depleted leukocytes from seronegative donors but did not induce secretion of immunoglobulin. Synergism could be inhibited with an anti-viral antibody that inhibited binding of EBV to CR2. No similar synergism was found between EBV and recombinant interleukin 2, interleukin 1 alpha, or gamma interferon or with the lipid A fraction of bacterial lipopolysaccharide. EBV may thus initiate B-cell activation as it binds to CR2. Infectious virus may, under normal circumstances, induce the cell to make those growth factors necessary to support B-cell proliferation; the difficulty of transforming cells with transfected EBV DNA may in part reflect the absence of an activation event provided by intact virus as it attaches to CR2. The synergism of EBV and B-cell growth factor more clearly distinguishes the effects of B-cell growth factor from those of interleukin 1 and interleukin 2 in other models of B-cell activation. Thus, this may be a useful model for further delineation of unique effects of B-cell growth factor on B-cell function. PMID:3027404

  14. Regulation of Cell Surface CB2 Receptor during Human B Cell Activation and Differentiation.

    PubMed

    Castaneda, Julie T; Harui, Airi; Roth, Michael D

    2017-03-31

    Cannabinoid receptor type 2 (CB2) is the primary receptor pathway mediating the immunologic consequences of cannabinoids. We recently reported that human peripheral blood B cells express CB2 on both the extracellular membrane and at intracellular sites, where-as monocytes and T cells only express intracellular CB2. To better understand the pattern of CB2 expression by human B cells, we examined CD20(+) B cells from three tissue sources. Both surface and intracellular expression were present and uniform in cord blood B cells, where all cells exhibited a naïve mature phenotype (IgD(+)/CD38(Dim)). While naïve mature and quiescent memory B cells (IgD(-)/CD38(-)) from tonsils and peripheral blood exhibited a similar pattern, tonsillar activated B cells (IgD(-)/CD38(+)) expressed little to no surface CB2. We hypothesized that regulation of the surface CB2 receptor may occur during B cell activation. Consistent with this, a B cell lymphoma cell line known to exhibit an activated phenotype (SUDHL-4) was found to lack cell surface CB2 but express intracellular CB2. Furthermore, in vitro activation of human cord blood resulted in a down-regulation of surface CB2 on those B cells acquiring the activated phenotype but not on those retaining IgD expression. Using a CB2 expressing cell line (293 T/CB2-GFP), confocal microscopy confirmed the presence of both cell surface expression and multifocal intracellular expression, the latter of which co-localized with endoplasmic reticulum but not with mitochondria, lysosomes, or nucleus. Our findings suggest a dynamic multi-compartment expression pattern for CB2 in B cells that is specifically modulated during the course of B cell activation.

  15. Ageing Adversely Affects the Migration and Function of Marginal Zone B Cells.

    PubMed

    Turner, Vivian M; Mabbott, Neil A

    2017-04-02

    Marginal zone (MZ) B cells are positioned within the spleen to capture blood-borne Ag and immune complexes and deliver them to follicular dendritic cells in the B cell follicles. We show that within the spleens of aged mice antigen (Ag) capture by MZ B cells, and their ability to shuttle between the follicle and MZ were impaired. The ability of aged MZ B cells to migrate towards the MZ chemoattractant sphingosine 1-phosphate was increased, suggesting that aged MZ B cells had a greater propensity to be retained within the MZ. An extrinsic impairment in aged B cell migration towards the MZ was demonstrated using bone marrow chimeras. The follicular shuttling of MZ B cells derived from either young or aged bone marrow was similarly reduced in aged recipient spleens, showing that ageing effects on splenic stromal cells were responsible for the impaired follicular shuttling of MZ B cells. MZ B cells rapidly mount T cell-independent (TI) antibody-responses to microbial polysaccharide Ag. In aged mice the ability to produce immunoglobulins in response to the TI-type 1 Ag, TNP-LPS, was impaired. These ageing related changes to the MZ and MZ B cells have implications for the clearance of blood-borne pathogens. Indeed elderly people have increased susceptibility to Streptococcus pneumoniae, a TI Ag, and decreased responses to vaccination. A thorough analysis of the mechanisms that underpin the ageing-related decline in the status of the MZ and MZ B cells will help the design of novel treatments to improve immunity in the elderly. This article is protected by copyright. All rights reserved.

  16. Nuclear safety

    NASA Technical Reports Server (NTRS)

    Buden, D.

    1991-01-01

    Topics dealing with nuclear safety are addressed which include the following: general safety requirements; safety design requirements; terrestrial safety; SP-100 Flight System key safety requirements; potential mission accidents and hazards; key safety features; ground operations; launch operations; flight operations; disposal; safety concerns; licensing; the nuclear engine for rocket vehicle application (NERVA) design philosophy; the NERVA flight safety program; and the NERVA safety plan.

  17. B cell depletion for autoimmune diseases in paediatric patients.

    PubMed

    Jansson, Annette F; Sengler, Claudia; Kuemmerle-Deschner, Jasmin; Gruhn, Bernd; Kranz, A Birgitta; Lehmann, Hartwig; Kleinert, Daniela; Pape, Lars; Girschick, Hermann J; Foeldvari, Ivan; Haffner, Dieter; Haas, Johannes P; Moebius, Dagmar; Foell, Dirk; Peitz, Joachim; Grote, Veit

    2011-01-01

    Data on B cell depletion therapy in severe autoimmune diseases in paediatric patients are very limited. We conducted a retrospective cohort study and recruited patients who were treated with rituximab (RTX) and followed up for at least 6 months through the German societies of paediatric rheumatology and nephrology. The aim was to describe the spectrum of autoimmune disorders for which RTX was used and to describe the applied therapeutic regimens, the observed efficacy, as well as potential immunological side effects. The need to develop standard treatment guidelines for future trials should be discussed. Sixty-five patients were included. Nineteen patients suffered from systemic lupus erythematosus, 13 from vasculitic disorders, 12 from hematological autoimmune diseases, 5 from mixed connective tissue disorders, 4 from juvenile idiopathic arthritis, and 9 had other autoimmune diseases. Adverse, infusion-related events were reported in 12/65 (18%) patients. Considering laboratory and clinical parameters, 13 patients (22%) were in complete remission, 31 (52%) were in partial remission, 6 (10%) were unchanged and 10 (17%) had progressed after 6 months. In 46% of the patients, the steroid dose could be more than halved. IgG, IgM and IgA decreased from normal levels prior to RTX therapy to below normal levels at 6 months in 2/22 (9%), 10/21 (48%), and 4/22 (18%) patients, respectively. Immunoglobulin deficiency or prolonged CD20 depletion was reported in eight patients after an observation period longer than 12 months. RTX therapy led to a perceivable reduction in disease activity. However, long-term immunological alterations may occur in more than 10% of the patients. Guidelines and protocols for off-label therapy are desirable to document reasonable follow-up data. Controlled prospective studies for RTX therapies in children with standardised therapeutic and diagnostic protocols are urgently needed.

  18. Carfilzomib, Rituximab, Ifosfamide, Carboplatin, and Etoposide in Treating Patients With Relapsed or Refractory Stage I-IV Diffuse Large B-cell Lymphoma

    ClinicalTrials.gov

    2017-02-15

    CD20 Positive; Recurrent Diffuse Large B-Cell Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Stage I Diffuse Large B-Cell Lymphoma; Stage II Diffuse Large B-Cell Lymphoma; Stage III Diffuse Large B-Cell Lymphoma; Stage IV Diffuse Large B-Cell Lymphoma

  19. Immune tolerance negatively regulates B cells in knock-in mice expressing broadly neutralizing HIV antibody 4E10

    PubMed Central

    Cooper, Anthony B.; Ota, Takayuki; Skog, Patrick; Dawson, Phillip E.; Zwick, Michael B.; Schief, William R.; Burton, Dennis R.; Nemazee, David

    2013-01-01

    A major goal of HIV research is to develop vaccines reproducibly eliciting broadly neutralizing antibodies (bNAbs). This has proved to be challenging, however. One suggested explanation for this difficulty is that epitopes seen by bNAbs mimic self, leading to immune tolerance. We generated “knock-in” mice expressing bNAb 4E10, which recognizes the membrane proximal external region of gp41. Unlike b12 knock-in mice, described in the accompanying study, 4E10HL mice were found to undergo profound negative selection of B cells, indicating that 4E10 is, to a physiologically significant extent, autoreactive. Negative selection occurred by various mechanisms including receptor editing, clonal deletion and receptor downregulation. Despite significant deletion, small amounts of IgM and IgG anti-gp41 were found in the sera of 4E10HL mice. On a Rag1−/− background 4E10HL mice had virtually no serum immunoglobulins of any kind. These results are consistent with a model in which B cells with 4E10 specificity are counterselected, raising the question of how 4E10 was generated in the patient from whom it was isolated. This represents the second example of an MPER-directed bNAb that is apparently autoreactive in a physiological setting. The relative conservation in HIV of the 4E10 epitope might reflect the fact that it is under less intense immunological selection as a result of B cell self-tolerance. The safety and desirability of targeting this epitope by a vaccine is discussed in light of the newly-described bNAb 10E8. PMID:23940276

  20. CRITICALITY SAFETY CONTROLS AND THE SAFETY BASIS AT PFP

    SciTech Connect

    Kessler, S

    2009-04-21

    With the implementation of DOE Order 420.1B, Facility Safety, and DOE-STD-3007-2007, 'Guidelines for Preparing Criticality Safety Evaluations at Department of Energy Non-Reactor Nuclear Facilities', a new requirement was imposed that all criticality safety controls be evaluated for inclusion in the facility Documented Safety Analysis (DSA) and that the evaluation process be documented in the site Criticality Safety Program Description Document (CSPDD). At the Hanford site in Washington State the CSPDD, HNF-31695, 'General Description of the FH Criticality Safety Program', requires each facility develop a linking document called a Criticality Control Review (CCR) to document performance of these evaluations. Chapter 5, Appendix 5B of HNF-7098, Criticality Safety Program, provided an example of a format for a CCR that could be used in lieu of each facility developing its own CCR. Since the Plutonium Finishing Plant (PFP) is presently undergoing Deactivation and Decommissioning (D&D), new procedures are being developed for cleanout of equipment and systems that have not been operated in years. Existing Criticality Safety Evaluations (CSE) are revised, or new ones written, to develop the controls required to support D&D activities. Other Hanford facilities, including PFP, had difficulty using the basic CCR out of HNF-7098 when first implemented. Interpretation of the new guidelines indicated that many of the controls needed to be elevated to TSR level controls. Criterion 2 of the standard, requiring that the consequence of a criticality be examined for establishing the classification of a control, was not addressed. Upon in-depth review by PFP Criticality Safety staff, it was not clear that the programmatic interpretation of criterion 8C could be applied at PFP. Therefore, the PFP Criticality Safety staff decided to write their own CCR. The PFP CCR provides additional guidance for the evaluation team to use by clarifying the evaluation criteria in DOE-STD-3007-2007. In

  1. A multi-scale model for correlation in B cell VDJ usage of zebrafish

    NASA Astrophysics Data System (ADS)

    Pan, Keyao; Deem, Michael W.

    2011-10-01

    The zebrafish (Danio rerio) is one of the model animals used for the study of immunology because the dynamics in the adaptive immune system of zebrafish are similar to that in higher animals. In this work, we built a multi-scale model to simulate the dynamics of B cells in the primary and secondary immune responses of zebrafish. We use this model to explain the reported correlation between VDJ usage of B cell repertoires in individual zebrafish. We use a delay ordinary differential equation (ODE) system to model the immune responses in the 6-month lifespan of a zebrafish. This mean field theory gives the number of high-affinity B cells as a function of time during an infection. The sequences of those B cells are then taken from a distribution calculated by a 'microscopic' random energy model. This generalized NK model shows that mature B cells specific to one antigen largely possess a single VDJ recombination. The model allows first-principle calculation of the probability, p, that two zebrafish responding to the same antigen will select the same VDJ recombination. This probability p increases with the B cell population size and the B cell selection intensity. The probability p decreases with the B cell hypermutation rate. The multi-scale model predicts correlations in the immune system of the zebrafish that are highly similar to that from experiment.

  2. Glycosidase inhibitors (castanospermine and swainsonine) and neuraminidase inhibit pokeweed mitogen-induced B cell maturation.

    PubMed

    Karasuno, T; Kanayama, Y; Nishiura, T; Nakao, H; Yonezawa, T; Tarui, S

    1992-08-01

    Castanospermine (CSP), an inhibitor of alpha-glucosidase, enhanced immunoglobulin (Ig) release in a Staphylococcus aureus Cowan I (SAC)-induced lymphocyte culture (Scand. J. Immunol. 1990. 32: 529). In a pokeweed mitogen (PWM)-human lymphocyte culture, unlike the SAC-stimulated system, CSP strongly decreased the number of IgG-, IgA- and IgM-secreting cells as well as that of Ig-bearing cells. Peripheral blood lymphocytes treated with swainsonine, a mannosidase II inhibitor, or with neuraminidase also showed a reduced response to PWM. In cross-culture experiments, only a mixture of B cells pretreated with either agent and untreated T cells showed such a suppressive effect. Adhesion was decreased between B cells treated with either agent and untreated T cells, but not between treated T cells and untreated B cells. These results demonstrate that a certain alteration in B cell membrane oligosaccharides inhibited the T cell-B cell adhesion in the PWM culture, leading to an arrest of B cell maturation. Considering that these inhibitors eventually prevent terminal sialic acid addition, the present study provides evidence that sialic acids on B cell surface oligosaccharides play a biological role in the T cell-B cell interaction.

  3. Blood B Cell and Regulatory Subset Content in Multiple Sclerosis Patients

    PubMed Central

    Habib, Jakob; Deng, Jiusheng; Lava, Neil; Tyor, William; Galipeau, Jacques

    2015-01-01

    Objective B cell targeted therapies have been effective in slowing multiple sclerosis (MS) disease progression suggesting a direct causal link for this lymphoid subset. A small subset of B cells with regulative properties (Bregs) exists in peripheral blood, and induction of Bregs ameliorates experimental autoimmune encephalomyelitis (EAE), the murine model for MS. Therefore the frequency of B cell subsets and regulatory B cells in particular in peripheral blood of MS patients is of interest. Methods The phenotype and frequency of B cell subsets in peripheral blood from 32 MS patients and 34 healthy controls (HC) were examined using flow cytometry. Results We found that there is an increase in CD19+ cell number in MS 1347 ± 159 cells/μL, (average ± SEM) compared to HC, 935 ± 129 cells/μL and no apparent deficiency in B-cells with a regulatory phenotype. In addition, we observed a loss of correlation between CD19+ B cells and total lymphocyte count in MS. Conclusion These findings suggest altered blood B-cell homeostasis in MS patients. PMID:26137596

  4. A Transcriptional Regulatory Switch Underlying B-Cell Terminal Differentiation and Its Disruption by Dioxin (S)

    EPA Science Inventory

    The terminal differentiation of B cells in lymphoid organs into antibody-secreting plasma cells upon antigen stimulation is a crucial step in the humoral immune response. The architecture of the B-cell transcriptional regulatory network consists of coupled mutually-repressive fee...

