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. Safety and Tolerability Study of PCI-32765 in B Cell Lymphoma and Chronic Lymphocytic Leukemia

    ClinicalTrials.gov

    2017-10-09

    B-cell Chronic Lymphocytic Leukemia; Small Lymphocytic Lymphoma; Diffuse Well-differentiated Lymphocytic Lymphoma; B Cell Lymphoma; Follicular Lymphoma; Mantle Cell Lymphoma; Non-Hodgkin's Lymphoma; Waldenstrom Macroglobulinemia; Burkitt Lymphoma; B-Cell Diffuse Lymphoma

  6. 1. PERSPECTIVE VIEW OF WEST (REAR) SHOWING OPENING OR CLEANOUT ...

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

    1. PERSPECTIVE VIEW OF WEST (REAR) SHOWING OPENING OR CLEAN-OUT FOR PRIVY AT BOTTOM, AND RELATIONSHIP OF SOUTH OUTBUILDING TO THE MAIN HOUSE IN BACKGROUND - Naylor House, Privy, Swift & Silver Lake Roads, Langhorne, Bucks County, PA

  7. 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

  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 § 225...

  9. 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 § 225.65...

  10. Mechanisms, safety and efficacy of a B cell epitope-based vaccine for immunotherapy of grass pollen allergy.

    PubMed

    Zieglmayer, Petra; Focke-Tejkl, Margarete; Schmutz, René; Lemell, Patrick; Zieglmayer, René; Weber, Milena; Kiss, Renata; Blatt, Katharina; Valent, Peter; Stolz, Frank; Huber, Hans; Neubauer, Angela; Knoll, Anette; Horak, Friedrich; Henning, Rainer; Valenta, Rudolf

    2016-09-01

    We have developed a recombinant B cell epitope-based vaccine (BM32) for allergen-specific immunotherapy (AIT) of grass pollen allergy. The vaccine contains recombinant fusion proteins consisting of allergen-derived peptides and the hepatitis B surface protein domain preS as immunological carrier. We conducted a randomized, double-blind, placebo-controlled AIT study to determine safety, clinical efficacy and immunological mechanism of three subcutaneous injections of three BM32 doses adsorbed to aluminum hydroxide versus aluminum hydroxide (placebo) applied monthly to grass pollen allergic patients (n=70). Primary efficacy endpoint was the difference in total nasal symptom score (TNSS) through grass pollen chamber exposure before treatment and 4weeks after the last injection. Secondary clinical endpoints were total ocular symptom score (TOSS) and allergen-specific skin response evaluated by titrated skin prick testing (SPT) at the same time points. Treatment-related side effects were evaluated as safety endpoints. Changes in allergen-specific antibody, cellular and cytokine responses were measured in patients before and after treatment. Sixty-eight patients completed the trial. TNSS significantly decreased with mean changes of -1.41 (BM32/20μg) (P=0.03) and -1.34 (BM32/40μg) (P=0.003) whereas mean changes in the BM32/10μg and placebo group were not significant. TOSS and SPT reactions showed a dose-dependent decrease. No systemic immediate type side effects were observed. Only few grade 1 systemic late phase reactions occurred in BM32 treated patients. The number of local injection site reactions was similar in actively and placebo-treated patients. BM32 induced highly significant allergen-specific IgG responses (P<0.0001) but no allergen-specific IgE. Allergen-induced basophil activation was reduced in BM32 treated patients and addition of therapy-induced IgG significantly suppressed T cell activation (P=0.0063). The B cell epitope-based recombinant grass pollen

  11. 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

  12. Pico-Salax versus polyethylene glycol for bowel cleanout before colonoscopy in children: a randomized controlled trial.

    PubMed

    Turner, D; Benchimol, E I; Dunn, H; Griffiths, A M; Frost, K; Scaini, V; Avolio, J; Ling, S C

    2009-12-01

    Comparison of bowel preparation for colonoscopy in children with either Pico-Salax (sodium picosulphate with magnesium citrate) or polyethylene glycol with electrolyte solution (PEG-ELS). In this investigator-blinded, randomized controlled trial, 83 children (12.5 +/- 3.1 years) requiring elective colonoscopy at a referral hospital were randomly allocated to Pico-Salax (n = 43) or PEG-ELS (n = 40), and an intention-to treat analysis was applied. Pico-Salax was administered in two doses, one the evening before and one on the morning of the procedure. PEG-ELS was administered over 4 hours. Efficacy was scored using the Ottawa scale and other constructs. Tolerability and toxicity were measured by patient and nursing questionnaires and serum biochemistry. 35 of Pico-Salax patients (81 %) were satisfied or very satisfied with the cleanout, compared with 19 (48 %) in the PEG-ELS group (P = 0.001). No differences were found in bowel cleanout effectiveness, as judged by the Ottawa score (P = 0.24), completion rates (P = 0.69), colonoscopy duration (P = 0.59), need for enemas (P = 0.25), or physician's global impression (P = 0.7). Except for one case of mild dehydration in the Pico-Salax group, no clinically significant adverse events were recorded. Serum biochemistry results were similar between groups except for more hypermagnesemia associated with Pico-Salax and hypokalemia with PEG-ELS; neither was clinically significant. Children tolerate Pico-Salax better than PEG-ELS for bowel cleanout before colonoscopy. This study did not demonstrate superiority of effectiveness or safety for either regimen. Georg Thieme Verlag KG Stuttgart New York.

  13. Safety, efficacy and pharmacokinetics of humanized anti-CD52 monoclonal antibody alemtuzumab in Japanese patients with relapsed or refractory B-cell chronic lymphocytic leukemia.

    PubMed

    Ishizawa, Kenichi; Fukuhara, Noriko; Nakaseko, Chiaki; Chiba, Shigeru; Ogura, Michinori; Okamoto, Akihiko; Sunaga, Yoshinori; Tobinai, Kensei

    2017-01-01

    To evaluate the safety, efficacy and pharmacokinetics of alemtuzumab in Japanese patients, we conducted a phase I study in patients with relapsed or refractory B-cell chronic lymphocytic leukemia. Six patients received alemtuzumab by intravenous infusion every other day three times a week for 12 weeks. The dose was gradually escalated on daily basis (3, 10 and then 30 mg) until the patient tolerated. The primary objective was to evaluate the safety of alemtuzumab in Japanese patients and the secondary objectives were to evaluate the overall response rate and the pharmacokinetics. The major treatment-emergent adverse events were anemia, neutropenia (6/6 patients each) and thrombocytopenia (5/6 patients) in hematologic adverse events, and nausea, vomiting, decreased appetite, cytomegalovirus test positive and pyrexia (4/6 patients) in non-hematologic adverse events. As serious adverse events, cytomegalovirus infection, pulmonary tuberculosis and diffuse large B-cell lymphoma were reported in 1/6 patient each. The overall response rate was 33% (95% confidence interval: 4-78) (1/6 patient each achieved complete response and partial response, respectively) and 3/6 patients had stable disease and 1/6 patient had progressive disease. The median time to response was 2.9 months. After last intravenous dosing (Week 12) of alemtuzumab 30 mg every other day three times a week, Cmax, tmax, AUC0-τ and t1/2 were higher and CL and Vss were lower than the values observed after the first dose. The efficacy, safety and pharmacokinetics results observed with alemtuzumab in Japanese patients were generally similar to those reported in overseas clinical studies. Alemtuzumab at 30 mg by intravenous infusion every other day three times a week for 12 weeks should be safe and effective similarly in Japanese B-cell chronic lymphocytic leukemia patients. NCT00923182. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. 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

  15. Safety and efficacy of a genetic vaccine targeting telomerase plus chemotherapy for the therapy of canine B-cell lymphoma.

    PubMed

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

    2013-08-01

    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 clinical

  16. 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

  17. 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.

  18. 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

  19. Feasibility and Safety of RNA-transfected CD20-specific Chimeric Antigen Receptor T Cells in Dogs with Spontaneous B Cell Lymphoma

    PubMed Central

    Panjwani, M Kazim; Smith, Jenessa B; Schutsky, Keith; Gnanandarajah, Josephine; O'Connor, Colleen M; Powell, Daniel J; Mason, Nicola J

    2016-01-01

    Preclinical murine models of chimeric antigen receptor (CAR) T cell therapy are widely applied, but are greatly limited by their inability to model the complex human tumor microenvironment and adequately predict safety and efficacy in patients. We therefore sought to develop a system that would enable us to evaluate CAR T cell therapies in dogs with spontaneous cancers. We developed an expansion methodology that yields large numbers of canine T cells from normal or lymphoma-diseased dogs. mRNA electroporation was utilized to express a first-generation canine CD20-specific CAR in expanded T cells. The canine CD20 (cCD20) CAR expression was efficient and transient, and electroporated T cells exhibited antigen-specific interferon-gamma (IFN-γ) secretion and lysed cCD20+ targets. In a first-in-canine study, autologous cCD20-ζ CAR T cells were administered to a dog with relapsed B cell lymphoma. Treatment was well tolerated and led to a modest, but transient, antitumor activity, suggesting that stable CAR expression will be necessary for durable clinical remissions. Our study establishes the methodologies necessary to evaluate CAR T cell therapy in dogs with spontaneous malignancies and lays the foundation for use of outbred canine cancer patients to evaluate the safety and efficacy of next-generation CAR therapies and their optimization prior to translation into humans. PMID:27401141

  20. Drug residues recovered in feed after various feedlot mixer truck cleanout procedures.

    PubMed

    Van Donkersgoed, Joyce; Sit, Dan; Gibbons, Nicole; Ramogida, Caterina; Hendrick, Steve

    2010-01-01

    A study was conducted to determine the effectiveness of two methods of equipment cleanout, sequencing or flushing, for reducing drug carryover in feedlot mixer trucks. Feed samples were collected from total mixed rations before and after various feed mixer equipment cleanout procedures. Medicated rations contained either 11 ppm of tylosin or 166 or 331 ppm of chlortetracycline. There were no differences between sequencing and flushing or between flushing with dry barley and flushing with barley silage in the median proportion of drug recovered in the next ration. A larger drug reduction was achieved using flush material at a volume of 10 versus 5% of the mixer capacity and mixing the flush material for 3 versus 4 min. Regardless of the drug or prescription concentrations in the total mixed rations or the equipment cleanout procedure used, concentrations of chlortetracycline and tylosin recovered were very low.

  1. 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.

  2. 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.

  3. Human memory B cells.

    PubMed

    Seifert, M; Küppers, R

    2016-12-01

    A key feature of the adaptive immune system is the generation of memory B and T cells and long-lived plasma cells, providing protective immunity against recurring infectious agents. Memory B cells are generated in germinal center (GC) reactions in the course of T cell-dependent immune responses and are distinguished from naive B cells by an increased lifespan, faster and stronger response to stimulation and expression of somatically mutated and affinity matured immunoglobulin (Ig) genes. Approximately 40% of human B cells in adults are memory B cells, and several subsets were identified. Besides IgG(+) and IgA(+) memory B cells, ∼50% of peripheral blood memory B cells express IgM with or without IgD. Further smaller subpopulations have additionally been described. These various subsets share typical memory B cell features, but likely also fulfill distinct functions. IgM memory B cells appear to have the propensity for refined adaptation upon restimulation in additional GC reactions, whereas reactivated IgG B cells rather differentiate directly into plasma cells. The human memory B-cell pool is characterized by (sometimes amazingly large) clonal expansions, often showing extensive intraclonal IgV gene diversity. Moreover, memory B-cell clones are frequently composed of members of various subsets, showing that from a single GC B-cell clone a variety of memory B cells with distinct functions is generated. Thus, the human memory B-cell compartment is highly diverse and flexible. Several B-cell malignancies display features suggesting a derivation from memory B cells. This includes a subset of chronic lymphocytic leukemia, hairy cell leukemia and marginal zone lymphomas. The exposure of memory B cells to oncogenic events during their generation in the GC, the longevity of these B cells and the ease to activate them may be key determinants for their malignant transformation.

  4. 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

  5. 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.

  6. B cells flying solo.

    PubMed

    Groom, Joanna; Mackay, Fabienne

    2008-01-01

    Systemic autoimmunity such as systemic lupus erythematosus (SLE) is associated with the loss of B-cell tolerance, B-cell dysregulation and autoantibody production. While some autoantibodies may contribute to the pathology seen with SLE, numerous studies have shown that dysregulation of T-cell function is another critical aspect driving disease. The positive results obtained in clinical trials using T-cell- or B-cell-specific treatments have suggested that cooperation between T and B cells probably underlies disease progression in many patients. A similar cooperative mechanism seemed to explain SLE developing in mice overexpressing the B-cell-activating factor from the tumor necrosis factor family (BAFF). However, surprisingly, T-cell-deficient BAFF transgenic (Tg) mice develop SLE similar to T-cell-sufficient BAFF Tg mice, and the disease was linked to innate activation of B cells and production of proinflammatory autoantibody isotypes. In conclusion, dysregulated innate activation of B cells alone can drive disease independently of T cells, and as such this aspect represents a new pathogenic mechanism in autoimmunity.

  7. Systematic review of the recent evidence for the efficacy and safety of chlorambucil in the treatment of B-cell malignancies.

    PubMed

    Lepretre, Stéphane; Dartigeas, C; Feugier, P; Marty, M; Salles, G

    2016-01-01

    Emergence of new agents has deeply modified treatment options and the role of chlorambucil (CLB) in B-cell malignancies. We conducted a systematic review of prospective, randomized, controlled trials (RCTs) investigating the benefits and harms of CLB used alone or in combination with other treatment in patients suffering from chronic lymphocytic leukemia (CLL), low-grade non-Hodgkin lymphoma (NHL) or Waldenström macroglobulinemia (WM). For CLL, review of the nine RCTs showed that the main advantage of CLB is its low toxicity in comparison with purine nucleoside analogs like fludarabine in either CLL or NHL. In CLL, the major disadvantage is the very low rate of complete response, except when combining an anti-CD20 antibody. For B-cell lymphoma and WM, six RCTs were summarized. Results according to the usual criteria are presented and the role of CLB, used mostly in combination with an anti-CD20 antibody, is discussed for each indication, in particular for unfit patients.

  8. Efficacy and safety of subcutaneous and intravenous rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone in first-line diffuse large B-cell lymphoma: the randomized MabEase study.

    PubMed

    Lugtenburg, Pieternella; Avivi, Irit; Berenschot, Henriette; Ilhan, Osman; Marolleau, Jean Pierre; Nagler, Arnon; Rueda, Antonio; Tani, Monica; Turgut, Mehmet; Osborne, Stuart; Smith, Rodney; Pfreundschuh, Michael

    2017-09-21

    Intravenous rituximab plus chemotherapy is standard treatment for diffuse large B-cell lymphoma. A subcutaneous formulation of rituximab is expected to simplify and shorten drug preparation and administration, and to reduce treatment burden. MabEase (NCT01649856) examined efficacy, safety and patient satisfaction with subcutaneous rituximab plus chemotherapy in treatment-naïve patients with diffuse large B-cell lymphoma. Patients were randomized 2:1 to subcutaneous rituximab (intravenous 375 mg/m(2) cycle 1; subcutaneous 1,400 mg cycles 2-8) or intravenous rituximab (375 mg/m(2) cycles 1-8) plus cyclophosphamide, doxorubicin, vincristine, and prednisone every 14 or 21 days. The primary endpoint was investigator-assessed complete response/unconfirmed complete response. Secondary endpoints included safety, treatment satisfaction (Cancer Treatment Satisfaction Questionnaire and Rituximab Administration Satisfaction Questionnaire), time savings, and survival. Of 576 randomized patients, 572 (378 subcutaneous; 194 intravenous) received treatment. End-of-induction complete response/unconfirmed complete response rates were 50.6% (subcutaneous) and 42.4% (intravenous). After a median 35 months, median overall, event-free and progression-free survivals were not reached. Grade ≥3 adverse events (subcutaneous 58.3%; intravenous 54.3%) and administration-related adverse events (both groups 21%) were similar between arms. Injection-site reactions were more common with subcutaneous (5.7% versus 0%). Rituximab Administration Satisfaction Questionnaire scores for 'impact on activities of daily living, convenience, and satisfaction were improved with subcutaneous versus intravenous; Cancer Treatment Satisfaction Questionnaire scores were similar between arms. Median administration time (6 minutes vs 2.6-3.0 hours), chair/bed and overall hospital times were shorter with subcutaneous versus intravenous rituximab. Overall, subcutaneous and intravenous rituximab had similar efficacy

  9. 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.

  10. 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.

  11. Efficacy and safety of subcutaneous tabalumab, a monoclonal antibody to B-cell activating factor, in patients with systemic lupus erythematosus: results from ILLUMINATE-2, a 52-week, phase III, multicentre, randomised, double-blind, placebo-controlled study.

    PubMed

    Merrill, J T; van Vollenhoven, R F; Buyon, J P; Furie, R A; Stohl, W; Morgan-Cox, M; Dickson, C; Anderson, P W; Lee, C; Berclaz, P-Y; Dörner, T

    2016-02-01

    To evaluate the efficacy and safety of tabalumab, a human IgG4 monoclonal antibody that neutralises membrane and soluble B-cell activating factor (BAFF). This randomised, placebo-controlled study enrolled 1124 patients with moderate-to-severe systemic lupus erythematosus (SLE) (Safety of Estrogens in Lupus Erythematosus National Assessment- SLE Disease Activity Index ≥6 at baseline). Patients received standard of care plus subcutaneous study drug, starting with a loading dose (240 mg) at week 0 and followed by 120 mg every 2 weeks (120 Q2W), 120 mg every 4 weeks (120 Q4W) or placebo. Primary endpoint was proportion achieving SLE Responder Index 5 (SRI-5) improvement at week 52. Clinical characteristics were balanced across groups. The primary endpoint was met with 120 Q2W (38.4% vs 27.7%, placebo; p=0.002), but not with the less frequent 120 Q4W regimen (34.8%, p=0.051). Although key secondary endpoints (time to severe flare, corticosteroid sparing and fatigue) were not met, patients treated with tabalumab had greater SRI-5 response rates in a serologically active subset and improvements in more stringent SRI cut-offs, SELENA-SLEDAI, Physician's Global Assessment, anti-double-stranded DNA antibodies, complement, total B cells and immunoglobulins. The incidences of deaths, serious adverse events (AEs), and treatment-emergent AEs were similar in the 120 Q2W, 120 Q4W and placebo groups, but depression and suicidal ideation, albeit rare events, were more commonly reported with tabalumab. SRI-5 was met with 120 Q2W and although key secondary endpoints were not met, numerous other secondary endpoints significantly improved in addition to pharmacodynamic evidence of BAFF pathway blockade. The safety profile for tabalumab was similar to placebo, except for depression and suicidality, which were uncommon. NCT01205438. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  12. B Cells in Autoimmune Diseases

    PubMed Central

    Hampe, Christiane S.

    2012-01-01

    The role of B cells in autoimmune diseases involves different cellular functions, including the well-established secretion of autoantibodies, autoantigen presentation and ensuing reciprocal interactions with T cells, secretion of inflammatory cytokines, and the generation of ectopic germinal centers. Through these mechanisms B cells are involved both in autoimmune diseases that are traditionally viewed as antibody mediated and also in autoimmune diseases that are commonly classified as T cell mediated. This new understanding of the role of B cells opened up novel therapeutic options for the treatment of autoimmune diseases. This paper includes an overview of the different functions of B cells in autoimmunity; the involvement of B cells in systemic lupus erythematosus, rheumatoid arthritis, and type 1 diabetes; and current B-cell-based therapeutic treatments. We conclude with a discussion of novel therapies aimed at the selective targeting of pathogenic B cells. PMID:23807906

  13. 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.

  14. 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.

  15. Comparison of the efficacy and safety of Rituximab (Mabthera™) and its biosimilar (Reditux™) in diffuse large B-cell lymphoma patients treated with chemo-immunotherapy: A retrospective analysis.

    PubMed

    Roy, Partha Sarathi; John, Shiji; Karankal, Sadashiv; Kannan, Sadhana; Pawaskar, Preeti; Gawande, Jayanta; Bagal, Bhausaheb; Khattry, Navin; Sengar, Manju; Menon, Hari; Gujral, Sumeet; Nair, Reena

    2013-10-01

    Rituximab (Mabthera™) have been in use in India since 2000. A biosimilar molecule of rituximab (Reditux™) was approved in India in 2007. This retrospective audit was done to compare the efficacy and safety of Mabthera™ with Reditux™. We reviewed the charts of 223 adult diffuse large B-cell lymphoma patients who had received cyclophosphamide, doxorubicin, vincristine and prednisolone with rituximab chemotherapy. Tumor recurrence, survival and toxicities experienced during chemotherapy were obtained from the patient charts. The survival analysis was restricted to patients who received at least 4 cycles of the same brand. Of the 223 patients evaluated, 101 received Mabthera™, 72 received Reditux™. There were no differences in the infusional reaction rates, grades 3 and 4 neutropenia and oral mucositis between the two brands. Complete-remission (CR) rates were similar with Mabthera™ and Reditux™ (75% and 82%, respectively; P = 0.294). The progression free survival (PFS) rate at 5 years were 72% in Mabthera™ and 81% in Reditux™ (P = 0.382). The overall survival (OS) at 5 years were comparable in the two groups (66% in Mabthera™ and 76% in Reditux™; P = 0.264). We observed no significant differences in the toxicity, tumor response rates, PFS and OS between the two available brands of rituximab.

  16. 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

  17. 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

  18. 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.

  19. Spent Fuel and Waste Management Activities for Cleanout of the 105 F Fuel Storage Basin at Hanford

    SciTech Connect

    Morton, M. R.; Rodovsky, T. J.; Day, R. S.

    2002-02-25

    Clean-out of the F Reactor fuel storage basin (FSB) by the Environmental Restoration Contractor (ERC) is an element of the FSB decontamination and decommissioning and is required to complete interim safe storage (ISS) of the F Reactor. Following reactor shutdown and in preparation for a deactivation layaway action in 1970, the water level in the F Reactor FSB was reduced to approximately 0.6 m (2 ft) over the floor. Basin components and other miscellaneous items were left or placed in the FSB. The item placement was performed with a sense of finality, and no attempt was made to place the items in an orderly manner. The F Reactor FSB was then filled to grade level with 6 m (20 ft) of local surface material (essentially a fine sand). The reactor FSB backfill cleanout involves the potential removal of spent nuclear fuel (SNF) that may have been left in the basin unintentionally. Based on previous cleanout of four water-filled FSBs with similar designs (i.e., the B, C, D, and DR FSBs in the 1980s), it was estimated that up to five SNF elements could be discovered in the F Reactor FSB (1). In reality, a total of 10 SNF elements have been found in the first 25% of the F Reactor FSB excavation. This paper discusses the technical and programmatic challenges of performing this decommissioning effort with some of the controls needed for SNF management. The paper also highlights how many various technologies were married into a complete package to address the issue at hand and show how no one tool could be used to complete the job; but by combining the use of multiple tools, progress is being made.

  20. 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

  1. 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

  2. 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.

  3. 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.

  4. 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. PMID:28408984

  5. 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.

  6. Multiple Curricula for B Cell Developmental Programming.

    PubMed

    Rothenberg, Ellen V

    2016-09-20

    B-1 B cells differ from conventional B-2 B cells functionally, but how these differences relate to the ontogeny of these lineages has been unclear. Two recent Immunity articles, Kristiansen et al. (2016) and Montecino-Rodriguez et al. (2016), now provide insight into the origins of B-1 and B-2 B cells, revealing a multi-layered developmental program and successive waves of B cell precursors. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. A Phase 2/3 Multicenter, Randomized, Open-Label Study to Compare the Efficacy and Safety of Lenalidomide Versus Investigator's Choice in Patients with Relapsed or Refractory Diffuse Large B-Cell Lymphoma.

    PubMed

    Czuczman, Myron S; Trněný, Marek; Davies, Andrew; Rule, Simon; Linton, Kim M; Wagner-Johnston, Nina; Gascoyne, Randy D; Slack, Graham W; Brousset, Pierre; Eberhard, David A; Hernandez-Ilizaliturri, Francisco J; Salles, Gilles; Witzig, Thomas E; Zinzani, Pier Luigi; Wright, George W; Staudt, Louis M; Yang, Yandan; Williams, P Mickey; Lih, Chih-Jian; Russo, Jacqueline; Thakurta, Anjan; Hagner, Patrick; Fustier, Pierre; Song, Dale; Lewis, Ian D

    2017-08-01

    Purpose: Randomized, multicenter, open-label, phase 2/3 trial investigating lenalidomide versus investigator's choice (IC) in relapsed/refractory diffuse large B-cell lymphoma (DLBCL).Experimental Design: Patients with DLBCL who received ≥2 prior therapies were stratified by DLBCL subtype [germinal center B-cell (GCB) vs. non-GCB; determined by immunohistochemistry (IHC)] and then randomized 1:1 to lenalidomide (25 mg/day, 21 days of 28-day cycle) or IC (gemcitabine, rituximab, etoposide, or oxaliplatin). Crossover to lenalidomide was permitted for IC-treated patients with radiologically confirmed progressive disease. The primary endpoint was overall response rate (ORR). Progression-free survival (PFS), overall survival, and subtype analysis [GCB vs. activated B-cell (ABC)] using gene expression profiling (GEP) were exploratory endpoints.Results: Stage 1: 102 DLBCL patients (by IHC: non-GCB, n = 54; GCB, n = 48) received ≥1 dose of lenalidomide or IC. Hematologic treatment-emergent adverse events with lenalidomide versus IC included neutropenia (42.6%; 36.4%), anemia (33.3%; 47.3%), thrombocytopenia (24.1%; 43.6%), and leukopenia (5.6%; 12.7%), respectively. Overall, lenalidomide-treated patients had an ORR of 27.5% versus 11.8% in IC (ORRs were similar regardless of IHC-defined DLBCL subtype). Median PFS was increased in patients receiving lenalidomide (13.6 weeks) versus IC (7.9 weeks; P = 0.041), with greater improvements in non-GCB patients (15.1 vs. 7.1 weeks, respectively; P = 0.021) compared with GCB (10.1 vs. 9.0 weeks, respectively; P = 0.550).Conclusions: The clinical benefit of lenalidomide monotherapy in DLBCL patients was more evident in the non-GCB subtype. Exploratory analyses suggest that this preferential benefit was more pronounced in the GEP-defined ABC population, demonstrating a need for additional studies of lenalidomide in DLBCL using GEP subtyping. Clin Cancer Res; 23(15); 4127-37. ©2017 AACR. ©2017 American Association for Cancer

  8. 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

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 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

  18. 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

  19. Altered B cell signalling in autoimmunity

    PubMed Central

    Rawlings, David J.; Metzler, Genita; Wray-Dutra, Michelle; Jackson, Shaun W.

    2017-01-01

    Recent work has provided new insights into how altered B cell-intrinsic signals — through the B cell receptor (BCR) and key co-receptors — function together to promote the pathogenesis of autoimmunity. These combined signals affect B cells at two distinct stages: first, in the selection of the naive repertoire; and second, during extrafollicular or germinal centre activation responses. Thus, dysregulated signalling can lead to both an altered naive BCR repertoire and the generation of autoantibody-producing B cells. Strikingly, high-affinity autoantibodies predate and predict disease in several autoimmune disorders, including type 1 diabetes and systemic lupus erythematosus. This Review summarizes how, rather than being a downstream consequence of autoreactive T cell activation, dysregulated B cell signalling can function as a primary driver of many human autoimmune diseases. PMID:28393923

  20. 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.

  1. B cell delivered gene therapy for tolerance induction: role of autoantigen-specific B cells

    PubMed Central

    Zhang, Ai-Hong; Li, Xin; Onabajo, Olusegun O.; Su, Yan; Skupsky, Jonathan; Thomas, James W.; Scott, David W.

    2010-01-01

    Antigen-specific tolerance induction using autologous B-cell gene therapy is a potential treatment to eliminate undesirable immune responses. For example, we have shown that experimental autoimmune encephalomyelitis (EAE) and type 1 diabetes in NOD mice can be ameliorated using antigen-Ig fusion protein transduced B cells. However, it is well established that autoreactive antigen-specific B cells are activated in many autoimmune diseases and can contribute to pathogenesis. While syngeneic B cells from immunized or autoimmune mice can serve as tolerogenic antigen-presenting cells (APC), this observation begs the question of whether the antigen-specific B cells per se can be transduced as tolerogenic APC. To test this, we employed two model systems employing B cell receptor (BCR) transgenic or wild type (wt) mice as B cell donors. While adoptively transferred MOG-Ig transduced wt C57Bl/6 B cells were highly tolerogenic and ameliorated EAE, MOG-Ig transduced anti-MOG B cells from BCR transgenic mice were not. This phenomenon was reproduced in the NOD diabetes model in which pro-insulin-Ig transduced polyclonal wt NOD B cells were protective, whereas similarly transduced anti-insulin BCR B cells were not. Since the frequency of antigen-specific B cells in an immunized animal is quite low, we wished to determine the threshold numbers of BCR transgenic B cells that could be present in an effective transduced population. Therefore, we “spiked” polyclonal wt C57Bl/6 B cells with different numbers of anti-MOG BCR transgenic B cells. In the EAE model, we found protection when BCR B cells were present at 1%, but they prevented tolerance induction at 10%. Antigen-specific B cells expressed normal levels of co-stimulatory molecules and were tolerogenic when transduced with an irrelevant antigen (OVA). Thus, the presence of a BCR specific for the target autoantigen may interfere with the tolerogenic process to that antigen, but BCR-specific B cells are not intrinsically

  2. 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.

  3. 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.