  5. Microfluidic squeezing for intracellular antigen loading in polyclonal B-cells as cellular vaccines

    PubMed Central

    Lee Szeto, Gregory; Van Egeren, Debra; Worku, Hermoon; Sharei, Armon; Alejandro, Brian; Park, Clara; Frew, Kirubel; Brefo, Mavis; Mao, Shirley; Heimann, Megan; Langer, Robert; Jensen, Klavs; Irvine, Darrell J

    2015-01-01

    B-cells are promising candidate autologous antigen-presenting cells (APCs) to prime antigen-specific T-cells both in vitro and in vivo. However to date, a significant barrier to utilizing B-cells as APCs is their low capacity for non-specific antigen uptake compared to “professional” APCs such as dendritic cells. Here we utilize a microfluidic device that employs many parallel channels to pass single cells through narrow constrictions in high throughput. This microscale “cell squeezing” process creates transient pores in the plasma membrane, enabling intracellular delivery of whole proteins from the surrounding medium into B-cells via mechano-poration. We demonstrate that both resting and activated B-cells process and present antigens delivered via mechano-poration exclusively to antigen-specific CD8+T-cells, and not CD4+T-cells. Squeezed B-cells primed and expanded large numbers of effector CD8+T-cells in vitro that produced effector cytokines critical to cytolytic function, including granzyme B and interferon-γ. Finally, antigen-loaded B-cells were also able to prime antigen-specific CD8+T-cells in vivo when adoptively transferred into mice. Altogether, these data demonstrate crucial proof-of-concept for mechano-poration as an enabling technology for B-cell antigen loading, priming of antigen-specific CD8+T-cells, and decoupling of antigen uptake from B-cell activation. PMID:25999171

  6. SIGLEC-G deficiency increases susceptibility to develop B-cell lymphoproliferative disorders

    PubMed Central

    Simonetti, Giorgia; Bertilaccio, Maria Teresa Sabrina; Rodriguez, Tania Veliz; Apollonio, Benedetta; Dagklis, Antonis; Rocchi, Martina; Innocenzi, Anna; Casola, Stefano; Winkler, Thomas H.; Nitschke, Lars; Ponzoni, Maurilio; Caligaris-Cappio, Federico; Ghia, Paolo

    2014-01-01

    The sialic-acid-binding immunoglobulin-like lectin SIGLEC-G is a negative regulator of B-cell receptor-mediated calcium signaling. Its deficiency leads to reduced turnover and increased proliferation and survival of murine B-1a cells. Siglecg−/− mice show a premature expansion of polyclonal CD5+ B cells in the spleen and the peritoneal cavity. Here we studied the fate of B lymphocytes in Siglecg−/− mice over time. We demonstrate that in aging animals SIGLEC-G deficiency promotes progressive accumulation of monoclonal B lymphocytes and increases the susceptibility to develop B-cell lymphoproliferative disorders. Lymphoid tumors arising in aged Siglecg−/− mice are monoclonal and histologically heterogeneous as they include diffuse large B-cell lymphoma, follicular lymphoma, and medium-to-large B-cell monomorphic lymphoma but surprisingly not chronic lymphocytic leukemia. The tumors express high levels of BCL-2 and are transplantable. In keeping with these findings we have also observed a remarkable down-regulation of the human ortholog SIGLEC10 in human B-cell lymphoma and leukemia cell lines. Taken together, these observations indicate that the down-regulation of negative B-cell receptor regulators such as SIGLEC-G/SIGLEC10 may represent another mechanism relevant to the pathogenesis of B-cell lymphomas. PMID:24859880

  7. Whole-genome fingerprint of the DNA methylome during human B cell differentiation.

    PubMed

    Kulis, Marta; Merkel, Angelika; Heath, Simon; Queirós, Ana C; Schuyler, Ronald P; Castellano, Giancarlo; Beekman, Renée; Raineri, Emanuele; Esteve, Anna; Clot, Guillem; Verdaguer-Dot, Néria; Duran-Ferrer, Martí; Russiñol, Nuria; Vilarrasa-Blasi, Roser; Ecker, Simone; Pancaldi, Vera; Rico, Daniel; Agueda, Lidia; Blanc, Julie; Richardson, David; Clarke, Laura; Datta, Avik; Pascual, Marien; Agirre, Xabier; Prosper, Felipe; Alignani, Diego; Paiva, Bruno; Caron, Gersende; Fest, Thierry; Muench, Marcus O; Fomin, Marina E; Lee, Seung-Tae; Wiemels, Joseph L; Valencia, Alfonso; Gut, Marta; Flicek, Paul; Stunnenberg, Hendrik G; Siebert, Reiner; Küppers, Ralf; Gut, Ivo G; Campo, Elías; Martín-Subero, José I

    2015-07-01

    We analyzed the DNA methylome of ten subpopulations spanning the entire B cell differentiation program by whole-genome bisulfite sequencing and high-density microarrays. We observed that non-CpG methylation disappeared upon B cell commitment, whereas CpG methylation changed extensively during B cell maturation, showing an accumulative pattern and affecting around 30% of all measured CpG sites. Early differentiation stages mainly displayed enhancer demethylation, which was associated with upregulation of key B cell transcription factors and affected multiple genes involved in B cell biology. Late differentiation stages, in contrast, showed extensive demethylation of heterochromatin and methylation gain at Polycomb-repressed areas, and genes with apparent functional impact in B cells were not affected. This signature, which has previously been linked to aging and cancer, was particularly widespread in mature cells with an extended lifespan. Comparing B cell neoplasms with their normal counterparts, we determined that they frequently acquire methylation changes in regions already undergoing dynamic methylation during normal B cell differentiation.

  8. Targeting the B cell receptor signaling pathway in B lymphoid malignancies

    PubMed Central

    Buchner, Maike; Müschen, Markus

    2014-01-01

    PURPOSE OF REVIEW Normal B cells that failed to productively rearrange immunoglobulin V region genes, encoding a functional B cell receptor (BCR) are destined to die. Likewise, the majority of B cell malignancies remain dependent on functional BCR signaling, while in some subtypes BCR expression is missing and, apparently, counterselected. Here we summarize recent the experimental evidence for the importance of BCR signaling and clinical concepts to target the BCR pathway in B cell leukemia and lymphoma. RECENT FINDINGS While the dependency on pre-BCR signaling in pre-B acute lymphoblastic leukemia (ALL) seems to be limited to few ALL subtypes (e.g. TCF3-PBX1), most mature B cell lymphomas rely on BCR signaling provided by different stimuli e.g. tonic B cell signaling, chronic (auto)-antigen exposure, and self-binding properties of the BCR. The finding that in chronic lymphocytic leukemia (CLL), BCRs bind to an epitope on the BCR itself unravels a novel concept for CLL pathogenesis. SUMMARY Targeting of the B cell receptor tyrosine kinases SYK, BTK, and PI3K achieve promising clinical responses in various mature B cell malignancies and might also be useful in defined subsets of ALL. However, further understanding of the BCR signal integration in the different disease groups are required to accurately predict, which groups of patients will benefit from BCR pathway-inhibition. PMID:24811161

  9. Mechanistic insights into the impairment of memory B cells and antibody production in the elderly.

    PubMed

    Aberle, Judith H; Stiasny, Karin; Kundi, Michael; Heinz, Franz X

    2013-04-01

    It is well established that immunologic memory generated early in life can be maintained into old age and mediate robust anamnestic antibody responses. Little is known, however, about the initiation of memory B cells in the elderly. We have conducted a prospective analysis of the quantities and functionalities of antigen-specific B cell responses and its association with the functional helper CD4(+)T cell responses. The ability of naïve B cells from old (60-80 years) and young (20-31 years) humans to establish functional memory was examined following primary and booster vaccination with an inactivated-virus vaccine against tick-borne encephalitis. Our data show that the number of antigen-specific memory B cells generated during primary vaccination was ~3-fold lower in old than in young individuals. The maintenance and booster responsiveness of these memory B cells were not compromised, as evidenced by similar increases in specific memory B cell frequencies upon revaccination in old and young adults. In contrast, the Ab response mediated per memory B cell after revaccination was dramatically diminished in the elderly. Also, antigen-specific IL-2-positive CD4(+)T cell responses were strongly reduced in the elderly and displayed an excellent correlation with Ab titres. The data suggest that the dramatically lower antibody response in the elderly could only partially be accounted for by the reduced B cell numbers and was strongly correlated with profound functional defects in CD4 help.

  10. IgG-Immune Complexes Promote B Cell Memory by Inducing BAFF.

    PubMed

    Kang, SunAh; Keener, Amanda B; Jones, Shannon Z; Benschop, Robert J; Caro-Maldonado, Alfredo; Rathmell, Jeffrey C; Clarke, Stephen H; Matsushima, Glenn K; Whitmire, Jason K; Vilen, Barbara J

    2016-01-01

    Memory B cell responses are vital for protection against infections but must also be regulated to prevent autoimmunity. Cognate T cell help, somatic hypermutation, and affinity maturation within germinal centers (GCs) are required for high-affinity memory B cell formation; however, the signals that commit GC B cells to the memory pool remain unclear. In this study, we identify a role for IgG-immune complexes (ICs), FcγRs, and BAFF during the formation of memory B cells in mice. We found that early secretion of IgG in response to immunization with a T-dependent Ag leads to IC-FcγR interactions that induce dendritic cells to secrete BAFF, which acts at or upstream of Bcl-6 in activated B cells. Loss of CD16, hematopoietic cell-derived BAFF, or blocking IC:FcγR regions in vivo diminished the expression of Bcl-6, the frequency of GC and memory B cells, and secondary Ab responses. BAFF also contributed to the maintenance and/or expansion of the follicular helper T cell population, although it was dispensable for their formation. Thus, early Ab responses contribute to the optimal formation of B cell memory through IgG-ICs and BAFF. Our work defines a new role for FcγRs in GC and memory B cell responses.

  11. The Other Function: Class II-Restricted Antigen Presentation by B Cells

    PubMed Central

    Adler, Lital N.; Jiang, Wei; Bhamidipati, Kartik; Millican, Matthew; Macaubas, Claudia; Hung, Shu-chen; Mellins, Elizabeth D.

    2017-01-01

    Mature B lymphocytes (B cells) recognize antigens using their B cell receptor (BCR) and are activated to become antibody-producing cells. In addition, and integral to the development of a high-affinity antibodies, B cells utilize the specialized major histocompatibility complex class II (MHCII) antigen presentation pathway to process BCR-bound and internalized protein antigens and present selected peptides in complex with MHCII to CD4+ T cells. This interaction influences the fate of both types of lymphocytes and shapes immune outcomes. Specific, effective, and optimally timed antigen presentation by B cells requires well-controlled intracellular machinery, often regulated by the combined effects of several molecular events. Here, we delineate and summarize these events in four steps along the antigen presentation pathway: (1) antigen capture and uptake by B cells; (2) intersection of internalized antigen/BCRs complexes with MHCII in peptide-loading compartments; (3) generation and regulation of MHCII/peptide complexes; and (4) exocytic transport for presentation of MHCII/peptide complexes at the surface of B cells. Finally, we discuss modulation of the MHCII presentation pathway across B cell development and maturation to effector cells, with an emphasis on the shaping of the MHCII/peptide repertoire by two key antigen presentation regulators in B cells: HLA-DM and HLA-DO. PMID:28386257

  12. Innate Response Activator (IRA) B Cells Reside in Human Tonsils and Internalize Bacteria In Vitro.

    PubMed

    Chiappini, Nico; Cantisani, Rocco; Pancotto, Laura; Ruggiero, Paolo; Rosa, Domenico; Manetti, Andrea; Romano, Antonio; Montagnani, Francesca; Bertholet, Sylvie; Castellino, Flora; Del Giudice, Giuseppe

    2015-01-01

    Innate response activator (IRA) B cells have been described in mice as a subset of B-1a B cells that produce granulocyte/macrophage colony-stimulating factor (GM-CSF) and have been found in the spleen upon activation. In humans, identification, tissue localization and functionality of these lymphocytes are poorly understood. We hypothesized that IRA B cells could reside in human palatine tonsils, which are a first line of defense from infection of the upper respiratory tract. In the present work, we used flow cytometry and confocal microscopy to identify and characterize human IRA (hIRA) B cells in tonsils. We show that CD19⁺CD20⁺GM-CSF⁺ B cells are present in the tonsils of all the subjects studied at a frequency ranging between ~0.2% and ~0.4% of the conventional CD19⁺CD20⁺GM-CSF⁻ B cells. These cells reside within the B cell follicles, are mostly IgM⁺IgD⁺, express CD5 and show phagocytic activity. Our results support a role for hIRA B cells in the effector immune response to infections in tonsils.

  13. Regulatory B cells present in lymph nodes draining a murine tumor.

    PubMed

    Maglioco, Andrea; Machuca, Damián G; Camerano, Gabriela; Costa, Héctor A; Ruggiero, Raúl; Dran, Graciela I

    2014-01-01

    In cancer, B cells have been classically associated with antibody secretion, antigen presentation and T cell activation. However, a possible role for B lymphocytes in impairing antitumor response and collaborating with tumor growth has been brought into focus. Recent reports have described the capacity of B cells to negatively affect immune responses in autoimmune diseases. The highly immunogenic mouse tumor MCC loses its immunogenicity and induces systemic immune suppression and tolerance as it grows. We have previously demonstrated that MCC growth induces a distinct and progressive increase in B cell number and proportion in the tumor draining lymph nodes (TDLN), as well as a less prominent increase in T regulatory cells. The aim of this research was to study B cell characteristics and function in the lymph node draining MCC tumor and to analyze whether these cells may be playing a role in suppressing antitumor response and favoring tumor progression. Results indicate that B cells from TDLN expressed increased CD86 and MHCII co-stimulatory molecules indicating activated phenotype, as well as intracellular IL-10, FASL and Granzyme B, molecules with regulatory immunosuppressive properties. Additionally, B cells showed high inhibitory upon T cell proliferation ex vivo, and a mild capacity to secrete antibodies. Our conclusion is that even when evidence of B cell-mediated activity of the immune response is present, B cells from TDLN exhibit regulatory phenotype and inhibitory activity, probably contributing to the state of immunological tolerance characteristic of the advanced tumor condition.

  14. Changes in Circulating B Cell Subsets Associated with Aging and Acute SIV Infection in Rhesus Macaques

    PubMed Central

    Gonzalez, Denise F.; Kieu, Hung T.; Castillo, Luis D.; Messaoudi, Ilhem; Shen, Xiaoying; Tomaras, Georgia D.; Shacklett, Barbara L.; Barry, Peter A.; Sparger, Ellen E.

    2017-01-01

    Aging and certain viral infections can negatively impact humoral responses in humans. To further develop the nonhuman primate (NHP) model for investigating B cell dynamics in human aging and infectious disease, a flow cytometric panel was developed to characterize circulating rhesus B cell subsets. Significant differences between human and macaque B cells included the proportions of cells within IgD+ and switched memory populations and a prominent CD21-CD27+ unswitched memory population detected only in macaques. We then utilized the expanded panel to analyze B cell alterations associated with aging and acute simian immunodeficiency virus (SIV) infection in the NHP model. In the aging study, distinct patterns of B cell subset frequencies were observed for macaques aged one to five years compared to those between ages 5 and 30 years. In the SIV infection study, B cell frequencies and absolute number were dramatically reduced following acute infection, but recovered within four weeks of infection. Thereafter, the frequencies of activated memory B cells progressively increased; these were significantly correlated with the magnitude of SIV-specific IgG responses, and coincided with impaired maturation of anti-SIV antibody avidity, as previously reported for HIV-1 infection. These observations further validate the NHP model for investigation of mechanisms responsible for B cells alterations associated with immunosenescence and infectious disease. PMID:28095513

  15. IDO2 Modulates T Cell-Dependent Autoimmune Responses through a B Cell-Intrinsic Mechanism.

    PubMed

    Merlo, Lauren M F; DuHadaway, James B; Grabler, Samantha; Prendergast, George C; Muller, Alexander J; Mandik-Nayak, Laura

    2016-06-01

    Mechanistic insight into how adaptive immune responses are modified along the self-nonself continuum may offer more effective opportunities to treat autoimmune disease, cancer, and other sterile inflammatory disorders. Recent genetic studies in the KRN mouse model of rheumatoid arthritis demonstrate that the immunomodulatory molecule IDO2 modifies responses to self-antigens; however, the mechanisms involved are obscure. In this study, we show that IDO2 exerts a critical function in B cells to support the generation of autoimmunity. In experiments with IDO2-deficient mice, adoptive transplant experiments demonstrated that IDO2 expression in B cells was both necessary and sufficient to support robust arthritis development. IDO2 function in B cells was contingent on a cognate, Ag-specific interaction to exert its immunomodulatory effects on arthritis development. We confirmed a similar requirement in an established model of contact hypersensitivity, in which IDO2-expressing B cells are required for a robust inflammatory response. Mechanistic investigations showed that IDO2-deficient B cells lacked the ability to upregulate the costimulatory marker CD40, suggesting IDO2 acts at the T-B cell interface to modulate the potency of T cell help needed to promote autoantibody production. Overall, our findings revealed that IDO2 expression by B cells modulates autoimmune responses by supporting the cross talk between autoreactive T and B cells.

  16. The aryl hydrocarbon receptor controls cell-fate decisions in B cells.

    PubMed

    Vaidyanathan, Bharat; Chaudhry, Ashutosh; Yewdell, William T; Angeletti, Davide; Yen, Wei-Feng; Wheatley, Adam K; Bradfield, Christopher A; McDermott, Adrian B; Yewdell, Jonathan W; Rudensky, Alexander Y; Chaudhuri, Jayanta

    2017-01-01

    Generation of cellular heterogeneity is an essential feature of the adaptive immune system. This is best exemplified during humoral immune response when an expanding B cell clone assumes multiple cell fates, including class-switched B cells, antibody-secreting plasma cells, and memory B cells. Although each cell type is essential for immunity, their generation must be exquisitely controlled because a class-switched B cell cannot revert back to the parent isotype, and a terminally differentiated plasma cell cannot contribute to the memory pool. In this study, we show that an environmental sensor, the aryl hydrocarbon receptor (AhR) is highly induced upon B cell activation and serves a critical role in regulating activation-induced cell fate outcomes. We find that AhR negatively regulates class-switch recombination ex vivo by altering activation-induced cytidine deaminase expression. We further demonstrate that AhR suppresses class switching in vivo after influenza virus infection and immunization with model antigens. In addition, by regulating Blimp-1 expression via Bach2, AhR represses differentiation of B cells into plasmablasts ex vivo and antibody-secreting plasma cells in vivo. These experiments suggest that AhR serves as a molecular rheostat in B cells to brake the effector response, possibly to facilitate optimal recall responses. Thus, AhR might represent a novel molecular target for manipulation of B cell responses during vaccination.

  17. Patient-Specific B-Cell Antibody Factories to Treat Metastatic Disease

    DTIC Science & Technology

    2012-08-01

    Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...clinical interface training and education to assure optimal sample viability and lack of the unique immortalization virus, Epstein Barr Virus ( EBV ). All...Breast Cancer, Sentinel lymph node, B-cell, EBV immortalization, Cancer Antigens Patient-Specific B-Cell Antibody Factories to Treat Metastatic

  18. Loss of B cell regulatory function is associated with delayed healing in patients with tibia fracture.

    PubMed

    Yang, Shufeng; Ding, Wei; Feng, Dapeng; Gong, Haiyang; Zhu, Dongmei; Chen, Bin; Chen, Jianmin

    2015-11-01

    The process of bone regeneration after fracture is a complex and well-orchestrated process usually requiring 3-12 weeks. A subset of patients, however, exhibit delayed healing time and even incomplete restoration of the normal bone structure. Although the precise mechanism is unknown, studies have shown that smurf1 may play a role during the process. Here, we sought to determine the involvement of the immune system in impaired bone healing. We found that immediately after fracture, the B-cell composition was shifted toward increased frequency of plasmablasts and decreased frequency of naïve B cells, reflecting higher inflammatory status. The percentage of CD19(+) CD24(+) CD38(+) regulatory B cells was also upregulated in response to bone fracture. The production of IL-10, a pivotal cytokine in regulatory B-cell function, was upregulated in all patients. Interestingly, the increase in IL-10 production was only sustained throughout the healing course in normal healing patients but not in delayed healing patients. Rather, delayed healing patients downregulated B-cell IL-10 secretion early and had reduced level of regulatory B-cell activity. Together, these data revealed a role of regulatory B cells in the endogenous bone regeneration process and an alternation in B-cell-mediated regulation in delayed healing patients.

  19. Microfluidic squeezing for intracellular antigen loading in polyclonal B-cells as cellular vaccines

    NASA Astrophysics Data System (ADS)

    Lee Szeto, Gregory; van Egeren, Debra; Worku, Hermoon; Sharei, Armon; Alejandro, Brian; Park, Clara; Frew, Kirubel; Brefo, Mavis; Mao, Shirley; Heimann, Megan; Langer, Robert; Jensen, Klavs; Irvine, Darrell J.

    2015-05-01

    B-cells are promising candidate autologous antigen-presenting cells (APCs) to prime antigen-specific T-cells both in vitro and in vivo. However to date, a significant barrier to utilizing B-cells as APCs is their low capacity for non-specific antigen uptake compared to “professional” APCs such as dendritic cells. Here we utilize a microfluidic device that employs many parallel channels to pass single cells through narrow constrictions in high throughput. This microscale “cell squeezing” process creates transient pores in the plasma membrane, enabling intracellular delivery of whole proteins from the surrounding medium into B-cells via mechano-poration. We demonstrate that both resting and activated B-cells process and present antigens delivered via mechano-poration exclusively to antigen-specific CD8+T-cells, and not CD4+T-cells. Squeezed B-cells primed and expanded large numbers of effector CD8+T-cells in vitro that produced effector cytokines critical to cytolytic function, including granzyme B and interferon-γ. Finally, antigen-loaded B-cells were also able to prime antigen-specific CD8+T-cells in vivo when adoptively transferred into mice. Altogether, these data demonstrate crucial proof-of-concept for mechano-poration as an enabling technology for B-cell antigen loading, priming of antigen-specific CD8+T-cells, and decoupling of antigen uptake from B-cell activation.

  20. Differential requirement of MALT1 for BAFF-induced outcomes in B cell subsets.

    PubMed

    Tusche, Michael W; Ward, Lesley A; Vu, Frances; McCarthy, Doug; Quintela-Fandino, Miguel; Ruland, Jurgen; Gommerman, Jennifer L; Mak, Tak W

    2009-11-23

    B cell activation factor of the TNF family (BAFF) activates noncanonical nuclear factor kappaB (NF-kappaB) heterodimers that promote B cell survival. We show that although MALT1 is largely dispensable for canonical NF-kappaB signaling downstream of the B cell receptor, the absence of MALT1 results in impaired BAFF-induced phosphorylation of NF-kappaB2 (p100), p100 degradation, and RelB nuclear translocation in B220(+) B cells. This corresponds with impaired survival of MALT1(-/-) marginal zone (MZ) but not follicular B cells in response to BAFF stimulation in vitro. MALT1(-/-) MZ B cells also express higher amounts of TRAF3, a known negative regulator of BAFF receptor-mediated signaling, and TRAF3 was found to interact with MALT1. Furthermore, phenotypes associated with overexpression of BAFF, including increased MZ B cell numbers, elevated serum immunoglobulin titers, and spontaneous germinal center formation, were found to be dependent on B cell-intrinsic MALT1 expression. Our results demonstrate a novel role for MALT1 in biological outcomes induced by BAFF-mediated signal transduction.

  1. Rituximab and Interleukin-12 in Treating Patients With B-Cell Non-Hodgkin's Lymphoma

    ClinicalTrials.gov

    2013-08-23

    Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Nodal Marginal Zone B-cell Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Small Lymphocytic Lymphoma; Splenic Marginal Zone Lymphoma

  2. Control of memory B cell responses by extrinsic and intrinsic mechanisms.

    PubMed

    Wienands, Jürgen; Engels, Niklas

    2016-10-01

    Following primary activation, B lymphocytes generate a long-lived memory compartment to harness the organism for future reinfections by the same pathogen species. Only recently the composition and signaling signature of the scarce memory B cell pool could be explored in more detail. This review highlights current concepts of how B cells preserve their antigen experience at the cellular and molecular level.

  3. Yin-yang effect of tumor infiltrating B cells in breast cancer: From mechanism to immunotherapy.

    PubMed

    Zhang, Zhigang; Zhu, Ying; Wang, Zhen; Zhang, Ting; Wu, Pin; Huang, Jian

    2017-05-01

    Breast cancer cells secrete chemokines, such as CXCL13, and antigens or express high endothelial venules, attracting B cells to infiltrate into the tumor microenvironment and play a "yin-yang" effect. They not only enhance the anti-tumor immune effect via secreting antibodies and influencing the Fas/FasL, CXCR4/CXCL12 and perforin pathways but they also promote the tumor to form a suppressive milieu by producing immunomodulatory factors and cytokines or using cell-to-cell education to induce the generation of Tregs or myeloid-derived suppressor cells (MDSCs). Currently, most studies on breast cancer tissue have indicated that B cell infiltration could predict better survival and response to therapy, but two studies have reported opposite results. In a 4T1 tumor-bearing BALB/c mice model, B cell-based immunotherapies were administered, but the efficiency was unstable. Herein, we review the "yin-yang" effect of B cells in breast cancer and discuss B cell-based immunotherapy. B cells are complex aggregates, and breast cancer is a heterogeneous disease. Further studies are urgently required to define the B cell subsets and to discover ways to use B cell-based immunotherapy in breast cancer.

  4. TSPAN33 is a novel marker of activated and malignant B cells

    PubMed Central

    Luu, Van Phi; Hevezi, Peter; Vences-Catalan, Felipe; Maravillas-Montero, Jose Luis; White, Clayton Alexander; Casali, Paolo; Llorente, Luis; Jakez-Ocampo, Juan; Lima, Guadalupe; Vilches-Cisneros, Natalia; Flores-Gutiérrez, Juan Pablo; Santos-Argumedo, Leopoldo; Zlotnik, Albert

    2014-01-01

    We have identified Tspan33 as a gene encoding a transmembrane protein exhibiting a restricted expression pattern including expression in activated B cells. TSPAN33 is a member of the tetraspanin family. TSPAN33 is not expressed in resting B cells, but is strongly induced in primary human B cells following activation. Human 2E2 cells, a Burkitt’s lymphoma-derived B cell model of activation and differentiation, also upregulate TSPAN33 upon activation. TSPAN33 is expressed in several lymphomas including Hodgkin’s and Diffuse large B Cell Lymphoma. TSPAN33 is also expressed in some autoimmune diseases where B cells participate in the pathology, including rheumatoid arthritis patients, systemic lupus erythematosus (SLE), and in spleen B cells from MRL/Faslpr/lpr mice (a mouse model of SLE). We conclude that TSPAN33 may be used as a diagnostic biomarker or as a target for therapeutic antibodies for treatment of certain B cell lymphomas or autoimmune diseases. PMID:24211713

  5. Innate Response Activator (IRA) B Cells Reside in Human Tonsils and Internalize Bacteria In Vitro

    PubMed Central

    Pancotto, Laura; Ruggiero, Paolo; Rosa, Domenico; Manetti, Andrea; Romano, Antonio; Montagnani, Francesca; Bertholet, Sylvie; Castellino, Flora; Del Giudice, Giuseppe

    2015-01-01

    Innate response activator (IRA) B cells have been described in mice as a subset of B-1a B cells that produce granulocyte/macrophage colony-stimulating factor (GM-CSF) and have been found in the spleen upon activation. In humans, identification, tissue localization and functionality of these lymphocytes are poorly understood. We hypothesized that IRA B cells could reside in human palatine tonsils, which are a first line of defense from infection of the upper respiratory tract. In the present work, we used flow cytometry and confocal microscopy to identify and characterize human IRA (hIRA) B cells in tonsils. We show that CD19+CD20+GM-CSF+ B cells are present in the tonsils of all the subjects studied at a frequency ranging between ~0.2% and ~0.4% of the conventional CD19+CD20+GM-CSF- B cells. These cells reside within the B cell follicles, are mostly IgM+IgD+, express CD5 and show phagocytic activity. Our results support a role for hIRA B cells in the effector immune response to infections in tonsils. PMID:26066485

  6. Monosodium glutamate induces apoptosis in naive and memory human B cells.

    PubMed

    Jovic, Z; Veselinovic, M; Vasic, K; Stankovic-Djordjevic, D; Cekic, S; Milovanovic, M; Sarac, M

    2009-01-01

    The aim of this study was to establish the existence of mGluR7 in normal B lymphocytes and analyse the effect of monosodium glutamate (MSG) on B cell apoptosis in vitro. B cells were purified by magnetic cell sorting using anti-CD19-coupled magnetic beads. Cells (10(6)/ml) were cultured with increasing MSG concentrations (1-100 mM). Detection of apoptosis by flow cytometry was performed using the Annexin V-FITC/Propidium iodide (PI) apoptosis detection kit. Naïve and memory B cell population were identified by CD27 staining. Expression of GluRs was determined using PCR. Exposure to increasing MSG concentrations displayed dose dependent effect on B cell viability altogether, ranging from 35% with 100 mM up to 80% with 1 mM MSG. Moreover, the number of late apoptotic cells as well as necrotic cells was dose dependant. Both CD27- as well as CD27+ B cells were affected by MSG. Basal expression of GluRs7 was detected in unstimulated B cells. Glutamate induced apoptosis can be seen in memory as well as naive B cell population and is probably mediated through mGluR7, whose expression in B cells we also confirmed. Our study suggests a new possible mechanism of crosstalk between the nervous and the immune system through glutamate as a potential key mediator (Fig. 4, Ref. 27). Full Text (Free, PDF) www.bmj.sk.

  7. Study of BKM120 & Rituximab in Patients With Relapsed or Refractory Indolent B-Cell Lymphoma

    ClinicalTrials.gov

    2016-10-18

    Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Nodal Marginal Zone B-cell Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Splenic Marginal Zone Lymphoma; Waldenström Macroglobulinemia

  8. B cells from African American lupus patients exhibit an activated phenotype

    PubMed Central

    Menard, Laurence C.; Habte, Sium; Gonsiorek, Waldemar; Lee, Deborah; Banas, Dana; Holloway, Deborah A.; Cunningham, Mark; Stetsko, Dawn; Casano, Francesca; Kansal, Selena; Davis, Patricia M.; Carman, Julie; Zhang, Clarence K.; Abidi, Ferva; Furie, Richard; Nadler, Steven G.; Suchard, Suzanne J.

    2016-01-01

    Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disease driven by both innate and adaptive immune cells. African Americans tend to present with more severe disease at an earlier age compared with patients of European ancestry. In order to better understand the immunological differences between African American and European American patients, we analyzed the frequencies of B cell subsets and the expression of B cell activation markers from a total of 68 SLE patients and 69 normal healthy volunteers. We found that B cells expressing the activation markers CD86, CD80, PD1, and CD40L, as well as CD19+CD27–IgD– double-negative B cells, were enriched in African American patients vs. patients of European ancestry. In addition to increased expression of CD40L, surface levels of CD40 on B cells were lower, suggesting the engagement of the CD40 pathway. In vitro experiments confirmed that CD40L expressed by B cells could lead to CD40 activation and internalization on adjacent B cells. To conclude, these results indicate that, compared with European American patients, African American SLE patients present with a particularly active B cell component, possibly via the activation of the CD40/CD40L pathway. These data may help guide the development of novel therapies. PMID:27699274

  9. 604 Phenotypic and Functional Analysis of B Cells in Patients with Common Variable Immunodeficiency

    PubMed Central

    Berrón-Ruiz, Laura; Martínez, Dolores Mogica; Santos-Argumedo, Leopoldo; Herrera, Gabriela López; Espinosa-Rosales, Francisco; Blancas-Galicia, Lizbeth

    2012-01-01

    Background Common variable immunodeficiency (CVID) is a primary antibody deficiency characterized by a decrease in antibody production and low or normal B cell numbers. To elucidate the clinical and immunological heterogeneity of this condition, we studied 13 patients diagnosed with CVID, examined the status of B-cell maturation in patients with CVID by analyzing IgD/CD27 expression, and we analyze the in vitro B cell differentiation to plasma cells. Methods T, B and NK cell populations was analyzed by flow citometry, expression of CD27 marker was determined to define B cell subsets; we also assessed molecules important for B cell proliferation and differentiation, such as TNFRSF13B (TACI), inducible costimulator (ICOS), CD154, CD20, ICOSL and BAFFR. For B cell differentiation assays, total PBMCs were cultured with CpG alone, or with SAC Cowan, Pokweed and CpG; flow cytometric analysis of plasmablast generation was perfomed after 7 days of culture. Results Reduced numbers of T and B cells was observed in CVID patients, this reduction was more prominent in adults than in children. One group of 8 patients showed a significant reduction in IgD+CD27+ memory B cells while 3 patients had similar percentage than the healthy control group. The IgD-CD27+ memory B cell population was low in 10 patients (<12%); while it was similar to the healthy control group in 2 of the patients. BAFFR expression in B cells was reduced in 4 patients. Finally, the differentiation to plasmablasts was reduced in patients, stimulation with CpG induced 18.5% of plasmablasts (SD = 12.5%) whereas it was 24% (SD = 8.3%) in healthy controls. Conclusions These results suggest that a combined defect in T and B cells may account for CVID, at least in some patients. On the other hand, the complete analysis of markers important for B proliferation and differentiation such as ICOS, CD40, CD154 and TACI can be a useful tool for understanding this heterogeneous disease. B cells from CVID patients fail to

  10. UCH-L1 is induced in germinal center B cells and identifies patients with aggressive germinal center diffuse large B-cell lymphoma.

    PubMed

    Bedekovics, Tibor; Hussain, Sajjad; Feldman, Andrew L; Galardy, Paul J

    2016-03-24

    Gene expression profiling has identified 2 major subclasses of diffuse large B-cell lymphoma (DLBCL). Cases resembling germinal center (GC) B cells (GCB-DLBCL) generally occur in younger patients, have a distinct molecular pathophysiology, and have improved outcomes compared with those similar to activated post-GC cells (activated B-cell DLBCL). We previously found that the ubiquitin hydrolase UCH-L1 is frequently overexpressed in mature B-cell malignancies and is a potent oncogene in mice. The cause for its overexpression in lymphoma, and whether it impacts the outcome of patients with DLBCL is unknown. Here, we show that UCH-L1 reflects GC lineage in lymphoma and is an oncogenic biomarker of aggressive GCB-DLBCL. We find that UCH-L1 is specifically induced in GC B cells in mice and humans, and that its expression correlates highly with the GCB subtype in DLBCL. We also find that UCH-L1 cooperates with BCL6 in a mouse model of GC B-cell lymphoma, but not with the development of multiple myeloma derived from post-GC cells. Despite the typically good outcomes of GCB-DLBCL, increased UCHL1 identifies a subgroup with early relapses independent of MYC expression, suggesting biological diversity in this subset of disease. Consistent with this, forced Uchl1 overexpression had a substantial impact on gene expression in GC B cells including pathways of cell cycle progression, cell death and proliferation, and DNA replication. These data demonstrate a novel role for UCH-L1 outside of the nervous system and suggest its potential use as a biomarker and therapeutic target in DLBCL.