  4. Gene therapy for B cell lymphomas.

    PubMed

    Fielding, A K; Russell, S J

    1997-01-01

    The use of genes or genetically modified cells for therapeutic benefit is likely to have a significant therapeutic role for patients with B cell lymphomas in the future. To date, most gene therapy strategies applicable to the therapy of these diseases have not reached the point of clinical study. Adoptive immunotherapy using donor leucocyte infusion to treat aggressive B cell neoplasms in immunosuppressed patients has, however, shown great promise clinically, and studies of idiotypic vaccination in patients with low grade B cell neoplasms are also under way. Results from in vitro and animal studies continue to suggest that it may become possible to use the immune system for therapeutic benefit, and many current basic research strategies in the gene therapy of B cell non-Hodgkin's lymphoma are based on immune modulation of T cells or tumour cells themselves. Other major approaches to gene therapy for B cell malignancies include the introduction of directly toxic or "suicide genes" into B cells or the chemoprotection of haemopoietic stem cells by the introduction of drug resistance genes. All of these approaches require efficient and accurate gene transfer as well as correct expression of the gene product within the target cell. Although some way from therapeutic use, specific targeting of gene delivery is an area of active investigation and will be of value in many of the gene therapy strategies applicable to B cell lymphomas.

  5. Ikaros limits follicular B cell activation by regulating B cell receptor signaling pathways

    SciTech Connect

    Heizmann, Beate; Sellars, MacLean; Macias-Garcia, Alejandra; Chan, Susan; Kastner, Philippe

    2016-02-12

    The Ikaros transcription factor is essential for early B cell development, but its effect on mature B cells is debated. We show that Ikaros is required to limit the response of naive splenic B cells to B cell receptor signals. Ikaros deficient follicular B cells grow larger and enter cell cycle faster after anti-IgM stimulation. Unstimulated mutant B cells show deregulation of positive and negative regulators of signal transduction at the mRNA level, and constitutive phosphorylation of ERK, p38, SYK, BTK, AKT and LYN. Stimulation results in enhanced and prolonged ERK and p38 phosphorylation, followed by hyper-proliferation. Pharmacological inhibition of ERK and p38 abrogates the increased proliferative response of Ikaros deficient cells. These results suggest that Ikaros functions as a negative regulator of follicular B cell activation.

  6. 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.

  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. B cell receptor revision diminishes the autoreactive B cell response after antigen activation in mice

    PubMed Central

    Wang, Ying-Hua; Diamond, Betty

    2008-01-01

    Autoreactive B cells are regulated in the BM during development through mechanisms, including editing of the B cell receptor (BCR), clonal deletion, and anergy. Peripheral B cell tolerance is also important for protection from autoimmune damage, although the mechanisms are less well defined. Here we demonstrated, using a mouse model of SLE-like serology, that during an autoimmune response, RAG was reinduced in antigen-activated early memory or preplasma B cells. Expression of RAG was specific to antigen-reactive B cells, required the function of the IL-7 receptor (IL-7R), and contributed to maintenance of humoral tolerance. We also showed that soluble antigen could diminish a non-autoreactive antibody response through induction of BCR revision. These data suggest that tolerance induction operates in B cells at a postactivation checkpoint and that BCR revision helps regulate autoreactivity generated during an ongoing immune response. PMID:18636122

  12. Obesity induces pro-inflammatory B cells and impairs B cell function in old mice.

    PubMed

    Frasca, Daniela; Diaz, Alain; Romero, Maria; Vazquez, Thomas; Blomberg, Bonnie B

    2017-03-01

    We analyzed B cells infiltrating the Visceral Adipose Tissue (VAT) of young and old mice to identify contributors to the phenotypic and functional changes observed in aged B cells. We found higher percentages of pro-inflammatory (age-associated B cells, ABC) and less Follicular (FO) B cells in VAT as compared to spleen. VAT B cells express higher pro-adipogenic and inflammatory markers, including NF-kB, as compared to splenic B cells, and also secrete IgG2c antibodies, some of which have been shown to be autoimmune in other studies. Moreover, we found that in the presence of an adipocyte-conditioned medium FO B cells differentiated into ABC. Additional results showed production of pro-inflammatory chemokines by the adipocytes, suggesting a mechanism for B cell attraction by the VAT. These results are the first to show a direct effect of adipocytes on the generation of pro-inflammatory B cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. 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

  14. 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.

  15. 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

  16. 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

  17. 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

  18. Mls presentation by peritoneal cavity B cells.

    PubMed

    Riggs, James E; Howell, Koko F; Taylor, Justin; Mahjied, Tazee; Prokopenko, Nataliya; Alvarez, John; Coleman, Clenton

    2004-01-01

    DBA/2J spleen and peritoneal cells were compared for their ability to present the minor lymphocyte stimulatory superantigen Mls-1a. Although capable of Mls presentation in vivo, peritoneal cells were less effective than spleen cells in vitro. This difference was not due to cell concentration or culture duration. Flow cytometric comparison of spleen and peritoneal B cells revealed no significant differences in cell surface markers needed for cognate interaction with T cells. Resolution of peritoneal B cell subsets by cell sorting revealed that even though B-1 cells were capable of Mls presentation, they were less effective than B-2 cells. Mixing experiments showed that B-1 cells did not inhibit B-2 cell presentation of Mls. In contrast, total peritoneal cells inhibited T cell responses to Mls presented by spleen cells. The peritoneal cavity harbors B cells that can present Mls as well as other cells that can suppress this response.

  19. B-cells and mixed cryoglobulinemia.

    PubMed

    Ferri, Clodoveo; Antonelli, Alessandro; Mascia, Maria Teresa; Sebastiani, Marco; Fallahi, Poupak; Ferrari, Daniela; Giunti, Marco; Pileri, Stefano A; Zignego, Anna Linda

    2007-12-01

    Mixed cryoglobulinemia (MC) is a systemic small-vessel vasculitis; B-cell expansion is the biological substrate of the disease. It can be regarded as benign lymphoproliferative condition that may evolve to frank lymphoma. HCV infection is the main causative factor of MC, as well as of other overlapping disorders, through multifactorial and multistep pathogenetic process. HCV-related B-cell proliferation represents an important model of virus-driven autoimmune/neoplastic disorder. The term HCV syndrome is referred to a wide spectrum of both hepatic and extrahepatic disorders. The present review analyzes the complex virological, clinico-pathological, and therapeutic implications of B-cell proliferation, with or without HCV infection, in MC patients.

  20. Effects of aging on B cell function

    PubMed Central

    Frasca, Daniela; Blomberg, Bonnie B.

    2009-01-01

    Summary of recent advances Ability to make an optimal immune response to vaccines and infectious agents declines with age in humans and animal models. Recent advances have shown intrinsic B cell defects in aged mice and humans, including decreases in Ig class switch recombination (CSR), activation-induced cytidine deaminase (AID), and E47 transcription factor. Effects on somatic hypermutation (SHM) have been varied depending on the system studied. Increase of AID in mice has shown improved CSR but not SHM. The reported microarray analysis of human B cell subsets may now be used to delineate B cell defects with aging and all the advances presented should lead to selecting agents for improved immune response in the elderly. PMID:19608393

  1. 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.

  2. Innate control of B cell responses

    PubMed Central

    Cerutti, Andrea; Puga, Irene; Cols, Montserrat

    2011-01-01

    Mature B cells generate protective immunity by undergoing immunoglobulin (Ig) class switching and somatic hypermutation, two Ig gene-diversifying processes that usually require cognate interactions with T cells that express CD40 ligand. This T cell-dependent pathway provides immunological memory but is relatively slow to occur. Thus it must be integrated with a faster, T cell-independent pathway for B cell activation through CD40 ligand-like molecules that are released by innate immune cells in response to microbial products. Here we discuss recent advances in our understanding of the interplay between the innate immune system and B cells, particularly at the mucosal interface. We also review the role of innate signals in the regulation of Ig diversification and production PMID:21419699

  3. B cell phenotypes in patients with rheumatoid arthritis relapsing after Rituximab: Expression of B cell activating factor-binding receptors on B cell subsets.

    PubMed

    Becerra, Elena; De La Torre, Inmaculada; Leandro, Maria J; Cambridge, Geraldine

    2017-08-11

    Serum levels of B cell activating factor (BAFF) rise following Rituximab (RTX) therapy in patients with Rheumatoid arthritis (RA). Initiation of naïve B cell return to the periphery and autoreactive B cell expansion leading to relapse after RTX may therefore be linked to interactions between BAFF and BAFF-binding receptors (BBR). Relationships between serum BAFF and BBR expression (BAFFR, TACI and BCMA) were determined on B cell subsets, defined using IgD/CD38. 20 pre-RTX and 18 RA patients relapsing after B cell depletion were included. Results were analysed with respect to timing of relapse up to 7 months after peripheral B cell return (≥5 B cells/μL) and to serum BAFF levels. After B cell return, B cell populations from relapsing patients had significantly lower BAFFR+ expression compared to HC and pre-RTX patients. %BAFFR+ B cells increased with time after B cell return and was inversely correlated with serum BAFF levels. BAFFR expression remained reduced. %TACI+ memory B cells were lower in RA patients after RTX compared with HC. BCMA expression (% and expression) did not differ between patients and HC. Relapse following B cell return appeared largely independent of the %BAFFR or %BCMA positive B cells or serum BAFF levels. The lower %TACI+ memory B cells may reduce inhibitory signaling for B cell differentiation. In patients relapsing at longer periods after B cell return, recovery of the B cell pool was more complete, suggesting that selection or expansion of autoreactive B cells may be needed to precipitate relapse. This article is protected by copyright. All rights reserved. © 2017 British Society for Immunology.

  4. Targeting Bruton's tyrosine kinase with ibrutinib in B-cell malignancies.

    PubMed

    Wang, Y; Zhang, L L; Champlin, R E; Wang, M L

    2015-05-01

    The B-cell receptor signaling pathway, which is critical to the development and maturation of normal B-cells, is emerging as an attractive therapeutic target in B-cell malignancies. Ibrutinib is a potent irreversible inhibitor of Bruton's tyrosine kinase (Btk), a key kinase important for signal transduction in the B-cell receptor (BCR) pathway. In preclinical studies, ibrutinib potently bound to Btk, inhibited BCR signaling, and decreased tumor cell proliferation and survival in many B-cell malignancy models. Excellent safety and efficacy data in clinical trials have led to US Food and Drug Administration (FDA) approval of ibrutinib for previously treated mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL), as well as CLL with 17p deletion. Ongoing clinical studies have also demonstrated great potency of ibrutinib in treating other types of non-Hodgkin's lymphoma (NHL), including diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and Waldenström's macroglobulinemia (WM). Combination of ibrutinib with chemoimmunotherapy and other promising novel agents in B-cell malignancy therapy has also been under clinical investigation. © 2015 American Society for Clinical Pharmacology and Therapeutics.

  5. 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

  6. 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

  7. B-cell responses to HIV infection.

    PubMed

    Moir, Susan; Fauci, Anthony S

    2017-01-01

    The induction of neutralizing antibodies directed against the human immunodeficiency virus (HIV) has received considerable attention in recent years, in part driven by renewed interest and opportunities for antibody-based strategies for prevention such as passive transfer of antibodies and the development of preventive vaccines, as well as immune-based therapeutic interventions. Advances in the ability to screen, isolate, and characterize HIV-specific antibodies have led to the identification of a new generation of potent broadly neutralizing antibodies (bNAbs). The majority of these antibodies have been isolated from B cells of chronically HIV-infected individuals with detectable viremia. In this review, we provide insight into the phenotypic and functional attributes of human B cells, with a focus on HIV-specific memory B cells and plasmablasts/cells that are responsible for sustaining humoral immune responses against HIV. We discuss the abnormalities in B cells that occur in HIV infection both in the peripheral blood and lymphoid tissues, especially in the setting of persisting viremia. Finally, we consider the opportunities and drawbacks of intensively interrogating antibodies isolated from HIV-infected individuals to guide strategies aimed at developing effective antibody-based vaccine and therapeutic interventions for HIV. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.

  8. B Cells and Humoral Immunity in Atherosclerosis

    PubMed Central

    Tsiantoulas, Dimitrios; Diehl, Cody J.; Witztum, Joseph L.; Binder, Christoph J.

    2014-01-01

    Insights into the important contribution of inflammation and immune functions in the development and progression of atherosclerosis have greatly improved our understanding of this disease. Although the role of T cells has been extensively studied for decades, only recently has the role of B cells gained more attention. Recent studies have identified differential effects of different B-cell subsets and helped to clarify the still poorly understood mechanisms by which these act. B1 cells have been shown to prevent lesion formation, whereas B2 cells have been suggested to promote it. Natural IgM antibodies, mainly derived from B1 cells, have been shown to mediate atheroprotective effects, but the functional role of other immunoglobulin classes, particularly IgG, still remains elusive. In this review, we will focus on recent insights on the role of B cells and various immunoglobulin classes and how these may mediate their effects in atherosclerotic lesion formation. Moreover, we will highlight potential therapeutic approaches focusing on B-cell depletion that could be used to translate experimental evidence to human disease. PMID:24855199

  9. 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.

  10. 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

  11. B cell-intrinsic CD84 and Ly108 maintain germinal center B cell tolerance

    PubMed Central

    Wong, Eric B.; Soni, Chetna; Chan, Alice Y.; Domeier, Phillip P.; Shwetank; Abraham, Thomas; Limaye, Nisha; Khan, Tahsin N.; Elias, Melinda J.; Chodisetti, Sathi Babu; Wakeland, Edward K.; Rahman, Ziaur S.M.

    2015-01-01

    Signaling lymphocyte activation molecules (SLAMs) play an integral role in immune regulation. Polymorphisms in the SLAM family receptors are implicated in human and mouse model of lupus disease. The lupus-associated, somatically mutated and class-switched pathogenic autoantibodies are generated in spontaneously developed germinal centers (Spt-GCs) in secondary lymphoid organs. The role and mechanism of B cell-intrinsic expression of polymorphic SLAM receptors that affect B cell tolerance at the GC checkpoint is not clear. Here, we generated several bacterial artificial chromosome (BAC) transgenic mice that overexpress B6 alleles of different SLAM family genes in autoimmune-prone B6.Sle1b mice. B6.Sle1b mice overexpressing B6-derived Ly108 and CD84 exhibit a significant reduction in the Spt-GC response and autoantibody production compared to B6.Sle1b mice. These data suggest a prominent role of Sle1b-derived Ly108 and CD84 in altering the GC checkpoint. We further confirm that expression of lupus-associated CD84 and Ly108 specifically on GC B cells in B6.Sle1b mice is sufficient to break B cell tolerance leading to an increase in autoantibody production. In addition, we observe that B6.Sle1b B cells have reduced BCR signaling, and a lower frequency of B cell-T cell conjugates, which are reversed in B6.Sle1b mice overexpressing B6 alleles of CD84 and Ly108. Finally, we find a significant decrease in apoptotic GC B cells in B6.Sle1b mice compared to B6 controls. Our study establishes the central role of GC B cell-specific CD84 and Ly108 expression in maintaining B cell tolerance in GCs and in preventing autoimmunity. PMID:25801429

  12. 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

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

    SciTech Connect

    Coffman, R.L.; Weissman, I.L.

    1981-02-01

    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.

  14. 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

  15. 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)

  16. 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)

  17. Aberrant B cell selection and activation in systemic lupus erythematosus.

    PubMed

    Kil, Laurens P; Hendriks, Rudi W

    2013-08-01

    The detrimental role of B lymphocytes in systemic lupus erythematosus (SLE) is evident from the high levels of pathogenic antinuclear autoantibodies (ANAs) found in SLE patients. Affirming this causative role, additional antibody-independent roles of B cells in SLE were appreciated. In recent years, many defects in B cell selection and activation have been identified in murine lupus models and SLE patients that explain the increased emergence and persistence of autoreactive B cells and their lowered activation threshold. Therefore, clinical trials with B cell depletion regimens in SLE patients were initiated but disappointingly the efficacy of B cell depleting agents proved to be limited. Remarkably however, a major breakthrough in SLE therapy was accomplished by blocking B cell survival factors rather then eliminating B cells. This surprising finding indicates that although SLE is a B cell-driven disease, the amplifying crosstalk between B cells and other cells of the immune system likely evokes the observed tolerance breakdown in B cells. Moreover, this implies that intelligent interception of pro-inflammatory loops rather then selectively silencing B cells will be key to the development of new SLE therapies. In this review, we will not only highlight the intrinsic B cell defects that facilitate the persistence of autoreactive B cells and their activation, but in addition we will focus on B cell extrinsic signals derived from T cells and innate immune cells that lower the activation threshold for B cells.

  18. 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

  19. 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

    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.

  20. 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

  1. Advances in Human B Cell Phenotypic Profiling

    PubMed Central

    Kaminski, Denise A.; Wei, Chungwen; Qian, Yu; Rosenberg, Alexander F.; Sanz, Ignacio

    2012-01-01

    To advance our understanding and treatment of disease, research immunologists have been called-upon to place more centralized emphasis on impactful human studies. Such endeavors will inevitably require large-scale study execution and data management regulation (“Big Biology”), necessitating standardized and reliable metrics of immune status and function. A well-known example setting this large-scale effort in-motion is identifying correlations between eventual disease outcome and T lymphocyte phenotype in large HIV-patient cohorts using multiparameter flow cytometry. However, infection, immunodeficiency, and autoimmunity are also characterized by correlative and functional contributions of B lymphocytes, which to-date have received much less attention in the human Big Biology enterprise. Here, we review progress in human B cell phenotyping, analysis, and bioinformatics tools that constitute valuable resources for the B cell research community to effectively join in this effort. PMID:23087687

  2. B cell differentiation factor-induced B cell maturation: regulation via reduction in cAMP.

    PubMed

    Huang, R; Cioffi, J; Berg, K; London, R; Cidon, M; Maayani, S; Mayer, L

    1995-04-15

    We have previously described a novel human B cell differentiation factor (BCDF), 446-BCDF, that is distinct biochemically and functionally from other cytokines. Since signal transduction pathways involved in human B cell differentiation have been incompletely studied and are poorly understood, we assessed the effects of 446-BCDF on various intracellular second messenger systems. After exposure of B cells to 446-BCDF, intracellular cAMP concentration started to decrease at 5 min and was significantly lower at 30 min and reached the lowest level at 4 hr. In most cases, cAMP concentrations returned toward baseline by 24 hr. A cAMP analog (dibutyryl cAMP), a stimulator of adenyl cyclase (forskolin), and phosphodiesterase inhibitors (aminophylline and IBMX) which inhibited the 446-BCDF-induced decrease in intracellular cAMP, inhibited 446-BCDF-induced B cell differentiation, suggesting that the fall in intracellular cAMP was a critical event in this process. To understand the mechanism involved in the reduction of cAMP, B cells were treated with pertussis toxin (PTX), a Gi protein inhibitor. Pertussis toxin blocked 446-BCDF-induced B cell differentiation as well, suggesting that 446-BCDF may function by stimulation of a Gi-linked receptor resulting in the inhibition of adenylate cyclase with a consequent reduction in cAMP. Other cytokines known to promote Ig secretion (IL2 and IL6) also caused a reduction in cAMP, suggesting that this pathway may be generally important in B cell differentiation. Taken together, these data suggest that at least one pathway of terminal maturation in B cells may involve the reduction of intracellular cAMP.

  3. 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.

  4. In Senescence, Age-associated B Cells (ABC) Secrete TNFα and Inhibit Survival of B Cell Precursors1

    PubMed Central

    Ratliff, Michelle; Alter, Sarah; Frasca, Daniela; Blomberg, Bonnie B.; Riley, Richard L.

    2013-01-01

    Aged mice exhibit ~ 5-10 fold increases in an ordinarily minor CD21/35− CD23− mature B cell subset termed age-associated B cells (ABC). ABC from old, but not young, mice induce apoptosis in pro-B cells directly through secretion of TNFα. In addition, aged ABC, via TNFα, stimulate bone marrow cells to suppress pro-B cell growth. ABC effects can be prevented by the anti-inflammatory cytokine IL-10. Notably, CD21/35+ CD23+ follicular (FO) splenic and FO-like recirculating bone marrow B cells in both young and aged mice contain a subpopulation which produces IL-10. Unlike young adult FO B cells, old FO B cells also produce TNFα; however, secretion of IL-10 within this B cell population ameliorates the TNFα-mediated effects on B cell precursors. Loss of B cell precursors in the bone marrow of old mice in vivo was significantly associated with increased ABC relative to recirculating FO-like B cells. Adoptive transfer of aged ABC into RAG-2 KO recipients resulted in significant losses of pro-B cells within the bone marrow. These results suggest that alterations in B cell composition during old age, in particular the increase in ABC within the B cell compartments contribute to a pro-inflammatory environment within the bone marrow. This provides a mechanism of inappropriate B cell “feedback” which promotes down-regulation of B lymphopoiesis in old age. PMID:23410004

  5. B Cell Repopulation After Alemtuzumab Induction—Transient Increase in Transitional B Cells and Long-Term Dominance of Naïve B Cells

    PubMed Central

    Heidt, S; Hester, J; Shankar, S; Friend, P J; Wood, K J

    2012-01-01

    In organ transplantation, the composition of the B-cell compartment is increasingly identified as an important determinant for graft outcome. Whereas naïve and transitional B cells have been associated with long-term allograft survival and operational tolerance, memory B cells have been linked to decreased allograft survival. Alemtuzumab induction therapy effectively depletes B cells, but is followed by rapid repopulation up to levels exceeding base line. The characteristics of the repopulating B cells are currently unknown. We studied the phenotypic and functional characteristics of B cells longitudinally in 19 kidney transplant recipients, before and at 6, 9 and 12 months after alemtuzumab induction therapy. A transient increase in transitional B cells and cells with phenotypic characteristics of regulatory B cells, as well as a long-term dominance in naïve B cells was found in alemtuzumab-treated kidney transplant recipients, which was not influenced by conversion from tacrolimus to sirolimus. At all time-points after treatment, B cells showed unaltered proliferative and IgM-producing capacity as compared to pretransplant samples, whereas the ability to produce IgG was inhibited long-term. In conclusion, induction therapy with alemtuzumab results in a long-term shift toward naïve B cells with altered phenotypic and functional characteristics. PMID:22420490

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. Diffuse Large B-Cell Lymphoma

    PubMed Central

    Friedberg, Jonathan W.

    2008-01-01

    Synopsis Diffuse Large B-Cell Lymphoma (DLBCL) remains a curable lymphoma, with improved outcome due in large part to incorporation of rituximab in standard regimens. The disease is heterogeneous clinically, morphologically, and molecularly. Recent insights into the molecular heterogeneity of DLBCL are beginning to yield novel therapeutics with significant promise for key subsets of patients. Although CHOP chemotherapy with rituximab remains a standard therapeutic approach for most patients with DLBCL, we anticipate that novel agents will be included in treatment regimens for many patients in the near future. PMID:18954744

  14. Chronic B-Cell Leukemias and Agent Orange

    MedlinePlus

    ... here Enter ZIP code here Chronic B-cell Leukemias and Agent Orange Veterans who develop chronic B- ... care and disability compensation. About chronic B-cell leukemias Leukemia is a cancer of the blood cells. ...

  15. 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 ...

  16. Chronic B-Cell Leukemias and Agent Orange

    MedlinePlus

    ... here Enter ZIP code here Chronic B-cell Leukemias and Agent Orange Veterans who develop chronic B- ... care and disability compensation. About chronic B-cell leukemias Leukemia is a cancer of the blood cells. ...

  17. A graded approach to safety analysis for Rover Processing Facility deactivation

    SciTech Connect

    Henrikson, D.J.

    1997-08-01

    The Rover Fuels Processing Facility operated in the early 1980`s, recovering uranium from graphite fuels. In 1996 clean-out began of uranium bearing material remaining in the Rover cells where combustion processes had occurred. Success of the Rover Deactivation Project depends on the safe, timely, and cost-effective repackaging and removal of the uranium bearing material. Due to a number of issues which could not be resolved prior to clean-out, and consideration of cost and schedule objectives, a graded approach was taken to projected design and criticality safety analysis. The safety authorization basis was upgraded primarily by a specific Deactivation addendum, instead of being completely rewritten to current format and content standards. In place of having all design activities completed prior to the start of the Deactivation, the project design and accompanying safety documentation evolved as the project progressed. The Unreviewed Safety Question determination process was used to ensure that new project activities were within the safety envelope. This graded approach allowed operational flexibility while maintaining a critically safe work environment.

  18. A brief history of T cell help to B cells

    PubMed Central

    Crotty, Shane

    2015-01-01

    In celebration of the 50th anniversary of the discovery of B cells, I take a look back at the history of T cell help to B cells, which was discovered 47 years ago. In addition, I summarize and categorize the distinct molecules that are expressed by CD4+ T cells that constitute ‘help’ to B cells, and particularly the molecules expressed by T follicular helper (TFH) cells, which are the specialized providers of help to B cells. PMID:25677493

  19. A brief history of T cell help to B cells.

    PubMed

    Crotty, Shane

    2015-03-01

    In celebration of the 50th anniversary of the discovery of B cells, I take a look back at the history of T cell help to B cells, which was discovered 47 years ago. In addition, I summarize and categorize the distinct molecules that are expressed by CD4(+) T cells that constitute 'help' to B cells, and particularly the molecules expressed by T follicular helper (TFH) cells, which are the specialized providers of help to B cells.

  20. Primary Mediastinal B-Cell Lymphoma

    PubMed Central

    Pileri, Stefano A.; Gaidano, Gianluca; Zinzani, Pier Luigi; Falini, Brunangelo; Gaulard, Philippe; Zucca, Emanuele; Pieri, Federica; Berra, Eva; Sabattini, Elena; Ascani, Stefano; Piccioli, Milena; Johnson, Peter W. M.; Giardini, Roberto; Pescarmona, Edoardo; Novero, Domenico; Piccaluga, Pier Paolo; Marafioti, Teresa; Alonso, Miguel A.; Cavalli, Franco

    2003-01-01

    Although primary mediastinal (thymic) large B-cell lymphoma has been primarily studied, its precise phenotype, molecular characteristics, and histogenesis are still a matter of debate. The International Extranodal Lymphoma Study Group collected 137 such cases for extensive pathological review. Histologically, the lymphomatous growth was predominantly diffuse with fibrosis that induced compartmentalized cell aggregation. It consisted of large cells with varying degrees of nuclear polymorphism and clear to basophilic cytoplasm. On immunohistochemistry, the following phenotype was observed: CD45+, CD20+, CD79a+, PAX5/BSAP+, BOB.1+, Oct-2+, PU.1+, Bcl-2+, CD30+, HLA-DR+, MAL protein+/−, Bcl-6+/−, MUM1/IRF4+/−, CD10−/+, CD21−, CD15−, CD138−, CD68−, and CD3−. Immunoglobulins were negative both at immunohistochemistry and in situ hybridization. Molecular analysis, performed in 45 cases, showed novel findings. More than half of the cases displayed BCL-6 gene mutations, which usually occurred along with functioning somatic IgVH gene mutations and Bcl-6 and/or MUM1/IRF4 expression. The present study supports the concept that a sizable fraction of cases of this lymphoma are from activated germinal center or postgerminal center cells. However, it differs from other aggressive B-cell lymphomas in that it shows defective immunoglobulin production despite the expression of OCT-2, BOB.1, and PU.1 transcription factors and the lack of IgVH gene crippling mutations. PMID:12507907

  1. Pathogenesis of diffuse large B cell lymphoma.

    PubMed

    Chan, Wing John C

    2010-09-01

    Substantial additional insight has been obtained in the past decade regarding the pathogenesis of diffuse large B cell lymphoma (DLBCL). Distinct subtypes of DLBCL have been defined by gene expression profiling (GEP) and they differ not only in GE profiles but also in the pattern of genetic abnormalities. The ability to correlate corresponding genetic and GEP data markedly facilitates the identification of target genes in regions with copy number abnormalities. Oncogenic pathways are often differentially activated in these different subtypes of DLBCL, suggesting that therapy should be targeted according to these differences. The tumor microenvironment plays a significant role in determining outcome and may be a novel target for therapy. The role of microRNA in lymphomagenesis is increasingly being recognized and mutation of key genes has been demonstrated to drive the activation of the NF-kappaB pathway and B cell receptor signaling. The pace of discovery will be even more rapid in the near future with the convergence of data from multiple complementary genome-wide studies and technological innovations including the rapid advance in the technology of high-throughput sequencing.

  2. The skin, a novel niche for recirculating B cells1

    PubMed Central

    Geherin, Skye A.; Fintushel, Sarah R.; Lee, Michael H.; Wilson, R. Paul; Patel, Reema T.; Alt, Carsten; Young, Alan J.; Hay, John B.; Debes, Gudrun F.

    2012-01-01

    B cells infiltrate the skin in many chronic inflammatory diseases caused by autoimmunity or infection. Despite potential contribution to disease, skin-associated B cells remain poorly characterized. Using an ovine model of granulomatous skin inflammation, we demonstrate that B cells increase in the skin and skin-draining afferent lymph during inflammation. Surprisingly, skin B cells are a heterogeneous population that is distinct from lymph node B cells, with more large lymphocytes as well as B-1-like B cells that co-express high levels IgM and CD11b. Skin B cells have increased MHCII, CD1, and CD80/86 expression compared with lymph node B cells, suggesting that they are well-suited for T cell activation at the site of inflammation. Furthermore, we show that skin accumulation of B cells and antibody-secreting cells during inflammation increases local antibody titers, which could augment host defense and autoimmunity. While skin B cells express typical skin homing receptors such as E-selectin ligand and alpha-4 and beta-1 integrins, they are unresponsive to ligands for chemokine receptors associated with T cell homing into skin. Instead, skin B cells migrate toward the cutaneously expressed CCR6 ligand CCL20. Our data support a model in which B cells use CCR6-CCL20 to recirculate through the skin, fulfilling a novel role in skin immunity and inflammation. PMID:22561151

  3. 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.