  11. MCL-1 is required throughout B-cell development and its loss sensitizes specific B-cell subsets to inhibition of BCL-2 or BCL-XL

    PubMed Central

    Vikström, Ingela B; Slomp, Anne; Carrington, Emma M; Moesbergen, Laura M; Chang, Catherine; Kelly, Gemma L; Glaser, Stefan P; Jansen, J H Marco; Leusen, Jeanette H W; Strasser, Andreas; Huang, David C S; Lew, Andrew M; Peperzak, Victor; Tarlinton, David M

    2016-01-01

    Pro-survival BCL-2 family members protect cells from programmed cell death that can be induced by multiple internal or external cues. Within the haematopoietic lineages, the BCL-2 family members BCL-2, BCL-XL and MCL-1 are known to support cell survival but the individual and overlapping roles of these pro-survival BCL-2 proteins for the persistence of individual leukocyte subsets in vivo has not yet been determined. By combining inducible knockout mouse models with the BH3-mimetic compound ABT-737, which inhibits BCL-2, BCL-XL and BCL-W, we found that dependency on MCL-1, BCL-XL or BCL-2 expression changes during B-cell development. We show that BCL-XL expression promotes survival of immature B cells, expression of BCL-2 is important for survival of mature B cells and long-lived plasma cells (PC), and expression of MCL-1 is important for survival throughout B-cell development. These data were confirmed with novel highly specific BH3-mimetic compounds that target either BCL-2, BCL-XL or MCL-1. In addition, we observed that combined inhibition of these pro-survival proteins acts in concert to delete specific B-cell subsets. Reduced expression of MCL-1 further sensitized immature as well as transitional B cells and splenic PC to loss of BCL-XL expression. More markedly, loss of MCL-1 greatly sensitizes PC populations to BCL-2 inhibition using ABT-737, even though the total wild-type PC pool in the spleen is not significantly affected by this drug and the bone marrow (BM) PC population only slightly. Combined loss or inhibition of MCL-1 and BCL-2 reduced the numbers of established PC >100-fold within days. Our data suggest that combination treatment targeting these pro-survival proteins could be advantageous for treatment of antibody-mediated autoimmune diseases and B-cell malignancies. PMID:27560714

  12. Engagement of the B cell receptor for antigen differentially affects B cell responses to Toll-like receptor-7 agonists and antagonists in BXSB mice

    PubMed Central

    Layer, T; Steele, A; Goeken, J A; Fleenor, S; Lenert, P

    2011-01-01

    Nucleic acid sensors of the Toll-like receptor (TLR) family play a well-established role in the pathogenesis of lupus. This is particularly true for a single-stranded RNA-sensing TLR-7 receptor, as lupus mice lacking TLR-7 show ameliorated disease. Cytosine–guanosine dinucleotide (CpG)-DNA-sensing TLR-9, conversely, has a complex regulatory role in systemic lupus erythematosus (SLE). Much less is known about whether signals through the B cell receptor for antigen (BCR) may affect the ability of B cells to respond to suboptimal TLR-7 agonists and antagonists. We studied this question in prediseased BXSB male and female B cells. We found that male B cells responded more vigorously to numerous TLR-7 ligands and this responsiveness was enhanced further upon co-engagement of the BCR. This synergy was seen primarily with the interleukin (IL)-6 secretion. A number of 32-mer inhibitory oligonucleotides (INH-ODNs) with a nuclease-resistant phosphorothioate backbone were capable of blocking TLR-7, but not BCR-induced B cell activation, with an inhibitory concentration (IC)50 of approximately 100 nm. Surprisingly, while the presence of a single TGC motif at the 5′ end of an ODN did not increase its inhibitory capacity, INH-ODNs containing multiple TGC motifs had greater inhibitory potency. When BCR and TLR-7 were co-engaged, INH-ODNs showed a differential effect on B cell activation. Whereas apoptosis protection and G1-M entry completely escaped suppression, IL-6 secretion remained sensitive to inhibition, although with a 10-fold lower potency. Our results suggest that while TLR-7 antagonists may be considered as lupus therapeutics, simultaneous co-engagement of the TLR-7 and BCR might favour autoreactive B cell survival. This hypothesis needs further experimental validation. PMID:21235537

  13. Identification of a germ-line pro-B cell subset that distinguishes the fetal/neonatal from the adult B cell development pathway.

    PubMed

    Lu, Li-Sheng; Tung, James; Baumgarth, Nicole; Herman, Ometa; Gleimer, Michael; Herzenberg, Leonard A; Herzenberg, Leonore A

    2002-03-05

    Studies presented here show that the expression of CD4, MHC class II (Ia,) and B220 cleanly resolves a major and a minor subset within the earliest pro-B cell population (germ-line pro-B) in adult bone marrow (BM). The major subset expresses intermediate B220 and low CD4 levels. The minor subset, which constitutes roughly 20% of the adult germ-line pro-B, expresses very low B220 levels and does not express CD4. Ia is clearly detectable at low levels on the major germ-line pro-B subset, both in wild-type adult mice and in gene-targeted mice (RAG2-/- and microMT), in which B cell development terminates before the pre-B cell stage. A small proportion of cells in the more mature pro-B cell subsets (Hardy Fractions B and C) also express Ia at this level. In contrast, Ia levels on the minor subset are barely above (or equal to) background. Surprisingly, the major germ-line pro-B cell subset found in adults is missing in fetal and neonatal animals. All of the germ-line pro-B in these immature animals express a phenotype (very low B220, no CD4, or Ia) similar to that of the minor pro-B cell subset in adult BM. Because B cell development in fetal/neonatal animals principally results in B-1 cells, these findings demonstrate that the B-1 development pathway does not include the major germ-line pro-B subset found in adult BM and hence identify a very early difference between the B-1 and -2 development pathways.

  14. Short-Circuiting Gene Regulatory Networks: Origins of B Cell Lymphoma

    PubMed Central

    Koues, Olivia I.; Oltz, Eugene M.; Payton, Jacqueline E.

    2015-01-01

    B cell lymphomas (BCL) are characterized by widespread deregulation of gene expression when compared with their normal B cell counterparts. Recent epigenomic studies defined cis-regulatory elements (REs) whose activities are altered in BCL to drive some of these pathogenic expression changes. During transformation, multiple mechanisms are employed to alter RE activities, including perturbations in the function of chromatin modifiers, which can lead to revision of the B cell epigenome. Inherited and somatic variants also alter RE function via disruption of TF binding. Aberrant expression of non-coding RNAs deregulates genes involved in B cell differentiation via direct repression and post-transcriptional targeting. These discoveries have established epigenetic etiologies for B cell transformation that are being exploited by novel therapeutic approaches. PMID:26604030

  15. Increased B cell proliferation and reduced Ig production in DREAM transgenic mice.

    PubMed

    Savignac, Magali; Mellström, Britt; Bébin, Anne-Gaëlle; Oliveros, Juan C; Delpy, Laurent; Pinaud, Eric; Naranjo, Jose R

    2010-12-15

    DREAM/KChIP-3 is a calcium-dependent transcriptional repressor highly expressed in immune cells. Transgenic mice expressing a dominant active DREAM mutant show reduced serum Ig levels. In vitro assays show that reduced Ig secretion is an intrinsic defect of transgenic B cells that occurs without impairment in plasma cell differentiation, class switch recombination, or Ig transcription. Surprisingly, transgenic B cells show an accelerated entry in cell division. Transcriptomic analysis of transgenic B cells revealed that hyperproliferative B cell response could be correlated with a reduced expression of Klf9, a cell-cycle regulator. Pulse-chase experiments demonstrated that the defect in Ig production is associated with reduced translation rather than with increased protein degradation. Importantly, transgenic B cells showed reduced expression of the Eif4g3 gene, which encodes a protein related to protein translation. Our results disclose, to our knowledge, a novel function of DREAM in proliferation and Ig synthesis in B lymphocytes.

  16. Pediatric common variable immunodeficiency: immunologic and phenotypic associations with switched memory B cells.

    PubMed

    Yong, Pierre L; Orange, Jordan S; Sullivan, Kathleen E

    2010-08-01

    Recent studies suggest that patients with common variable immunodeficiency (CVID) and low numbers of switched memory B cells have lower IgG levels and higher rates of autoimmune disease, splenomegaly, and granulomatous disease; however, no prior literature has focused exclusively on pediatric cases. We examined the relationship between switched memory B cells and clinical and immunologic manifestations of CVID in a pediatric population. Forty-five patients were evaluated. Patients were categorized as Group I (<5 switched memory B cells/ml, n = 24) or Group II (> or =5 switched memory B cells/mL, n = 21). CD3(+) T-cell counts and CD19(+) B-cell levels were lower among Group I patients. Only those in Group I had meningitis, sepsis, bronchiectasis, granulomatous lung disease, autoimmune cytopenias, or hematologic malignancies. Segregation of pediatric patients into high risk (Group I) and average risk (Group II) may assist in targeting surveillance appropriately.

  17. B cells Regulate Macrophage Phenotype and Response to Chemotherapy in Squamous Carcinomas

    PubMed Central

    Medler, Terry R.; Gunderson, Andrew J.; Johansson, Magnus; Bornstein, Sophia; Bergsland, Emily; Steinhoff, Martin; Li, Yijin; Gong, Qian; Ma, Yan; Wiesen, Jane F.; Wong, Melissa H.; Kulesz-Martin, Molly; Irving, Bryan; Coussens, Lisa M.

    2014-01-01

    SUMMARY B cells foster squamous cell carcinogenesis (SCC) through deposition of immunoglobulin-containing immune complexes in premalignant tissue and Fcγreceptor-dependent activation of myeloid cells. Since human SCCs of the vulva and head and neck exhibited hallmarks of B cell infiltration, we examined B cell-deficient mice and found reduced ability to support SCC growth. Although ineffective as a single agent, treatment of mice bearing pre-existing SCCs with B cell-depleting αCD20 monoclonal antibodies improved response to platinum- and taxol-based chemotherapy. Improved chemo-responsiveness was dependent on altered chemokine expression by macrophages that fostered tumor infiltration of activated CD8+ T cells via CCR5-dependent mechanisms. These data reveal that B cells, and the downstream myeloid-based pathways they regulate, represent tractable targets for anti-cancer therapy in select tumors. PMID:24909985

  18. Differential development of progenitor activity for three B-cell lineages.

    PubMed Central

    Kantor, A B; Stall, A M; Adams, S; Herzenberg, L A; Herzenberg, L A

    1992-01-01

    Cell-transfer studies presented here distinguish three murine B cell lineages: conventional B cells, which develop late and are continually replenished from progenitors in adult bone marrow; Ly-1 B cells (B-1a), which develop early and maintain their numbers by self-replenishment; and Ly-1B "sister" (B-1b) cells, which share many of the properties of Ly-1 B cells, including self-replenishment and feedback regulation of development but can also readily develop from progenitors in adult bone marrow. The sequential emergence of these lineages, the time at which their progenitors function during ontogeny, and the distinctions among their repertoires and functions suggest that evolution has created a layered immune system in which the immune response potential of each successive lineage is adapted to its particular niche. Images PMID:1565622

  19. Salmonella Modulates B Cell Biology to Evade CD8+ T Cell-Mediated Immune Responses

    PubMed Central

    Lopez-Medina, Marcela; Perez-Lopez, Araceli; Alpuche-Aranda, Celia; Ortiz-Navarrete, Vianney

    2014-01-01

    Although B cells and antibodies are the central effectors of humoral immunity, B cells can also produce and secrete cytokines and present antigen to helper T cells. The uptake of antigen is mainly mediated by endocytosis; thus, antigens are often presented by MHC-II molecules. However, it is unclear if B cells can present these same antigens via MHC-I molecules. Recently, Salmonella bacteria were found to infect B cells, allowing possible antigen cross-processing that could generate bacterial peptides for antigen presentation via MHC-I molecules. Here, we will discuss available knowledge regarding Salmonella antigen presentation by infected B cell MHC-I molecules and subsequent inhibitory effects on CD8+ T cells for bacterial evasion of cell-mediated immunity. PMID:25484884

  20. New insights into pre-BCR and BCR signalling with relevance to B cell malignancies.

    PubMed

    Rickert, Robert C

    2013-08-01

    The B cell receptor (BCR) and its precursor (pre-BCR) control B cell homeostasis, differentiation and function. Moreover, aberrant pre-BCR and BCR signalling have a central role in B cell neoplasia; for example, enhanced positive signalling or disrupted negative signalling downstream of the pre-BCR promotes B cell acute lymphocytic leukaemia. The emerging distinctions between tonic and chronic active BCR signalling have contributed to the identification of oncogenic targets downstream of BCR signalling in mature B cell neoplasms. Indeed, the encouraging results of several ongoing clinical trials that target the activity of phosphoinositide 3-kinase δ-isoform (PI3Kδ), Bruton tyrosine kinase (BTK) or spleen tyrosine kinase (SYK) downstream of the BCR highlight the therapeutic potential of inhibiting BCR signalling.

  1. B-cell tolerance in transplantation: is repertoire remodeling the answer?

    PubMed Central

    Parsons, Ronald F; Vivek, Kumar; Redfield, Robert R; Migone, Thi-Sau; Cancro, Michael P; Naji, Ali; Noorchashm, Hooman

    2010-01-01

    T lymphocytes are the primary targets of immunotherapy in clinical transplantation; however, B lymphocytes and their secreted alloantibodies are also highly detrimental to the allograft. Therefore, the achievement of sustained organ transplant survival will likely require the induction of B-lymphocyte tolerance. During development, acquisition of B-cell tolerance to self-antigens relies on clonal deletion in the early stages of B-cell compartment ontogeny. We contend that this mechanism should be recapitulated in the setting of alloantigens and organ transplantation to eliminate the alloreactive B-cell subset from the recipient. Clinically feasible targets of B-cell-directed immunotherapy, such as CD20 and B-lymphocyte stimulator (BLyS), should drive upcoming clinical trials aimed at remodeling the recipient B-cell repertoire. PMID:20161663

  2. Follicular B cell trafficking within the spleen actively restricts humoral immune responses

    PubMed Central

    Hoek, Kristen L.; Gordy, Laura E.; Collins, Patrick L.; Parekh, Vrajesh V.; Aune, Thomas M.; Joyce, Sebastian; Thomas, James W.; Van Kaer, Luc; Sebzda, Eric

    2010-01-01

    Summary Follicular (FO) and marginal zone (MZ) B cells are maintained in distinct locations within the spleen but the genetic basis for this separation is still enigmatic. We now report that B cell sequestration requires lineage-specific regulation of migratory receptors by the transcription factor, Klf2. Moreover, using gene-targeted mice we show that altered splenic B cell migration confers a significant in vivo gain-of-function phenotype to FO B cells, including the ability to quickly respond to MZ-associated antigens and pathogens in a T cell-dependent manner. This work demonstrates that in wild-type animals, naïve FO B cells are actively removed from the MZ, thus restricting their capacity to respond to blood-borne pathogens. PMID:20691614

  3. Rituximab in the treatment of primary cutaneous B-cell lymphoma: a review.

    PubMed

    Fernández-Guarino, M; Ortiz-Romero, P L; Fernández-Misa, R; Montalbán, C

    2014-06-01

    Rituximab is a chimeric mouse-human antibody that targets the CD20 antigen, which is found in both normal and neoplastic B cells. In recent years, it has been increasingly used to treat cutaneous B-cell lymphoma and is now considered an alternative to classic treatment (radiotherapy and surgery) of 2 types of indolent lymphoma, namely, primary cutaneous follicle center lymphoma and primary cutaneous marginal zone B-cell lymphoma. Rituximab is also administered as an alternative to polychemotherapy in the treatment of primary cutaneous large B-cell lymphoma, leg type. Its use as an alternative drug led to it being administered intralesionally, with beneficial effects. In the present article, we review the literature published on the use of rituximab to treat primary cutaneous B-cell lymphoma.

  4. In aged mice, low surrogate light chain promotes pro-B-cell apoptotic resistance, compromises the PreBCR checkpoint, and favors generation of autoreactive, phosphorylcholine-specific B cells.

    PubMed

    Ratliff, Michelle; Alter, Sarah; McAvoy, Kelly; Frasca, Daniela; Wright, Jacqueline A; Zinkel, Sandra S; Khan, Wasif N; Blomberg, Bonnie B; Riley, Richard L

    2015-06-01

    In aged mice, new B-cell development is diminished and the antibody repertoire becomes more autoreactive. Our studies suggest that (i) apoptosis contributes to reduced B lymphopoiesis in old age and preferentially eliminates those B-cell precursors with higher levels of the surrogate light chain (SLC) proteins (λ5/VpreB) and (ii) λ5(low) B-cell precursors generate new B cells which show increased reactivity to the self-antigen/bacterial antigen phosphorylcholine (PC). Pro-B cells in old bone marrow as well as pro-B cells from young adult λ5-deficient mice are resistant to cytokine-induced apoptosis (TNFα; TGFβ), indicating that low λ5 expression in pro-B cells is sufficient to cause increased survival. Transfer of TNFα-producing 'age-associated B cells' (ABC; CD21/35(-) CD23(-)) or follicular (FO) B cells from aged mice into RAG-2 KO recipients led to preferential loss of λ5(high) pro-B cells, but retention of λ5(low), apoptosis-resistant pro-B cells. In old mice, there is increased reactivity to PC in both immature bone marrow B cells and mature splenic FO B cells. In young mice, absence of λ5 expression led to a similar increase in PC reactivity among bone marrow and splenic B cells. We propose that in old age, increased apoptosis, mediated in part by TNFα-producing B cells, results in preferential loss of SLC(high) pro-B cells within the bone marrow. Further B-cell development then occurs via an 'SLC(low)' pathway that not only impairs B-cell generation, but promotes autoreactivity within the naïve antibody repertoires in the bone marrow and periphery.