  4. Cell of origin associated classification of B-cell malignancies by gene signatures of the normal B-cell hierarchy.

    PubMed

    Johnsen, Hans Erik; Bergkvist, Kim Steve; Schmitz, Alexander; Kjeldsen, Malene Krag; Hansen, Steen Møller; Gaihede, Michael; Nørgaard, Martin Agge; Bæch, John; Grønholdt, Marie-Louise; Jensen, Frank Svendsen; Johansen, Preben; Bødker, Julie Støve; Bøgsted, Martin; Dybkær, Karen

    2014-06-01

    Recent findings have suggested biological classification of B-cell malignancies as exemplified by the "activated B-cell-like" (ABC), the "germinal-center B-cell-like" (GCB) and primary mediastinal B-cell lymphoma (PMBL) subtypes of diffuse large B-cell lymphoma and "recurrent translocation and cyclin D" (TC) classification of multiple myeloma. Biological classification of B-cell derived cancers may be refined by a direct and systematic strategy where identification and characterization of normal B-cell differentiation subsets are used to define the cancer cell of origin phenotype. Here we propose a strategy combining multiparametric flow cytometry, global gene expression profiling and biostatistical modeling to generate B-cell subset specific gene signatures from sorted normal human immature, naive, germinal centrocytes and centroblasts, post-germinal memory B-cells, plasmablasts and plasma cells from available lymphoid tissues including lymph nodes, tonsils, thymus, peripheral blood and bone marrow. This strategy will provide an accurate image of the stage of differentiation, which prospectively can be used to classify any B-cell malignancy and eventually purify tumor cells. This report briefly describes the current models of the normal B-cell subset differentiation in multiple tissues and the pathogenesis of malignancies originating from the normal germinal B-cell hierarchy.

  5. Circulating CD21low B cells in common variable immunodeficiency resemble tissue homing, innate-like B cells.

    PubMed

    Rakhmanov, Mirzokhid; Keller, Baerbel; Gutenberger, Sylvia; Foerster, Christian; Hoenig, Manfred; Driessen, Gertjan; van der Burg, Mirjam; van Dongen, Jacques J; Wiech, Elisabeth; Visentini, Marcella; Quinti, Isabella; Prasse, Antje; Voelxen, Nadine; Salzer, Ulrich; Goldacker, Sigune; Fisch, Paul; Eibel, Hermann; Schwarz, Klaus; Peter, Hans-Hartmut; Warnatz, Klaus

    2009-08-11

    The homeostasis of circulating B cell subsets in the peripheral blood of healthy adults is well regulated, but in disease it can be severely disturbed. Thus, a subgroup of patients with common variable immunodeficiency (CVID) presents with an extraordinary expansion of an unusual B cell population characterized by the low expression of CD21. CD21(low) B cells are polyclonal, unmutated IgM(+)IgD(+) B cells but carry a highly distinct gene expression profile which differs from conventional naïve B cells. Interestingly, while clearly not representing a memory population, they do share several features with the recently defined memory-like tissue, Fc receptor-like 4 positive B cell population in the tonsils of healthy donors. CD21(low) B cells show signs of previous activation and proliferation in vivo, while exhibiting defective calcium signaling and poor proliferation in response to B cell receptor stimulation. CD21(low) B cells express decreased amounts of homeostatic but increased levels of inflammatory chemokine receptors. This might explain their preferential homing to peripheral tissues like the bronchoalveolar space of CVID or the synovium of rheumatoid arthritis patients. Therefore, as a result of the close resemblance to the gene expression profile, phenotype, function and preferential tissue homing of murine B1 B cells, we suggest that CD21(low) B cells represent a human innate-like B cell population.

  6. 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.

  7. FcgammaRIIB is differentially expressed during B cell maturation and in B-cell lymphomas.

    PubMed

    Camilleri-Broët, Sophie; Cassard, Lydie; Broët, Philippe; Delmer, Alain; Le Touneau, Agnès; Diebold, Jacques; Fridman, Wolf Herman; Molina, Thierry Jo; Sautès-Fridman, Catherine

    2004-01-01

    FcgammaRIIB, a low affinity receptor for the Fc portion of immunoglobulin G (IgG), is thought to drive negative selection of B cells in germinal centers (GC) by inducing apoptosis upon interaction with immune complexes. Its expression was investigated by immunohistochemistry in 22 reactive lymphoid tissues and 112 B-cell lymphomas. Pre-GC mantle cells, marginal zone cells and their neoplastic counterparts expressed FcgammaRIIB. The B chronic lymphocytic leukaemia (B-CLL)/small lymphocytic lymphomas were also positive. Not detected in GC, FcgammaRIIB was expressed in 52% of follicular lymphomas and in 20% of diffuse large B cell lymphomas (DLBCL). In DLBCL, FcgammaRIIB expression was linked to transformation (P < 0.001). Re-analysis of a gene profile data set from the Lymphochip microarrays showed that FcgammaRIIB expression in the activated B-like DLBCL subgroup was higher than in the GC-like one (P < 0.04), and was associated with an adverse prognostic both in univariate (P < 0.003) and in multivariate analysis including the International Prognostic Indicator (IPI) (P < 0.01). Thus these results challenge the potential role of FcgammaRIIB during B-cell selection in GC, and suggest a prognostic value of FcgammaRIIB expression in DLBCL.

  8. 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

  9. Regulation of normal B-cell differentiation and malignant B-cell survival by OCT2.

    PubMed

    Hodson, Daniel J; Shaffer, Arthur L; Xiao, Wenming; Wright, George W; Schmitz, Roland; Phelan, James D; Yang, Yandan; Webster, Daniel E; Rui, Lixin; Kohlhammer, Holger; Nakagawa, Masao; Waldmann, Thomas A; Staudt, Louis M

    2016-04-05

    The requirement for the B-cell transcription factor OCT2 (octamer-binding protein 2, encoded by Pou2f2) in germinal center B cells has proved controversial. Here, we report that germinal center B cells are formed normally after depletion of OCT2 in a conditional knockout mouse, but their proliferation is reduced and in vivo differentiation to antibody-secreting plasma cells is blocked. This finding led us to examine the role of OCT2 in germinal center-derived lymphomas. shRNA knockdown showed that almost all diffuse large B-cell lymphoma (DLBCL) cell lines are addicted to the expression of OCT2 and its coactivator OCA-B. Genome-wide chromatin immunoprecipitation (ChIP) analysis and gene-expression profiling revealed the broad transcriptional program regulated by OCT2 that includes the expression of STAT3, IL-10, ELL2, XBP1, MYC, TERT, and ADA. Importantly, genetic alteration of OCT2 is not a requirement for cellular addiction in DLBCL. However, we detected amplifications of the POU2F2 locus in DLBCL tumor biopsies and a recurrent mutation of threonine 223 in the DNA-binding domain of OCT2. This neomorphic mutation subtly alters the DNA-binding preference of OCT2, leading to the transactivation of noncanonical target genes including HIF1a and FCRL3 Finally, by introducing mutations designed to disrupt the OCT2-OCA-B interface, we reveal a requirement for this protein-protein interface that ultimately might be exploited therapeutically. Our findings, combined with the predominantly B-cell-restricted expression of OCT2 and the absence of a systemic phenotype in our knockout mice, suggest that an OCT2-targeted therapeutic strategy would be efficacious in both major subtypes of DLBCL while avoiding systemic toxicity.

  10. 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.

  11. Central B-Cell Tolerance: Where Selection Begins

    PubMed Central

    Pelanda, Roberta; Torres, Raul M.

    2012-01-01

    The development of an adaptive immune system based on the random generation of antigen receptors requires a stringent selection process that sifts through receptor specificities to remove those reacting with self-antigens. In the B-cell lineage, this selection process is first applied to IgM+ immature B cells. By using increasingly sophisticated mouse models, investigators have identified the central tolerance mechanisms that negatively select autoreactive immature B cells and prevent inclusion of their antigen receptors into the peripheral B-cell pool. Additional studies have uncovered mechanisms that promote the differentiation of nonautoreactive immature B cells and their positive selection into the peripheral B-cell population. These mechanisms of central selection are fundamental to the generation of a naïve B-cell repertoire that is largely devoid of self-reactivity while capable of reacting with any foreign insult. PMID:22378602

  12. 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

  13. 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.

  14. 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.

  15. Defective B-cell memory in patients with Down syndrome.

    PubMed

    Verstegen, Ruud H J; Driessen, Gertjan J; Bartol, Sophinus J W; van Noesel, Carel J M; Boon, Louis; van der Burg, Mirjam; van Dongen, Jacques J M; de Vries, Esther; van Zelm, Menno C

    2014-12-01

    Patients with Down syndrome carry immunologic defects, as evidenced by the increased risks for autoimmune diseases, hematologic malignancies, and respiratory tract infections. Moreover, the low numbers of circulating B cells suggest impaired humoral immunity. We sought to study how immunodeficiency in patients with Down syndrome results from immunologic defects in the B-cell compartment. We studied blood B-cell subset composition, replication history, somatic hypermutation status, and class-switch recombination in 17 children with Down syndrome. Germinal centers and plasma cells were studied in tonsils from 4 additional children with Down syndrome. Blood transitional B-cell numbers were normal, but naive mature and memory B-cell numbers were reduced despite slightly increased serum B cell-activating factor levels. Germinal centers and plasma cells in tonsils appeared normal, as were serum immunoglobulin levels. CD27(+)IgD(+)IgM(+) "natural effector" B cells showed reduced proliferation and somatic hypermutation levels, whereas these were normal in CD27(+)IgD(-) memory B cells. Furthermore, IgM(+) and IgA(+), but not IgG(+), memory B cells showed impaired molecular signs for antigen selection. The B-cell pattern was highly similar to that of patients with common variable immunodeficiency and a defect in B-cell activation and proliferation. Children with Down syndrome seem capable of normal germinal center and plasma cell formation. Still, blood memory B-cell numbers were reduced and showed impaired molecular maturation of IgA and IgM, which are important for mucosal immunity. The observed molecular defects in circulating IgA and IgM B-cell memory could reflect impaired local responses, which underlie the increased susceptibility to respiratory tract infections of patients with Down syndrome. Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  16. 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

  17. Tonic B-cell receptor signaling in diffuse large B-cell lymphoma.

    PubMed

    Havranek, Ondrej; Xu, Jingda; Köhrer, Stefan; Wang, Zhiqiang; Becker, Lisa; Comer, Justin M; Henderson, Jared; Ma, Wencai; Man Chun Ma, John; Westin, Jason R; Ghosh, Dipanjan; Shinners, Nicholas; Sun, Luhong; Yi, Allen F; Karri, Anusha R; Burger, Jan A; Zal, Tomasz; Davis, R Eric

    2017-08-24

    We used clustered regularly interspaced short palindromic repeats/Cas9-mediated genomic modification to investigate B-cell receptor (BCR) signaling in cell lines of diffuse large B-cell lymphoma (DLBCL). Three manipulations that altered BCR genes without affecting surface BCR levels showed that BCR signaling differs between the germinal center B-cell (GCB) subtype, which is insensitive to Bruton tyrosine kinase inhibition by ibrutinib, and the activated B-cell (ABC) subtype. Replacing antigen-binding BCR regions had no effect on BCR signaling in GCB-DLBCL lines, reflecting this subtype's exclusive use of tonic BCR signaling. Conversely, Y188F mutation in the immunoreceptor tyrosine-based activation motif of CD79A inhibited tonic BCR signaling in GCB-DLBCL lines but did not affect their calcium flux after BCR cross-linking or the proliferation of otherwise-unmodified ABC-DLBCL lines. CD79A-GFP fusion showed BCR clustering or diffuse distribution, respectively, in lines of ABC and GCB subtypes. Tonic BCR signaling acts principally to activate AKT, and forced activation of AKT rescued GCB-DLBCL lines from knockout (KO) of the BCR or 2 mediators of tonic BCR signaling, SYK and CD19. The magnitude and importance of tonic BCR signaling to proliferation and size of GCB-DLBCL lines, shown by the effect of BCR KO, was highly variable; in contrast, pan-AKT KO was uniformly toxic. This discrepancy was explained by finding that BCR KO-induced changes in AKT activity (measured by gene expression, CXCR4 level, and a fluorescent reporter) correlated with changes in proliferation and with baseline BCR surface density. PTEN protein expression and BCR surface density may influence clinical response to therapeutic inhibition of tonic BCR signaling in DLBCL. © 2017 by The American Society of Hematology.

  18. 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.

  19. Regulation of normal B-cell differentiation and malignant B-cell survival by OCT2

    PubMed Central

    Hodson, Daniel J.; Shaffer, Arthur L.; Xiao, Wenming; Wright, George W.; Schmitz, Roland; Phelan, James D.; Yang, Yandan; Webster, Daniel E.; Rui, Lixin; Kohlhammer, Holger; Nakagawa, Masao; Waldmann, Thomas A.; Staudt, Louis M.

    2016-01-01

    The requirement for the B-cell transcription factor OCT2 (octamer-binding protein 2, encoded by Pou2f2) in germinal center B cells has proved controversial. Here, we report that germinal center B cells are formed normally after depletion of OCT2 in a conditional knockout mouse, but their proliferation is reduced and in vivo differentiation to antibody-secreting plasma cells is blocked. This finding led us to examine the role of OCT2 in germinal center-derived lymphomas. shRNA knockdown showed that almost all diffuse large B-cell lymphoma (DLBCL) cell lines are addicted to the expression of OCT2 and its coactivator OCA-B. Genome-wide chromatin immunoprecipitation (ChIP) analysis and gene-expression profiling revealed the broad transcriptional program regulated by OCT2 that includes the expression of STAT3, IL-10, ELL2, XBP1, MYC, TERT, and ADA. Importantly, genetic alteration of OCT2 is not a requirement for cellular addiction in DLBCL. However, we detected amplifications of the POU2F2 locus in DLBCL tumor biopsies and a recurrent mutation of threonine 223 in the DNA-binding domain of OCT2. This neomorphic mutation subtly alters the DNA-binding preference of OCT2, leading to the transactivation of noncanonical target genes including HIF1a and FCRL3. Finally, by introducing mutations designed to disrupt the OCT2–OCA-B interface, we reveal a requirement for this protein–protein interface that ultimately might be exploited therapeutically. Our findings, combined with the predominantly B-cell–restricted expression of OCT2 and the absence of a systemic phenotype in our knockout mice, suggest that an OCT2-targeted therapeutic strategy would be efficacious in both major subtypes of DLBCL while avoiding systemic toxicity. PMID:26993806

  20. 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.

  1. Adipose Tissue Inflammation Induces B Cell Inflammation and Decreases B Cell Function in Aging

    PubMed Central

    Frasca, Daniela; Blomberg, Bonnie B.

    2017-01-01

    Aging is the greatest risk factor for developing chronic diseases. Inflamm-aging, the age-related increase in low-grade chronic inflammation, may be a common link in age-related diseases. This review summarizes recent published data on potential cellular and molecular mechanisms of the age-related increase in inflammation, and how these contribute to decreased humoral immune responses in aged mice and humans. Briefly, we cover how aging and related inflammation decrease antibody responses in mice and humans, and how obesity contributes to the mechanisms for aging through increased inflammation. We also report data in the literature showing adipose tissue infiltration with immune cells and how these cells are recruited and contribute to local and systemic inflammation. We show that several types of immune cells infiltrate the adipose tissue and these include macrophages, neutrophils, NK cells, innate lymphoid cells, eosinophils, T cells, B1, and B2 cells. Our main focus is how the adipose tissue affects immune responses, in particular B cell responses and antibody production. The role of leptin in generating inflammation and decreased B cell responses is also discussed. We report data published by us and by other groups showing that the adipose tissue generates pro-inflammatory B cell subsets which induce pro-inflammatory T cells, promote insulin resistance, and secrete pathogenic autoimmune antibodies.

  2. Adipose Tissue Inflammation Induces B Cell Inflammation and Decreases B Cell Function in Aging.

    PubMed

    Frasca, Daniela; Blomberg, Bonnie B

    2017-01-01

    Aging is the greatest risk factor for developing chronic diseases. Inflamm-aging, the age-related increase in low-grade chronic inflammation, may be a common link in age-related diseases. This review summarizes recent published data on potential cellular and molecular mechanisms of the age-related increase in inflammation, and how these contribute to decreased humoral immune responses in aged mice and humans. Briefly, we cover how aging and related inflammation decrease antibody responses in mice and humans, and how obesity contributes to the mechanisms for aging through increased inflammation. We also report data in the literature showing adipose tissue infiltration with immune cells and how these cells are recruited and contribute to local and systemic inflammation. We show that several types of immune cells infiltrate the adipose tissue and these include macrophages, neutrophils, NK cells, innate lymphoid cells, eosinophils, T cells, B1, and B2 cells. Our main focus is how the adipose tissue affects immune responses, in particular B cell responses and antibody production. The role of leptin in generating inflammation and decreased B cell responses is also discussed. We report data published by us and by other groups showing that the adipose tissue generates pro-inflammatory B cell subsets which induce pro-inflammatory T cells, promote insulin resistance, and secrete pathogenic autoimmune antibodies.

  3. Differential Programming of B Cells in AID Deficient Mice

    PubMed Central

    Hogenbirk, Marc A.; Heideman, Marinus R.; Velds, Arno; van den Berk, Paul CM.; Kerkhoven, Ron M.; van Steensel, Bas; Jacobs, Heinz

    2013-01-01

    The Aicda locus encodes the activation induced cytidine deaminase (AID) and is highly expressed in germinal center (GC) B cells to initiate somatic hypermutation (SHM) and class switch recombination (CSR) of immunoglobulin (Ig) genes. Besides these Ig specific activities in B cells, AID has been implicated in active DNA demethylation in non-B cell systems. We here determined a potential role of AID as an epigenetic eraser and transcriptional regulator in B cells. RNA-Seq on different B cell subsets revealed that Aicda−/− B cells are developmentally affected. However as shown by RNA-Seq, MethylCap-Seq, and SNP analysis these transcriptome alterations may not relate to AID, but alternatively to a CBA mouse strain derived region around the targeted Aicda locus. These unexpected confounding parameters provide alternative, AID-independent interpretations on genotype-phenotype correlations previously reported in numerous studies on AID using the Aicda−/− mouse strain. PMID:23922811

  4. 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.

  5. 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

  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. 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

  9. Double-Hit Large B Cell Lymphoma.

    PubMed

    Khelfa, Yousef; Lebowicz, Yehuda; Jamil, Muhammad Omer

    2017-09-26

    Diffuse large B cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma (NHL), accounting for approximately 25% of NHL cases. It is a heterogeneous group of diseases. BCL2, BCL6, and MYC are the most frequent mutated genes in DLBCL. Double-hit lymphoma (DHL) is an aggressive form of DLBCL with an unmet treatment need, in which MYC rearrangement is present with either BCL2 or BCL6 rearrangement. Patients typically present with a rapidly growing mass with B symptoms. DHL has been linked to very poor outcomes when treated with RCHOP chemotherapy. Dual-expressor lymphoma is a form of DLBCL with overexpression of MYC and BCL2/BCL6. There is a paucity of prospective trials evaluating the treatment of DHL. Retrospective series suggest that more aggressive treatment regimens such as DA-EPOCH and hyper CVAD may be more efficacious. However, there remains a lack of consensus regarding optimal treatment for DHL. Further clinical trials, including novel agents, are needed for improvement in outcomes.

  10. 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

  11. Comparative analyses of B cell populations in trout kidney and mouse bone marrow; establishing “B cell signatures”

    PubMed Central

    Zwollo, Patty; Mott, Katrina; Barr, Maggie

    2010-01-01

    This study aimed to identify the frequency and distribution of developing B cell populations in the kidney of the rainbow trout, using four molecular B cell markers that are highly conserved between species, including two transcription factors, Pax5 and EBF1, recombination activating gene RAG1, and the immunoglobulin heavy chain mu. Three distinct B cell stages were defined: early developing B cells (CLP, pro-B, and early pre-B cells), late developing B cell (late pre-B, immature B, and mature B cells), and IgM-secreting cells. Developmental stage-specific, combinatorial expression of Pax5, EBF1, RAG1 and immunoglobulin mu was determined in trout anterior kidney cells by flow cytometry. Trout staining patterns were compared to a well-defined primary immune tissue, mouse bone marrow, and using mouse surface markers B220 and CD43. A remarkable level of similarity was uncovered between the primary immune tissues of both species. Subsequent analysis of the entire trout kidney, divided into five contiguous segments K1-K5, revealed a complex pattern of early developing, late developing, and IgM-secreting B cells. Patterns in anterior kidney segment K1 were most similar to those of mouse bone marrow, while the most posterior part of the kidney, K5, had many IgM-secreting cells, but lacked early developing B cells. A potential second B lymphopoiesis site was uncovered in segment K4 of the kidney. The B cell patterns, or “B cell signatures” described here provide information on the relative abundance of distinct developing B cell populations in the trout kidney, and can be used in future studies on B cell development in other vertebrate species. PMID:20705088

  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 Central

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

    2016-01-01

    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. PMID:26764382

  14. 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.

  15. B-cell targeted therapeutics in clinical development

    PubMed Central

    2013-01-01

    B lymphocytes are the source of humoral immunity and are thus a critical component of the adaptive immune system. However, B cells can also be pathogenic and the origin of disease. Deregulated B-cell function has been implicated in several autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis. B cells contribute to pathological immune responses through the secretion of cytokines, costimulation of T cells, antigen presentation, and the production of autoantibodies. DNA-and RNA-containing immune complexes can also induce the production of type I interferons, which further promotes the inflammatory response. B-cell depletion with the CD20 antibody rituximab has provided clinical proof of concept that targeting B cells and the humoral response can result in significant benefit to patients. Consequently, the interest in B-cell targeted therapies has greatly increased in recent years and a number of new biologics exploiting various mechanisms are now in clinical development. This review provides an overview on current developments in the area of B-cell targeted therapies by describing molecules and subpopulations that currently offer themselves as therapeutic targets, the different strategies to target B cells currently under investigation as well as an update on the status of novel therapeutics in clinical development. Emerging data from clinical trials are providing critical insight regarding the role of B cells and autoantibodies in various autoimmune conditions and will guide the development of more efficacious therapeutics and better patient selection. PMID:23566679

  16. B-cell subpopulations in children: National reference values

    PubMed Central

    Duchamp, Marie; Sterlin, Delphine; Diabate, Aminata; Uring-Lambert, Béatrice; Guérin-El Khourouj, Valérie; Le Mauff, Brigitte; Monnier, Delphine; Malcus, Christophe; Labalette, Myriam; Picard, Capucine

    2014-01-01

    Peripheral B-lymphocytes undergo a series of changes during the first few years of life. Encounters with foreign antigens lead to maturation and differentiation. Several primary antibody deficiencies (PADs) affecting B-cell development are associated with abnormalities in the composition and/or differentiation of B-cell compartments. The most recent international classifications of primary immunodeficiencies (PIDs) and common variable immunodeficiencies (CVID) have highlighted the importance of B-cell immunophenotyping and age-specific reference intervals for diagnostic purposes. We established national reference values for memory B-cell subpopulations, on the basis of CD27 and surface IgD expression in the peripheral blood of 242 healthy children. We report here the absolute counts and percentages of naive, switched and non-switched memory B-cells for seven age groups, from neonates to adults. We found that the naive B-cells percentage declined between the ages of 6 months and 8 years, after which it remained stable at about 70–80%. Memory B-cells are already present at birth and their numbers increase throughout childhood, stabilizing between the ages of 12 and 18 years. The definition of reference intervals for pediatric B-cell levels should facilitate the screening and diagnosis of various B-cell immunodeficiencies. This multicenter study, providing national reference values, should thus facilitate immunological diagnosis in children. PMID:25505547

  17. B-cell subpopulations in children: National reference values.

    PubMed

    Duchamp, Marie; Sterlin, Delphine; Diabate, Aminata; Uring-Lambert, Béatrice; Guérin-El Khourouj, Valérie; Le Mauff, Brigitte; Monnier, Delphine; Malcus, Christophe; Labalette, Myriam; Picard, Capucine

    2014-11-01

    Peripheral B-lymphocytes undergo a series of changes during the first few years of life. Encounters with foreign antigens lead to maturation and differentiation. Several primary antibody deficiencies (PADs) affecting B-cell development are associated with abnormalities in the composition and/or differentiation of B-cell compartments. The most recent international classifications of primary immunodeficiencies (PIDs) and common variable immunodeficiencies (CVID) have highlighted the importance of B-cell immunophenotyping and age-specific reference intervals for diagnostic purposes. We established national reference values for memory B-cell subpopulations, on the basis of CD27 and surface IgD expression in the peripheral blood of 242 healthy children. We report here the absolute counts and percentages of naive, switched and non-switched memory B-cells for seven age groups, from neonates to adults. We found that the naive B-cells percentage declined between the ages of 6 months and 8 years, after which it remained stable at about 70-80%. Memory B-cells are already present at birth and their numbers increase throughout childhood, stabilizing between the ages of 12 and 18 years. The definition of reference intervals for pediatric B-cell levels should facilitate the screening and diagnosis of various B-cell immunodeficiencies. This multicenter study, providing national reference values, should thus facilitate immunological diagnosis in children.

  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. 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

  20. 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.

  1. 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.

  2. Obesity decreases B cell responses in young and elderly individuals.

    PubMed

    Frasca, Daniela; Ferracci, Franco; Diaz, Alain; Romero, Maria; Lechner, Suzanne; Blomberg, Bonnie B

    2016-03-01

    To evaluate the effects of obesity-associated inflammation on influenza vaccine responses. In young and elderly individuals, both lean and with obesity, antibody responses to influenza vaccination were measured. A decrease in in vivo vaccine responses, circulating switched memory, and transitional B cells and an increase in pro-inflammatory late/exhausted memory B cells were found. In vitro B cell function was measured by activation-induced cytidine deaminase and E47, markers of optimal antibody responses. Moreover, IL-6 production was increased, whereas IL-10 production was decreased in cultures of B cells from individuals with obesity. Markers of immune activation (TNF-α, TLR4, micro-RNAs) in unstimulated B cells were also found increased and were negatively correlated with B cell function. In order to reveal potential mechanisms, we stimulated B cells from lean individuals in vitro with leptin, the adipokine increased in obesity. Leptin increased phospho-STAT3, crucial for TNF-α production, and decreased phospho-AMPK, the energy sensing enzyme upstream of phospho-p38 MAPK and E47. Leptin-induced phospho-STAT3 and phospho-AMPK levels were similar to those in B cells from individuals with obesity. These results demonstrate that leptin can be responsible for decreased B cell function in obesity. © 2016 The Obesity Society.

  3. 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

  4. 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.

  5. Reduced non-switched memory B cell subsets cause imbalance in B cell repertoire in systemic sclerosis.

    PubMed

    Simon, Diána; Balogh, Péter; Bognár, András; Kellermayer, Zoltán; Engelmann, Péter; Németh, Péter; Farkas, Nelli; Minier, Tünde; Lóránd, Veronika; Czirják, László; Berki, Tímea

    2016-01-01

    Analysis of peripheral blood B lymphocytes in patients with systemic sclerosis (SSc) has provided evidence for specific alterations in naive and memory B cell balance. However, memory B cell subsets in SSc have not been thoroughly investigated. This study sought to identify phenotypic abnormalities and activation markers in peripheral blood memory B cells in SSc subtypes. Blood samples were obtained from 28 SSc patients with early form of disease (9 limited (lcSSc), 19 diffuse cutaneous SSc (dcSSc)) and 15 healthy controls. After magnetic bead separation of CD19+ B cells, multiparametric flow cytometry was performed and CD19+CD27- IgD+ naive, CD19+CD27+ memory, CD19+CD27+IgD+ non-switched memory CD19+CD27+IgD- switched memory, CD19+CD27-IgD- double negative (DN) memory, CD80+ or CD95+ activated cells were identified. The proportion of naive B cells was higher (p=0.046) in SSc than in controls, with a decreased percentage of memory (p=0.018), especially non-switched memory B cells (p=0.015). The dcSSc patients had a significantly higher frequency of switched memory and DN memory B cells compared to lcSSc patients (p=0.025 and p=0.031). Percentage of CD95+CD27+ memory and CD95+ DN memory B cells was also significantly elevated in dcSSc compared to lcSSc patients (p=0.038 and p=0.045). We conclude that the decreased proportion of memory B cells in SSc is due to reduction of non- switched memory B cells, resulting in an imbalance between the tolerogenic and activated memory B cell types. Elevated switched and activated CD95+ DN memory B cells may serve as a biomarker for dcSSc and can have a pathogenic potential by cytokine and autoantibody production.

  6. 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

  7. 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

  8. B-cell selection and the development of autoantibodies

    PubMed Central

    2012-01-01

    The clearest evidence that B cells play an important role in human autoimmunity is that immunotherapies that deplete B cells are very effective treatments for many autoimmune diseases. All people, healthy or ill, have autoreactive B cells, but not at the same frequency. A number of genes influence the level of these autoreactive B cells and whether they are eliminated or not during development at a central checkpoint in the bone marrow (BM) or at a later checkpoint in peripheral lymphoid tissues. These genes include those encoding proteins that regulate signaling through the B-cell receptor complex such as Btk and PTPN22, proteins that regulate innate signaling via Toll-like receptors (TLRs) such as MyD88 and interleukin-1 receptor-associated kinase 4, as well as the gene encoding the activation-induced deaminase (AID) essential for B cells to undergo class switch recombination and somatic hypermutation. Recent studies have revealed that TLR signaling elements and AID function not only in peripheral B cells to help mediate effective antibody responses to foreign antigens, but also in the BM to help remove autoreactive B-lineage cells at a very early point in B-cell development. Newly arising B cells that leave the BM and enter the blood and splenic red pulp can express both AID and TLR signaling elements like TLR7, and thus are fully equipped to respond rapidly to antigens (including autoantigens), to isotype class switch, and to undergo somatic hypermutation. These red pulp B cells may thus be an important source of autoantibody-producing cells arising particularly in extrafollicular sites, and indeed may be as significant a source of autoantibody-producing cells as B cells arising from germinal centers. PMID:23281837

  9. 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

  10. 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

  11. Calcium dependence of the induction of B cell class I molecules and of proliferation by various B cell mitogens

    SciTech Connect

    Dennis, G.; Mizuguchi, J.; Finkelman, F.D.; Mond, J.J.