  5. B cells undergo unique compartmentalized redistribution in multiple sclerosis.

    PubMed

    Haas, Jürgen; Bekeredjian-Ding, Isabelle; Milkova, Miriam; Balint, Bettina; Schwarz, Alexander; Korporal, Mirjam; Jarius, Sven; Fritz, Brigitte; Lorenz, Hanns-Martin; Wildemann, Brigitte

    2011-12-01

    Increasing evidence fosters the role of B cells (BC) in multiple sclerosis (MS). The compartmentalized distribution of BC in blood and cerebrospinal fluid (CSF) is incompletely understood. In this study, we analyzed BC-patterns and BC-immunoreactivity at these sites during active and during stable disease and the impact of disease modifying drugs (DMD) on peripheral BC-homeostasis. For this purpose we assessed BC-subsets in blood and CSF from patients with clinically isolated syndrome (CIS), relapsing remitting MS (RRMS), rheumatoid arthritis (RA), and healthy controls (HC) by flow cytometric detection of whole (W-BC), naïve, transitional (TN-BC), class-switched memory (CSM-BC), unswitched memory (USM-BC), double-negative memory (DNM-BC) BC-phenotypes, plasma blasts (PB), and plasma cells (PC). FACS-data were correlated with BC-specific chemotactic activities in CSF, intrathecal CXCL13-levels, and immunoreactivity of peripheral W-BC. Our study revealed that frequencies of systemic CSM-BC/USM-BC became contracted in active CIS/MS while proportions of naive BC, TN-BC and DNM-BC were reciprocally expanded. Moreover, the shifted BC-composition promoted reduced immunoreactivity of W-BC and resolved during remission. Cross-over changes in CSF included privileged accumulation of CSM-BC linked to intrathecal CXCL13-concentrations and expansion of PB/PC. Treatment with interferon-beta and natalizumab evoked distinct though differing redistribution of circulating BC-subsets. We conclude that symptomatic CIS and MS are accompanied by distinctive changes in peripheral and CSF BC-homeostasis. The privileged reciprocal distribution between naïve versus CSM-phenotypes in both compartments together with the marked chemotactic driving force towards BC prompted by CSF supernatants renders it likely that CSF BC are mainly recruited from peripheral blood during active CIS/MS, whereas constantly low percentages of circulating PB/PC and their failure to respond to migratory stimuli

  6. Molecular characterization of the early B cell response to pulmonary Cryptococcus neoformans infection.

    PubMed

    Rohatgi, Soma; Pirofski, Liise-anne

    2012-12-15

    The role of B cells in host defense against fungi has been difficult to establish. We quantified and determined the molecular derivation of B-1a, B-1b, and B-2 B cell populations in C57BL/6 mice after pulmonary infection with Cryptococcus neoformans. Total B-1 and B-2 cell numbers increased in lungs and peritoneal cavity as early as day 1 postinfection, but lacked signs of clonal expansion. Labeled capsular (24067) and acapsular (Cap67) C. neoformans strains were used to identify C. neoformans-binding B cell subsets by flow cytometry. Peritoneal cavity B-1a B cells exhibited the most acapsular and capsular C. neoformans binding in C. neoformans-infected mice, and C. neoformans-selected B-1 B cells secreted laminarin- and C. neoformans-binding IgM. Single-cell PCR-based sequence analysis of B-1a, B-1b, and B-2 cell IgH V region H chain (V(H)) genes revealed increased usage of V(H)11 and V(H)12, respectively, in acapsular and capsular C. neoformans-selected B-1a cells. Germline V(H) segments were used, with capsular C. neoformans-selected cells having less junctional diversity than acapsular C. neoformans-selected cells. Further studies in B-1 B cell-depleted mice showed that these mice had higher brain and lung fungal burdens and less alveolar macrophage phagocytosis of C. neoformans than did control and B-1a B cell-reconstituted mice. Taken together, these results establish a mechanistic role for B-1 B cells in the innate B cell response to pulmonary infection with C. neoformans and reveal that IgM-producing B-1a cells, which express germline V(H) genes, bind C. neoformans and contribute to early fungal clearance. Thus, B-1a B cells provide a first line of defense during pulmonary C. neoformans infection in mice.

  7. Murine complement receptor 1 is required for germinal center B cell maintenance but not initiation.

    PubMed

    Donius, Luke R; Weis, Janis J; Weis, John H

    2014-06-01

    Germinal centers are the anatomic sites for the generation of high affinity immunoglobulin expressing plasma cells and memory B cells. The germinal center B cells that are precursors of these cells circulate between the light zone B cell population that interact with antigen laden follicular dendritic cells (FDC) and the proliferative dark zone B cell population. Antigen retention by follicular dendritic cells is dependent on Fc receptors and complement receptors, and complement receptor 1 (Cr1) is the predominant complement receptor expressed by FDC. The newly created Cr1KO mouse was used to test the effect of Cr1-deficiency on the kinetics of the germinal center reaction and the generation of IgM and switched memory B cell formation. Immunization of Cr1KO mice with a T cell-dependent antigen resulted in the normal initial expansion of B cells with a germinal center phenotype however these cells were preferentially lost in the Cr1KO animal over time (days). Bone marrow chimera animals documented the surprising finding that the loss of germinal center B cell maintenance was linked to the expression of Cr1 on B cells, not the FDC. Cr1-deficiency further resulted in antigen-specific IgM titer and IgM memory B cell reductions, but not antigen-specific IgG after 35-37 days. Investigations of nitrophenyl (NP)-specific IgG demonstrated that Cr1 is not necessary for affinity maturation during the response to particulate antigen. These data, along with those generated in our initial description of the Cr1KO animal describe unique functions of Cr1 on the surface of both B cells and FDC.

  8. Dimethyl fumarate treatment of relapsing-remitting multiple sclerosis influences B-cell subsets

    PubMed Central

    Lundy, Steven K.; Wu, Qi; Wang, Qin; Dowling, Catherine A.; Taitano, Sophina H.; Mao, Guangmei

    2016-01-01

    Objective: To test the hypothesis that dimethyl fumarate (Tecfidera, BG-12) affects B-cell subsets in patients with relapsing-remitting multiple sclerosis (RRMS). Methods: Peripheral blood B cells were compared for surface marker expression in patients with RRMS prior to initiation of treatment, after 4–6 months, and at more than 1 year of treatment with BG-12. Production of interleukin (IL)–10 by RRMS patient B cells was also analyzed. Results: Total numbers of peripheral blood B lymphocytes declined after 4–6 months of BG-12 treatment, due to losses in both the CD27+ memory B cells and CD27neg B-cell subsets. Some interpatient variability was observed. In contrast, circulating CD24highCD38high (T2-MZP) B cells increased in percentage in the majority of patients with RRMS after 4–6 months and were present in higher numbers in all of the patients after 12 months of treatment. The CD43+CD27+ B-1 B cells also increased at the later time point in most patients but were unchanged at 4–6 months compared to pretreatment levels. Purified B cells from 7 of the 9 patients with RRMS tested after 4–6 months of treatment were able to produce IL-10 following CD40 ligand stimulation, and the amount corresponded with the combined levels of T2-MZP and B-1 B cells in the sample. None of the patients with RRMS in this study have had a relapse while taking BG-12. Conclusions: These data suggest that BG-12 differentially affects B-cell subsets in patients with RRMS, resulting in increased numbers of circulating B lymphocytes with regulatory capacity. PMID:27006972

  9. High proportion of CD5+ B cells in infants predicts development of allergic disease.

    PubMed

    Lundell, Anna-Carin; Johansen, Susanne; Adlerberth, Ingegerd; Wold, Agnes E; Hesselmar, Bill; Rudin, Anna

    2014-07-15

    Delayed maturation of the immune system has been proposed to be a risk factor for development of allergy, but B cell maturation in relation to allergic disease has not been examined. B cells lose CD5 and acquire CD27 during maturation from immature via mature/naive to Ig-secreting cells and memory cells. We sought to investigate B cell maturation in relation to development of allergic disease and sensitization in the FARMFLORA birth cohort including 65 Swedish children. Total B cell numbers, proportions of CD5(+) and CD27(+) B cells, and levels of IgM, IgG, IgA, and IgE were measured in blood on repeated occasions from birth to 36 mo of age, and related to allergic disease and sensitization at 18 and 36 mo of age with multivariate discriminant analysis. We also compared the expression of CD24 and CD38 within CD5(+) and CD5(neg) B cells in children and in adults. We found that infants with a high proportion of CD5(+) B cells at birth and at 1 mo of age had an increased risk for having allergic disease at 18 and 36 mo of life. Further, the proportions of CD5(+) B cells at 1 mo of age were inversely correlated with total IgG levels at 18 and 36 mo of age. The majority of the CD5(+) B cells were of a CD24(hi/+)CD38(hi/+) immature/naive phenotype at birth (97%), 7 y of age (95%), and in adults (86%). These results suggest that development of allergic disease is preceded by an immaturity in neonatal B cell phenotype.

  10. IL-35-producing B cells are critical regulators of immunity during autoimmune and infectious diseases.

    PubMed

    Shen, Ping; Roch, Toralf; Lampropoulou, Vicky; O'Connor, Richard A; Stervbo, Ulrik; Hilgenberg, Ellen; Ries, Stefanie; Dang, Van Duc; Jaimes, Yarúa; Daridon, Capucine; Li, Rui; Jouneau, Luc; Boudinot, Pierre; Wilantri, Siska; Sakwa, Imme; Miyazaki, Yusei; Leech, Melanie D; McPherson, Rhoanne C; Wirtz, Stefan; Neurath, Markus; Hoehlig, Kai; Meinl, Edgar; Grützkau, Andreas; Grün, Joachim R; Horn, Katharina; Kühl, Anja A; Dörner, Thomas; Bar-Or, Amit; Kaufmann, Stefan H E; Anderton, Stephen M; Fillatreau, Simon

    2014-03-20

    B lymphocytes have critical roles as positive and negative regulators of immunity. Their inhibitory function has been associated primarily with interleukin 10 (IL-10) because B-cell-derived IL-10 can protect against autoimmune disease and increase susceptibility to pathogens. Here we identify IL-35-producing B cells as key players in the negative regulation of immunity. Mice in which only B cells did not express IL-35 lost their ability to recover from the T-cell-mediated demyelinating autoimmune disease experimental autoimmune encephalomyelitis (EAE). In contrast, these mice displayed a markedly improved resistance to infection with the intracellular bacterial pathogen Salmonella enterica serovar Typhimurium as shown by their superior containment of the bacterial growth and their prolonged survival after primary infection, and upon secondary challenge, compared to control mice. The increased immunity found in mice lacking IL-35 production by B cells was associated with a higher activation of macrophages and inflammatory T cells, as well as an increased function of B cells as antigen-presenting cells (APCs). During Salmonella infection, IL-35- and IL-10-producing B cells corresponded to two largely distinct sets of surface-IgM(+)CD138(hi)TACI(+)CXCR4(+)CD1d(int)Tim1(int) plasma cells expressing the transcription factor Blimp1 (also known as Prdm1). During EAE, CD138(+) plasma cells were also the main source of B-cell-derived IL-35 and IL-10. Collectively, our data show the importance of IL-35-producing B cells in regulation of immunity and highlight IL-35 production by B cells as a potential therapeutic target for autoimmune and infectious diseases. This study reveals the central role of activated B cells, particularly plasma cells, and their production of cytokines in the regulation of immune responses in health and disease.

  11. B cell origin of non-T cell acute lymphoblastic leukemia. A model for discrete stages of neoplastic and normal pre-B cell differentiation.

    PubMed Central

    Nadler, L M; Korsmeyer, S J; Anderson, K C; Boyd, A W; Slaughenhoupt, B; Park, E; Jensen, J; Coral, F; Mayer, R J; Sallan, S E

    1984-01-01

    The expression of B cell associated and restricted antigens on tumor cells isolated from 138 patients with non-T cell acute lymphoblastic leukemia (non-T cell ALL) was investigated by flow cytometric analysis by means of a panel of monoclonal antibodies. Tumor cells from these patients could be assigned to one of four subgroups: human leukocyte antigen-DR-related Ia-like antigens (Ia) alone (4%, stage I); IaB4 (14%, stage II); IaB4CALLA (33%, stage III); and IaB4CALLAB1 (49%, stage IV). The expression of B cell-restricted antigens (B4 and B1) and rearrangements of Ig heavy chain genes provided strong evidence for the B cell lineage of stages II, III, and IV tumors. The lineage of the Ia alone group is still unknown. The B4 antigen was expressed on approximately 95% of all non-T cell ALLs tested, and given its absence on T cell and myeloid tumors, it appears to be an exceptional marker to define cells of B lineage. The demonstration that Ia alone, IaB4, IaB4CALLA, and IaB4CALLAB1 positive cells can be readily identified by dual fluorescence analysis in normal fetal and adult bone marrow provided critical support for the view that these leukemic pre-B cell phenotypes were representative of the stages of normal pre-B cell differentiation. It was interesting that the IaB4+ cell was more frequently identified in fetal bone marrow than in adult marrow, whereas the predominant cell found in adult marrow expressed the IaB4CALLAB1 phenotype. These data suggest that the leukemogenic event may be random, since the predominant pre-B cell leukemic phenotype appears to correspond to the normal pre-B cell phenotype present in these hematopoietic organs. Our observations provide an additional distinction between adult and childhood ALL, since these studies show that most non-T cell ALLs seen in children less than 2 yr old are of stage II phenotype, whereas the majority of non-T ALLs in adults are of stage IV phenotype. Finally, it should be noted that the present study suggests

  12. The double-edge role of B cells in mediating antitumor T-cell immunity: Pharmacological strategies for cancer immunotherapy.

    PubMed

    Wang, Jing-Zhang; Zhang, Yu-Hua; Guo, Xin-Hua; Zhang, Hong-Yan; Zhang, Yuan

    2016-07-01

    Emerging evidence reveals the controversial role of B cells in antitumor immunity, but the underlying mechanisms have to be explored. Three latest articles published in the issue 521 of Nature in 2015 reconfirmed the puzzling topic and put forward some explanations of how B cells regulate antitumor T-cell responses both positively and negatively. This paper attempts to demonstrate that different B-cell subpopulations have distinct immunological properties and that they are involved in either antitumor responses or immunosuppression. Recent studies supporting the positive and negative roles of B cells in tumor development were summarized comprehensively. Several specific B-cell subpopulations, such as IgG(+), IgA(+), IL-10(+), and regulatory B cells, were described in detail. The mechanisms underlying the controversial B-cell effects were mainly attributed to different B-cell subpopulations, different B-cell-derived cytokines, direct B cell-T cell interaction, different cancer categories, and different malignant stages, and the immunological interaction between B cells and T cells is mediated by dendritic cells. Promising B-cell-based antitumor strategies were proposed and novel B-cell regulators were summarized to present interesting therapeutic targets. Future investigations are needed to make sure that B-cell-based pharmacological strategies benefit cancer immunotherapy substantially.

  13. In vivo expansion of the endogenous B-cell compartment stimulated by radiation and serial bone marrow transplantation induces B-cell leukaemia in mice.

    PubMed

    Holyoake, T L; Freshney, M G; Samuel, K; Ansell, J; Watson, G E; Wright, E G; Graham, G J; Pragnell, I B

    2001-07-01

    Chronic lymphocytic leukaemia (CLL) is a malignancy of CD5(+) B cells. This B-cell lineage is established during ontogeny and replenished by the process of self-renewal. Spontaneous and induced leukaemias that frequently affect this lineage are thought to arise as a result of the frequent cell division required to maintain the population throughout adulthood and in response to repeated exposure to environmental antigens. In a series of bone marrow transplant (BMT) experiments performed in B6D2F1 mice, B-cell leukaemia occurred in recipients of serially transplanted syngeneic bone marrow. This study was therefore designed to determine the frequency and phenotype of the observed leukaemia. Male donor cells were initially transplanted into lethally irradiated female hosts and secondary (2 degrees ) BMT was performed at 3 months. At 1, 2, 3 and 16 months following primary (1 degrees ) BMT, and when 2 degrees BMT recipients developed leukaemia, animals were sacrificed and their tissues extensively examined. These analyses confirmed a host-derived CD5(+) transplantable B-cell leukaemia that was initiated in 50% of 1 degrees BMT recipients. With serial passage, the leukaemia became more aggressive and lost CD5 expression, suggesting transformation to a high-grade leukaemia/lymphoma. This previously unreported observation suggests that the combination of radiation and subsequent serial transplantation induces a proliferative stress to the host B-cell compartment that is causative in leukaemic transformation.

  14. B cell antigen receptors of the IgM and IgD classes are clustered in different protein islands that are altered during B cell activation.

    PubMed

    Maity, Palash Chandra; Blount, Amy; Jumaa, Hassan; Ronneberger, Olaf; Lillemeier, Björn F; Reth, Michael

    2015-09-15

    The B cell antigen receptors (BCRs) play an important role in the clonal selection of B cells and their differentiation into antibody-secreting plasma cells. Mature B cells have both immunoglobulin M (IgM) and IgD types of BCRs, which have identical antigen-binding sites and are both associated with the signaling subunits Igα and Igβ, but differ in their membrane-bound heavy chain isoforms. By two-color direct stochastic optical reconstruction microscopy (dSTORM), we showed that IgM-BCRs and IgD-BCRs reside in the plasma membrane in different protein islands with average sizes of 150 and 240 nm, respectively. Upon B cell activation, the BCR protein islands became smaller and more dispersed such that the IgM-BCRs and IgD-BCRs were found in close proximity to each other. Moreover, specific stimulation of one class of BCR had minimal effects on the organization of the other. These conclusions were supported by the findings from two-marker transmission electron microscopy and proximity ligation assays. Together, these data provide evidence for a preformed multimeric organization of BCRs on the plasma membrane that is remodeled after B cell activation.