    1986-03-01

    The concentration of calcium in the cytosol influences the metabolism of phosphoinositides which play essential roles as intracellular messengers in B lymphocytes. To investigate the calcium requirements for various stages of B cell activation the authors studied the effect of altering calcium availability for B cells stimulated by different classes of mitogens. 1mM EGTA inhibited B cell thymidine incorporation stimulated by LPS, 8-mercaptoguanosine (8sGuo) or anti-Ig antibodies, but had no effect on cell viability in the culture system used. The slow phase calcium channel blocker verapamil suppressed /sup 3/H-thymidine incorporation to a lesser degree. B cell sIa expression was used as an indicator of an earlier B cell activation event. The calcium ionophore A23187 stimulated a dramatic increase in B cell sIa in a dose dependent manner which was inhibited in the presence of 1mM EGTA. This reduction in extracellular calcium only partially diminished the sIa augmentation resulting from anti-Ig antibody, and had no effect on that stimulated by LPS or 8sGuo. These findings suggest that extracellular calcium is required for later events in B cells activation while earlier events may be primarily dependent upon intracellular calcium stores. Furthermore, membrane Ig mediated B cell activation may require higher concentrations of intracellular calcium than other B cell activation pathways.

  12. Pro-B cells propagated in stromal cell-free cultures reconstitute functional B-cell compartments in immunodeficient mice.

    PubMed

    von Muenchow, Lilly; Tsapogas, Panagiotis; Albertí-Servera, Llucia; Capoferri, Giuseppina; Doelz, Marianne; Rolink, Hannie; Bosco, Nabil; Ceredig, Rhodri; Rolink, Antonius G

    2017-02-01

    Up to now long-term in vitro growth of pro-B cells was thought to require stromal cells. However, here we show that fetal liver (FL) and bone marrow (BM) derived pro-B cells can be propagated long-term in stromal cell-free cultures supplemented with IL-7, stem cell factor and FLT3 ligand. Within a week, most cells expressed surface CD19, CD79A, λ5, and VpreB antigens and had rearranged immunoglobulin D-J heavy chain genes. Both FL and BM pro-B cells reconstituted the B-cell compartments of immuno-incompetent Rag2-deficient mice, with FL pro-B cells generating follicular, marginal zone (MZB) and B1a B cells, and BM pro-B cells giving rise mainly to MZB cells. Reconstituted Rag2-deficient mice generated significant levels of IgM and IgG antibodies to a type II T-independent antigen; mice reconstituted with FL pro-B cells generated surprisingly high IgG1 titers. Finally, we show for the first time that mice reconstituted with mixtures of pro-B and pro-T cells propagated in stromal cell-free in vitro cultures mounted a T-cell-dependent antibody response. This novel stromal cell-free culture system facilitates our understanding of B-cell development and might be applied clinically. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. B-cell signaling in persistent polyclonal B lymphocytosis (PPBL).

    PubMed

    Voelxen, Nadine; Wehr, Claudia; Gutenberger, Sylvia; Keller, Baerbel; Erlacher, Miriam; Dominguez-Conde, Cecilia; Bertele, Daniela; Emmerich, Florian; Pantic, Milena; Jennings, Stefanie; Rakhmanov, Mirzokhid; Foerster, Christian; Martens, Uwe M; Platzbecker, Uwe; Peter, Hans-Hartmut; Fisch, Paul; Boztug, Kaan; Eibel, Hermann; Salzer, Ulrich; Warnatz, Klaus

    2016-10-01

    Persistent polyclonal B lymphocytosis (PPBL) is a benign hematological disorder characterized by a selective expansion of circulating polyclonal marginal zone (MZ)-like B cells. Previous reports demonstrated that cases of PPBL showed poor activation, proliferation and survival of B cells in vitro, yet the underlying defect remains unknown. Here we report for the first time an attenuated activation of the canonical NF-κB (nuclear factor of kappa light polypeptide gene enhancer in B cells) and mitogen-activated protein kinase/extracellular signal-regulated kinase pathway after CD40 stimulation. This defect was selective, as alternative NF-κB signaling after CD40 stimulation and both B-cell receptor- and Toll-like receptor 9-mediated activation remained unaffected. Reduced canonical NF-κB activation resulted in decreased IκBα and CD40 expression in resting cells. In PPBL patients, expression of Bcl-xL in MZ-like B cells did not increase upon activation, consistent with the high apoptosis rates of PPBL-derived B cells that were observed in vitro. The B-cell phenotype of mice with selective knockouts of early components of the CD40 signaling pathway resembles PPBL, but sequencing corresponding genes in sorted MZ-like B cells of PPBL patients did not reveal relevant genetic alterations. Nevertheless, the frequently observed mutations in early signaling components of the NF-κB pathway in MZ lymphomas underline the relevance of our findings for the pathogenesis of PPBL.

  18. 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. © 2013 Wiley Periodicals, Inc.

  19. Low level exposure to inorganic mercury interferes with B cell receptor signaling in transitional type 1 B cells.

    PubMed

    Gill, R; McCabe, M J; Rosenspire, A J

    2017-09-01

    Mercury (Hg) has been implicated as a factor contributing to autoimmune disease in animal models and humans. However the mechanism by which this occurs has remained elusive. Since the discovery of B cells it has been appreciated by immunologists that during the normal course of B cell development, some immature B cells must be generated that produce immunoglobulin reactive to self-antigens (auto-antibodies). However in the course of normal development, the vast majority of immature auto-reactive B cells are prevented from maturing by processes collectively known as tolerance. Autoimmune disease arises when these mechanisms of tolerance are disrupted. In the B cell compartment, it is firmly established that tolerance depends in part upon negative selection of self-reactive immature (transitional type 1) B cells. In these cells negative selection depends upon signals generated by the B Cell Receptor (BCR), in the sense that those T1 B cells who's BCRs most strongly bind to, and so generate the strongest signals to self-antigens are neutralized. In this report we have utilized multicolor phosphoflow cytometry to show that in immature T1 B cells Hg attenuates signal generation by the BCR through mechanisms that may involve Lyn, a key tyrosine kinase in the BCR signal transduction pathway. We suggest that exposure to low, environmentally relevant levels of Hg, disrupts tolerance by interfering with BCR signaling in immature B cells, potentially leading to the appearance of mature auto-reactive B cells which have the ability to contribute to auto-immune disease. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. TLR7/TLR9- and B Cell Receptor-Signaling Crosstalk: Promotion of Potentially Dangerous B Cells.

    PubMed

    Suthers, Amy N; Sarantopoulos, Stefanie

    2017-01-01

    B cells are capable of receptor-mediated responses to foreign antigens. Recognition of microbial-derived nucleic acid (NA) by toll-like receptors (TLRs) 7 and 9 in B cells has been substantiated. Endogenous NA released from damaged or dying cells can also be immunogenic in certain contexts and can incite aberrant activation of B cells. When TLR-driven B cell receptor (BCR)-activated B cells are not properly constrained, pathologic autoantibodies are produced. It is also clear that endosomal TLR7/TLR9 can operate in conjunction with BCR. In addition to BCR signaling, a balance between TLR7 and TLR9 is pivotal in the development of B cell autoreactivity. While TLR9 is important in normal memory B cell responses through BCR, TLR9 activation has been implicated in autoantibody production. Paradoxically, TLR9 also plays known protective roles against autoimmunity by directly and indirectly inhibiting TLR7-mediated autoantibody production. Herein, we summarize literature supporting mechanisms underpinning the promotion of pathological BCR-activated B cells by TLR7 and TLR9. We focus on the literature regarding known points of TLR7/TLR9 and BCR crosstalk. Data also suggest that the degree of TLR responsiveness relies on alterations of certain intrinsic B-cell signaling molecules and is also context specific. Because allogeneic hematopoietic stem cell transplantation is a high NA and B cell-activating factor environment, we conclude that B cell studies of synergistic TLR-BCR signaling in human diseases like chronic graft-versus-host disease are warranted. Further understanding of the distinct molecular pathways mediating TLR-BCR synergy will lead to the development of therapeutic strategies in autoimmune disease states.

  1. B cell function in the immune response to helminths

    PubMed Central

    Harris, Nicola

    2010-01-01

    Similar T helper (Th)2-type immune responses are generated against different helminths parasites, but the mechanisms that initiate Th2 immunity, and the specific immune components that mediate protection against these parasites, can vary greatly. B cells are increasingly recognized as important during the Th2-type immune response to helminths, and B cell activation might be a target for effective vaccine development. Antibody production is a function of B cells during helminth infection and understanding how polyclonal and antigen-specific antibodies contribute should provide important insights into how protective immunity develops. In addition, B cells might also contribute to the host response against helminths through antibody-independent functions including, antigen-presentation, as well as regulatory and effector activity. In this review, we examine the role of B cells during Th2-type immune response to these multicellular parasites. PMID:21159556

  2. 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

  3. Murid Herpesvirus-4 Exploits Dendritic Cells to Infect B Cells

    PubMed Central

    Frederico, Bruno; Gill, Michael B.; Smith, Christopher M.; Belz, Gabrielle T.; Stevenson, Philip G.

    2011-01-01

    Dendritic cells (DCs) play a central role in initiating immune responses. Some persistent viruses infect DCs and can disrupt their functions in vitro. However, these viruses remain strongly immunogenic in vivo. Thus what role DC infection plays in the pathogenesis of persistent infections is unclear. Here we show that a persistent, B cell-tropic gamma-herpesvirus, Murid Herpesvirus-4 (MuHV-4), infects DCs early after host entry, before it establishes a substantial infection of B cells. DC-specific virus marking by cre-lox recombination revealed that a significant fraction of the virus latent in B cells had passed through a DC, and a virus attenuated for replication in DCs was impaired in B cell colonization. In vitro MuHV-4 dramatically altered the DC cytoskeleton, suggesting that it manipulates DC migration and shape in order to spread. MuHV-4 therefore uses DCs to colonize B cells. PMID:22102809

  4. GSK3 is a metabolic checkpoint regulator in B cells

    PubMed Central

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

    2016-01-01

    B cells predominate in a quiescent state until antigen is encountered, which results in rapid growth, proliferation and differentiation. These distinct cell states are likely 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 naïve recirculating B cells by restricting cell mass accumulation. In antigen-driven responses, GSK3 was selectively required for CD40-mediated regulation of B cell size, mitochondria biogenesis, glycolysis and reactive oxygen species (ROS) production. GSK3 was required to prevent metabolic collapse and ROS-induced apoptosis when glucose became limiting, functioning in part by repressing c-Myc-dependent growth. Importantly, 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. PMID:28114292

  5. Memory B cells in Guillain-Barré syndrome.

    PubMed

    Wang, Qian; Xing, Chunye; Hao, Yanlei; Shi, Qiguang; Qi, Ziyou; Lv, Zhanyun; Song, Yan; Xu, Peng; Feng, Xungang; Zhang, Lili; Zhang, Yong; Wang, Yuzhong; Yuki, Nobuhiro

    2017-04-15

    IgG autoantibodies against gangliosides show the highest titers at the disease onset of axonal Guillain-Barré syndrome (GBS), in which there are no IgM anti-ganglioside antibodies. We hypothesized that memory B cells take part in the development of producing IgG autoantibodies. In this study, we analyzed the memory B cells in patients with GBS using flow cytometry. There was significantly higher percentage of memory B cells in patients with GBS than the healthy controls. The Spearman correlation analysis demonstrated that increased percentage of memory B cells was positively correlated with the clinical severity of the patients with GBS. Our study provides the evidences that memory B cells may be involved in mechanism of GBS. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. 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

  7. 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

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

    PubMed

    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; Hodes, Richard J

    2015-11-12

    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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. IL-10 critically modulates B cell responsiveness in Rankl-/- mice.

    PubMed

    Marrella, Veronica; Lo Iacono, Nadia; Fontana, Elena; Sobacchi, Cristina; Sic, Heiko; Schena, Francesca; Sereni, Lucia; Castiello, Maria Carmina; Poliani, Pietro Luigi; Vezzoni, Paolo; Cassani, Barbara; Traggiai, Elisabetta; Villa, Anna

    2015-05-01

    The immune and the skeletal system are tightly interconnected, and B lymphocytes are uniquely endowed with osteo-interactive properties. In this context, receptor activator of NF-κB (RANK) ligand (RANKL) plays a pivotal role in lymphoid tissue formation and bone homeostasis. Although murine models lacking RANK or RANKL show defects in B cell number, the role of the RANKL-RANK axis on B physiology is still a matter of debate. In this study, we have characterized in detail B cell compartment in Rankl(-/-) mice, finding a relative expansion of marginal zone B cells, B1 cells, and plasma cells associated with increased Ig serum levels, spontaneous germinal center formation, and hyperresponse to CD40 triggering. Such abnormalities were associated with an increased frequency of regulatory B cells and augmented B cell-derived IL-10 production. Remarkably, in vivo IL-10-R blockade reduced T cell-triggered plasma cell differentiation and restrained the expansion of regulatory B cells. These data point to a novel role of the RANKL-RANK axis in the regulation of B cell homeostasis and highlight an unexpected link between IL-10 CD40 signaling and the RANKL pathway. Copyright © 2015 by The American Association of Immunologists, Inc.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  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 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

  1. 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.

  2. 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.

  3. 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.

  4. [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.

  5. HLA-specific B cells: II. Application to transplantation.

    PubMed

    Zachary, Andrea A; Kopchaliiska, Dessislava; Montgomery, Robert A; Melancon, Joseph K; Leffell, Mary S

    2007-04-15

    Differences in the antibody response to allogeneic transplantation exist between groups defined by race or gender. These differences may reflect differences in immune competency and/or exposure to alloantigens. We have investigated the frequencies and phenotypes of HLA-specific B cells to address those possibilities. HLA-specific B cells were identified by staining with HLA tetramers (tet) as described previously and the distribution of CD27 and CD38 among those cells were measured in groups defined by various parameters. Possible correlation between frequencies of HLA-specific B cells and production of HLA-specific antibody after transplantation was also investigated. We found no correlation between the frequencies of CD27+tet+ (33%-44% vs. 34%-36%) or CD38+tet+ (57%-65% vs. 59%-66%) B cells and a previous mismatch for the HLA antigen of the tetramer. However, there was an increase in CD38+tet+ B cells among patients making antibody to the tetramer antigen (67%-72% vs. 53%-56%). Blacks had lower frequencies of CD27+ B cells than did whites (11.8% vs. 28.9%, P=0.003), but had greater increases of these cells among tet+ cells than did whites. There was a higher frequency of tet+ B cells among patients who developed "new" antibody to the HLA antigen (3.9%-8.6%) of the tetramer after transplantation than among those who did not (1.1%-3.7%). The phenotype of HLA-specific B cells reflects current or historic sensitization to HLA and may reflect inherent differences between groups defined by race and/or gender. The frequencies of HLA-specific B cells may predict patients at risk for production of donor-specific antibody after transplantation.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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

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

    PubMed Central

    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. PMID:27047488

  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 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.

  14. 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.

  15. Revisiting the role of B cells in skin immune surveillance.

    PubMed

    Egbuniwe, Isioma U; Karagiannis, Sophia N; Nestle, Frank O; Lacy, Katie E

    2015-02-01

    Whereas our understanding of the skin immune system has increased exponentially in recent years, the role of B cells in cutaneous immunity remains poorly defined. Recent studies have revealed the presence of B cells within lymphocytic infiltrates in chronic inflammatory skin diseases and cutaneous malignancies including melanoma, and have examined their functional significance in these settings. We review these findings and discuss them in the context of the current understanding of the role of B cells in normal skin physiology, as well as in both animal and human models of skin pathology. We integrate these findings into a model of cutaneous immunity wherein crosstalk between B cells and other skin-resident immune cells plays a central role in skin immune homeostasis. Copyright © 2015. Published by Elsevier Ltd.

  16. Recent advances in B-cell epitope prediction methods

    PubMed Central

    2010-01-01

    Identification of epitopes that invoke strong responses from B-cells is one of the key steps in designing effective vaccines against pathogens. Because experimental determination of epitopes is expensive in terms of cost, time, and effort involved, there is an urgent need for computational methods for reliable identification of B-cell epitopes. Although several computational tools for predicting B-cell epitopes have become available in recent years, the predictive performance of existing tools remains far from ideal. We review recent advances in computational methods for B-cell epitope prediction, identify some gaps in the current state of the art, and outline some promising directions for improving the reliability of such methods. PMID:21067544

  17. Computational prediction of B cell epitopes from antigen sequences.

    PubMed

    Gao, Jianzhao; Kurgan, Lukasz

    2014-01-01

    Computational identification of B-cell epitopes from antigen chains is a difficult and actively pursued research topic. Efforts towards the development of method for the prediction of linear epitopes span over the last three decades, while only recently several predictors of conformational epitopes were released. We review a comprehensive set of 13 recent approaches that predict linear and 4 methods that predict conformational B-cell epitopes from the antigen sequences. We introduce several databases of B-cell epitopes, since the availability of the corresponding data is at the heart of the development and validation of computational predictors. We also offer practical insights concerning the use and availability of these B-cell epitope predictors, and motivate and discuss feature research in this area.

  18. 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

  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. [Eosinophilic pneumonia revealing B-cell non-Hodgkin lymphoma].

    PubMed

    Fikal, Siham; Sajiai, Hafsa; Serhane, Hind; Aitbatahar, Salma; Amro, Lamyae

    2016-01-01

    The diagnosis of eosinophilic pneumonia is rare and malignant etiology remains exceptional. Eosinophilic pneumonia etiology varies and is mainly dominated by allergic and drug causes. We report the case of a 61-year-old patient with B-cell non-Hodgkin lymphoma revealed by eosinophilic pneumonia. The diagnosis of eosinophilic pneumonia was confirmed by eosinophil count of 56% in bronchoalveolar lavage. Immunohistochemical examination of bone marrow biopsy revealed malignant Small B cells non-Hodgkin lymphoma.

  2. B Cell Reconstitution after Rituximab Treatment in Idiopathic Nephrotic Syndrome

    PubMed Central

    Carsetti, Rita; Cascioli, Simona; Casiraghi, Federica; Perna, Annalisa; Ravà, Lucilla; Ruggiero, Barbara; Emma, Francesco; Vivarelli, Marina

    2016-01-01

    The pathogenesis of nephrotic syndrome is unclear. However, the efficacy of rituximab, a B cell–depleting antibody, in nephrotic syndrome suggests a pathogenic role of B cells. In this retrospective study, we determined by flow cytometry levels of B and T cell subpopulations before and after rituximab infusion in 28 pediatric patients with frequently relapsing or steroid–dependent nephrotic syndrome. At baseline, patients had lower median percentages of transitional and mature B cells than age–matched healthy controls (P<0.001). Rituximab induced full depletion of B cells (<1% of lymphocytes). At 1 year, most patients exhibited complete total and mature B cell recovery, whereas memory B cell subsets remained significantly depleted. Total T cell concentration did not change with rituximab, whereas the CD4+/CD8+ T cell ratio tended to increase. Fourteen patients relapsed within 24 months, with a median follow-up of 11.2 months (interquartile range, 8–17.7 months). We observed no difference at baseline between nonrelapsing and relapsing patients in several clinical parameters and cell subset concentrations. Reconstitution of all memory B cell subpopulations, number of immunosuppressive drugs, and dose of tacrolimus during the last 4 months of follow-up were predictive of relapse in univariate Cox regression analysis. However, only delayed reconstitution of switched memory B cells, independent of immunosuppressive treatment, was protective against relapse in multivariate (P<0.01) and receiver operator characteristic (P<0.01 for percentage of lymphocytes; P=0.02 for absolute count) analyses. Evaluation of switched memory B cell recovery after rituximab may be useful for predicting relapse in patients with nephrotic syndrome. PMID:26567244

  3. 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.

  4. Analysis of B-cell subpopulations in monoclonal gammopathies.

    PubMed

    Všianská, Pavla; Říhová, Lucie; Varmužová, Tamara; Suská, Renata; Kryukov, Fedor; Mikulášová, Aneta; Kupská, Renata; Penka, Miroslav; Pour, Luděk; Adam, Zdeněk; Hájek, Roman

    2015-04-01

    Multiple myeloma (MM) is characterized by accumulation of pathological plasma cells (PCs) in bone marrow (BM) as a result of deregulation of B-cell development. To clarify its pathophysiology it is necessary to investigate in detail the developmental stages of B-cells. Enumeration of total CD19-positive (CD19(+)) cells and their subpopulations together with PCs was done in peripheral blood (PB) and BM of newly diagnosed monoclonal gammopathy patients and control subjects. Representation of subsets was compared among groups and relationships between subset percentage and cytogenetic/biochemical findings were analyzed. A lower number of total CD19(+) cells was found in MM, particularly in advanced stages of disease. Reduction of naive (P < .01) and transitional B-cells (P < .05) and increase of switched memory and switched CD27(-) B-cells and germinal center founder cells were detected in PB of MM compared with controls (P < .01). Similar results were found in BM. β2 microglobulin level in MM positively correlated with the number of PCs and negatively with percentage of naive B-cells (P < .05). Our results provided a detailed phenotypic profile and enumeration of B and PC subpopulations in monoclonal gammopathy patients. A reduced number of B-cells and particularly a differentiation shift to more numerous antigen-stimulated forms was observed in MM. This might indicate a potential source of myeloma-initiating cells in one of these subpopulations. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. 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

  6. 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

  7. B cell depletion reduces the development of atherosclerosis in mice

    PubMed Central

    Ait-Oufella, Hafid; Herbin, Olivier; Bouaziz, Jean-David; Binder, Christoph J.; Uyttenhove, Catherine; Laurans, Ludivine; Taleb, Soraya; Van Vré, Emily; Esposito, Bruno; Vilar, José; Sirvent, Jérôme; Van Snick, Jacques; Tedgui, Alain; Tedder, Thomas F.

    2010-01-01

    B cell depletion significantly reduces the burden of several immune-mediated diseases. However, B cell activation has been until now associated with a protection against atherosclerosis, suggesting that B cell–depleting therapies would enhance cardiovascular risk. We unexpectedly show that mature B cell depletion using a CD20-specific monoclonal antibody induces a significant reduction of atherosclerosis in various mouse models of the disease. This treatment preserves the production of natural and potentially protective anti–oxidized low-density lipoprotein (oxLDL) IgM autoantibodies over IgG type anti-oxLDL antibodies, and markedly reduces pathogenic T cell activation. B cell depletion diminished T cell–derived IFN-γ secretion and enhanced production of IL-17; neutralization of the latter abrogated CD20 antibody–mediated atheroprotection. These results challenge the current paradigm that B cell activation plays an overall protective role in atherogenesis and identify new antiatherogenic strategies based on B cell modulation. PMID:20603314

  8. 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.

  9. The role of regulatory B cells in digestive system diseases.

    PubMed

    Zhou, Zhenyu; Gong, Lei; Wang, Xiaoyun; Hu, Zhen; Wu, Gaojue; Tang, Xuejun; Peng, Xiaobin; Tang, Shuan; Meng, Miao; Feng, Hui

    2017-04-01

    The past decade has provided striking insights into a newly identified subset of B cells known as regulatory B cells (Bregs). In addition to producing antibody, Bregs also regulate diseases via cytokine production and antigen presentation. This subset of B cells has protective and potentially therapeutic effects. However, the particularity of Bregs has caused some difficulties in conducting research on their roles. Notably, human B10 cells, which are Bregs that produce interleukin 10, share phenotypic characteristics with other previously defined B cell subsets, and currently, there is no known surface phenotype that is unique to B10 cells. An online search was performed in the PubMed and Web of Science databases for articles published providing evidences on the role of regulatory B cells in digestive system diseases. Abundant evidence has demonstrated that Bregs play a regulatory role in inflammatory, autoimmune, and tumor diseases, and regulatory B cells play different roles in different diseases, but future work needs to determine the mechanisms by which Bregs are activated and how these cells affect their target cells.

  10. 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

  11. Mechanisms Promoting Translocations in Editing and Switching Peripheral B Cells

    PubMed Central

    Wang, Jing H.; Gostissa, Monica; Yan, Catherine T.; Goff, Peter; Hickernell, Thomas; Hansen, Erica; Difilippantonio, Simone; Wesemann, Duane R.; Zarrin, Ali A.; Rajewsky, Klaus; Nussenzweig, Andre; Alt, Frederick W.

    2010-01-01

    V(D)J recombination assembles immunoglobulin (Ig) heavy or light chain (IgH or IgL) variable region exons in developing bone marrow B cells, while class switch recombination (CSR) exchanges IgH constant region exons in peripheral B cells. Both processes employ DNA double strand breaks (DSBs) repaired by non-homologous end-joining (NHEJ). Errors in either V(D)J recombination or CSR can initiate chromosomal translocations, including oncogenic IgH/c-myc translocations of peripheral B cell lymphomas. Collaboration between these processes also has been proposed to initiate translocations. However, occurrence of V(D)J recombination in peripheral B cells is controversial. Here, we report that activated NHEJ-deficient splenic B cells accumulate V(D)J recombination-associated IgL chromosomal breaks, as well as CSR-associated IgH breaks, often in the same cell. Moreover, IgL breaks frequently are joined to IgH breaks to form translocations, a phenomenon associated with specific IgH/IgL co-localization. IgH and c-myc also co-localize in these cells; correspondingly, introduction of frequent c-myc DSBs robustly promotes IgH/c-myc translocations. Our studies reveal peripheral B cells that attempt secondary V(D)J recombination and elucidate a role for mechanistic factors in promoting recurrent translocations in tumors. PMID:19587764

  12. 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

  13. Targeting TRAF3 Downstream Signaling Pathways in B cell Neoplasms

    PubMed Central

    Moore, Carissa R; Edwards, Shanique KE; Xie, Ping

    2015-01-01

    B cell neoplasms comprise >50% of blood cancers. However, many types of B cell malignancies remain incurable. Identification and validation of novel genetic risk factors and oncogenic signaling pathways are imperative for the development of new therapeutic strategies. We and others recently identified TRAF3, a cytoplasmic adaptor protein, as a novel tumor suppressor in B lymphocytes. We found that TRAF3 inactivation results in prolonged survival of mature B cells, which eventually leads to spontaneous development of B lymphomas in mice. Corroborating our findings, TRAF3 deletions and inactivating mutations frequently occur in human B cell chronic lymphocytic leukemia, splenic marginal zone lymphoma, mantle cell lymphoma, multiple myeloma, Waldenström’s macroglobulinemia, and Hodgkin lymphoma. In this context, we have been investigating TRAF3 signaling mechanisms in B cells, and are developing new therapeutic strategies to target TRAF3 downstream signaling pathways in B cell neoplasms. Here we discuss our new translational data that demonstrate the therapeutic potential of targeting TRAF3 downstream signaling pathways in B lymphoma and multiple myeloma. PMID:25960828

  14. The clinicopathologic spectrum of mature aggressive B cell lymphomas.

    PubMed

    Rimsza, Lisa; Pittaluga, Stefania; Dirnhofer, Stephan; Copie-Bergman, Christiane; de Leval, Laurence; Facchetti, Fabio; Pileri, Stefano; Rosenwald, Andreas; Wotherspoon, Andrew; Fend, Falko

    2017-08-26

    Our understanding of mature aggressive B cell lymphomas has evolved significantly in the last years as reflected in the 2016 update of the WHO lymphoma classification. A main topic of the 2016 European Association for Haematopathology/Society of Hematopathology lymphoma workshop in Basel therefore was the clinicopathological spectrum of mature aggressive B cell lymphomas with the exception of conventional diffuse large B cell lymphoma. In this review, we summarize two sessions dedicated to "high-grade B cell lymphomas, with MYC and BCL2 and/or BCL6 rearrangements (so-called double/triple-hit lymphomas)" and "high-grade B cell lymphomas, NOS" as defined in the 2016 update of the WHO lymphoma classification, Burkitt lymphoma and related neoplasms, and terminally differentiated aggressive B cell lymphomas. One focus was on cases of Burkitt lymphoma with unusual clinical features such as spontaneous regression or association with immunosuppression, and the new provisional category of Burkitt-like lymphoma with 11q aberration. The large numbers of cases submitted for the new high-grade categories with or without genetic "double/triple hit" demonstrated the broad clinical and pathological spectrum of this group and gave ample opportunity for discussion. In this review, current definitions and our understanding of the main high-grade categories, potential problem areas, and suggestions for the immunophenotypic and genetic work-up of these neoplasms are discussed and illustrated by many interesting and challenging cases submitted to the workshop.

  15. 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

  16. B cells with regulatory properties in transplantation tolerance.

    PubMed

    Durand, Justine; Chiffoleau, Elise

    2015-12-24

    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.

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. Cutting edge: regulation of TLR4-driven B cell proliferation by RP105 is not B cell autonomous.

    PubMed

    Allen, Jessica L; Flick, Leah M; Divanovic, Senad; Jackson, Shaun W; Bram, Richard; Rawlings, David J; Finkelman, Fred D; Karp, Christopher L

    2012-03-01

    Mechanistic understanding of RP105 has been confounded by the fact that this TLR homolog has appeared to have opposing, cell type-specific effects on TLR4 signaling. Although RP105 inhibits TLR4-driven signaling in cell lines and myeloid cells, impaired LPS-driven proliferation by B cells from RP105(-/-) mice has suggested that RP105 facilitates TLR4 signaling in B cells. In this article, we show that modulation of B cell proliferation by RP105 is not a function of B cell-intrinsic expression of RP105, and identify a mechanistic role for dysregulated BAFF expression in the proliferative abnormalities of B cells from RP105(-/-) mice: serum BAFF levels are elevated in RP105(-/-) mice, and partial BAFF neutralization rescues aberrant B cell proliferative responses in such mice. These data indicate that RP105 does not have dichotomous effects on TLR4 signaling and emphasize the need for caution in interpreting the results of global genetic deletion.

  2. Cutting Edge: Regulation of TLR4-driven B cell proliferation by RP105 is not B cell-autonomous

    PubMed Central

    Allen, Jessica L.; Flick, Leah M.; Divanovic, Senad; Jackson, Shaun W.; Bram, Richard; Rawlings, David J.; Finkelman, Fred D.; Karp, Christopher L.