  15. Simultaneous Assessment of Rotavirus-Specific Memory B Cells and Serological Memory after B Cell Depletion Therapy with Rituximab

    PubMed Central

    Herrera, Daniel; Rojas, Olga L.; Duarte-Rey, Carolina; Mantilla, Rubén D.; Ángel, Juana; Franco, Manuel A.

    2014-01-01

    The mechanisms that contribute to the maintenance of serological memory are still unclear. Rotavirus (RV) memory B cells (mBc) are enriched in IgM+ and CD27- subpopulations, which are associated with autoimmune diseases pathogenesis. In patients with autoimmune diseases treated with Rituximab (RTX), some autoantibodies (auto-Abs) decrease after treatment, but other auto-Abs and pathogen-specific IgG Abs remain unchanged. Thus, maintenance of autoimmune and pathogen-specific serological memory may depend on the type of antigen and/or Ab isotype evaluated. Antigen-specific mBc and antigen-specific Abs of different isotypes have not been simultaneously assessed in patients after RTX treatment. To study the relationship between mBc subpopulations and serological memory we characterized total, RV- and tetanus toxoid (TT)-specific mBc by flow cytometry in patients with autoimmune diseases before and after treatment with RTX. We also measured total, RV- and TT-Abs, and some auto-Abs by kinetic nephelometry, ELISA, and EliA tests, respectively. Minor differences were observed between the relative frequencies of RV-mBc in healthy controls and patients with autoimmune disease. After RTX treatment, naïve Bc and total, RV- and TT-specific mBc [IgM+, switched (IgA+/IgG+), IgM+ only, IgD+ only, and CD27- (IgA+/IgG+/IgM+)] were significantly diminished. An important decrease in total plasma IgM and minor decreases in total IgG and IgA levels were also observed. IgM rheumatoid factor, IgG anti-CCP, and IgG anti-dsDNA were significantly diminished. In contrast, RV-IgA, RV-IgG and RV-IgG1, and TT-IgG titers remained stable. In conclusion, in patients with autoimmunity, serological memory against RV and TT seem to be maintained by long-lived plasma cells, unaffected by RTX, and an important proportion of total IgM and serological memory against some auto-antigens seem to be maintained by short-lived plasma cells, dependent on mBc precursors depleted by RTX. PMID:24819618

  16. Simultaneous assessment of rotavirus-specific memory B cells and serological memory after B cell depletion therapy with rituximab.

    PubMed

    Herrera, Daniel; Rojas, Olga L; Duarte-Rey, Carolina; Mantilla, Rubén D; Angel, Juana; Franco, Manuel A

    2014-01-01

    The mechanisms that contribute to the maintenance of serological memory are still unclear. Rotavirus (RV) memory B cells (mBc) are enriched in IgM(+) and CD27- subpopulations, which are associated with autoimmune diseases pathogenesis. In patients with autoimmune diseases treated with Rituximab (RTX), some autoantibodies (auto-Abs) decrease after treatment, but other auto-Abs and pathogen-specific IgG Abs remain unchanged. Thus, maintenance of autoimmune and pathogen-specific serological memory may depend on the type of antigen and/or Ab isotype evaluated. Antigen-specific mBc and antigen-specific Abs of different isotypes have not been simultaneously assessed in patients after RTX treatment. To study the relationship between mBc subpopulations and serological memory we characterized total, RV- and tetanus toxoid (TT)-specific mBc by flow cytometry in patients with autoimmune diseases before and after treatment with RTX. We also measured total, RV- and TT-Abs, and some auto-Abs by kinetic nephelometry, ELISA, and EliA tests, respectively. Minor differences were observed between the relative frequencies of RV-mBc in healthy controls and patients with autoimmune disease. After RTX treatment, naïve Bc and total, RV- and TT-specific mBc [IgM(+), switched (IgA(+)/IgG(+)), IgM(+) only, IgD(+) only, and CD27- (IgA(+)/IgG(+)/IgM(+))] were significantly diminished. An important decrease in total plasma IgM and minor decreases in total IgG and IgA levels were also observed. IgM rheumatoid factor, IgG anti-CCP, and IgG anti-dsDNA were significantly diminished. In contrast, RV-IgA, RV-IgG and RV-IgG1, and TT-IgG titers remained stable. In conclusion, in patients with autoimmunity, serological memory against RV and TT seem to be maintained by long-lived plasma cells, unaffected by RTX, and an important proportion of total IgM and serological memory against some auto-antigens seem to be maintained by short-lived plasma cells, dependent on mBc precursors depleted by RTX.

  17. Phase I study of obinutuzumab (GA101) in Japanese patients with relapsed or refractory B-cell non-Hodgkin lymphoma.

    PubMed

    Ogura, Michinori; Tobinai, Kensei; Hatake, Kiyohiko; Uchida, Toshiki; Suzuki, Tatsuya; Kobayashi, Yukio; Mori, Masakazu; Terui, Yasuhito; Yokoyama, Masahiro; Hotta, Tomomitsu

    2013-01-01

    As CD20 has become an established target for treating B-cell malignancies, there is interest in developing anti-CD20 antibodies with different functional activity from rituximab that might translate into improved efficacy. Obinutuzumab (GA101) is a glycoengineered, humanized type II anti-CD20 monoclonal antibody that has demonstrated superior activity to type I antibodies in preclinical studies and is currently being investigated in phase III trials. In this phase I dose-escalating study in Japanese patients with relapsed/refractory B-cell non-Hodgkin lymphoma, the primary endpoint was to characterize the safety of GA101; secondary endpoints were efficacy, pharmacokinetics and pharmacodynamics. Patients received up to nine doses of GA101 with up to 52 weeks' follow up. Most adverse events were grade 1 or 2 infusion-related reactions, and 10 grade 3/4 adverse events occurred. No dose-limiting toxicities were observed and the maximum tolerated dose was not identified. Out of 12 patients, 7 responded (end-of-treatment response rate 58%), with 2 complete responses and 5 partial responses. Responses were observed from low to high doses, and no dose-efficacy relationship was observed. B-cell depletion occurred in all patients after the first infusion and was maintained for the duration of treatment. Serum levels of GA101 increased in a dose-dependent fashion, although there was inter-patient variability. This phase I study demonstrated that GA101 has an acceptable safety profile and offers encouraging activity to Japanese patients with relapsed/refractory B-cell non-Hodgkin lymphoma.

  18. Establishment of a novel feline leukemia virus (FeLV)-negative B-cell cell line from a cat with B-cell lymphoma.

    PubMed

    Mochizuki, Hiroyuki; Takahashi, Masashi; Nishigaki, Kazuo; Ide, Tetsuya; Goto-Koshino, Yuko; Watanabe, Shinya; Sato, Hirofumi; Sato, Masahiko; Kotera, Yukiko; Fujino, Yasuhito; Ohno, Koichi; Uchida, Kazuyuki; Tsujimoto, Hajime

    2011-04-15

    We established a novel feline B-cell line, MS4, from the neoplastic pleural effusion of a cat with cutaneous B-cell lymphoma. Immunophenotype staining of the MS4 cells was positive for CD20, CD79α, and IgA and negative for CD3, CD4, CD5, CD8α, CD18, CD21, CD22, IgM, IgG, Ig light chain, and MHC class II. PCR analysis for immunoglobulin heavy chain gene rearrangements revealed a monoclonal rearrangement, whereas no clonal rearrangement of the T-cell receptor γ gene was detected. Southern blotting with an exogenous feline leukemia virus (FeLV) U3 probe revealed no integration of exogenous FeLV provirus. The MS4 cell line is the first FeLV-negative feline B-cell lymphoma cell line, and may be used to investigate the pathogenesis of spontaneously occurring feline lymphoma and the development of new therapies.

  19. An Introduction to B-Cell Epitope Mapping and In Silico Epitope Prediction

    PubMed Central

    Potocnakova, Lenka

    2016-01-01

    Identification of B-cell epitopes is a fundamental step for development of epitope-based vaccines, therapeutic antibodies, and diagnostic tools. Epitope-based antibodies are currently the most promising class of biopharmaceuticals. In the last decade, in-depth in silico analysis and categorization of the experimentally identified epitopes stimulated development of algorithms for epitope prediction. Recently, various in silico tools are employed in attempts to predict B-cell epitopes based on sequence and/or structural data. The main objective of epitope identification is to replace an antigen in the immunization, antibody production, and serodiagnosis. The accurate identification of B-cell epitopes still presents major challenges for immunologists. Advances in B-cell epitope mapping and computational prediction have yielded molecular insights into the process of biorecognition and formation of antigen-antibody complex, which may help to localize B-cell epitopes more precisely. In this paper, we have comprehensively reviewed state-of-the-art experimental methods for B-cell epitope identification, existing databases for epitopes, and novel in silico resources and prediction tools available online. We have also elaborated new trends in the antibody-based epitope prediction. The aim of this review is to assist researchers in identification of B-cell epitopes. PMID:28127568

  20. Pro-B-cell-specific transcription and proapoptotic function of protein kinase Ceta.

    PubMed

    Morrow, T A; Muljo, S A; Zhang, J; Hardwick, J M; Schlissel, M S

    1999-08-01

    Using a subtractive cloning scheme on cDNA prepared from primary pro-B and pre-B cells, we identified several genes whose products regulate apoptosis. We further characterized one of these genes, encoding protein kinase Ceta (PKCeta). PKCeta transcripts were readily detected in pro-B cells but were absent in pre-B cells. Although both a full-length and a truncated form of PKCeta were detectable in bone marrow pro-B cells, transition to the pre-B-cell stage was associated with increased relative levels of truncated PKCeta. We found that PKCeta is proteolyzed in apoptotic lymphocytes, generating a kinase-active fragment identical to the truncated form which is capable of inducing apoptosis when expressed in a pro-B cell line. Caspase-3 can generate an identical PKCeta cleavage product in vitro, and caspase inhibitors prevent the generation of this product during apoptosis in transfected cell lines. Inducible overexpression of either the full-length or truncated form of PKCeta results in cell cycle arrest at the G(1)/S transition. These results suggest that the expression and proteolytic activation of PKCeta play an important role in the regulation of cell division and cell death during early B-cell development.

  1. B Cell Function in Severe Combined Immunodeficiency after Stem Cell or Gene Therapy: A Review

    PubMed Central

    Buckley, Rebecca H.

    2010-01-01

    While bone marrow transplantation has resulted in life-saving T cell reconstitution in infants with severe combined immunodeficiency (SCID), correction of B cell function has been more problematic. This review examines B cell reconstitution results presented in 19 reports from the United States and Europe on post-transplantation immune reconstitution in SCID over the past two decades. The analysis considered whether pre-transplantation conditioning regimens were used, the overall survival rate, the percentage with donor B cell chimerism, the percentage with B cell function, and the percentage of survivors requiring immunoglobulin (IG) replacement. The survival rates were higher at those Centers that did not use pre-transplant conditioning or post-transplantation graft-versus-host disease prophylaxis. The percentage of survivors with B cell chimerism and/or function was higher and the percentage requiring IG replacement was lower at those Centers that used pre-transplant conditioning. However there were substantial numbers of patients requiring IG replacement at all Centers. Thus, pre-transplant conditioning does not guarantee that B cell function will develop. Since most infants with SCID either present with serious infections or are diagnosed as newborns, one must decide whether there is justification for using agents that compromise innate immunity and have intrinsic toxicities to gain B cell immune reconstitution. PMID:20371393

  2. Expression of CD45RO on circulating CD19+ B-cells in Crohn's disease.

    PubMed Central

    Yacyshyn, B R; Pilarski, L M

    1993-01-01

    Crohn's disease is an immunoregulatory disorder of the intestine that can be associated with systemic manifestations. This study analysed B-cell differentiation antigens to identify B-cell subpopulations unique to patients with Crohn's disease. CD45 isoform expression was used as an indicator of B-cell differentiation stage. This work shows that B-cells in blood and gut of patients with Crohn's disease are at an advanced stage of differentiation based on their unusual presentation of transitional (RA+ RO+) and late stage (RO+)CD45 isoforms on lamina propria lymphocytes, whereas normal intestinal lamina propria lymphocytes B-cells express primarily CD45RA. Crohn's disease patients had heightened expression of the CD45RO isoform on CD19+ lamina propria lymphocytes, and was found in a statistically significant proportion of Crohn's peripheral blood mononuclear cells (PBMC) where CD19+ PBMC had an expression pattern affecting an unexpectedly high proportion of these differentiated or late stage CD45RO+ B-cells. The expression of CD45RO varied greatly among CD19+ PBMC from patients with Crohn's disease, so multiple regression analysis was performed between these CD45 isoforms and several clinical parameters. After grouping high and low CD45RO expression on CD19+ B-cells, a significant statistical difference was found between high Crohn's disease activity index (CDAI) and low CDAI Crohn's disease patients respectively. PMID:7506695

  3. Cyclin D3 is selectively required for proliferative expansion of germinal center B cells.

    PubMed

    Cato, Matthew H; Chintalapati, Suresh K; Yau, Irene W; Omori, Sidne A; Rickert, Robert C

    2011-01-01

    The generation of robust T-cell-dependent humoral immune responses requires the formation and expansion of germinal center structures within the follicular regions of the secondary lymphoid tissues. B-cell proliferation in the germinal center drives ongoing antigen-dependent selection and the generation of high-affinity class-switched plasma and memory B cells. However, the mechanisms regulating B-cell proliferation within this microenvironment are largely unknown. Here, we report that cyclin D3 is uniquely required for germinal center progression. Ccnd3(-/-) mice exhibit a B-cell-intrinsic defect in germinal center maturation and fail to generate an affinity-matured IgG response. We determined that the defect resulted from failed proliferative expansion of GL7(+) IgD(-) PNA(+) B cells. Mechanistically, sustained expression of cyclin D3 was found to be regulated at the level of protein stability and controlled by glycogen synthase kinase 3 in a cyclic AMP-protein kinase A-dependent manner. The specific defect in proliferative expansion of GL7(+) IgD(-) PNA(+) B cells in Ccnd3(-/-) mice defines an underappreciated step in germinal center progression and solidifies a role for cyclin D3 in the immune response, and as a potential therapeutic target for germinal center-derived B-cell malignancies.

  4. Multiple signaling pathways promote B lymphocyte stimulator–dependent B-cell growth and survival

    PubMed Central

    Fox, Casey J.; Schmidt, Madelyn R.; Hammerman, Peter S.; Opferman, Joseph T.; Korsmeyer, Stanley J.; Hilbert, David M.; Thompson, Craig B.

    2008-01-01

    We investigated the mechanism by which B lymphocyte stimulator (BLyS)/BAFF, a tumor necrosis factor superfamily ligand, promotes B-cell survival and resistance to atrophy. BLyS stimulation activates 2 independent signaling pathways, Akt/mTOR and Pim 2, associated with cell growth and survival. BLyS blocks the cell volume loss (atrophy) that freshly isolated B cells normally undergo when maintained in vitro while concurrently increasing glycolytic activity and overall metabolism. This atrophy resistance requires Akt/mTOR. We used a genetic approach to resolve the contributions of Akt/mTOR and Pim kinase pathways to BLyS-mediated survival. Pim 2–deficient B cells are readily protected from death by BLyS stimulation, but this protection is completely abrogated by treatment with the mTOR inhibitor rapamycin. Furthermore, rapamycin treatment in vivo significantly reduces both follicular and marginal zone B cells in Pim-deficient but not healthy hosts. BLyS-dependent survival requires the antiapoptotic protein Mcl-1. Mcl-1 protein levels rise and fall in response to BLyS addition and withdrawal, respectively, and conditional deletion of the Mcl-1 gene renders B cells refractory to BLyS-mediated protection. Because BlyS is required for the normal homeostasis of all B cells, these data suggest a therapeutic strategy simultaneously inhibiting mTOR and Pim 2 could target pathogenic B cells. PMID:17942753

  5. Expression of the B cell repertoire and autoantibodies in human African trypanosomiasis.

    PubMed Central

    Kazyumba, G; Berney, M; Brighouse, G; Cruchaud, A; Lambert, P H

    1986-01-01

    The relative importance of polyclonal B cell activation has been studied in relation to the development of autoantibodies in human African trypanosomiasis. In 34 patients investigated before specific treatment a broad expression of the B cell repertoire was observed including the production of anti-hapten (FITC, Penicillin, Phosphorylcholin) antibodies, of high levels of antibodies against some heterologous protein antigens (ovalbumin and tetanus toxoid) and of autoantibodies. Anti-ssDNA antibodies were detected in 84% of the patients and anti-IgG rheumatoid factors in 88%. Anti-striated muscle and anti-smooth muscle antibodies were also observed in 57 and 63% of the patients. Correlation analysis indicated that the formation of anti-DNA antibodies is associated with polyclonal B cell activation but probably depends on an additional B cell stimulation by released DNA or cross-reacting antigens. Anti-immunoglobulin antibodies are closely correlated with polyclonal B cell activation and their production is likely to reflect the high frequency of anti-IgG B cell precursors in the normal human B cell repertoire. The significance of these observations in relation to the pathological expression of trypanosomiasis should be particularly considered in the generation of immune complexes either in circulating blood or locally at the sites of parasite destruction. PMID:3491699

  6. IRF4 is a suppressor of c-Myc induced B cell leukemia.

    PubMed

    Pathak, Simanta; Ma, Shibin; Trinh, Long; Eudy, James; Wagner, Kay-Uwe; Joshi, Shantaram S; Lu, Runqing

    2011-01-01

    Interferon regulatory factor 4 (IRF4) is a critical transcriptional regulator in B cell development and function. We have previously shown that IRF4, together with IRF8, orchestrates pre-B cell development by limiting pre-B cell expansion and by promoting pre-B cell differentiation. Here, we report that IRF4 suppresses c-Myc induced leukemia in EμMyc mice. Our results show that c-Myc induced leukemia was greatly accelerated in the IRF4 heterozygous mice (IRF4(+/-)Myc); the average age of mortality in the IRF4(+/-)Myc mice was only 7 to 8 weeks but was 20 weeks in the control mice. Our results show that IRF4(+/-)Myc leukemic cells were derived from large pre-B cells and were hyperproliferative and resistant to apoptosis. Further analysis revealed that the majority of IRF4(+/-)Myc leukemic cells inactivated the wild-type IRF4 allele and contained defects in Arf-p53 tumor suppressor pathway. p27(kip) is part of the molecular circuitry that controls pre-B cell expansion. Our results show that expression of p27(kip) was lost in the IRF4(+/-)Myc leukemic cells and reconstitution of IRF4 expression in those cells induced p27(kip) and inhibited their expansion. Thus, IRF4 functions as a classical tumor suppressor to inhibit c-Myc induced B cell leukemia in EμMyc mice.