    2012-01-01

    Mechanistic understanding of RP105 has been confounded by the fact that this TLR homolog has appeared to have opposing, cell type-specific effects on TLR4 signaling. While RP105 inhibits TLR4-driven signaling in cell lines and myeloid cells, impaired LPS-driven proliferation by B cells from RP105−/− mice has suggested that RP105 facilitates TLR4 signaling in B cells. We show here that modulation of B cell proliferation by RP105 is not a function of B cell-intrinsic expression of RP105, and identify a mechanistic role for dysregulated BAFF expression in the proliferative abnormalities of B cells from RP105−/− mice: serum BAFF levels are elevated in RP105−/− mice, and partial BAFF neutralization rescues aberrant B cell proliferative responses in such mice. These data indicate that RP105 does not have dichotomous effects on TLR4 signaling, and emphasize the need for caution in interpreting the results of global genetic deletion. PMID:22291190

  3. 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

  4. 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.

  5. Human regulatory B cells control the TFH cell response.

    PubMed

    Achour, Achouak; Simon, Quentin; Mohr, Audrey; Séité, Jean-François; Youinou, Pierre; Bendaoud, Boutahar; Ghedira, Ibtissem; Pers, Jacques-Olivier; Jamin, Christophe

    2017-07-01

    Follicular helper T (TFH) cells support terminal B-cell differentiation. Human regulatory B (Breg) cells modulate cellular responses, but their control of TFH cell-dependent humoral immune responses is unknown. We sought to assess the role of Breg cells on TFH cell development and function. Human T cells were polyclonally stimulated in the presence of IL-12 and IL-21 to generate TFH cells. They were cocultured with B cells to induce their terminal differentiation. Breg cells were included in these cultures, and their effects were evaluated by using flow cytometry and ELISA. B-cell lymphoma 6, IL-21, inducible costimulator, CXCR5, and programmed cell death protein 1 (PD-1) expressions increased on stimulated human T cells, characterizing TFH cell maturation. In cocultures they differentiated B cells into CD138(+) plasma and IgD(-)CD27(+) memory cells and triggered immunoglobulin secretions. Breg cells obtained by Toll-like receptor 9 and CD40 activation of B cells prevented TFH cell development. Added to TFH cell and B-cell cocultures, they inhibited B-cell differentiation, impeded immunoglobulin secretions, and expanded Foxp3(+)CXCR5(+)PD-1(+) follicular regulatory T cells. Breg cells modulated IL-21 receptor expressions on TFH cells and B cells, and their suppressive activities involved CD40, CD80, CD86, and intercellular adhesion molecule interactions and required production of IL-10 and TGF-β. Human Breg cells control TFH cell maturation, expand follicular regulatory T cells, and inhibit the TFH cell-mediated antibody secretion. These novel observations demonstrate a role for the Breg cell in germinal center reactions and suggest that deficient activities might impair the TFH cell-dependent control of humoral immunity and might lead to the development of aberrant autoimmune responses. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  6. 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.

  7. 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

  8. 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

  9. [Single B cell monoclonal antibody technologies and applications].

    PubMed

    Chi, Xiangyang; Yu, Changming; Chen, Wei

    2012-06-01

    Monoclonal antibodies (mAbs) contribute a lot to the development of numerous fields in life science as a pivotal tool in modern biological research. Development of the PCR methods and maturation of antibody production have made it possible to generate mAbs from single human B cells by single cell RT-PCR with successional cloning and expression in vitro. Compared to traditional monoclonal antibody technologies, single B cell technologies require relatively fewer cells, which are highly efficient in obtaining specific mAbs in a rapid way with preservation of the natural heavy and light chain pairing. With so many advantages, single B cell technologies have been proved to be an attractive approach for retrieval of naive and antigen-experienced antibody repertoires generated in vivo, design of rationale structure-based vaccine, evaluation and development of basic B cell biology concepts in health and autoimmunity, and prevention of infectious diseases by passive immunization and therapy for disorders. Accordingly, this review introduced recent progresses in the single B cell technologies for generating monoclonal antibodies and applications.

  10. 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.

  11. 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

  12. Editing Anti-DNA B Cells by Vλx

    PubMed Central

    Li, Yijin; Louzoun, Yoram; Weigert, Martin

    2004-01-01

    Receptor editing is performed by replacement of Vκ genes that contribute to autoreactivity. In addition, the Cκ locus can be deleted by Vκ rearrangement to intronic or 3′ of Cκ RS sequences (also referred to as κ deletion elements). B cells that delete the Cκ can then express λ light chains. However, the λ locus, either of man or mouse, does not allow V gene replacement. Nor does it appear to be deleted. Therefore, editing of autoreactive λ B cells may require alternative pathways. We have found that in anti-DNA heavy chain transgenic mice (tgs) VH3H9/56R, B cells that express anti-DNA receptors comprised of λ1 in association with an anti-DNA heavy chain often coexpress a κ chain that prevents DNA binding. We speculate that such isotypically included cells may have low anti-DNA receptor densities, a feature that may lead to self-tolerance. Here we describe a mechanism of preventing DNA binding by expression of a rarely used member of the Vλ family, Vλx. The λx B cells of the tgs also express CD25 and may represent B cells that have exhausted light chain editing possibilities. PMID:14757741

  13. B cells as effectors and regulators of autoimmunity.

    PubMed

    Mariño, Eliana; Grey, Shane T

    2012-08-01

    A classic understanding of the interplay between B and T cell components of the immune system that drive autoimmunity, where B cells provide an effector function, is represented by systemic lupus erythematosus (SLE), an autoimmune condition characterised by the production of auto-antibodies. In SLE, CD4+T cells provide cognate help to self-reactive B cells, which in turn produce pathogenic auto-antibodies (1). Thus, B cells act as effectors by producing auto-antibody aided by T cell help such that B and T cell interactions are unidirectional. However, this paradigm of B and T cell interactions is challenged by new clinical data demonstrating that B cell depletion is effective for T cell mediated autoimmune diseases including type I diabetes mellitus (T1D) (2), rheumatoid arthritis (3), and multiple sclerosis (4). These clinical data indicate a model whereby B cells can influence the developing autoimmune T cell response, and therefore act as effectors, in ways that extend beyond the production of autoantibody (5). In this review by largely focusing on type I diabetes we will develop a hypothesis that bi-directional B and T interactions control the course of autoimmunity.

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

    ClinicalTrials.gov

    2017-10-09

    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. 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

  16. Generation and identification of tumor-evoked regulatory B cells

    PubMed Central

    Biragyn, Arya; Lee-Chang, Catalina; Bodogai, Monica

    2014-01-01

    The involvement of Bregs in cancer remains poorly understood despite their well-documented regulation of responses to the self and protection from harmful autoimmunity. We recently discovered a unique regulatory B cell subset evoked by breast cancer to mediate protection of metastasizing cancer cells. These results together with the wealth of findings of the last 40 years on B cells in tumorigenesis suggest the existence of additional cancer Bregs modulating anticancer responses. To facilitate the search for them, here we provide our detailed protocol for the characterization and generation of tumor-evoked regulatory B cells. Wherever applicable, we also discuss nuances and uniqueness of a Breg study in cancer to warn potential pitfalls. PMID:25015287

  17. Inferring processes underlying B-cell repertoire diversity

    PubMed Central

    Elhanati, Yuval; Sethna, Zachary; Marcou, Quentin; Callan, Curtis G.; Mora, Thierry; Walczak, Aleksandra M.

    2015-01-01

    We quantify the VDJ recombination and somatic hypermutation processes in human B cells using probabilistic inference methods on high-throughput DNA sequence repertoires of human B-cell receptor heavy chains. Our analysis captures the statistical properties of the naive repertoire, first after its initial generation via VDJ recombination and then after selection for functionality. We also infer statistical properties of the somatic hypermutation machinery (exclusive of subsequent effects of selection). Our main results are the following: the B-cell repertoire is substantially more diverse than T-cell repertoires, owing to longer junctional insertions; sequences that pass initial selection are distinguished by having a higher probability of being generated in a VDJ recombination event; somatic hypermutations have a non-uniform distribution along the V gene that is well explained by an independent site model for the sequence context around the hypermutation site. PMID:26194757

  18. 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

  19. Prognostic value of immunohistochemical classification of diffuse large B-cell lymphoma into germinal center B-cell and non-germinal center B-cell subtypes.

    PubMed

    Saad, Abeer A; Awed, Nahla M; Abdel-Hafeez, Zeinab M; Kamal, Gihan M; Elsallaly, Hala M; Alloub, Amal I

    2010-02-01

    To study the expression of germinal center B-cell (GCB)/activated B-cell like-related proteins to get optimal stratification of diffuse large B-cell lymphoma (DLBCL) patients, and correlate this with the established clinical and laboratory parameters. This study was conducted retrospectively on 30 archival paraffin tissue blocks of DLBCL. All patients were diagnosed between April 2004 and January 2007 at Ain Shams University Hospital and National Cancer Institute, Cairo, Egypt. All patients received anthracycline-based regimens, and none of them received rituximab immunotherapy. Each case included in this study was investigated by immunohistochemical reaction for multiple myeloma-1/interferon regulatory factor-4, B-cell/lymphoma 6, and cluster of differentiation10 monoclonal antibodies. Patients were classified as GCB group (17 patients) and non-GCB group (13 patients). We found a statistically significant association between non-GCB phenotype and performance status (PS) more than 1, high lactate dehydrogenase (LDH) level, advanced international prognostic index (IPI), and poor patient outcome. Non-GCB phenotype, high LDH level, and PS more than 1 were all associated with increased mortality risk. The median survival time was 46.9 months in group A compared to 19.6 months in group B (hazard ratio[HR]=3.30; 95% confidence interval [CI]=0.52-21.10). Using multivariate Cox regression analysis, non-GCB phenotype was found to be the most predicting factor (HR=6.07; 95% CI=1.6-22.9; p=0.008). The subclassification of DLBCL into GCB and non-GCB groups using immunohistochemistry may be useful for identifying those patients whose prognosis is so poor that more aggressive therapy can be given at the time of diagnosis.

  20. A defined metabolic state in pre B cells governs B-cell development and is counterbalanced by Swiprosin-2/EFhd1.

    PubMed

    Stein, Merle; Dütting, Sebastian; Mougiakakos, Dimitrios; Bösl, Michael; Fritsch, Kristin; Reimer, Dorothea; Urbanczyk, Sophia; Steinmetz, Tobit; Schuh, Wolfgang; Bozec, Aline; Winkler, Thomas H; Jäck, Hans-Martin; Mielenz, Dirk

    2017-07-01

    B-cell development in the bone marrow comprises proliferative and resting phases in different niches. We asked whether B-cell metabolism relates to these changes. Compared to pro B and small pre B cells, large pre B cells revealed the highest glucose uptake and ROS but not mitochondrial mass, whereas small pre B cells exhibited the lowest mitochondrial membrane potential. Small pre B cells from Rag1(-/-);33.C9 μ heavy chain knock-in mice revealed decreased glycolysis (ECAR) and mitochondrial spare capacity compared to pro B cells from Rag1(-/-) mice. We were interested in the step regulating this metabolic switch from pro to pre B cells and uncovered that Swiprosin-2/EFhd1, a Ca(2+)-binding protein of the inner mitochondrial membrane involved in Ca(2+)-induced mitoflashes, is expressed in pro B cells, but downregulated by surface pre B-cell receptor expression. Knockdown and knockout of EFhd1 in 38B9 pro B cells decreased the oxidative phosphorylation/glycolysis (OCR/ECAR) ratio by increasing glycolysis, glycolytic capacity and reserve. Prolonged expression of EFhd1 in EFhd1 transgenic mice beyond the pro B cell stage increased expression of the mitochondrial co-activator PGC-1α in primary pre B cells, but reduced mitochondrial ATP production at the pro to pre B cell transition in IL-7 cultures. Transgenic EFhd1 expression caused a B-cell intrinsic developmental disadvantage for pro and pre B cells. Hence, coordinated expression of EFhd1 in pro B cells and by the pre BCR regulates metabolic changes and pro/pre B-cell development.

  1. 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

  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. 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.

  4. Successful differentiation to T cells, but unsuccessful B-cell generation, from B-cell-derived induced pluripotent stem cells.

    PubMed

    Wada, Haruka; Kojo, Satoshi; Kusama, Chie; Okamoto, Naoki; Sato, Yorino; Ishizuka, Bunpei; Seino, Ken-ichiro

    2011-01-01

    Forced expression of certain transcription factors in somatic cells results in generation of induced pluripotent stem (iPS) cells, which differentiate into various cell types. We investigated T-cell and B-cell lineage differentiation from iPS cells in vitro. To evaluate the impact of iPS cell source, murine splenic B-cell-derived iPS (B-iPS) cells were generated after retroviral transduction of four transcription factors (Oct4, Sox2, Klf4 and c-Myc). B-iPS cells were identical to embryonic stem (ES) cells and mouse embryonic fibroblast (MEF)-derived iPS cells in morphology, ES cell marker expression as well as teratoma and chimera mouse formation. Both B-iPS and MEF-derived iPS cells differentiated into lymphocytes in OP9 co-culture systems. Both efficiently differentiated into T-cell lineage that produced IFN-γ on T-cell receptor stimulation. However, iPS cells including B-iPS cells were relatively resistant to B-cell lineage differentiation. One of the reasons of the failure of B-cell lineage differentiation seemed due to a defect of Pax5 expression in the differentiated cells. Therefore, current in vitro differentiation systems using iPS cells are sufficient for inducing T-cell but not B-cell lineage.

  5. 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.

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

    PubMed Central

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

    2017-01-01

    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. PMID:27974642

  7. Targeting Bruton's tyrosine kinase in B cell malignancies.

    PubMed

    Hendriks, Rudi W; Yuvaraj, Saravanan; Kil, Laurens P

    2014-04-01

    Bruton's tyrosine kinase (BTK) is a key component of B cell receptor (BCR) signalling and functions as an important regulator of cell proliferation and cell survival in various B cell malignancies. Small-molecule inhibitors of BTK have shown antitumour activity in animal models and, recently, in clinical studies. High response rates were reported in patients with chronic lymphocytic leukaemia and mantle cell lymphoma. Remarkably, BTK inhibitors have molecular effects that cannot be explained by the classic role of BTK in BCR signalling. In this Review, we highlight the importance of BTK in various signalling pathways in the context of its therapeutic inhibition.

  8. 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. PMID:28400634

  9. 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.

  10. 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.

  11. 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

  12. A Gammaherpesvirus Bcl-2 Ortholog Blocks B Cell Receptor-Mediated Apoptosis and Promotes the Survival of Developing B Cells In Vivo

    PubMed Central

    Coleman, Carrie B.; McGraw, Jennifer E.; Feldman, Emily R.; Roth, Alexa N.; Keyes, Lisa R.; Grau, Katrina R.; Cochran, Stephanie L.; Waldschmidt, Thomas J.; Liang, Chengyu; Forrest, J. Craig; Tibbetts, Scott A.

    2014-01-01

    Gammaherpesviruses such as Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV, HHV-8) establish lifelong latency in their hosts and are associated with the development of several types of malignancies, including a subset of B cell lymphomas. These viruses are thought to co-opt the process of B cell differentiation to latently infect a fraction of circulating memory B cells, resulting in the establishment of a stable latency setpoint. However, little is known about how this infected memory B cell compartment is maintained throughout the life of the host. We have previously demonstrated that immature and transitional B cells are long-term latency reservoirs for murine gammaherpesvirus 68 (MHV68), suggesting that infection of developing B cells contributes to the maintenance of lifelong latency. During hematopoiesis, immature and transitional B cells are subject to B cell receptor (BCR)-mediated negative selection, which results in the clonal deletion of autoreactive B cells. Interestingly, numerous gammaherpesviruses encode homologs of the anti-apoptotic protein Bcl-2, suggesting that virus inhibition of apoptosis could subvert clonal deletion. To test this, we quantified latency establishment in mice inoculated with MHV68 vBcl-2 mutants. vBcl-2 mutant viruses displayed a marked decrease in the frequency of immature and transitional B cells harboring viral genome, but this attenuation could be rescued by increased host Bcl-2 expression. Conversely, vBcl-2 mutant virus latency in early B cells and mature B cells, which are not targets of negative selection, was remarkably similar to wild-type virus. Finally, in vivo depletion of developing B cells during chronic infection resulted in decreased mature B cell latency, demonstrating a key role for developing B cells in the maintenance of lifelong latency. Collectively, these findings support a model in which gammaherpesvirus latency in circulating mature B cells is sustained in part through the

  13. 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

  14. B-Cell Gene Therapy for Tolerance Induction: Host but Not Donor B-Cell Derived IL-10 is Necessary for Tolerance

    PubMed Central

    Su, Yan; Zhang, Ai-Hong; Noben-Trauth, Nancy; Scott, David W.

    2011-01-01

    Genetically modified B cells are excellent tolerogenic antigen-presenting cells (APCs) in multiple models of autoimmunity. However, the mechanisms of action are still not completely understood. In our models, we generate antigen-specific tolerogenic B cells by transducing naïve or primed B cells with an antigen–immunoglobulin G (peptide–IgG) construct. In order to be transduced, B cells require activation with mitogens such as LPS. We and others have found that LPS stimulation of B cells upregulates the production of IL-10, a key cytokine for maintaining immune tolerance. In the current study, we defined the role of B-cell produced IL-10 in tolerance induction by using IL-10 deficient B cells as donor APCs. We found that peptide–IgG transduced IL-10 KO B cells have the same effects as wt B cells in tolerance induction in an experimental autoimmune encephalomyelitis model. Moreover, we demonstrated that the tolerogenic effect of peptide–IgG B cells was completely abrogated in anti-IL-10 receptor antibody treated recipients. Taken together, our results suggest that tolerance induced by peptide–IgG B-cell gene therapy requires IL-10 from the host but not donor B cells. These data shed important insights into the mechanisms of tolerance induction mediated by B-cell gene therapy. PMID:21811487

  15. 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

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

    PubMed

    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.

  17. 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.

  18. PERSUADING NATURAL KILLER CELLS TO ELIMINATE BAD B CELLS

    PubMed Central

    Cooper, Laurence J.N.

    2009-01-01

    Summary Clinical trials are underway infusing T cells genetically modified to be specific for B-cell malignancies using a chimeric antigen receptor (CAR) to redirect specificity for CD19. However, issues remain regarding whether the CAR can provide a fully-competent application signal and whether other lymphocytes with lytic capacity can target CD19+ tumors. PMID:19638468

  19. 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).

  20. Lymphoma classification update: B-cell non-Hodgkin lymphomas.

    PubMed

    Jiang, Manli; Bennani, N Nora; Feldman, Andrew L

    2017-05-01

    Lymphomas are classified based on the normal counterpart, or cell of origin, from which they arise. Because lymphocytes have physiologic immune functions that vary both by lineage and by stage of differentiation, the classification of lymphomas arising from these normal lymphoid populations is complex. Recent genomic data have contributed additional complexity. Areas covered: Lymphoma classification follows the World Health Organization (WHO) system, which reflects international consensus and is based on pathological, genetic, and clinical factors. A 2016 revision to the WHO classification of lymphoid neoplasms recently was reported. The present review focuses on B-cell non-Hodgkin lymphomas, the most common group of lymphomas, and summarizes recent changes most relevant to hematologists and other clinicians who care for lymphoma patients. Expert commentary: Lymphoma classification is a continually evolving field that needs to be responsive to new clinical, pathological, and molecular understanding of lymphoid neoplasia. Among the entities covered in this review, the 2016 revision of the WHO classification particularly impact the subclassification and genetic stratification of diffuse large B-cell lymphoma and high-grade B-cell lymphomas, and reflect evolving criteria and nomenclature for indolent B-cell lymphomas and lymphoproliferative disorders.

  1. 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.

  2. 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

  3. 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

  4. Signals that drive T-bet expression in B cells.

    PubMed

    Myles, Arpita; Gearhart, Patricia J; Cancro, Michael P

    2017-09-11

    Transcription factors regulate various developmental and functional aspects of B cells. T-bet is a recently appreciated transcription factor associated with "Age-associated B cells" or ABCs, the development of autoimmunity, and viral infections. T-bet expression is favored by nucleic acid-containing antigens and immune complexes and is regulated by interplay between various cytokines, notably, the TFH cytokines IL-21, IL-4 and IFNγ. Adaptive signals by themselves cannot upregulate T-bet; however, they have a synergistic effect on induction of T-bet by innate receptors. The functional role of T-bet+ B cells is unclear, although it is known that T-bet promotes class switching to IgG2a/c. It is likely T-bet serves dichotomous roles in B cells, promoting pathogenic autoreactive antibodies on one hand but mediating microbial immunity on the other, making it a target of interest in both therapeutic and prophylactic settings. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. 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

  6. 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

  7. Monoclonal B cell lymphocytosis in hepatitis C virus infected individuals.

    PubMed

    Fazi, Claudia; Dagklis, Antonis; Cottini, Francesca; Scarfò, Lydia; Bertilaccio, Maria Teresa Sabrina; Finazzi, Renato; Memoli, Massimo; Ghia, Paolo

    2010-01-01

    Monoclonal B cell lymphocytosis (MBL) is a preclinical condition characterized by an expansion of clonal B cells in the absence of B lymphocytosis (BALC < 5 × 10(9)/L) in the peripheral blood, without clinical signs, suggestive of a lymphoproliferative disorder. B cell clonal expansions are also associated with hepatitis C virus (HCV) infection and they can evolve into lymphoproliferative disorders such as mixed cryoglobulinemia and non-Hodgkin lymphomas (NHL). The relationship between MBL and HCV infection has not been established yet. By five-colour flow cytometry, we analyzed 123 HCV positive subjects with diagnosis of chronic hepatitis (94) or cirrhosis (29); 16 of those with cirrhosis had a diagnosis of hepatocellular carcinoma. MBL were identified in 35/123 (28.5%), at significantly higher frequency than in the general population. Sixteen/thirty-five were atypical-chronic lymphocytic leukemia (CLL) MBL (CD5(+), CD20(bright)), 13/35 were CLL-like MBL (CD5(bright), CD20(dim)), and 6/35 were CD5(-) MBL. Twenty-four/ninety-four (25.5%) patients affected by chronic hepatitis had MBL, whereas 11/29 (37.9%) patients with cirrhosis showed a B cell clone. A biased usage of IGHVgenes similar to HCV-associated NHL was evident. All three types of MBL can be identified in HCV-infected individuals at a higher frequency than in the general population, and their presence appears to correlate with a more advanced disease stage. The phenotypic heterogeneity is reminiscent of the diversity of NHL arising in the context of HCV infection. The persistence of HCV may be responsible for the dysregulation of the immune system and in particular of the B cell compartment. © 2010 International Clinical Cytometry Society.

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

    PubMed

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

    2015-08-01

    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. Copyright © 2015 The Authors.

  9. 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

  10. 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.

  11. 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

  12. ICAMs support B cell interactions with T follicular helper cells and promote clonal selection.

    PubMed

    Zaretsky, Irina; Atrakchi, Ofir; Mazor, Roei D; Stoler-Barak, Liat; Biram, Adi; Feigelson, Sara W; Gitlin, Alexander D; Engelhardt, Britta; Shulman, Ziv

    2017-09-22

    The germinal center (GC) reaction begins with a diverse and expanded group of B cell clones bearing a wide range of antibody affinities. During GC colonization, B cells engage in long-lasting interactions with T follicular helper (Tfh) cells, a process that depends on antigen uptake and antigen presentation to the Tfh cells. How long-lasting T-B interactions and B cell clonal expansion are regulated by antigen presentation remains unclear. Here, we use in vivo B cell competition models and intravital imaging to examine the adhesive mechanisms governing B cell selection for GC colonization. We find that intercellular adhesion molecule 1 (ICAM-1) and ICAM-2 on B cells are essential for long-lasting cognate Tfh-B cell interactions and efficient selection of low-affinity B cell clones for proliferative clonal expansion. Thus, B cell ICAMs promote efficient antibody immune response by enhancement of T cell help to cognate B cells. © 2017 Zaretsky et al.

  13. 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.

  14. 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

  15. 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.

  16. Diffuse large B-cell lymphoma classification system that associates normal B-cell subset phenotypes with prognosis.

    PubMed

    Dybkær, Karen; Bøgsted, Martin; Falgreen, Steffen; Bødker, Julie S; Kjeldsen, Malene K; Schmitz, Alexander; Bilgrau, Anders E; Xu-Monette, Zijun Y; Li, Ling; Bergkvist, Kim S; Laursen, Maria B; Rodrigo-Domingo, Maria; Marques, Sara C; Rasmussen, Sophie B; Nyegaard, Mette; Gaihede, Michael; Møller, Michael B; Samworth, Richard J; Shah, Rajen D; Johansen, Preben; El-Galaly, Tarec C; Young, Ken H; Johnsen, Hans E

    2015-04-20

    Current diagnostic tests for diffuse large B-cell lymphoma use the updated WHO criteria based on biologic, morphologic, and clinical heterogeneity. We propose a refined classification system based on subset-specific B-cell-associated gene signatures (BAGS) in the normal B-cell hierarchy, hypothesizing that it can provide new biologic insight and diagnostic and prognostic value. We combined fluorescence-activated cell sorting, gene expression profiling, and statistical modeling to generate BAGS for naive, centrocyte, centroblast, memory, and plasmablast B cells from normal human tonsils. The impact of BAGS-assigned subtyping was analyzed using five clinical cohorts (treated with cyclophosphamide, doxorubicin, vincristine, and prednisone [CHOP], n = 270; treated with rituximab plus CHOP [R-CHOP], n = 869) gathered across geographic regions, time eras, and sampling methods. The analysis estimated subtype frequencies and drug-specific resistance and included a prognostic meta-analysis of patients treated with first-line R-CHOP therapy. Similar BAGS subtype frequencies were assigned across 1,139 samples from five different cohorts. Among R-CHOP-treated patients, BAGS assignment was significantly associated with overall survival and progression-free survival within the germinal center B-cell-like subclass; the centrocyte subtype had a superior prognosis compared with the centroblast subtype. In agreement with the observed therapeutic outcome, centrocyte subtypes were estimated as being less resistant than the centroblast subtype to doxorubicin and vincristine. The centroblast subtype had a complex genotype, whereas the centrocyte subtype had high TP53 mutation and insertion/deletion frequencies and expressed LMO2, CD58, and stromal-1-signature and major histocompatibility complex class II-signature genes, which are known to have a positive impact on prognosis. Further development of a diagnostic platform using BAGS-assigned subtypes may allow pathogenetic studies to

  17. The B Cell Antigen Receptor and Overexpression of MYC Can Cooperate in the Genesis of B Cell Lymphomas

    PubMed Central

    Refaeli, Yosef; Young, Ryan M; Turner, Brian C; Duda, Jennifer; Field, Kenneth A; Bishop, J. Michael

    2008-01-01

    A variety of circumstantial evidence from humans has implicated the B cell antigen receptor (BCR) in the genesis of B cell lymphomas. We generated mouse models designed to test this possibility directly, and we found that both the constitutive and antigen-stimulated state of a clonal BCR affected the rate and outcome of lymphomagenesis initiated by the proto-oncogene MYC. The tumors that arose in the presence of constitutive BCR differed from those initiated by MYC alone and resembled chronic B cell lymphocytic leukemia/lymphoma (B-CLL), whereas those that arose in response to antigen stimulation resembled large B-cell lymphomas, particularly Burkitt lymphoma (BL). We linked the genesis of the BL-like tumors to antigen stimulus in three ways. First, in reconstruction experiments, stimulation of B cells by an autoantigen in the presence of overexpressed MYC gave rise to BL-like tumors that were, in turn, dependent on both MYC and the antigen for survival and proliferation. Second, genetic disruption of the pathway that mediates signaling from the BCR promptly killed cells of the BL-like tumors as well as the tumors resembling B-CLL. And third, growth of the murine BL could be inhibited by any of three distinctive immunosuppressants, in accord with the dependence of the tumors on antigen-induced signaling. Together, our results provide direct evidence that antigenic stimulation can participate in lymphomagenesis, point to a potential role for the constitutive BCR as well, and sustain the view that the constitutive BCR gives rise to signals different from those elicited by antigen. The mouse models described here should be useful in exploring further the pathogenesis of lymphomas, and in preclinical testing of new therapeutics. PMID:18578569

  18. The microRNA-212/132 cluster regulates B cell development by targeting Sox4

    PubMed Central

    Mehta, Arnav; Mann, Mati; Zhao, Jimmy L.; Marinov, Georgi K.; Majumdar, Devdoot; Garcia-Flores, Yvette; Du, Xiaomi; Erikci, Erdem; Chowdhury, Kamal

    2015-01-01

    MicroRNAs have emerged as key regulators of B cell fate decisions and immune function. Deregulation of several microRNAs in B cells leads to the development of autoimmune disease and cancer in mice. We demonstrate that the microRNA-212/132 cluster (miR-212/132) is induced in B cells in response to B cell receptor signaling. Enforced expression of miR-132 results in a block in early B cell development at the prepro–B cell to pro–B cell transition and induces apoptosis in primary bone marrow B cells. Importantly, loss of miR-212/132 results in accelerated B cell recovery after antibody-mediated B cell depletion. We find that Sox4 is a target of miR-132 in B cells. Co-expression of SOX4 with miR-132 rescues the defect in B cell development from overexpression of miR-132 alone, thus suggesting that miR-132 may regulate B lymphopoiesis through Sox4. In addition, we show that the expression of miR-132 can inhibit cancer development in cells that are prone to B cell cancers, such as B cells expressing the c-Myc oncogene. We have thus uncovered miR-132 as a novel contributor to B cell development. PMID:26371188

  19. Memory in the B-cell compartment: antibody affinity maturation.

    PubMed Central

    Neuberger, M S; Ehrenstein, M R; Rada, C; Sale, J; Batista, F D; Williams, G; Milstein, C

    2000-01-01

    In the humoral arm of the immune system, the memory response is not only more quickly elicited and of greater magnitude than the primary response, but it is also different in quality. In the recall response to antigen, the antibodies produced are of higher affinity and of different isotype (typically immunoglobulin G rather than immunoglobulin M). This maturation rests on the antigen dependence of B-cell maturation and is effected by programmed genetic modifications of the immunoglobulin gene loci. Here we consider how the B-cell response to antigen depends on the affinity of the antigen receptor interaction. We also compare and draw parallels between the two processes, which underpin the generation of secondary-response antibodies: V gene somatic hypermutation and immunoglobulin heavy-chain class switching. PMID:10794054

  20. 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

  1. 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

  2. 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;

  3. B cell autoimmunity and bone damage in rheumatoid arthritis.

    PubMed

    Bugatti, S; Bogliolo, L; Montecucco, C; Manzo, A

    2016-12-16

    Rheumatoid arthritis (RA) is a chronic immune-inflammatory disease associated with significant bone damage. Pathological bone remodeling in RA is primarily driven by persistent inflammation. Indeed, pro-inflammatory cytokines stimulate the differentiation of bone-resorbing osteoclasts and, in parallel, suppress osteoblast function, resulting in net loss of bone. Abating disease activity thus remains the major goal of any treatment strategy in patients with RA. Autoantibody-positive patients, however, often show a rapidly progressive destructive course of the disease, disproportionate to the level of inflammation. The epidemiological association between RA-specific autoantibodies, in particular anti-citrullinated protein autoantibodies, and poor structural outcomes has recently found mechanistic explanation in the multiple roles that B cells play in bone remodeling. In this review, we will summarize the substantial progress that has been made in deciphering how B cells and autoantibodies negatively impact on bone in the course of RA, through both inflammation-dependent and independent mechanisms.