  7. Induction of B cell immune tolerance by antigen-modified CTL

    PubMed Central

    Nguyen, Phuong; Geiger, Terrence L.

    2010-01-01

    Background Third party-specific CTL, or veto CTL, are being assessed as a cellular therapeutic for the induction of T cell tolerance during transplantation. Conceptually, veto cell expressed antigens may induce B cell immune responses, and this may have deleterious consequences. Whether veto cells induce immunity, tolerance, or are ignored by B lymphocytes has, however, not been addressed. Methods CTL were retrovirally transduced with a model cell surface antigen to generate veto CTL. The impact of CTL-specific antigen expression on the activation and tolerization of antigen specific B cells was assessed in vitro and, using adoptive transfer models, in vivo. Results In vitro, CTL-expressed antigen induced an abortive proliferative response in specific B lymphocytes, whereby an initial proliferative burst was followed by cell death. In vivo, the administration of veto CTL also induced B cell tolerance. Specific immunoglobulin was not detected after subsequent immunization with a veto cell-expressed antigen. Modeling of this effect with antigen-specific B cell receptor (BCR) transgenic B lymphocytes demonstrated that antigen-specific B cells were eliminated by the veto CTL; cell division was accompanied by the exhaustion and depletion of responding cells. Veto-induced B cell tolerance could be wholly abrogated by treatment with the toll-like receptor ligand LPS, implying that this tolerance resulted from the absence of adequate supplemental signals during antigenic stimulation. Conclusions Veto CTL are effective promoters of B cell tolerance. Further assessment of their therapeutic potential in this regard is warranted. PMID:20065917

  8. The impact of inflammation and immune activation on B cell differentiation during HIV-1 infection.

    PubMed

    Ruffin, Nicolas; Thang, Pham Hong; Rethi, Bence; Nilsson, Anna; Chiodi, Francesca

    2011-01-01

    One important pathogenic feature of human immunodeficiency virus (HIV)-1 infection is chronic immune activation and impaired survival of T and B cells. A decline of resting memory B cells was reported to occur in both children and adults infected with HIV-1; these cells are responsible for maintaining an adequate serological response to antigens previously encountered in life through natural infection or vaccination. Further understanding of the mechanisms leading to impaired B cell differentiation and germinal center reaction might be essential to design new HIV vaccines and therapies that could improve humoral immune responses in HIV-1 infected individuals. In the present article we summarize the literature and present our view on critical mechanisms of B cell development impaired during HIV-1 infection. We also discuss the impact of microbial translocation, a driving force for persistent inflammation during HIV-1 infection, on survival of terminally differentiated B cells and how the altered expression of cytokines/chemokines pivotal for communication between T and B cells in lymphoid tissues may impair formation of memory B cells.

  9. The Impact of Inflammation and Immune Activation on B Cell Differentiation during HIV-1 Infection

    PubMed Central

    Ruffin, Nicolas; Thang, Pham Hong; Rethi, Bence; Nilsson, Anna; Chiodi, Francesca

    2012-01-01

    One important pathogenic feature of human immunodeficiency virus (HIV)-1 infection is chronic immune activation and impaired survival of T and B cells. A decline of resting memory B cells was reported to occur in both children and adults infected with HIV-1; these cells are responsible for maintaining an adequate serological response to antigens previously encountered in life through natural infection or vaccination. Further understanding of the mechanisms leading to impaired B cell differentiation and germinal center reaction might be essential to design new HIV vaccines and therapies that could improve humoral immune responses in HIV-1 infected individuals. In the present article we summarize the literature and present our view on critical mechanisms of B cell development impaired during HIV-1 infection. We also discuss the impact of microbial translocation, a driving force for persistent inflammation during HIV-1 infection, on survival of terminally differentiated B cells and how the altered expression of cytokines/chemokines pivotal for communication between T and B cells in lymphoid tissues may impair formation of memory B cells. PMID:22566879

  10. VNAR single-domain antibodies specific for BAFF inhibit B cell development by molecular mimicry.

    PubMed

    Häsler, Julien; Flajnik, Martin F; Williams, Gareth; Walsh, Frank S; Rutkowski, J Lynn

    2016-07-01

    B cell-activating factor (BAFF) plays a dominant role in the B cell homeostasis. However, excessive BAFF promotes the development of autoreactive B-cells and several antibodies have been developed to block its activity. Bispecific antibodies with added functionality represent the next wave of biologics that may be more effective in the treatment of complex autoimmune disease. The single variable domain from the immunoglobulin new antigen receptor (VNAR) is one of the smallest antibody recognition units that could be combined with monospecific antibodies to develop bispecific agents. We isolated a panel of BAFF-binding VNARs with low nM potency from a semi-synthetic phage display library and examined their functional activity. The anti-BAFF VNARs blocked the binding of BAFF to all three of its receptors (BR3, TACI and BCMA) and the presence of the conserved DXL receptor motif found in the CDR3 regions suggests molecular mimicry as the mechanism of antagonism. One clone was formatted as an Fc fusion for functional testing and it was found to inhibit both mouse and human BAFF with equal potency ex vivo in a splenocyte proliferation assay. In mice, subchronic administration reduced the number of immature and transitional intermediates B cells and mature B cell subsets. These results indicate that VNAR single domain antibodies function as selective B-cell inhibitors and offer an alternative molecular format for targeting B-cell disorders.

  11. B-cell receptor signalling and its crosstalk with other pathways in normal and malignant cells.

    PubMed

    Seda, Vaclav; Mraz, Marek

    2015-03-01

    The physiology of B cells is intimately connected with the function of their B-cell receptor (BCR). B-cell lymphomas frequently (dys)regulate BCR signalling and thus take advantage of this pre-existing pathway for B-cell proliferation and survival. This has recently been underscored by clinical trials demonstrating that small molecules (fosfamatinib, ibrutinib, idelalisib) inhibiting BCR-associated kinases (SYK, BTK, PI3K) have an encouraging clinical effect. Here we describe the current knowledge of the specific aspects of BCR signalling in diffuse large B-cell lymphoma (DLBCL), follicular lymphoma, chronic lymphocytic leukaemia (CLL) and normal B cells. Multiple factors can contribute to BCR pathway (dys)regulation in these malignancies and the activation of 'chronic' or 'tonic' BCR signalling. In lymphoma B cells, the balance of initiation, amplitude and duration of BCR activation can be influenced by a specific immunoglobulin structure, the expression and mutations of adaptor molecules (like GAB1, BLNK, GRB2, CARD11), the activity of kinases (like LYN, SYK, PI3K) or phosphatases (like SHIP-1, SHP-1 and PTEN) and levels of microRNAs. We also discuss the crosstalk of BCR with other signalling pathways (NF-κB, adhesion through integrins, migration and chemokine signalling) to emphasise that the 'BCR inhibitors' target multiple pathways interconnected with BCR, which might explain some of their clinical activity.

  12. Distinct mechanisms of neonatal tolerance induced by dendritic cells and thymic B cells

    PubMed Central

    1991-01-01

    To assess the role of different types of antigen-presenting cells (APC) in the induction of tolerance, we isolated B cells, macrophages, and dendritic cells from thymus and spleen, and injected these into neonatal BALB/c mice across an Mls-1 antigenic barrier. One week after injection of APC from Mls-1-incompatible mice or from control syngeneic mice, we measured the number of thymic, Mls-1a-reactive, V beta 6+ T cells and the capacity of thymocytes to induce a graft-vs.-host (GVH) reaction in popliteal lymph nodes of Mls-1a mice. Injection of thymic but not spleen B cells deleted thymic, Mls-1a-reactive V beta 6+ T cells and induced tolerance in the GVH assay. The thymic B cells were primarily of the CD5+ type, and fluorescence-activated cell sorter- purified CD5+ thymic B cells were active. Injection of dendritic cells from spleen or thymus also induced tolerance, but the V beta 6 cells were anergized rather than deleted. Macrophages from thymus did not induce tolerance. Dendritic cells and thymic B cells were also effective in inducing tolerance even when injected into Mls-, major histocompatibility complex-incompatible, I-E- mice, but only thymic B cells depleted V beta 6-expressing T cells. Therefore, different types of bone marrow-derived APC have different capacities for inducing tolerance, and the active cell types (dendritic cells and CD5+ thymic B cells) can act by distinct mechanisms. PMID:1900075

  13. Exogenous and endogenous TLR ligands activate anti-chromatin and polyreactive B cells.

    PubMed

    Fields, Michele L; Metzgar, Michele H; Hondowicz, Brian D; Kang, Sun-Ah; Alexander, Shawn T; Hazard, Kristin D; Hsu, Alice C; Du, Yang-Zhu; Prak, Eline Luning; Monestier, Marc; Erikson, Jan

    2006-06-01

    Autoreactive B cells may become activated in a T-independent manner via synergistic engagement of the BCR and TLRs. Using the VH3H9 Ig H chain transgene to track anti-chromatin B cells, we demonstrate that VH3H9/Vlambda1 anti-chromatin B cells proliferate in response to stimulatory oligodeoxynucleotides containing CpG motifs, suggesting that these autoreactive B cells are responsive to TLR9 signaling. Strikingly, some VH3H9 B cells, but not the well-characterized VH3H9/Vlambda1 B cells, proliferate spontaneously in culture medium. This proliferation is blocked by inhibitory CpG oligodeoxynucleotides, implicating the TLR9 (or possibly TLR7) pathway. Most hybridomas generated from the proliferating cells are polyreactive, and one exhibits binding to nuclear Ags but not to the other Ags tested. Thus, B cells carrying autoreactive and/or polyreactive specificities may be susceptible to T cell-independent activation via dual engagement of the BCR and TLRs.

  14. Censoring of self-reactive B cells by follicular dendritic cell-displayed self-antigen.

    PubMed

    Yau, Irene W; Cato, Matthew H; Jellusova, Julia; Hurtado de Mendoza, Tatiana; Brink, Robert; Rickert, Robert C

    2013-08-01

    In the secondary lymphoid organs, intimate contact with follicular dendritic cells (FDCs) is required for B cell retention and Ag-driven selection during the germinal center response. However, selection of self-reactive B cells by Ag on FDCs has not been addressed. To this end, we generated a mouse model to conditionally express a membrane-bound self-antigen on FDCs and to monitor the fate of developing self-reactive B cells. In this article, we show that self-antigen displayed on FDCs mediates effective elimination of self-reactive B cells at the transitional stage. Notwithstanding, some self-reactive B cells persist beyond this checkpoint, showing evidence of Ag experience and intact proximal BCR signaling, but they are short-lived and unable to elicit T cell help. These results implicate FDCs as an important component of peripheral B cell tolerance that prevents the emergence of naive B cells capable of responding to sequestered self-antigens.

  15. SHEP1 partners with CasL to promote marginal zone B-cell maturation.

    PubMed

    Browne, Cecille D; Hoefer, Melanie M; Chintalapati, Suresh K; Cato, Matthew H; Wallez, Yann; Ostertag, Derek V; Pasquale, Elena B; Rickert, Robert C

    2010-11-02

    The marginal zone is a cellular niche bordering the marginal sinus of the spleen that contains specialized B-cell and macrophage subsets poised to capture bloodborne antigens. Marginal zone B cells are retained in this niche by integrin-mediated signaling induced by G protein-coupled receptors (GPCRs) and, likely, the B-cell receptor (BCR). Sphingosine-1-phosphate (S1P) signaling via the S1P family of GPCRs is known to be essential for B-cell localization in the marginal zone, but little is known about the downstream signaling events involved. Here, we demonstrate that the adaptor protein SHEP1 is required for marginal zone B-cell maturation. SHEP1 functions in concert with the scaffolding protein CasL, because we show that SHEP1 and CasL are constitutively associated in B cells. SHEP1 association is required for the BCR or S1P receptor(s) to induce the conversion of CasL into its serine/threonine hyperphosphorylated form, which is important for lymphocyte adhesion and motility. Thus, SHEP1 orchestrates marginal zone B-cell movement and retention as a key downstream effector of the BCR and S1P receptors.

  16. Signaling by the tumor necrosis factor receptor superfamily in B-cell biology and disease.

    PubMed

    Rickert, Robert C; Jellusova, Julia; Miletic, Ana V

    2011-11-01

    Members of the tumor necrosis factor receptor superfamily (TNFRSF) participate prominently in B-cell maturation and function. In particular, B-cell activating factor belonging to the TNF family receptor (BAFF-R), B-cell maturation antigen (BCMA), and transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI) play critical roles in promoting B-cell survival at distinct stages of development by engaging a proliferation-inducing ligand (APRIL) and/or BAFF. CD40 is also essential for directing the humoral response to T-cell-dependent antigens. Signaling by the TNFRSF is mediated primarily, albeit not exclusively, via the TNFR-associated factor (TRAF) proteins and activation of the canonical and/or non-canonical nuclear factor-κB (NF-κB) pathways. Dysregulated signaling by TNFRSF members can promote B-cell survival and proliferation, causing autoimmunity and neoplasia. In this review, we present a current understanding of the functions of and distinctions between APRIL/BAFF signaling by their respective receptors expressed on particular B-cell subsets. These findings are compared and contrasted with CD40 signaling, which employs similar signaling conduits to achieve distinct cellular outcomes in the context of the germinal center response. We also underscore how new findings and conceptual insights into TNFRSF signaling are facilitating the understanding of B-cell malignancies and autoimmune diseases.

  17. Differing Requirements for MALT1 Function in Peripheral B Cell Survival and Differentiation.

    PubMed

    Lee, Peishan; Zhu, Zilu; Hachmann, Janna; Nojima, Takuya; Kitamura, Daisuke; Salvesen, Guy; Rickert, Robert C

    2017-02-01

    During a T cell-dependent immune response, formation of the germinal center (GC) is essential for the generation of high-affinity plasma cells and memory B cells. The canonical NF-κB pathway has been implicated in the initiation of GC reaction, and defects in this pathway have been linked to immune deficiencies. The paracaspase MALT1 plays an important role in regulating NF-κB activation upon triggering of Ag receptors. Although previous studies have reported that MALT1 deficiency abrogates the GC response, the relative contribution of B cells and T cells to the defective phenotype remains unclear. We used chimeric mouse models to demonstrate that MALT1 function is required in B cells for GC formation. This role is restricted to BCR signaling where MALT1 is critical for B cell proliferation and survival. Moreover, the proapoptotic signal transmitted in the absence of MALT1 is dominant to the prosurvival effects of T cell-derived stimuli. In addition to GC B cell differentiation, MALT1 is required for plasma cell differentiation, but not mitogenic responses. Lastly, we show that ectopic expression of Bcl-2 can partially rescue the GC phenotype in MALT1-deficient animals by prolonging the lifespan of BCR-activated B cells, but plasma cell differentiation and Ab production remain defective. Thus, our data uncover previously unappreciated aspects of MALT1 function in B cells and highlight its importance in humoral immunity.

  18. Morphologic and functional effects of gamma secretase inhibition on splenic marginal zone B cells.

    PubMed

    de Vera Mudry, Maria Cristina; Regenass-Lechner, Franziska; Ozmen, Laurence; Altmann, Bernd; Festag, Matthias; Singer, Thomas; Müller, Lutz; Jacobsen, Helmut; Flohr, Alexander

    2012-01-01

    The γ-secretase complex is a promising target in Alzheimer's disease because of its role in the amyloidogenic processing of β-amyloid precursor protein. This enzyme also catalyzes the cleavage of Notch receptor, resulting in the nuclear translocation of intracellular Notch where it modulates gene transcription. Notch signaling is essential in cell fate decisions during embryogenesis, neuronal differentiation, hematopoiesis, and development of T and B cells, including splenic marginal zone (MZ) B cells. This B cell compartment participates in the early phases of the immune response to blood-borne bacteria and viruses. Chronic treatment with the oral γ-secretase inhibitor RO4929097 resulted in dose-dependent decreased cellularity (atrophy) of the MZ of rats and mice. Significant decreases in relative MZ B-cell numbers of RO4929097-treated animals were confirmed by flow cytometry. Numbers of MZ B cells reverted to normal after a sufficient RO4929097-free recovery period. Functional characterization of the immune response in relation to RO4929097-related MZ B cell decrease was assessed in mice vaccinated with inactivated vesicular stomatitis virus (VSV). Compared with the immunosuppressant cyclosporin A, RO4929097 caused only mild and reversible delayed early neutralizing IgM and IgG responses to VSV. Thus, the functional consequence of MZ B cell decrease on host defense is comparatively mild.

  19. Regulation of Marginal Zone B-Cell Differentiation by MicroRNA-146a

    PubMed Central

    King, Jennifer K.; Ung, Nolan M.; Paing, May H.; Contreras, Jorge R.; Alberti, Michael O.; Fernando, Thilini R.; Zhang, Kelvin; Pellegrini, Matteo; Rao, Dinesh S.

    2017-01-01

    B-cell development in the bone marrow is followed by specification into functional subsets in the spleen, including marginal zone (MZ) B-cells. MZ B-cells are classically characterized by T-independent antigenic responses and require the elaboration of distinct gene expression programs for development. Given their role in gene regulation, it is not surprising that microRNAs are important factors in B-cell development. Recent work demonstrated that deficiency of the NFκB feedback regulator, miR-146a, led to a range of hematopoietic phenotypes, but B-cell phenotypes have not been extensively characterized. Here, we found that miR-146a-deficient mice demonstrate a reduction in MZ B-cells, likely from a developmental block. Utilizing high-throughput sequencing and comparative analysis of developmental stage-specific transcriptomes, we determined that MZ cell differentiation was impaired due to decreases in Notch2 signaling. Our studies reveal miR-146a-dependent B-cell phenotypes and highlight the complex role of miR-146a in the hematopoietic system. PMID:28138326

  20. Germinal center reentries of BCL2-overexpressing B cells drive follicular lymphoma progression

    PubMed Central

    Sungalee, Stéphanie; Mamessier, Emilie; Morgado, Ester; Grégoire, Emilie; Brohawn, Philip Z.; Morehouse, Christopher A.; Jouve, Nathalie; Monvoisin, Céline; Menard, Cédric; Debroas, Guilhaume; Faroudi, Mustapha; Mechin, Violaine; Navarro, Jean-Marc; Drevet, Charlotte; Eberle, Franziska C.; Chasson, Lionel; Baudimont, Fannie; Mancini, Stéphane J.; Tellier, Julie; Picquenot, Jean-Michel; Kelly, Rachel; Vineis, Paolo; Ruminy, Philippe; Chetaille, Bruno; Jaffe, Elaine S.; Schiff, Claudine; Hardwigsen, Jean; Tice, David A.; Higgs, Brandon W.; Tarte, Karin; Nadel, Bertrand; Roulland, Sandrine

    2014-01-01

    It has recently been demonstrated that memory B cells can reenter and reengage germinal center (GC) reactions, opening the possibility that multi-hit lymphomagenesis gradually occurs throughout life during successive immunological challenges. Here, we investigated this scenario in follicular lymphoma (FL), an indolent GC-derived malignancy. We developed a mouse model that recapitulates the FL hallmark t(14;18) translocation, which results in constitutive activation of antiapoptotic protein B cell lymphoma 2 (BCL2) in a subset of B cells, and applied a combination of molecular and immunofluorescence approaches to track normal and t(14;18)+ memory B cells in human and BCL2-overexpressing B cells in murine lymphoid tissues. BCL2-overexpressing B cells required multiple GC transits before acquiring FL-associated developmental arrest and presenting as GC B cells with constitutive activation–induced cytidine deaminase (AID) mutator activity. Moreover, multiple reentries into the GC were necessary for the progression to advanced precursor stages of FL. Together, our results demonstrate that protracted subversion of immune dynamics contributes to early dissemination and progression of t(14;18)+ precursors and shapes the systemic presentation of FL patients. PMID:25384217

  1. Metabolic activity is necessary for activation of T suppressor cells by B cells

    SciTech Connect

    Elkins, K.L.; Stashak, P.W.; Baker, P.J. )

    1990-04-15

    Ag-primed B cells must express cell-surface IgM, but not IgD or Ia Ag, and must remain metabolically active, in order to activate suppressor T cells (Ts) specific for type III pneumococcal polysaccharide. Ag-primed B cells that were gamma-irradiated with 1000r, or less, retained the ability to activate Ts; however, Ag-primed B cells exposed to UV light were not able to do so. gamma-Irradiated and UV-treated Ag-primed B cells both expressed comparable levels of cell-surface IgM, and both localized to the spleen after in vivo transfer; neither could proliferate in vitro in response to mitogens. By contrast, gamma-irradiated primed B cells were still able to synthesize proteins, whereas UV-treated primed B cells could not. These findings suggest that in order for Ag-primed B cells to activate Ts, they must (a) express cell-associated IgM (sIgM) antibody bearing the idiotypic determinants of antibody specific for type III pneumococcal polysaccharide, and (b) be able to synthesize protein for either the continued expression of sIgM after cell transfer, or for the elaboration of another protein molecule that is also required for the activation of Ts; this molecule does not appear to be Ia Ag.

  2. An Introduction to B-Cell Epitope Mapping and In Silico Epitope Prediction.

    PubMed

    Potocnakova, Lenka; Bhide, Mangesh; Pulzova, Lucia Borszekova

    2016-01-01

    Identification of B-cell epitopes is a fundamental step for development of epitope-based vaccines, therapeutic antibodies, and diagnostic tools. Epitope-based antibodies are currently the most promising class of biopharmaceuticals. In the last decade, in-depth in silico analysis and categorization of the experimentally identified epitopes stimulated development of algorithms for epitope prediction. Recently, various in silico tools are employed in attempts to predict B-cell epitopes based on sequence and/or structural data. The main objective of epitope identification is to replace an antigen in the immunization, antibody production, and serodiagnosis. The accurate identification of B-cell epitopes still presents major challenges for immunologists. Advances in B-cell epitope mapping and computational prediction have yielded molecular insights into the process of biorecognition and formation of antigen-antibody complex, which may help to localize B-cell epitopes more precisely. In this paper, we have comprehensively reviewed state-of-the-art experimental methods for B-cell epitope identification, existing databases for epitopes, and novel in silico resources and prediction tools available online. We have also elaborated new trends in the antibody-based epitope prediction. The aim of this review is to assist researchers in identification of B-cell epitopes.

  3. Evaluation of EBV transformation of human memory B-cells isolated by FACS and MACS techniques.

    PubMed

    Sadreddini, Sanam; Jadidi-Niaragh, Farhad; Younesi, Vahid; Pourlak, Tala; Afkham, Amir; Shokri, Fazel; Yousefi, Mehdi

    2016-07-01

    Several studies have been performed to develop effective neutralizing monoclonal antibodies. The Epstein-Barr virus (EBV) can efficiently immortalize B-cells to establish lymphoblastoid cell lines (LCL) and so it has been used extensively for transformation of B-cells to produce and secrete immunoglobulin. The present study addressed the effect of TLR7/8 agonist (R848), feeder cells layer and fluorescence-activated cell sorting (FACS) and magnetic-activated cell sorting (MACS) cell separation methods on the transformation efficiency of antibody-producing memory B-cells. For these studies, the antigen used for analyses of antibody formation was the tetanus neurotoxin (TeNT) derived from Clostridium tetani. The results here showed that employing an HFFF.PI6 feeder cell layer, R848 agonist and FACS-mediated purification of memory B-cells led to increased transformation efficiency. Altogether, the effects of the R848 and the feeder cells provided an efficient method for EBV transformation of human B-cells. Moreover, there was an advantage in using FACS sorting of B-cells over the MACS method in the context of EBV transformation and immortalization of precursors of antigen-specific B-cells.

  4. Dock10 regulates CD23 expression and sustains B-cell lymphopoiesis in secondary lymphoid tissue.

    PubMed

    García-Serna, Azahara-María; Alcaraz-García, María-José; Ruiz-Lafuente, Natalia; Sebastián-Ruiz, Silvia; Martínez, Carlos-Manuel; Moya-Quiles, María-Rosa; Minguela, Alfredo; García-Alonso, Ana-María; Martín-Orozco, Elena; Parrado, Antonio

    2016-12-01

    Dock10, a guanine nucleotide exchange factor for the Rho GTPases Rac1 and Cdc42, affects cell morphology, membrane protrusive activity, and cell movement. Dock10 is prominently expressed in lymphoid tissue and upregulated by IL-4 in B cells. To investigate the physiological role of Dock10, WT mice and Dock10 KO mice were used. KO mice showed decreased numbers of B cells in spleen, both follicular B cells and marginal zone B cells, and in peripheral blood, but not in bone marrow. The antiapoptotic effect of IL-4 in vitro, the migratory response to CXCL13 or CCL21 in vitro, and the whole genome expression profile were intact in spleen B cells from KO mice. CD23, the low-affinity receptor for immunoglobulin E, was overexpressed on follicular B cells from KO mice, suggesting that Dock10 negatively regulates membrane CD23 expression. Negative regulation of CD23 expression by Dock10 could play a role in B cell maturation and function.

  5. A B-cell subset uniquely responsive to innate stimuli accumulates in aged mice

    PubMed Central

    Hao, Yi; O'Neill, Patrick; Naradikian, Martin S.; Scholz, Jean L.

    2011-01-01

    We have discovered a distinct mature B-cell subset that accumulates with age, which we have termed age-associated B cells. These cells comprise up to 30% of mature B cells by 22 months. Despite sharing some features with other mature B-cell subsets, they are refractory to BCR and CD40 stimulation. Instead, they respond to TLR9 or TLR7 stimulation and divide maximally on combined BCR and TLR ligation, leading to Ig production and preferential secretion of IL-10 and IL-4. Although similar to follicular B cells in both B-lymphocyte stimulator (BLyS) receptor expression and BLyS binding capacity, these cells do not rely on BLyS for survival. They are neither cycling nor the result of intrinsically altered B lymphopoiesis in aged BM, but instead appear to be generated from mature B cells that exhaustively expand during the individual's lifetime. Finally, they present Ag effectively and favor polarization to a TH17 profile. Together, these findings reveal that while the magnitude of the mature primary B-cell niche is maintained with age, it is increasingly occupied by cells refractory to BCR-driven activation yet responsive to innate receptor stimulation. PMID:21562046

  6. BCR and Endosomal TLR Signals Synergize to Increase AID Expression and Establish Central B Cell Tolerance.

    PubMed

    Kuraoka, Masayuki; Snowden, Pilar B; Nojima, Takuya; Verkoczy, Laurent; Haynes, Barton F; Kitamura, Daisuke; Kelsoe, Garnett

    2017-02-14

    Activation-induced cytidine deaminase (AID) is required to purge autoreactive immature and transitional-1 (immature/T1) B cells at the first tolerance checkpoint, but how AID selectively removes self-reactive B cells is unclear. We now show that B cell antigen receptor (BCR) and endosomal Toll-like receptor (TLR) signals synergize to elicit high levels of AID expression in immature/T1 B cells. This synergy is restricted to ligands for endocytic TLR and requires phospholipase-D activation, endosomal acidification, and MyD88. The first checkpoint is significantly impaired in AID- or MyD88-deficient mice and in mice doubly heterozygous for AID and MyD88, suggesting interaction of these factors in central B cell tolerance. Moreover, administration of chloroquine, an inhibitor of endosomal acidification, results in a failure to remove autoreactive immature/T1 B cells in mice. We propose that a BCR/TLR pathway coordinately establishes central tolerance by hyper-activating AID in immature/T1 B cells that bind ligands for endosomal TLRs.

  7. Results of a phase II study of bendamustine and ofatumumab in untreated indolent B cell non-Hodgkin's lymphoma.

    PubMed

    Czuczman, Myron S; Kahanic, Stephen; Forero, Andres; Davis, Glen; Munteanu, Mihaela; Van Den Neste, Eric; Offner, Fritz; Bron, Dominique; Quick, Donald; Fowler, Nathan

    2015-04-01

    The efficacy/tolerability of bendamustine, a unique alkylator, plus ofatumumab, a human anti-CD20 monoclonal antibody, was evaluated for previously untreated indolent B cell non-Hodgkin's lymphoma (NHL). The study investigated whether the overall response rate (ORR) for bendamustine-ofatumumab was similar to historical bendamustine-rituximab ORRs (≥90 %). In this multicenter, open-label, single-arm, phase II study, patients received six planned 28-day cycles of bendamustine (90 mg/m(2) on days 1 and 2 of each cycle) and ofatumumab (300 mg on day 1, 1000 mg on day 8 of cycle 1, and on day 1 of subsequent cycles). The primary outcome was ORR. Secondary objectives included safety and tolerability. Exploratory evaluations included percentage of patients with positive baseline [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) scans who converted to negative postbaseline and quality of life (QOL) scores. The treated/safety analysis population received ≥1 dose of either therapy. The bendamustine-ofatumumab ORR was 90 % (95 % confidence interval, 77.8-96.6) in 49 treated patients (67 % complete response, 22 % partial response). No patients had progressive disease. Bendamustine-ofatumumab was acceptably tolerated. All 49 patients had ≥1 adverse event, the most common being nausea (61 %), fatigue (55 %), and infusion-related reactions (45 %, all but 1 occurring during cycle 1). The proportion of patients whose FDG-PET scans converted to negative postbaseline was 88 %. Changes in QOL scores were minor. In patients with treatment-naive, indolent B cell NHL, bendamustine-ofatumumab exhibited a high degree of activity (90 % ORR), comparable with historical bendamustine-rituximab ORRs (≥90 %), and was adequately tolerated ( ClinicalTrials.gov identifier: NCT01108341).

  8. Homing of human B cells to lymphoid organs and B-cell lymphoma engraftment are controlled by cell adhesion molecule JAM-C.

    PubMed

    Doñate, Carmen; Ody, Christiane; McKee, Thomas; Ruault-Jungblut, Sylvie; Fischer, Nicolas; Ropraz, Patricia; Imhof, Beat A; Matthes, Thomas

    2013-01-15

    Junctional adhesion molecule C (JAM-C) is expressed by vascular endothelium and human but not mouse B lymphocytes. The level of JAM-C expression defines B-cell differentiation stages and allows the classification of marginal zone-derived (JAM-C-positive) and germinal center-derived (JAM-C-negative) B-cell lymphomas. In the present study, we investigated the role of JAM-C in homing of human B cells, using a xenogeneic nonobese diabetic/severe combined immunodeficient mouse model. Treatment with anti-JAM-C antibodies in short-term experiments reduced migration of normal and malignant JAM-C-expressing B cells to bone marrow, lymph nodes, and spleen. Blocking homing to the spleen is remarkable, as most other antiadhesion antibodies reduce homing of B cells only to bone marrow and lymph nodes. Long-term administration of anti-JAM-C antibodies prevented engraftment of JAM-Cpos lymphoma cells in bone marrow, spleen, and lymph nodes of mice. Plasmon resonance studies identified JAM-B as the major ligand for JAM-C, whereas homotypic JAM-C interactions remained at background levels. Accordingly, anti-JAM-C antibodies blocked adhesion of JAM-C-expressing B cells to their ligand JAM-B, and immunofluorescence analysis showed the expression of JAM-B on murine and human lymphatic endothelial cells. Targeting JAM-C could thus constitute a new therapeutic strategy to prevent lymphoma cells from reaching supportive microenvironments not only in the bone marrow and lymph nodes but also in the spleen.

  9. Heterogeneity of CD44 expression among human B-cell subpopulations.

    PubMed

    Kremmidiotis, G; Ridings, J; Hicks, M; Beckman, I G; Bryson, G; Collins, R; Zola, H

    1998-03-01

    CD44 is a widely distributed cell surface glycoprotein that participates in a number of cellular adhesion and signal transduction processes. Germinal center B cells express very low levels of CD44, whereas their precursors and differentiation products express much higher levels. In immunofluorescence studies comparing 20 antibodies classified as being against the hematopoietic isoform of CD44, one antibody, A1G3, was unreactive with germinal center B cells, whereas the other antibodies showed low intensity but definite reactivity. Western blotting and sequential immunoprecipitation studies of lysates from density-separated lymphocyte fractions showed two bands that were differentially expressed and reacted differently with A1G3 compared with the other CD44 antibodies. These results suggest that germinal center B cells and non-germinal center B cells express different forms of CD44. Of 21 malignant B-cell populations examined, 5 showed reactivity with a "standard" CD44 reagent and significantly reduced reactivity with A1G3, while one sample showed the opposite pattern and the remainder were positive for both reagents. Of 10 cell lines studied, 5 were differentially stained by A1G3 and a standard CD44 antibody. PCR amplification of reverse transcribed mRNA from sorted human tonsil B-cell subpopulations and Southern blotting showed that B cells express a number of splice isoforms of CD44. T