  4. 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

  5. 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.

  6. Monoclonal B-cell lymphocytosis and chronic lymphocytic leukemia.

    PubMed

    Rawstron, Andy C; Bennett, Fiona L; O'Connor, Sheila J M; Kwok, Marwan; Fenton, James A L; Plummer, Marieth; de Tute, Ruth; Owen, Roger G; Richards, Stephen J; Jack, Andrew S; Hillmen, Peter

    2008-08-07

    A diagnosis of chronic lymphocytic leukemia (CLL) requires a count of over 5000 circulating CLL-phenotype cells per cubic millimeter. Asymptomatic persons with fewer CLL-phenotype cells have monoclonal B-cell lymphocytosis (MBL). The goal of this study was to investigate the relation between MBL and CLL. We investigated 1520 subjects who were 62 to 80 years of age with a normal blood count and 2228 subjects with lymphocytosis (>4000 lymphocytes per cubic millimeter) for the presence of MBL, using flow cytometry. Monoclonal B cells were further characterized by means of cytogenetic and molecular analyses. A representative cohort of 185 subjects with CLL-phenotype MBL and lymphocytosis were monitored for a median of 6.7 years (range, 0.2 to 11.8). Monoclonal CLL-phenotype B cells were detected in 5.1% of subjects (78 of 1520) with a normal blood count and 13.9% (309 of 2228) with lymphocytosis. CLL-phenotype MBL had a frequency of 13q14 deletion and trisomy 12 similar to that of CLL and showed a skewed repertoire of the immunoglobulin heavy variable group (IGHV) genes. Among 185 subjects presenting with lymphocytosis, progressive lymphocytosis occurred in 51 (28%), progressive CLL developed in 28 (15%), and chemotherapy was required in 13 (7%). The absolute B-cell count was the only independent prognostic factor associated with progressive lymphocytosis. During follow-up over a median of 6.7 years, 34% of subjects (62 of 185) died, but only 4 of these deaths were due to CLL. Age above 68 years and hemoglobin level below 12.5 g per deciliter were the only independent prognostic factors for death. The CLL-phenotype cells found in the general population and in subjects with lymphocytosis have features in common with CLL cells. CLL requiring treatment develops in subjects with CLL-phenotype MBL and with lymphocytosis at the rate of 1.1% per year. 2008 Massachusetts Medical Society

  7. 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

  8. Precision Medicine for Diffuse Large B-cell Lymphoma.

    PubMed

    Lim, Megan S; Elenitoba-Johnson, Kojo S J

    2016-06-15

    This study demonstrates the clinical utility of a targeted gene sequencing panel "the Lymphopanel," which enables the detection of actionable mutations and subtype-enriched gene alterations in diffuse large B-cell lymphoma that will pave the way to precision therapy era for patients with this form of aggressive lymphoma. Clin Cancer Res; 22(12); 2829-31. ©2016 AACRSee related article by Dubois et al., p. 2919. ©2016 American Association for Cancer Research.

  9. 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.

  10. Early alterations of B cells in patients with septic shock

    PubMed Central

    2013-01-01

    Introduction It has recently been proposed that B lymphocytes are involved in sepsis pathogenesis. The goal of this study is to investigate potential abnormalities in a subset distribution and activation of circulating B lymphocytes in patients with septic shock. Methods This observational prospective study was conducted in a medical-surgical ICU. All patients with septic shock were eligible for inclusion. B-cell phenotypes (CD19+CD69+, CD19+CD23+, CD19+CD5+, CD19+CD80, CD19+CD86+, CD19+CD40 and CD19+CD95+) were assessed by quantitative flow cytometry upon admission to the ICU and 3, 7, 14 and 28 d later. Results Fifty-two patients were included. Thirty-six healthy volunteers matched for age and sex were used as controls. The patients had lymphopenia that was maintained during 28 d of follow-up. In patients with septic shock who died, the percentage of CD19+CD23+ was lower during the 7 d of follow-up than it was in survival patients. Moreover, the percentage of CD80+ and CD95+ expression on B cells was higher in patients who died than in survivors. Receiver operating characteristic curve analysis showed that a CD19+CD23+ value of 64.6% at ICU admission enabled discrimination between survivors and nonsurvivors with a sensitivity of 90.9% and a specificity of 80.0% (P = 0.0001). Conclusions Patients with septic shock who survive and those who don't have different patterns of abnormalities in circulating B lymphocytes. At ICU admission, a low percentage of CD23+ and a high of CD80+ and CD95+ on B cells were associated with increased mortality of patients with septic shock. Moreover, a drop in circulating B cells persisted during 28 d of ICU follow-up. PMID:23721745

  11. A Brake for B Cell Proliferation: Appropriate responses to metabolic stress are crucial to maintain B cell viability and prevent malignant outgrowth.

    PubMed

    Jellusova, Julia; Rickert, Robert C

    2017-09-29

    B cell activation is accompanied by metabolic adaptations to meet the increased energetic demands of proliferation. The metabolic composition of the microenvironment is known to change during a germinal center response, in inflamed tissue and to vary significantly between different organs. To sustain cellular homeostasis B cells need to be able to dynamically adapt to changes in their environment. An inability to take up and process available nutrients can result in impaired B cell growth and a diminished humoral immune response. Furthermore, the metabolic microenvironment can affect B cell signaling and provide a means to avoid aberrant proliferation or modulate B cell function. Thus, a better understanding of the intricate interplay between cell signaling and metabolism could provide novel insight into how B cell function is regulated and have implications for the development of vaccines or treatment of autoimmune disorders and B cell derived malignancies. © 2017 WILEY Periodicals, Inc.

  12. 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

  13. 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.

  14. Evolution of B cell analysis and Env trimer redesign.

    PubMed

    Karlsson Hedestam, Gunilla B; Guenaga, Javier; Corcoran, Martin; Wyatt, Richard T

    2017-01-01

    HIV-1 and its surface envelope glycoproteins (Env), gp120 and gp41, have evolved immune evasion strategies that render the elicitation of effective antibody responses to the functional Env entry unit extremely difficult. HIV-1 establishes chronic infection and stimulates vigorous immune responses in the human host; forcing selection of viral variants that escape cellular and antibody (Ab)-mediated immune pressure, yet possess contemporary fitness. Successful survival of fit variants through the gauntlet of the human immune system make this virus and these glycoproteins a formidable challenge to target by vaccination, requiring a systematic approach to Env mimetic immunogen design and evaluation of elicited responses. Here, we review key aspects of HIV-1 Env immunogenicity and immunogen re-design, based on experimental data generated by us and others over the past decade or more. We further provide rationale and details regarding the use of newly evolving tools to analyze B cell responses, including approaches to use next generation sequencing for antibody lineage tracing and B cell fate mapping. Together, these developments offer opportunities to address long-standing questions about the establishment of effective B cell immunity elicited by vaccination, not just against HIV-1. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. B-cell-depleting Therapy in Systemic Lupus Erythematosus

    PubMed Central

    Ramos-Casals, Manuel; Sanz, Iñaki; Bosch, Xavier; Stone, John H.; Khamashta, Munther A.

    2014-01-01

    The emergence of a new class of agents (B-cell-depleting therapies) has opened a new era in the therapeutic approach to systemic lupus erythematosus, with belimumab being the first drug licensed for use in systemic lupus erythematosus in more than 50 years. Four agents deserve specific mention: rituximab, ocrelizumab, epratuzumab, and belimumab. Controlled trials have shown negative results for rituximab, promising results for epratuzumab, and positive results for belimumab. Despite these negative results, rituximab is the most-used agent in patients who do not respond or are intolerant to standard therapy and those with life-threatening presentations. B-cell-depleting agents should not be used in patients with mild disease and should be tailored according to individual patient characteristics, including ethnicity, organ involvement, and the immunological profile. Forthcoming studies of B-cell-directed strategies, particularly data from investigations of off-label rituximab use and postmarketing studies of belimumab, will provide new insights into the utility of these treatments in the routine management of patients with systemic lupus erythematosus. PMID:22444096

  16. Practical guidelines for B-cell receptor repertoire sequencing analysis.

    PubMed

    Yaari, Gur; Kleinstein, Steven H

    2015-11-20

    High-throughput sequencing of B-cell immunoglobulin repertoires is increasingly being applied to gain insights into the adaptive immune response in healthy individuals and in those with a wide range of diseases. Recent applications include the study of autoimmunity, infection, allergy, cancer and aging. As sequencing technologies continue to improve, these repertoire sequencing experiments are producing ever larger datasets, with tens- to hundreds-of-millions of sequences. These data require specialized bioinformatics pipelines to be analyzed effectively. Numerous methods and tools have been developed to handle different steps of the analysis, and integrated software suites have recently been made available. However, the field has yet to converge on a standard pipeline for data processing and analysis. Common file formats for data sharing are also lacking. Here we provide a set of practical guidelines for B-cell receptor repertoire sequencing analysis, starting from raw sequencing reads and proceeding through pre-processing, determination of population structure, and analysis of repertoire properties. These include methods for unique molecular identifiers and sequencing error correction, V(D)J assignment and detection of novel alleles, clonal assignment, lineage tree construction, somatic hypermutation modeling, selection analysis, and analysis of stereotyped or convergent responses. The guidelines presented here highlight the major steps involved in the analysis of B-cell repertoire sequencing data, along with recommendations on how to avoid common pitfalls.

  17. Genetics and diffuse large B-Cell lymphoma.

    PubMed

    Niroula, Rabin; Butera, James

    2015-11-02

    Diffuse large B-Cell lymphoma (DLBCL) is one of the most common and aggressive subtypes of non-Hodgkin's lymphoma (NHL). Gene expression profiling (GEP) studies have identified at least two distinct molecular subtypes of DLBCL termed as germinal center B-cell (GCB) and activated B-cell (ABC). These molecular subtypes represent lymphomas that are driven by very different intracellular oncogenic signaling pathways which have prognostic value and could potentially be exploited for therapeutic benefit in future. There are other oncogenes, namely BCL-2, BCL-6 and MYC, which have been associated with the pathogenesis of DLBCL. Concurrent presence of two oncogenes is present in about 5% of DLBCL and it is termed "double hit lymphoma" (DHL). DHL are associated with an aggressive clinical course and do not respond well to the standard DLBCL immune-chemotherapy regimen, RCHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone). Other aggressive therapeutic approaches including autologous bone marrow transplant have not shown any survival benefit in this subgroup of DLBCL patients. New strategies in development to address this resistance in DHL include the regimen DA-EPOCH-R (dose adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin and rituximab). Recent studies have shown increased sensitivity of DHL to DA-EPOCH-R chemotherapy and will likely be the new standard of care in this subset of DLBCL patients in the future.

  18. Small B cell lymphocytic lymphoma presenting as obstructive sleep apnea.

    PubMed

    Tsou, Yung-An; Cheng, Yuan-Kai; Lin, Chia-Der; Chang, Weng-Cheng; Tsai, Ming-Hsui

    2004-07-29

    Most lymphomas that involve the tonsil are large B cell lymphomas. Large B-cell lymphoma is a high grade malignancy which progresses rapidly. Tonsillar lymphoma usually presents as either a unilaterally enlarged palatine tonsil or as an ulcerative and fungating lesion over the tonsillar area. Small lymphocytic lymphomas (SLL) of the Waldeyer's ring are uncommon. We report a 41-year-old male who presented with a ten-year history of snoring. Physical examination revealed smooth bilateral symmetrically enlarged tonsils without abnormal surface change or cervical lymphadenopathy. Palatal redundancy and a narrowed oropharyngeal airway were also noted. The respiratory disturbance index (RDI) was 66 per hour, and severe obstruction sleep apnea (OSA) was suspected. No B symptoms, sore throat, odynophagia or dysphagia was found. We performed uvulopalatopharyngoplasty (UPPP) and pathological examination revealed incidental small B-cell lymphocytic lymphoma (SLL). It is uncommon for lymphoma to initially present as OSA. SLL is an indolent malignancy and is not easy to detect in the early stage. We conclude that SLL may be a contributing factor of OSA in the present case.

  19. Small B cell lymphocytic lymphoma presenting as obstructive sleep apnea

    PubMed Central

    Tsou, Yung-An; Cheng, Yuan-Kai; Lin, Chia-Der; Chang, Weng-Cheng; Tsai, Ming-Hsui

    2004-01-01

    Background Most lymphomas that involve the tonsil are large B cell lymphomas. Large B-cell lymphoma is a high grade malignancy which progresses rapidly. Tonsillar lymphoma usually presents as either a unilaterally enlarged palatine tonsil or as an ulcerative and fungating lesion over the tonsillar area. Small lymphocytic lymphomas (SLL) of the Waldeyer's ring are uncommon. Case presentation We report a 41-year-old male who presented with a ten-year history of snoring. Physical examination revealed smooth bilateral symmetrically enlarged tonsils without abnormal surface change or cervical lymphadenopathy. Palatal redundancy and a narrowed oropharyngeal airway were also noted. The respiratory disturbance index (RDI) was 66 per hour, and severe obstruction sleep apnea (OSA) was suspected. No B symptoms, sore throat, odynophagia or dysphagia was found. We performed uvulopalatopharyngoplasty (UPPP) and pathological examination revealed incidental small B-cell lymphocytic lymphoma (SLL). Conclusion It is uncommon for lymphoma to initially present as OSA. SLL is an indolent malignancy and is not easy to detect in the early stage. We conclude that SLL may be a contributing factor of OSA in the present case. PMID:15282026

  20. Pancreatic A and B cell hyperfunction in the Mendenhall syndrome.

    PubMed

    Serrano Ríos, M; de la Viña, S; Carbó, M E; Nash, R E; Barrio, R; Heding, L G

    1983-07-01

    A 16-year-old boy with persistent hyperglycaemia (approximately 16 mmol/l in the fasting state) and acanthosis nigricans had insulin resistance and received daily up to 2800 U of short-acting, soluble, highly purified porcine insulin. The number and affinity of insulin receptors were markedly decreased. No significant insulin binding to IgG could be detected. Immunoreactive insulin varied between 1344 and 2400 mU/l. Endogenous insulin secretion and proinsulin levels were grossly elevated in the fasting state (C-peptide 2.2-3.5 pmol/ml; proinsulin approximately 1 pmol/ml). After an oral glucose tolerance test and intravenous arginine infusion, B cell hypersecretion was confirmed. The molar ratio of C-peptide to immunoreactive insulin, normally approximately 7, was about 0.3, clearly indicating that most of the immunoreactive insulin was exogenous. The molar ratio of proinsulin to C-peptide, which is about 0.05 in fasting control subjects, was 0.23-0.45, clearly showing that too high a proportion of proinsulin was being secreted. This may indicate that the constant hyperstimulation of the B cell leads to reduced conversion of proinsulin to insulin. Immunoreactive glucagon levels were within normal limits fasting but were above normal after intravenous arginine infusion. Thus, in this case of diabetes with acanthosis nigricans, the severe insulin resistance, probably caused by a receptor defect, was associated with markedly increased B cell function.

  1. 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

  2. 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.

  3. Is now the time for molecular driven therapy for diffuse large B-cell lymphoma?

    PubMed

    Di Rocco, Alice; De Angelis, Federico; Ansuinelli, Michela; Foà, Robin; Martelli, Maurizio

    2017-09-01

    Recent genetic and molecular discoveries regarding alterations in diffuse large B-cell lymphoma (DLBCL) deeply changed the approach to this lymphoproliferative disorder. Novel additional predictors of outcomes and new therapeutic strategies are being introduced to improve outcomes. Areas covered: This review aims to analyse the recent molecular discoveries in DLBCL, the rationale of novel molecular driven treatments and their impact on DLBCL prognosis, especially in ABC-DLBCL and High Grade B Cell Lymphoma. Pre-clinical and clinical evidences are reviewed to critically evaluate the novel DLBCL management strategies. Expert commentary: New insights in DLBCL molecular characteristics should guide the therapeutic approach; the results of the current studies which are investigating safety and efficacy of novel 'X-RCHOP' will probably lead, in future, to a cell of origin (COO) based upfront therapy. Moreover, it is necessary to identify early patients with DLBCL who carried MYC, BCL2 and/or BCL6 rearrangements double hit lymphomas (DHL) because they should not receive standard R-CHOP but high intensity treatment as reported in many retrospective studies. New prospective trials are needed to investigate the more appropriate treatment of DHL.

  4. Understanding the reconstitution of the B-cell compartment in bone marrow and blood after treatment for B-cell precursor acute lymphoblastic leukaemia.

    PubMed

    Theunissen, Prisca M J; van den Branden, Anouk; Van Der Sluijs-Gelling, Alita; De Haas, Valerie; Beishuizen, Auke; van Dongen, Jacques J M; Van Der Velden, Vincent H J

    2017-07-01

    A better understanding of the reconstitution of the B-cell compartment during and after treatment in B-cell precursor acute lymphoblastic leukaemia (BCP-ALL) will help to assess the immunological status and needs of post-treatment BCP-ALL patients. Using 8-colour flow cytometry and proliferation-assays, we studied the composition and proliferation of both the B-cell precursor (BCP) population in the bone marrow (BM) and mature B-cell population in peripheral blood (PB) during and after BCP-ALL therapy. We found a normal BCP differentiation pattern and a delayed formation of classical CD38(dim) -naive mature B-cells, natural effector B-cells and memory B-cells in patients after chemotherapy. This B-cell differentiation/maturation pattern was strikingly similar to that during initial B-cell development in healthy infants. Tissue-resident plasma cells appeared to be partly protected from chemotherapy. Also, we found that the fast recovery of naive mature B-cell numbers after chemotherapy was the result of increased de novo BCP generation, rather than enhanced B-cell proliferation in BM or PB. These results indicate that post-treatment BCP-ALL patients will eventually re-establish a B-cell compartment with a composition and B-cell receptor repertoire similar to that in healthy children. Additionally, the formation of a new memory B-cell compartment suggests that revaccination might be beneficial after BCP-ALL therapy. © 2017 John Wiley & Sons Ltd.

  5. 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.

  6. H-2 control of expression of an idiotype shared by normal B cells and a B-cell lymphoma.

    PubMed

    Bishop, G A; Haughton, G

    1985-01-01

    The spleens of normal B10.H-2aH-4bp/Wts (2a4b) mice contain cells which, in response to mitogen stimulation, secrete hemolytic antibody specific for a determinant present on both sheep and bromelain-treated mouse erythrocytes. These cells were found to be Ly-1 positive. Approximately 50% of these cells bear surface immunoglobulin (sIg) with the same idiotype as the sIg of a 2a4b-derived B-cell lymphoma, CH12. Backcross analysis revealed H-2 control of the frequency of the idiotype-positive B cell. The regulatory gene did not correlate with the Igh-1 allotype, and analysis of 22 inbred mouse strains mapped the gene to the I-E subregion. Surprisingly, only strains homozygous for Ek alpha expressed the idiotype, and expression was a recessive trait. Possible mechanisms for this control of idiotype expression and its relation to lymphomagenesis are discussed.

  7. TRPM4 expression is associated with activated B cell subtype and poor survival in diffuse large B cell lymphoma.

    PubMed

    Loo, Suet K; Ch'ng, Ewe S; Md Salleh, Md Salzihan; Banham, Alison H; Pedersen, Lars M; Møller, Michael B; Green, Tina M; Wong, Kah K

    2017-07-01

    Transient receptor potential channel melastatin 4 (TRPM4) is an ion channel that regulates influx of calcium cations (Ca(2+) ). Recent studies suggest that TRPM4 is an oncoprotein, and its up-regulated transcript level has been reported in diffuse large B cell lymphoma (DLBCL). We aimed to investigate TRPM4 protein expression pattern in non-malignant tissues and DLBCL cases, and its association with clinico-demographic parameters and survival in DLBCL. Analysis of publicly available DLBCL microarray data sets showed that TRPM4 transcripts were up-regulated in DLBCL compared to normal germinal centre B (GCB) cells, were expressed more highly in the activated B cell-like DLBCL (ABC-DLBCL) subtype and higher TRPM4 transcripts conferred worse overall survival (OS) in R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone)-treated DLBCL cases (P < 0.05). Our immunohistochemical analysis showed that TRPM4 was expressed in various human tissues but not in normal B cells within lymphoid tissues (reactive tonsil, lymph node and appendix). TRPM4 protein was present in 26% (n = 49 of 189) of our cohort of R-CHOP-treated DLBCL cases and this was associated significantly with more aggressive clinical parameters, including higher lactate dehydrogenase (LDH), Eastern Cooperative Oncology Group (ECOG) scores or stage (P < 0.01 for each of the parameters) and the ABC-DLBCL subtype (P = 0.016). TRPM4 positivity conferred significantly worse OS (P = 0.004) and progression-free survival (PFS) (P = 0.005). Worse OS remained associated significantly with TRPM4 positivity in multivariate analysis, including higher International Prognostic Index (IPI) or the non-GCB DLBCL phenotype (P < 0.05). TRPM4 protein expression is up-regulated in DLBCL cases compared to non-malignant B cells with preferential expression in ABC-DLBCL cases, and it confers significantly poorer DLBCL patient outcomes. © 2017 John Wiley & Sons Ltd.

  8. [Prevalence of germinal center B-cell-like and non-germinal center B-cell-like types of diffuse large B-cell lymphoma in Shanghai, China].

    PubMed

    Chen, Yan; Chen, Hui; Fu, Kai; Zhu, Xiong-zeng; Irons, Richard

    2010-05-01

    To study the prevalence of germinal center B-cell-like (GCB) and non-GCB-like types of diffuse large B-cell lymphoma (DLBCL) in Chinese patients. Immunohistochemical study for CD10, bcl-6, MUM1, GCET1 and FOXP1 was performed on 124 cases of DLBCL from Shanghai, China. The Hans algorithm and Choi algorithm were applied to classify DLBCL into GCB and non-GCB-like types. Fluorescence in-situ hybridization (FISH) for t (14;18) and bcl-6 gene rearrangement was also carried out on 118 cases. Of the 124 DLBCL cases studied, 27 cases (22%) showed a GCB-like type and 97 cases (78%) showed a non-GCB-like type, when using Hans algorithm. On the other hand, 34 cases (27%) belonged to GCB-like type and 90 cases (73%) belonged to non-GCB-like type when applying Choi algorithm. The prevalence of GCB-like type was significantly lower than that of non-GCB-like type (P=0.0001). Only four cases (3%) were positive for t (14;18), and three of them were classified as GCB-like type. bcl-6 rearrangement was found in 46 cases (39%) and more frequently encountered in the GCB-like type. There is no relationship between bcl-6 gene rearrangement and bcl-6 protein expression. The GCB-like type of DLBCL is significantly less common than non-GCB-like type in Chinese population. This phenomenon is possibly related to the low frequency of t (14;18).

  9. 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.

  10. Imprinting the Fate of Antigen-Reactive B Cells through the Affinity of the B Cell Receptor

    PubMed Central

    O'Connor, Brian P.; Vogel, Laura A.; Zhang, Weijun; Loo, William; Shnider, Danielle; Lind, Evan F.; Ratliff, Michelle; Noelle, Randolph J.; Erickson, Loren D.

    2010-01-01

    Long-lived plasma cells (PCs) and memory B cells (Bmem) constitute the cellular components of enduring humoral immunity, whereas short-lived PCs that rapidly produce Ig correspond to the host's need for immediate protection against pathogens. In this study we show that the innate affinity of the BCR for Ag imprints upon naive B cells their differentiation fate to become short-or long-lived PCs and Bmem. Using BCR transgenic mice with varying affinities for Ag, naive B cells with high affinity lose their capacity to form germinal centers (GCs), develop neither Bmem nor long-lived PCs, and are destined to a short-lived PC fate. Moderate affinity interactions result in hastened GC responses, and differentiation to long-lived PCs, but Bmem remain extinct. In contrast, lower affinity interactions show tempered GCs, producing Bmem and affinity-matured, long-lived PCs. Thus, a continuum of elementary to comprehensive humoral immune responses exists that is controlled by inherent BCR affinity. PMID:17114443

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 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

  18. Targeting of CD22-positive B-cell lymphoma cells by synthetic divalent sialic acid analogues.

    PubMed

    Schweizer, Astrid; Wöhner, Miriam; Prescher, Horst; Brossmer, Reinhard; Nitschke, Lars

    2012-10-01

    CD22 is an inhibitory co-receptor of the B-cell receptor (BCR) on B cells. Since CD22 is ubiquitously expressed in the B-cell lineage and CD22 endocytosis can be triggered efficiently, antibodies and antibody-based immunotoxins against CD22 are used to target B cells both in B-cell lymphomas and leukemias, as well as in autoimmune diseases. CD22 recognizes α2,6-linked sialic acids as endogenous ligands. We have developed new synthetic sialosides as ligands for human CD22. These sialosides bind CD22 on human B cells with high affinity and can efficiently enhance IgM-triggered Ca(2+) signaling. We coupled these sialosides to Pseudomonas exotoxin A to generate a novel CD22 ligand-based immunotoxin. This sialoside-exotoxin-A construct can specifically kill CD22-positive B-cell lymphoma cells. It binds specifically to CD22-positive B-cell lymphoma cells and is dominant over endogenous cis-ligands on the B-cell surface. The sialoside-exotoxin-A construct is efficiently internalized by endocytosis into B-cell lymphoma cell lines. Thus we show the development of a new therapeutic compound for targeting CD22 on human B cells, both for B-cell lymphoma, as well as for B-cell-mediated autoimmune diseases. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. 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

  20. 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

  1. 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.

  2. B Cell Development in the Spleen Takes Place in Discrete Steps and Is Determined by the Quality of B Cell Receptor–Derived Signals

    PubMed Central

    Loder, By Florienne; Mutschler, Bettina; Ray, Robert J.; Paige, Christopher J.; Sideras, Paschalis; Torres, Raul; Lamers, Marinus C.; Carsetti, Rita

    1999-01-01

    Only mature B lymphocytes can enter the lymphoid follicles of spleen and lymph nodes and thus efficiently participate in the immune response. Mature, long-lived B lymphocytes derive from short-lived precursors generated in the bone marrow. We show that selection into the mature pool is an active process and takes place in the spleen. Two populations of splenic B cells were identified as precursors for mature B cells. Transitional B cells of type 1 (T1) are recent immigrants from the bone marrow. They develop into the transitional B cells of type 2 (T2), which are cycling and found exclusively in the primary follicles of the spleen. Mature B cells can be generated from T1 or T2 B cells. PMID:10429672

  3. [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.

  4. Genetic lesions in diffuse large B-cell lymphomas

    PubMed Central

    Testoni, M.; Zucca, E.; Young, K. H.; Bertoni, F.

    2015-01-01

    Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma in adults, accounting for 35%–40% of all cases. The combination of the anti-CD20 monoclonal antibody rituximab with anthracycline-based combination chemotherapy (R-CHOP, rituximab with cyclophosphamide, doxorubicin, vincristine and prednisone) lead to complete remission in most and can cure more than half of patients with DLBCL. The diversity in clinical presentation, as well as the pathologic and biologic heterogeneity, suggests that DLBCL comprises several disease entities that might ultimately benefit from different therapeutic approaches. In this review, we summarize the current literature focusing on the genetic lesions identified in DLBCL. PMID:25605746

  5. [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.

  6. 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.

  7. 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

  8. Near infrared photoimmunotherapy of B-cell lymphoma.

    PubMed

    Nagaya, Tadanobu; Nakamura, Yuko; Sato, Kazuhide; Harada, Toshiko; Choyke, Peter L; Kobayashi, Hisataka

    2016-11-01

    Near infrared photoimmunotherapy (NIR-PIT) is a new, highly-selective cancer theranostics that employs an antibody-photo absorber conjugate (APC). NIR-PIT has successfully treated preclinical tumor models with APCs and is now in the first-in-human phase 1 clinical trial for head and neck cancer patients against EGFR. CD20 is highly expressed in many B-cell lymphomas and is emerging as a molecular target for this disease. Here, we describe the use of the anti-CD20 monoclonal antibody (mAb), rituximab-IR700 APC for NIR-PIT of B-cell lymphoma in two CD20-expressing lymphoma mouse models. CD20 expressing B-cell lymphoma cell lines (Daudi and Ramos) were used in this study. Rituximab-IR700, rituximab conjugated with IRDye700DX, showed specific binding, and cell-specific killing only after exposure of NIR light to both cells in vitro. To evaluate effects of NIR-PIT in vivo, tumor-bearing mice were separated into 4 groups: (1) control; (2) APC i.v. only; (3) NIR light exposure only; (4) APC and NIR light (NIR-PIT). These were performed every week for up to 3 weeks. Rituximab-IR700 showed high tumor accumulation and high target-to-background ratio in vivo. Tumor growth was significantly inhibited by NIR-PIT in comparison with the other groups (p < 0.001 for both tumors), and survival was significantly prolonged in both tumors (p < 0.001 for Daudi tumors and p < 0.0001 for Ramos tumors vs other groups). More than half of tumors were cured with this single regimen of NIR-PIT. In conclusion, anti-CD20 rituximab-IR700 works as a highly effective APC for NIR-PIT against B-cell lymphoma. Published by Elsevier B.V.

  9. 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

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. Cutting Edge: Redox signaling hypersensitivity distinguishes human germinal center B cells

    PubMed Central

    Polikowsky, Hannah G.; Wogsland, Cara E.; Diggins, Kirsten E.

    2015-01-01

    Differences in the quality of B-cell antigen receptor (BCR) signaling control key steps of B cell maturation and differentiation. Endogenously produced H2O2 is thought to fine tune the level of BCR signaling by reversibly inhibiting phosphatases. However, relatively little is known about how B cells at different stages sense and respond to such redox cues. Here, we used phospho-specific flow cytometry and high-dimensional mass cytometry (CyTOF) to compare BCR signaling responses in mature human tonsillar B cells undergoing germinal center (GC) reactions. GC B cells, in contrast to mature naïve B cells, memory B cells, and plasmablasts, were hypersensitive to a range of H2O2 concentrations and responded by phosphorylating SYK and other membrane proximal BCR effectors in the absence of BCR engagement. These findings reveal that stage specific redox responses distinguish human GC B cells. PMID:26157177

  16. 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

  17. Dual-reactive B cells are autoreactive and highly enriched in the plasmablast and memory B cell subsets of autoimmune mice

    PubMed Central

    Fournier, Emilie M.; Velez, Maria-Gabriela; Leahy, Katelyn; Swanson, Cristina L.; Rubtsov, Anatoly V.; Torres, Raul M.

    2012-01-01

    Rare dual-reactive B cells expressing two types of Ig light or heavy chains have been shown to participate in immune responses and differentiate into IgG+ cells in healthy mice. These cells are generated more often in autoreactive mice, leading us to hypothesize they might be relevant in autoimmunity. Using mice bearing Igk allotypic markers and a wild-type Ig repertoire, we demonstrate that the generation of dual-κ B cells increases with age and disease progression in autoimmune-prone MRL and MRL/lpr mice. These dual-reactive cells express markers of activation and are more frequently autoreactive than single-reactive B cells. Moreover, dual-κ B cells represent up to half of plasmablasts and memory B cells in autoimmune mice, whereas they remain infrequent in healthy mice. Differentiation of dual-κ B cells into plasmablasts is driven by MRL genes, whereas the maintenance of IgG+ cells is partly dependent on Fas inactivation. Furthermore, dual-κ B cells that differentiate into plasmablasts retain the capacity to secrete autoantibodies. Overall, our study indicates that dual-reactive B cells significantly contribute to the plasmablast and memory B cell populations of autoimmune-prone mice suggesting a role in autoimmunity. PMID:22927551

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. Immunotherapy After Chemotherapy in Treating Patients With Relapsed or Refractory B Cell Non-Hodgkin Lymphoma

    ClinicalTrials.gov

    2017-10-06

    CD20 Positive; Recurrent B-Cell Non-Hodgkin Lymphoma; Recurrent Chronic Lymphocytic Leukemia; Recurrent Diffuse Large B-Cell Lymphoma; Recurrent Follicular Lymphoma; Recurrent Lymphoplasmacytic Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Refractory B-Cell Non-Hodgkin Lymphoma; Refractory Transformed Indolent Lymphoma; Refractory Diffuse Large B-Cell Lymphoma; Refractory Follicular Lymphoma; Refractory Lymphoplasmacytic Lymphoma; Refractory Mantle Cell Lymphoma

  4. In vivo detection of peripherin-specific autoreactive B cells during type 1 diabetes pathogenesis1

    PubMed Central

    Garabatos, Nahir; Alvarez, Raimon; Carrillo, Jorge; Carrascal, Jorge; Izquierdo, Cristina; Chapman, Harold D.; Presa, Maximiliano; Mora, Conchi; Serreze, David V.; Verdaguer, Joan; Stratmann, Thomas

    2014-01-01

    Summary Autoreactive B cells are essential for the pathogenesis of type 1 diabetes. The genesis and dynamics of autoreactive B cells remain unknown. Here, we analyzed the immune response in the NOD mouse model to the neuronal protein peripherin (PRPH), a target antigen of islet-infiltrating B cells. PRPH autoreactive B cells recognized a single linear epitope of this protein, in contrast to the multiple epitope recognition commonly observed during autoreactive B cell responses. Autoantibodies to this epitope were also detected in the disease-resistant NOR and C57BL/6 strains. To specifically detect the accumulation of these B cells, we developed a novel approach, octameric peptide display, to follow the dynamics and localization of anti-PRPH B cell during disease progression. Before extended insulitis established, anti-PRPH B cells preferentially accumulated in the peritoneum. Anti-PRPH B cells were likewise detected in C57BL/6 mice, albeit at lower frequencies. As disease unfolded in NOD mice, anti-PRPH B cells invaded the islets and increased in number at the peritoneum of diabetic but not pre-diabetic mice. Isotype switched B cells were only detected in the peritoneum. Anti-PRPH B cells represent a heterogeneous population composed of both B1 and B2 subsets. In the spleen, anti-PRPH B cell were predominantly in the follicular subset. Therefore, anti-PRPH B cells represent a heterogeneous population that is generated early in life but proliferates as diabetes establishes. These findings on the temporal and spatial progression of autoreactive B cells should be relevant for our understanding of B cell function in diabetes pathogenesis. PMID:24610011

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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

  11. [Chronic B-cell lymphoproliferative disorders with hairy cells].

    PubMed

    Troussard, Xavier; Cornet, Édouard

    2015-01-01

    The standardized blood smear examination is the first step in the diagnosis of a B-cell chronic lymphoproliferative disorder and can guide further investigations. In the laboratory, the identification of hairy cells on blood smear is a matter of daily practice. Hairy cell proliferations represent heterogeneous entities and their respective diagnoses can be difficult. If hairy cell leukemia (HCL) and splenic marginal zone lymphoma (SMZL) represent separate entities, the variant form of HCL (HCLv) and splenic diffuse red pulp small B-cell lymphoma (SDRPL) remain provisional entities in the 2008 WHO classification. We discuss the main clinical and biological characteristics of these four entities and appropriate means to characterize, identify and distinguish from each other; standardized blood smear examination, multiparameter flow cytometry analysis, analysis of the repertoire of immunoglobulins heavy chains genes and their mutational status (mutated or unmutated profile), molecular analyses: BRAF gene V600E mutation in HCL and MAP2K1 gene mutations in HCLv. We also discuss the main therapeutic aspects with emphasis on the new targeted drugs that enter into force in the therapeutic arsenal.

  12. T-cells and B-cells in osteoporosis

    PubMed Central

    Weitzmann, M. Neale

    2015-01-01

    Purpose of review Bone disease is a leading cause of fractures and continues to be a source of significant morbidity and mortality worldwide. As the underlying mechanisms of osteoporosis are elucidated, immune dysfunction continues to emerge as a key precipitating factor in multiple bone disease contexts. This review examines recent findings in the osteoimmunology field and their implications for bone disease and for novel future therapeutic approaches to rejuvenate the skeleton. Recent findings T-cells and B-cells have long been recognized to play important roles in the etiology of inflammatory bone disease; however, new findings continue to challenge our understanding of the depth of the immuno-skeletal interface. In this review, we examine recent evidence for new roles of B-cells in oestrogen deficiency bone loss; central actions of interleukin-7 in the cause of T-cell mediated tissue destruction in rheumatoid arthritis; novel RANKL-independent alveolar bone loss in periodontal infection; and a putative role for γδ T-cells in bisphosphonate-associated osteonecrosis of the jaw. Finally, evidence for novel bone anabolic activities mediated through T-cells by the CD28 antagonist CTLA-4Ig and by intermittently administered parathyroid hormone are examined. Summary As the field of osteoimmunology continues to mature, new interrelationships between immune cells and bone turnover continue to emerge. PMID:25191854

  13. 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.

  14. Interleukin-35 induces regulatory B cells that suppress autoimmune disease.

    PubMed

    Wang, Ren-Xi; Yu, Cheng-Rong; Dambuza, Ivy M; Mahdi, Rashid M; Dolinska, Monika B; Sergeev, Yuri V; Wingfield, Paul T; Kim, Sung-Hye; Egwuagu, Charles E

    2014-06-01

    Interleukin-10 (IL-10)-producing regulatory B (Breg) cells suppress autoimmune disease, and increased numbers of Breg cells prevent host defense to infection and promote tumor growth and metastasis by converting resting CD4(+) T cells to regulatory T (Treg) cells. The mechanisms mediating the induction and development of Breg cells remain unclear. Here we show that IL-35 induces Breg cells and promotes their conversion to a Breg subset that produces IL-35 as well as IL-10. Treatment of mice with IL-35 conferred protection from experimental autoimmune uveitis (EAU), and mice lacking IL-35 (p35 knockout (KO) mice) or defective in IL-35 signaling (IL-12Rβ2 KO mice) produced less Breg cells endogenously or after treatment with IL-35 and developed severe uveitis. Adoptive transfer of Breg cells induced by recombinant IL-35 suppressed EAU when transferred to mice with established disease, inhibiting pathogenic T helper type 17 (TH17) and TH1 cells while promoting Treg cell expansion. In B cells, IL-35 activates STAT1 and STAT3 through the IL-35 receptor comprising the IL-12Rβ2 and IL-27Rα subunits. As IL-35 also induced the conversion of human B cells into Breg cells, these findings suggest that IL-35 may be used to induce autologous Breg and IL-35(+) Breg cells and treat autoimmune and inflammatory disease.

  15. Diffuse Large B-Cell Lymphoma Classification System That Associates Normal B-Cell Subset Phenotypes With Prognosis

    PubMed Central

    Dybkær, Karen; Bøgsted, Martin; Falgreen, Steffen; Bødker, Julie S.; Kjeldsen, Malene K.; Schmitz, Alexander; Bilgrau, Anders E.; Xu-Monette, Zijun Y.; Li, Ling; Bergkvist, Kim S.; Laursen, Maria B.; Rodrigo-Domingo, Maria; Marques, Sara C.; Rasmussen, Sophie B.; Nyegaard, Mette; Gaihede, Michael; Møller, Michael B.; Samworth, Richard J.; Shah, Rajen D.; Johansen, Preben; El-Galaly, Tarec C.; Young, Ken H.; Johnsen, Hans E.

    2015-01-01

    Purpose Current diagnostic tests for diffuse large B-cell lymphoma use the updated WHO criteria based on biologic, morphologic, and clinical heterogeneity. We propose a refined classification system based on subset-specific B-cell–associated gene signatures (BAGS) in the normal B-cell hierarchy, hypothesizing that it can provide new biologic insight and diagnostic and prognostic value. Patients and Methods We combined fluorescence-activated cell sorting, gene expression profiling, and statistical modeling to generate BAGS for naive, centrocyte, centroblast, memory, and plasmablast B cells from normal human tonsils. The impact of BAGS-assigned subtyping was analyzed using five clinical cohorts (treated with cyclophosphamide, doxorubicin, vincristine, and prednisone [CHOP], n = 270; treated with rituximab plus CHOP [R-CHOP], n = 869) gathered across geographic regions, time eras, and sampling methods. The analysis estimated subtype frequencies and drug-specific resistance and included a prognostic meta-analysis of patients treated with first-line R-CHOP therapy. Results Similar BAGS subtype frequencies were assigned across 1,139 samples from five different cohorts. Among R-CHOP–treated patients, BAGS assignment was significantly associated with overall survival and progression-free survival within the germinal center B-cell–like subclass; the centrocyte subtype had a superior prognosis compared with the centroblast subtype. In agreement with the observed therapeutic outcome, centrocyte subtypes were estimated as being less resistant than the centroblast subtype to doxorubicin and vincristine. The centroblast subtype had a complex genotype, whereas the centrocyte subtype had high TP53 mutation and insertion/deletion frequencies and expressed LMO2, CD58, and stromal-1–signature and major histocompatibility complex class II–signature genes, which are known to have a positive impact on prognosis. Conclusion Further development of a diagnostic platform using

  16. Lentiviral-mediated gene therapy restores B cell tolerance in Wiskott-Aldrich syndrome patients.

    PubMed

    Pala, Francesca; Morbach, Henner; Castiello, Maria Carmina; Schickel, Jean-Nicolas; Scaramuzza, Samantha; Chamberlain, Nicolas; Cassani, Barbara; Glauzy, Salome; Romberg, Neil; Candotti, Fabio; Aiuti, Alessandro; Bosticardo, Marita; Villa, Anna; Meffre, Eric

    2015-10-01

    Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency characterized by microthrombocytopenia, eczema, and high susceptibility to developing tumors and autoimmunity. Recent evidence suggests that B cells may be key players in the pathogenesis of autoimmunity in WAS. Here, we assessed whether WAS protein deficiency (WASp deficiency) affects the establishment of B cell tolerance by testing the reactivity of recombinant antibodies isolated from single B cells from 4 WAS patients before and after gene therapy (GT). We found that pre-GT WASp-deficient B cells were hyperreactive to B cell receptor stimulation (BCR stimulation). This hyperreactivity correlated with decreased frequency of autoreactive new emigrant/transitional B cells exiting the BM, indicating that the BCR signaling threshold plays a major role in the regulation of central B cell tolerance. In contrast, mature naive B cells from WAS patients were enriched in self-reactive clones, revealing that peripheral B cell tolerance checkpoint dysfunction is associated with impaired suppressive function of WAS regulatory T cells. The introduction of functional WASp by GT corrected the alterations of both central and peripheral B cell tolerance checkpoints. We conclude that WASp plays an important role in the establishment and maintenance of B cell tolerance in humans and that restoration of WASp by GT is able to restore B cell tolerance in WAS patients.

  17. Autoantigen-Specific B-Cell Depletion Overcomes Failed Immune Tolerance in Type 1 Diabetes

    PubMed Central

    Henry, Rachel A.; Kendall, Peggy L.; Thomas, James W.

    2012-01-01

    Eliminating autoantigen-specific B cells is an attractive alternative to global B-cell depletion for autoimmune disease treatment. To identify the potential for targeting a key autoimmune B-cell specificity in type 1 diabetes, insulin-binding B cells were tracked within a polyclonal repertoire using heavy chain B-cell receptor (BCR) transgenic (VH125Tg) mice. Insulin-specific B cells are rare in the periphery of nonautoimmune VH125Tg/C57BL/6 mice and WT/NOD autoimmune mice, whereas they clearly populate 1% of mature B-cell subsets in VH125Tg/NOD mice. Autoantigen upregulates CD86 in anti-insulin B cells, suggesting they are competent to interact with T cells. Endogenous insulin occupies anti-insulin BCR beginning with antigen commitment in bone marrow parenchyma, as identified by a second anti-insulin monoclonal antibody. Administration of this monoclonal antibody selectively eliminates insulin-reactive B cells in vivo and prevents disease in WT/NOD mice. Unexpectedly, developing B cells are less amenable to depletion, despite increased BCR sensitivity. These findings exemplify how a critical type 1 diabetes B-cell specificity escapes immune tolerance checkpoints. Disease liability is corrected by eliminating this B-cell specificity, providing proof of concept for a novel therapeutic approach for autoimmune disease. PMID:22698916

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

    USDA-ARS?s Scientific Manuscript database

    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...

  19. 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.

  20. 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

  1. 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.

  2. Lentiviral-mediated gene therapy restores B cell tolerance in Wiskott-Aldrich syndrome patients

    PubMed Central

    Pala, Francesca; Morbach, Henner; Castiello, Maria Carmina; Schickel, Jean-Nicolas; Scaramuzza, Samantha; Chamberlain, Nicolas; Cassani, Barbara; Glauzy, Salome; Romberg, Neil; Candotti, Fabio; Aiuti, Alessandro; Bosticardo, Marita; Villa, Anna; Meffre, Eric

    2015-01-01

    Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency characterized by microthrombocytopenia, eczema, and high susceptibility to developing tumors and autoimmunity. Recent evidence suggests that B cells may be key players in the pathogenesis of autoimmunity in WAS. Here, we assessed whether WAS protein deficiency (WASp deficiency) affects the establishment of B cell tolerance by testing the reactivity of recombinant antibodies isolated from single B cells from 4 WAS patients before and after gene therapy (GT). We found that pre-GT WASp-deficient B cells were hyperreactive to B cell receptor stimulation (BCR stimulation). This hyperreactivity correlated with decreased frequency of autoreactive new emigrant/transitional B cells exiting the BM, indicating that the BCR signaling threshold plays a major role in the regulation of central B cell tolerance. In contrast, mature naive B cells from WAS patients were enriched in self-reactive clones, revealing that peripheral B cell tolerance checkpoint dysfunction is associated with impaired suppressive function of WAS regulatory T cells. The introduction of functional WASp by GT corrected the alterations of both central and peripheral B cell tolerance checkpoints. We conclude that WASp plays an important role in the establishment and maintenance of B cell tolerance in humans and that restoration of WASp by GT is able to restore B cell tolerance in WAS patients. PMID:26368308

  3. Increased BCR responsiveness in B cells from patients with chronic GVHD.

    PubMed

    Allen, Jessica L; Tata, Prasanthi V; Fore, Matthew S; Wooten, Jenna; Rudra, Sharmistha; Deal, Allison M; Sharf, Andrew; Hoffert, Todd; Roehrs, Philip A; Shea, Thomas C; Serody, Jonathan S; Richards, Kristy L; Jagasia, Madan; Lee, Stephanie J; Rizzieri, David; Horwitz, Mitchell E; Chao, Nelson J; Sarantopoulos, Stefanie

    2014-03-27

    Although B cells have emerged as important contributors to chronic graft-versus-host-disease (cGVHD) pathogenesis, the mechanisms responsible for their sustained activation remain unknown. We previously showed that patients with cGVHD have significantly increased B cell-activating factor (BAFF) levels and that their B cells are activated and resistant to apoptosis. Exogenous BAFF confers a state of immediate responsiveness to antigen stimulation in normal murine B cells. To address this in cGVHD, we studied B-cell receptor (BCR) responsiveness in 48 patients who were >1 year out from allogeneic hematopoietic stem cell transplantation (HSCT). We found that B cells from cGVHD patients had significantly increased proliferative responses to BCR stimulation along with elevated basal levels of the proximal BCR signaling components B cell linker protein (BLNK) and Syk. After initiation of BCR signaling, cGVHD B cells exhibited increased BLNK and Syk phosphorylation compared with B cells from patients without cGVHD. Blocking Syk kinase activity prevented relative post-HSCT BCR hyper-responsiveness of cGVHD B cells. These data suggest that a lowered BCR signaling threshold in cGVHD associates with increased B-cell proliferation and activation in response to antigen. We reveal a mechanism underpinning aberrant B-cell activation in cGVHD and suggest that therapeutic inhibition of the involved kinases may benefit these patients.

  4. 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.

  5. 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

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

    ClinicalTrials.gov

    2017-05-23

    CD20 Positive; 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

  7. B-cell phenotype and IgD-CD27- memory B cells are affected by TNF-inhibitors and tocilizumab treatment in rheumatoid arthritis

    PubMed Central

    Gonçalves, Maria J.; Polido-Pereira, Joaquim; Romão, Vasco C.; Martins, Nádia; Canhão, Helena; Fonseca, João E.

    2017-01-01

    Background The use of TNF-inhibitors and/or the IL-6 receptor antagonist, tocilizumab, in rheumatoid arthritis (RA) have pleiotropic effects that also involve circulating B-cells. The main goal of this study was to assess the effect of TNF-inhibitors and tocilizumab on B-cell phenotype and gene expression in RA. Methods Blood samples were collected from untreated early RA (ERA) patients, established RA patients under methotrexate treatment, established RA patients before and after treatment with TNF-inhibitors and tocilizumab, and healthy donors. B-cell subpopulations were characterized by flow cytometry and B-cell gene expression was analyzed by real-time PCR on isolated B-cells. Serum levels of BAFF, CXCL13 and sCD23 were determined by ELISA. Results The frequency of total CD19+ B cells in circulation was similar between controls and all RA groups, irrespective of treatment, but double negative (DN) IgD-CD27- memory B cells were significantly increased in ERA and established RA when compared to controls. Treatment with TNF-inhibitors and tocilizumab restored the frequency of IgD-CD27- B-cells to normal levels, but did not affect other B cell subpopulations. TACI, CD95, CD5, HLA-DR and TLR9 expression on B-cells significantly increased after treatment with either TNF-inhibitors and/ or tocilizumab, but no significant changes were observed in BAFF-R, BCMA, CD69, CD86, CXCR5, CD23, CD38 and IgM expression on B-cells when comparing baseline with post-treatment follow-ups. Alterations in B-cell gene expression of BAFF-R, TACI, TLR9, FcγRIIB, BCL-2, BLIMP-1 and β2M were found in ERA and established RA patients, but no significant differences were observed after TNF-inhibitors and tocilizumab treatment when comparing baseline and follow-ups. Serum levels of CXCL13, sCD23 and BAFF were not significantly affected by treatment with TNF-inhibitors and tocilizumab. Conclusions In RA patients, the use of TNF-inhibitors and/ or tocilizumab treatment affects B-cell phenotype

  8. 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

  9. Aiolos Overexpression in Systemic Lupus Erythematosus B Cell Subtypes and BAFF-Induced Memory B Cell Differentiation Are Reduced by CC-220 Modulation of Cereblon Activity.

    PubMed

    Nakayama, Yumi; Kosek, Jolanta; Capone, Lori; Hur, Eun Mi; Schafer, Peter H; Ringheim, Garth E

    2017-10-01

    BAFF is a B cell survival and maturation factor implicated in the pathogenesis of systemic lupus erythematosus (SLE). In this in vitro study, we describe that soluble BAFF in combination with IL-2 and IL-21 is a T cell contact-independent inducer of human B cell proliferation, plasmablast differentiation, and IgG secretion from circulating CD27(+) memory and memory-like CD27(-)IgD(-) double-negative (DN) B cells, but not CD27(-)IgD(+) naive B cells. In contrast, soluble CD40L in combination with IL-2 and IL-21 induces these activities in both memory and naive B cells. Blood from healthy donors and SLE patients have similar circulating levels of IL-2, whereas SLE patients exhibit elevated BAFF and DN B cells and reduced IL-21. B cell differentiation transcription factors in memory, DN, and naive B cells in SLE show elevated levels of Aiolos, whereas Ikaros levels are unchanged. Treatment with CC-220, a modulator of the cullin ring ligase 4-cereblon E3 ubiquitin ligase complex, reduces Aiolos and Ikaros protein levels and BAFF- and CD40L-induced proliferation, plasmablast differentiation, and IgG secretion. The observation that the soluble factors BAFF, IL-2, and IL-21 induce memory and DN B cell activation and differentiation has implications for extrafollicular plasmablast development within inflamed tissue. Inhibition of B cell plasmablast differentiation by reduction of Aiolos and Ikaros may have utility in the treatment of SLE, where elevated levels of BAFF and Aiolos may prime CD27(+) memory and DN memory-like B cells to become Ab-producing plasmablasts in the presence of BAFF and proinflammatory cytokines. Copyright © 2017 by The American Association of Immunologists, Inc.

  10. Dysfunctional B-cell activation in cirrhosis due to hepatitis C infection associated with disappearance of CD27+ B-cell population

    PubMed Central

    Doi, Hiroyoshi; Iyer, Tara K.; Carpenter, Erica; Li, Hong; Chang, Kyong-Mi; Vonderheide, Robert H.; Kaplan, David E.

    2011-01-01

    Background Chronic hepatitis C virus infection is a leading cause of cirrhosis and hepatocellular carcinoma. Both advanced solid tumors and hepatitis C have previously been associated with memory B-cell dysfunction. In this study we sought to dissect the impact of viral infection, cirrhosis and liver cancer on memory B-cell frequency and function in the spectrum of HCV disease. Methods Peripheral blood from healthy donors, HCV-infected patients with F1–F2 liver fibrosis, HCV-infected patients with cirrhosis, patients with HCV-related hepatocellular carcinoma and non-HCV-infected cirrhotics were assessed for B-cell phenotype by flow cytometry. Isolated B-cells were stimulated with anti-CD40 antibodies and TLR9 agonist for assessment of costimulation marker expression, cytokine production, immunoglobulin production and CD4+ T-cell allostimulatory capacity. Results CD27+ memory B-cells, and more specifically CD27+IgM+ B-cells, were markedly less frequent in cirrhotic patients independent of HCV infection. Circulating B-cells in cirrhotics were hyporesponsive to CD40/TLR9 activation as characterized by CD70 upregulation, TNFβ secretion, IgG production and T-cell allostimulation. Lastly, blockade of TLR4 and TLR9 signaling abrogated the activation of normal donor B-cells by cirrhotic plasma suggesting a role for bacterial translocation in driving B-cell changes in cirrhosis. Conclusion Profound abnormalities in B-cell phenotype and function occur in cirrhosis independent of hepatitis C viral infection. These B-cell defects may explain in part the vaccine hyporesponsiveness and susceptibility to bacterial infection in this population. PMID:21932384

  11. 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

  12. Characterization of Regulatory B Cells in Graves’ Disease and Hashimoto’s Thyroiditis

    PubMed Central

    Kristensen, Birte; Hegedüs, Laszlo; Lundy, Steven K.; Brimnes, Marie K.; Smith, Terry J.; Nielsen, Claus H.

    2015-01-01

    A hallmark of regulatory B cells is IL-10 production, hence their designation as IL-10+ B cells. Little is known about the ability of self-antigens to induce IL-10+ B cells in Graves’ disease (GD), Hashimoto’s thyroiditis (HT), or other autoimmune disease. Here we pulsed purified B cells from 12 HT patients, 12 GD patients, and 12 healthy donors with the thyroid self-antigen, thyroglobulin (TG) and added the B cells back to the remaining peripheral blood mononuclear cells (PBMCs). This procedure induced IL-10+ B-cell differentiation in GD. A similar tendency was observed in healthy donors, but not in cells from patients with HT. In GD, B cells primed with TG induced IL-10-producing CD4+ T cells. To assess the maximal frequency of inducible IL-10+ B cells in the three donor groups PBMCs were stimulated with PMA/ionomycin. The resulting IL-10+ B-cell frequency was similar in the three groups and correlated with free T3 levels in GD patients. IL-10+ B cells from both patient groups displayed CD25 or TIM-1 more frequently than did those from healthy donors. B-cell expression of two surface marker combinations previously associated with regulatory B-cell functions, CD24hiCD38hi and CD27+CD43+, did not differ between patients and healthy donors. In conclusion, our findings indicate that autoimmune thyroiditis is not associated with reduced frequency of IL-10+ B cells. These results do not rule out regulatory B-cell dysfunction, however. The observed phenotypic differences between IL-10+ B cells from patients and healthy donors are discussed. PMID:26016954

  13. Characterization of Regulatory B Cells in Graves' Disease and Hashimoto's Thyroiditis.

    PubMed

    Kristensen, Birte; Hegedüs, Laszlo; Lundy, Steven K; Brimnes, Marie K; Smith, Terry J; Nielsen, Claus H

    2015-01-01

    A hallmark of regulatory B cells is IL-10 production, hence their designation as IL-10+ B cells. Little is known about the ability of self-antigens to induce IL-10+ B cells in Graves' disease (GD), Hashimoto's thyroiditis (HT), or other autoimmune disease. Here we pulsed purified B cells from 12 HT patients, 12 GD patients, and 12 healthy donors with the thyroid self-antigen, thyroglobulin (TG) and added the B cells back to the remaining peripheral blood mononuclear cells (PBMCs). This procedure induced IL-10+ B-cell differentiation in GD. A similar tendency was observed in healthy donors, but not in cells from patients with HT. In GD, B cells primed with TG induced IL-10-producing CD4+ T cells. To assess the maximal frequency of inducible IL-10+ B cells in the three donor groups PBMCs were stimulated with PMA/ionomycin. The resulting IL-10+ B-cell frequency was similar in the three groups and correlated with free T3 levels in GD patients. IL-10+ B cells from both patient groups displayed CD25 or TIM-1 more frequently than did those from healthy donors. B-cell expression of two surface marker combinations previously associated with regulatory B-cell functions, CD24hiCD38hi and CD27+CD43+, did not differ between patients and healthy donors. In conclusion, our findings indicate that autoimmune thyroiditis is not associated with reduced frequency of IL-10+ B cells. These results do not rule out regulatory B-cell dysfunction, however. The observed phenotypic differences between IL-10+ B cells from patients and healthy donors are discussed.

  14. 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

  15. Phenotypic and functional characteristics of CD39(high) human regulatory B cells (Breg).

    PubMed

    Figueiró, F; Muller, L; Funk, S; Jackson, E K; Battastini, A M O; Whiteside, T L

    2016-02-01

    CD39 and CD73 are key enzymes in the adenosine (ADO) pathway. ADO modulates pathophysiological responses of immune cells, including B cells. It has recently emerged that a subpopulation of ADO-producing CD39(+)CD73(+) B cells has regulatory properties. Here, we define the CD39(high) subset of these cells as the major contributor to the regulatory network operated by human B lymphocytes. Peripheral blood B cells were sorted into CD39(neg), CD39(inter) and CD39(high) subsets. The phenotype, proliferation and IL-10 secretion by these B cells were studied by flow cytometry. 5'-AMP and ADO levels were measured by mass spectrometry. Agonists or antagonists of A1R, A2AR and A3R were used to study ADO-receptor signaling in B cells. Inhibition of effector T-cell (Teff) activation/proliferation by B cells was assessed in co-cultures. Cytokine production was measured by Luminex. Upon in vitro activation and culture of B cells, the subset of CD39(high) B cells increased in frequency (p < 0.001). CD39(high) B cells upregulated CD73 expression, proliferated (approximately 40% of CD39(high) B cells were Ki-67(+) and secreted fold-2 higher IL-10 and ADO levels than CD39(neg) or CD39(inter) B cells. CD39(high) B cells co-cultured with autologous Teff suppressed T-cell activation/proliferation and secreted elevated levels of IL-6 and IL-10. The A1R and A2AR agonists promoted expansion and functions of CD39(high) B cells. CD39 ectonucleotidase is upregulated in a subset of in vitro-activated B cells which utilize ADO and IL-10 to suppress Teff functions. Proliferation and functions of these CD39(high) B cells are regulated by A1R- and A2AR-mediated autocrine signaling.

  16. 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.

  17. 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

    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

    2015-02-20

    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. 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. 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. 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. © 2014 by American Society of Clinical Oncology.

  18. 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

  19. 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.

  20. 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

  1. Btk Regulates B Cell Receptor-Mediated Antigen Processing and Presentation by Controlling Actin Cytoskeleton Dynamics in B Cells

    PubMed Central

    Sharma, Shruti; Orlowski, Gregory; Song, Wenxia

    2010-01-01

    The high efficiency of Ag processing and presentation by B cells requires Ag-induced BCR signaling and actin cytoskeleton reorganization, although the underlying mechanism for such requirements remains elusive. In this study, we identify Bruton's tyrosine kinase (Btk) as a linker connecting BCR signaling to actin dynamics and the Ag transport pathway. Using xid mice and a Btk inhibitor, we show that BCR engagement increases actin polymerization and Wiskott-Aldrich syndrome protein activation in a Btk-dependent manner. Concurrently, we observe Btk-dependent increases in the levels of phosphatidylinositide-4,5-bisphosphate and phosphorylated Vav upon BCR engagement. The rate of BCR internalization, its movement to late endosomes, and efficiency of BCR-mediated Ag processing and presentation are significantly reduced in both xid and Btk inhibitor-treated B cells. Thus, Btk regulates actin dynamics and Ag transport by activating Wiskott-Aldrich syndrome protein via Vav and phosphatidylinositides. This represents a novel mechanism by which BCR-mediated signaling regulates BCR-mediated Ag processing and presentation. PMID:19109164

  2. JE-ADVAX vaccine protection against Japanese encephalitis virus mediated by memory B cells in the absence of CD8(+) T cells and pre-exposure neutralizing antibody.

    PubMed

    Larena, Maximilian; Prow, Natalie A; Hall, Roy A; Petrovsky, Nikolai; Lobigs, Mario

    2013-04-01

    JE-ADVAX is a new, delta inulin-adjuvanted, Japanese encephalitis (JE) candidate vaccine with a strong safety profile and potent immunogenicity that confers efficient immune protection not only against JE virus but also against related neurotropic flaviviruses such as West Nile virus. In this study, we investigated the immunological mechanism of protection by JE-ADVAX vaccine using knockout mice deficient in B cells or CD8(+) T cells and poor persistence of neutralizing antibody or by adoptive transfer of immune splenocyte subpopulations. We show that memory B cells induced by JE-ADVAX provide long-lived protection against JE even in the absence of detectable pre-exposure serum neutralizing antibodies and without the requirement of CD8(+) T cells. Upon virus encounter, these vaccine-induced memory B cells were rapidly triggered to produce neutralizing antibodies that then protected immunized mice from morbidity and mortality. The findings suggest that the extent of the B-cell memory compartment might be a better immunological correlate for clinical efficacy of JE vaccines than the currently recommended measure of serum neutralizing antibody. This may explain the paradox where JE protection is observed in some subjects even in the absence of detectable serum neutralizing antibody. Our investigation also established the suitability of a novel flavivirus challenge model (β(2)-microglobulin-knockout mice) for studies of the role of B-cell memory responses in vaccine protection.

  3. 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

  4. 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

  5. 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.

  6. Essential role of BAX,BAK in B cell homeostasis and prevention of autoimmune disease

    PubMed Central

    Takeuchi, Osamu; Fisher, Jill; Suh, Heikyung; Harada, Hisashi; Malynn, Barbara A.; Korsmeyer, Stanley J.

    2005-01-01

    B cell homeostasis is maintained by a balance between the continual generation of new cells and their elimination. Here we show proapoptotic BCL-2 family members BAX and BAK are essential for regulating the number of B cells at both immature and mature developmental stages. BAX and BAK are critical mediators of B cell death induced by multiple stimuli. In addition, BAX- and BAK-deficient B cells display defective cell cycle progression to B cell receptor crosslinking and lipopolysaccharide, but not to CpG–DNA. Furthermore, inducible deletion of Bax and Bak in adult mice results in the development of severe autoimmune disease. PMID:16055554

  7. 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.

  8. Early B-cell Specific Inactivation of ATM Synergizes with Ectopic CyclinD1 Expression to Promote Pre-germinal center B-cell Lymphomas in Mice

    PubMed Central

    Yamamoto, Kenta; Lee, Brian J.; Li, Chen; Dubois, Richard L.; Hobeika, Elias; Bhagat, Govind; Zha, Shan

    2017-01-01

    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 (B-NHL), 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 naïve 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. While EμCyclinD1 is not sufficient to induce lymphomas, EμCyclinD1 accelerates the kinetics and increased the incidence of clonal lymphomas in ATM-deficient B-cells and skews the lymphomas towards pre-GC derived small lymphocytic neoplasms sharing morphological features of human MCL. This is in part due to CyclinD1-driven expansion of ATM-deficient naïve B cells with genomic instability, which promotes the deletions of additional tumor suppressor genes (i.g. Trp53, Mll2, Rb1 and Cdkn2a). Together these findings define a synergistic function of ATM and CyclinD1 in pre-germinal center B-cell proliferation and lymphomagenesis and provide a prototypic animal model to study the pathogenesis of human MCL. PMID:25676421

  9. Ras activation of Erk restores impaired tonic BCR signaling and rescues immature B cell differentiation

    PubMed Central

    Rowland, Sarah L.; DePersis, Corinne L.; Torres, Raul M.

    2010-01-01

    B cell receptors (BCRs) generate tonic signals critical for B cell survival and early B cell development. To determine whether these signals also mediate the development of transitional and mature B cells, we examined B cell development using a mouse strain in which nonautoreactive immunoglobulin heavy and light chain–targeted B cells express low surface BCR levels. We found that reduced BCR expression translated into diminished tonic BCR signals that strongly impaired the development of transitional and mature B cells. Constitutive expression of Bcl-2 did not rescue the differentiation of BCR-low B cells, suggesting that this defect was not related to decreased cell survival. In contrast, activation of the Ras pathway rescued the differentiation of BCR-low immature B cells both in vitro and in vivo, whereas extracellular signal-regulated kinase (Erk) inhibition impaired the differentiation of normal immature B cells. These results strongly suggest that tonic BCR signaling mediates the differentiation of immature into transitional and mature B cells via activation of Erk, likely through a pathway requiring Ras. PMID:20176802

  10. Checkpoints for Autoreactive B Cells in the Peripheral Blood of Lupus Patients Assessed by Flow Cytometry.

    PubMed

    Malkiel, Susan; Jeganathan, Venkatesh; Wolfson, Stacey; Manjarrez Orduño, Nataly; Marasco, Emiliano; Aranow, Cynthia; Mackay, Meggan; Gregersen, Peter K; Diamond, Betty

    2016-09-01

    Antinuclear antibodies (ANAs) are diagnostic in several autoimmune disorders, yet the failure to achieve B cell tolerance in these diseases is still poorly understood. Although secreted ANAs detected by an indirect immunofluorescence assay are the gold standard for autoreactivity, there has been no convenient assay with which to measure the frequency of circulating B cells that recognize nuclear antigens (ANA+ B cells) in patients. The aim of this study was to generate an assay to easily identify these B cells and to examine its utility in a study of autoreactive B cells in systemic lupus erythematosus (SLE). We developed and validated a novel flow cytometry-based assay that identifies ANA+ B cells using biotinylated nuclear extracts, and utilized it to examine B cell tolerance checkpoints in peripheral blood mononuclear cells obtained from SLE patients and healthy controls. We observed progressive selection against ANA+ B cells as they matured from transitional to naive to CD27+IgD- and CD27+IgD+ memory cells in both healthy subjects and SLE patients; however, ANA+ naive B cells in SLE patients were not anergized to the same extent as in healthy individuals. We also showed that anergy induction is restored in SLE patients treated with belimumab, an inhibitor of BAFF. This assay will enable studies of large populations to identify potential genetic or environmental factors affecting B cell tolerance checkpoints in healthy subjects and patients with autoimmune disease and permit monitoring of the B cell response to therapeutic interventions. © 2016, American College of Rheumatology.

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

    PubMed

    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.

  12. Increased BCR responsiveness in B cells from patients with chronic GVHD

    PubMed Central

    Allen, Jessica L.; Tata, Prasanthi V.; Fore, Matthew S.; Wooten, Jenna; Rudra, Sharmistha; Deal, Allison M.; Sharf, Andrew; Hoffert, Todd; Roehrs, Philip A.; Shea, Thomas C.; Serody, Jonathan S.; Richards, Kristy L.; Jagasia, Madan; Lee, Stephanie J.; Rizzieri, David; Horwitz, Mitchell E.; Chao, Nelson J.

    2014-01-01

    Although B cells have emerged as important contributors to chronic graft-versus-host-disease (cGVHD) pathogenesis, the mechanisms responsible for their sustained activation remain unknown. We previously showed that patients with cGVHD have significantly increased B cell–activating factor (BAFF) levels and that their B cells are activated and resistant to apoptosis. Exogenous BAFF confers a state of immediate responsiveness to antigen stimulation in normal murine B cells. To address this in cGVHD, we studied B-cell receptor (BCR) responsiveness in 48 patients who were >1 year out from allogeneic hematopoietic stem cell transplantation (HSCT). We found that B cells from cGVHD patients had significantly increased proliferative responses to BCR stimulation along with elevated basal levels of the proximal BCR signaling components B cell linker protein (BLNK) and Syk. After initiation of BCR signaling, cGVHD B cells exhibited increased BLNK and Syk phosphorylation compared with B cells from patients without cGVHD. Blocking Syk kinase activity prevented relative post-HSCT BCR hyper-responsiveness of cGVHD B cells. These data suggest that a lowered BCR signaling threshold in cGVHD associates with increased B-cell proliferation and activation in response to antigen. We reveal a mechanism underpinning aberrant B-cell activation in cGVHD and suggest that therapeutic inhibition of the involved kinases may benefit these patients. PMID:24532806

  13. 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.

  14. 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

  15. PAX-5 is invariably expressed in B-cell lymphomas without plasma cell differentiation.

    PubMed

    Dong, H Y; Browne, P; Liu, Z; Gangi, M

    2008-09-01

    The B-cell-specific transcription factor PAX-5 is physiologically expressed in normal B cells and silenced in plasma cells. The aim of this study was to determine whether PAX-5 expression is universal among B-cell malignancies. A wide spectrum of B-cell malignancies were subjected to immunohistochemical analysis for PAX-5 expression. The study was especially focused on cases lacking CD20, such as precursor B-cell acute lymphoblastic leukaemia (preB-ALL), CD20- B-cell lymphomas, classical Hodgkin's lymphoma (CHL) and B-cell lymphomas with significant plasmacytic differentiation. Strong PAX-5 expression was identified, without exception, in all cases of CD20+ B-lymphoproliferative disorders. It was also invariably detected in 31/31 cases of preB-ALL, 14/14 cases of CD20- diffuse large B-cell lymphoma without plasmacytic differentiation and 26/26 CD20- B-cell lymphoma status post rituximab treatment. The vast majority of CHLs had unequivocal PAX-5 expression of varying intensity (80/86). However, variants of B-cell malignancies with characteristic plasmacytic differentiation exhibited no detectable PAX-5 expression (0/17). PAX-5 is the most sensitive and reliable immunohistochemical marker for B-cell malignancies. Lack of PAX-5 expression correlates with the presence of marked plasma cell differentiation.

  16. 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. PMID:28405077

  17. 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.

  18. 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.

  19. Targeting B-cell maturation antigen in multiple myeloma

    PubMed Central

    Tai, Yu-Tzu; Anderson, Kenneth C

    2015-01-01

    Novel effective immunotherapies are needed for patients with multiple myeloma (MM), since disease recurrence remains a major obstacle. B-cell maturation antigen (BCMA), a cell surface protein universally expressed on malignant plasma cells , has emerged as a very selective antigen to be targeted in novel treatments for MM. We here first review BCMA-related biology, and then highlight the recent clinical development of a novel afucosylated anti-BCMA monoclonal antibody conjugated with monomethyl auristatin F via noncleavable linker (GSK2857916). Chimeric antigen receptor-expressing T cells targeting BCMA may also induce specific and durable anti-MM responses by patients’ own effector cells. Clinical trials testing these two approaches (NCT02064387, NCT02215967) are currently ongoing in relapsed and refractory MM patients. PMID:26370838

  20. [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.

  1. Stimulation of human lymphocytes by B-cell mitogens

    PubMed Central

    Ivanyi, L.; Lehner, T.

    1974-01-01

    B-cell mitogens stimulate human peripheral blood lymphocytes in the following order of effectiveness: levan, lipopolysaccharide, dextran. The incidence and magnitude of the response was increased in patients with chronic gingival and periodontal disease. Whereas in 45% of healthy subjects levan yielded a stimulation index >3, patients manifested an increased response according to the severity of the disease, reaching 75% in the advanced form of periodontitis. Levan and LPS stimulated spleen lymphocytes to yield higher stimulation indices than peripheral blood lymphocytes. The in vitro responses to these mitogens were abolished by the removal of B lymphocytes or by the depletion of phagocytic cells. It is now evident that a protein component of Veillonella alcalescens stimulates T lymphocytes, whereas lipid A fraction of lipopolysaccharide from the same organism stimulates B lymphocytes. PMID:4549732

  2. Natural autoantibodies and associated B cells in immunity and autoimmunity.

    PubMed

    Mannoor, Kaiissar; Xu, Yang; Chen, Ching

    2013-03-01

    A substantial proportion of circulating antibodies in healthy individuals exhibit self-reactivity. These antibodies, referred to as natural autoantibodies, are thought to arise naturally without actual antigen stimulation as they are present in human cord blood and in mice housed in germfree conditions and fed an antigen-free diet. Natural autoantibodies are mainly of the IgM class, unmutated, and typically polyreactive. They provide critical early protection against pathogens, and play important roles in maintenance of homeostasis and modulation of innate and adaptive immune responses, thereby conferring protection from rampant autoimmune and inflammatory injuries. In this review, we summarize current information regarding the properties of natural autoantibodies and the B cells that produce them, their roles in immunity and autoimmunity, their mechanisms of action, and their therapeutic potential.

  3. 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.

  4. 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

  5. B cells: no longer bystanders in liver fibrosis

    PubMed Central

    Bhogal, Rashpal K.; Bona, Constantin A.

    2005-01-01

    Cytokines secreted by cells that mediate the innate and adaptive immune responses play a critical role in regulating the synthesis of ECM components by fibroblasts. Overexpression and deposition of ECM components are dominant features of fibrotic diseases, including hepatic fibrosis. The contribution of CD4+ Th2 cells to hepatic fibrosis has been well described. Now, in this issue of the JCI, Novobrantseva et al. provide data to suggest that hepatic B cells also play a role in liver injury. In a carbon tetrachloride–induced mouse model of hepatic fibrosis, T cell–deficient mice developed severe liver fibrosis; however, in B cell–deficient animals, hepatic fibrosis was attenuated. This study provides new insight into our understanding of the cells involved in mediating the adaptive immune response that leads to hepatic fibrosis. PMID:16276407

  6. [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.

  7. 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.

  8. 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

  9. T cell-B cell interactions in primary immunodeficiencies.

    PubMed

    Tangye, Stuart G; Deenick, Elissa K; Palendira, Umaimainthan; Ma, Cindy S

    2012-02-01

    Regulated interactions between cells of the immune system facilitate the generation of successful immune responses, thereby enabling efficient neutralization and clearance of pathogens and the establishment of both cell- and humoral-mediated immunological memory. The corollary of this is that impediments to efficient cell-cell interactions, normally necessary for differentiation and effector functions of immune cells, underly the clinical features and disease pathogenesis of primary immunodeficiencies. In affected individuals, these defects manifest as impaired long-term humoral immunity and susceptibility to infection by specific pathogens. In this review, we discuss the importance of, and requirements for, effective interactions between B cells and T cells during the formation of CD4(+) T follicular helper cells and the elicitation of cytotoxic function of virus-specific CD8(+) T cells, as well as how these processes are abrogated in primary immunodeficiencies due to loss-of-function mutations in defined genes. © 2012 New York Academy of Sciences.

  10. 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.

  11. 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.

  12. 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

  13. Anti-CD79 Antibody Induces B cell Anergy That Protects Against Autoimmunity

    PubMed Central

    Hardy, Ian R.; Anceriz, Nadia; Rousseau, François; Seefeldt, Matt B.; Hatterer, Eric; Irla, Magali; Buatois, Vanessa; Chatel, Laurence E.; Getahun, Andrew; Fletcher, Ashley; Cons, Laura; Pontini, Guillemette; Hertzberg, Nicole A.; Magistrelli, Giovanni; Malinge, Pauline; Smith, Mia J.; Reith, Walter; Kosco-Vilbois, Marie H.; Ferlin, Walter G.; Cambier, John C.

    2014-01-01

    B cells play a major role in the pathogenesis of many autoimmune disorders including rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis and type I diabetes mellitus, as indicated by the efficacy of B cell-targeted therapies in these diseases. Therapeutic effects of the most commonly used B cell-targeted therapy, anti-CD20 monoclonal antibody, are contingent upon long-term depletion of peripheral B cells. Here, we describe an alternative approach involving the targeting of CD79, the transducer subunit of the B cell antigen receptor. Unlike anti-CD20 mAbs, the protective effects of CD79-targeted mAb are do not require cell depletion, but rather act by inducing an anergic-like state. Thus, we describe a novel B cell-targeted approach predicated on the induction of B cell anergy. PMID:24442438

  14. 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

  15. Anti-B-Cell Therapies in Autoimmune Neurological Diseases: Rationale and Efficacy Trials.

    PubMed

    Alexopoulos, Harry; Biba, Angie; Dalakas, Marinos C

    2016-01-01

    B cells have an ever-increasing role in the etiopathology of a number of autoimmune neurological disorders, acting as antibody-producing cells and, most importantly, as sensors, coordinators, and regulators of the immune response. B cells, among other functions, regulate the T-cell activation process through their participation in antigen presentation and production of cytokines. The availability of monoclonal antibodies or fusion proteins against B-cell surface molecules or B-cell trophic factors bestows a rational approach for treating autoimmune neurological disorders, even when T cells are the main effector cells. This review summarizes basic aspects of B-cell biology, discusses the role(s) of B cells in neurological autoimmunity, and presents anti-B-cell drugs that are either currently on the market or are expected to be available in the near future for treating neurological autoimmune disorders.

  16. B cells expressing the transcription factor T-bet drive lupus-like autoimmunity

    PubMed Central

    Rubtsov, Anatoly V.; Thurman, Joshua M.; Mennona, Johanna M.; Kappler, John W.; Marrack, Philippa

    2017-01-01

    B cells contribute to multiple aspects of autoimmune disorders and may play a role in triggering disease. Thus, targeting B cells may be a promising strategy for treating autoimmune disorders. Better understanding of the B cell subsets that are responsible for the development of autoimmunity will be critical for developing efficient therapies. Here we have reported that B cells expressing the transcription factor T-bet promote the rapid appearance of autoantibodies and germinal centers in spontaneous murine models of systemic lupus erythematosus (SLE). Conditional deletion of T-bet from B cells impaired the formation of germinal centers and mitigated the development of kidney damage and rapid mortality in SLE mice. B cell–specific deletion of T-bet was also associated with lower activation of both B cells and T cells. Taken together, our results suggest that targeting T-bet–expressing B cells may be a potential target for therapy for autoimmune diseases. PMID:28240602

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

    PubMed Central

    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.

    2016-01-01

    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. PMID:26759369

  18. 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.

  19. Idiotype vaccination following ABMT can stimulate specific anti-idiotype immune responses in patients with B-cell lymphoma.

    PubMed

    Davis, T A; Hsu, F J; Caspar, C B; van Beckhoven, A; Czerwinsk, D K; Liles, T M; Taidi, B; Benike, C J; Engleman, E G; Levy, R

    2001-01-01

    Vaccination with the idiotype (Id) protein derived from B-cell malignancies can produce Id-specific immune responses that correlate with improved remission duration and survival rates in patients with follicular non-Hodgkin's lymphoma (NHL). A state of minimal or no residual disease correlates strongly with the laboratory detection of a cellular or humoral immune response. High-dose cytotoxic therapy (HDCT) with autologous stem cell support (autologous bone marrow transplantation [ABMT]) can provide profound cytoreduction of B-cell NHL, but the potential immune suppression associated with myeloablative therapy may compromise a patient's ability to mount a specific immune response. To determine whether patients with NHL could mount detectable immuneresponses following ABMT, Id vaccines were administered at 2 to 12 months following myeloablative therapy to a series of patients with relapsed or resistant B-cell NHL. Two different vaccination strategies produced robust immune responses against KLH in all patients, supporting the capacity of the reconstituted immune system following HDCT to react against a strong antigen. Combining the results from both vaccination strategies, 10 of 12 patients mounted Id-specific humoral or cellular responses. Vaccinations were consistently well tolerated. Of the 12 patients, 7 have experienced prolonged remissions with a follow-up from HDCT ranging from 3 to more than 11 years. Our experience serves to document the ability of the recovering immune system to react against both self and xenotypic antigens and supports the feasibility and safety of antigen-specific vaccination following myeloablative therapy in patients with B-cell NHL.

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

    PubMed

    Savsek, Lina; Opaskar, Tanja Ros

    2016-03-01

    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. 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, 8(th) 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. 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.

  1. 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

  2. BAFF receptor and TACI in B-1b cell maintenance and antibacterial responses.

    PubMed

    Dickinson, Gregory S; Akkoyunlu, Mustafa; Bram, Richard J; Alugupalli, Kishore R

    2015-12-01

    Although evidence of the protective immunity conferred by B-1b cells (CD19(+) B220(+) IgM(hi) Mac1(+) CD5(-)) has been established, the mechanisms governing the maintenance and activation of B-1b cells following pathogen encounter remain unclear. B cell-activating factor (BAFF) and a proliferation-inducing ligand (APRIL) mediate their function in mature B cells through the BAFF receptor (BAFFR) and transmembrane activator and CAML interactor (TACI). BAFFR-deficient mice have lower numbers of B-1b cells, and this reduction is directly proportional to BAFFR levels. The generation of B-1b cells is also dependent on the strength of B cell receptor (BCR) signaling. Mice with impaired BCR signaling, such as X-linked immunodeficient (xid) mice, have B-1b cell deficiency, indicating that both BCR- and BAFFR-mediated signaling are critical for B-1b cell homeostasis. Borrelia hermsii induces expansion and persistence of B-1b cells in xid mice, and these B-1b cells provide a heightened protective response. Toll-like receptor (TLR)-mediated stimulation of xid B cells results in a significant increase in TACI expression and restoration of TACI-mediated functions. The activation of TLR signaling by B. hermsii and BCR/TLR costimulation-mediated upregulation of BAFFR and TACI on B-1b cells suggests that B-1b cell maintenance and function following bacterial exposure may depend on BAFFR- and TACI-mediated signaling. In fact, the loss of both BAFFR and TACI results in a greater impairment in anti-B. hermsii responses compared to deficiency of BAFFR or TACI alone. © 2015 New York Academy of Sciences.

  3. A molecular mechanism for TNF-α-mediated down-regulation of B cell responses1

    PubMed Central

    Frasca, Daniela; Romero, Maria; Diaz, Alain; Alter-Wolf, Sarah; Ratliff, Michelle; Landin, Ana Marie; Riley, Richard L; Blomberg, Bonnie B.

    2011-01-01

    B cell function with age is decreased in class switch recombination (CSR), activation-induced cytidine deaminase (AID) and stability of E47 mRNA. The latter is regulated at least in part by tristetraprolin (TTP) which is increased in aged B cells and also negatively regulates TNF-α. Here, we investigate whether B cells produce TNF-α, whether this changes with age, and how this affects their function upon stimulation. Our hypothesis is that in aging there is a feedback mechanism of autocrine inflammatory cytokines (TNF-α) that lowers the expression of AID and CSR. Our results show that unstimulated B cells from old BALB/c mice make significantly more TNF-α mRNA and protein than B cells from young mice, but after stimulation the old make less than young, thus they are refractory to stimulation. The increase in TNF-α made by old B cells is primarily due to follicular, but not minor subsets of B cells. Pre-incubation of B cells with TNF-α before LPS stimulation decreases both young and old B cell responses. Importantly, B cell function was restored by adding anti-TNF-α antibody in cultured B cells. To address a molecular mechanism, we found that pre-incubation of B cells with TNF-α, before LPS stimulation, induces tristetraprolin, a physiological regulator of mRNA stability of the transcription factor E47, crucial for CSR. Finally, anti-TNF-α given in vivo was able to increase follicular B cell function in old but not in young follicular B cells. These results suggest new molecular mechanisms which contribute to reduced antibody responses in aging. PMID:22116831

  4. Generation mechanism of RANKL(+) effector memory B cells: relevance to the pathogenesis of rheumatoid arthritis.

    PubMed

    Ota, Yuri; Niiro, Hiroaki; Ota, Shun-Ichiro; Ueki, Naoko; Tsuzuki, Hirofumi; Nakayama, Tsuyoshi; Mishima, Koji; Higashioka, Kazuhiko; Jabbarzadeh-Tabrizi, Siamak; Mitoma, Hiroki; Akahoshi, Mitsuteru; Arinobu, Yojiro; Kukita, Akiko; Yamada, Hisakata; Tsukamoto, Hiroshi; Akashi, Koichi

    2016-03-16

    The efficacy of B cell-depleting therapies for rheumatoid arthritis underscores antibody-independent functions of effector B cells such as cognate T-B interactions and production of pro-inflammatory cytokines. Receptor activator of nuclear factor κB ligand (RANKL) is a key cytokine involved in bone destruction and is highly expressed in synovial fluid B cells in patients with rheumatoid arthritis. In this study we sought to clarify the generation mechanism of RANKL(+) effector B cells and their impacts on osteoclast differentiation. Peripheral blood and synovial fluid B cells from healthy controls and patients with rheumatoid arthritis were isolated using cell sorter. mRNA expression of RANKL, osteoprotegerin, tumor necrosis factor (TNF)-α, and Blimp-1 was analyzed by quantitative real-time polymerase chain reaction. Levels of RANKL, CD80, CD86, and CXCR3 were analyzed using flow cytometry. Functional analysis of osteoclastogenesis was carried out in the co-culture system using macrophage RAW264 reporter cells. RANKL expression was accentuated in CD80(+)CD86(+) B cells, a highly activated B-cell subset more abundantly observed in patients with rheumatoid arthritis. Upon activation via B-cell receptor and CD40, switched-memory B cells predominantly expressed RANKL, which was further augmented by interferon-γ (IFN-γ) but suppressed by interleukin-21. Strikingly, IFN-γ also enhanced TNF-α expression, while it strongly suppressed osteoprotegerin expression in B cells. IFN-γ increased the generation of CXCR3(+)RANKL(+) effector B cells, mimicking the synovial B cell phenotype in patients with rheumatoid arthritis. Finally, RANKL(+) effector B cells in concert with TNF-α facilitated osteoclast differentiation in vitro. Our current findings have shed light on the generation mechanism of pathogenic RANKL(+) effector B cells that would be an ideal therapeutic target for rheumatoid arthritis in the future.

  5. 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.

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

    ClinicalTrials.gov

    2017-10-06

    BCL2 Gene Rearrangement; BCL6 Gene Rearrangement; Diffuse Large B-Cell Lymphoma, Not Otherwise Specified; High-Grade B-Cell Lymphoma With MYC and BCL2 and/or BCL6 Rearrangements; MYC Gene Rearrangement; 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

  7. Type III hypersensitivity reactions to a B cell epitope antigen are abrogated using a depot forming vaccine platform.

    PubMed

    MacDonald, Lisa D; MacKay, Alecia; Kaliaperumal, Valarmathy; Weir, Genevieve; Penwell, Andrea; Rajagopalan, Rajkannan; Langley, Joanne; Halperin, Scott; Mansour, Marc; Stanford, Marianne M

    2017-09-21

    Peptide antigens are combined with an adjuvant in order to increase immunogenicity in vivo. The immunogenicity and safety of a RSV vaccine formulated in a novel oil-based platform, DepoVax™ (DPX), was compared to an alum formulation. A peptide B cell epitope derived from RSV small hydrophobic ectodomain (SHe) served as the antigen. Both vaccines induced SHe-specific antibodies after immunization of mice. A single dose of the DPX-based formulation resulted in anti-SHe titres for up to 20 weeks. Boosting with Alum-SHe, but not with DPX-SHe, led to unexpected clinical signs such as decreased activity, cyanosis and drop in body temperature in mice but not in rabbits. The severity of adverse reactions correlated with magnitude of SHe-specific IgG immune responses and decreased complement component 3 plasma levels, indicating a type III hypersensitivity reaction. By RP-HPLC analysis, we found that only 8-20% of the antigen was found to be adsorbed to alum in vitro, indicating that this antigen is likely released systemically upon injection in vivo. Clinical signs were not observed in rabbits, indicating the response correlates with peptide dose relative to size of animal. These results suggest that peptide antigens targeted to produce B cell mediated response may result in increased incidence of type III hypersensitivity reactions when delivered in non-depot forming vaccines. The DPX formulation induced strong antibody titres to the antigen without causing adverse events, likely due to the strength of the depot in vivo, and demonstrates the potential safety and immunogenicity of this platform for B cell peptide antigens.

  8. 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.

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

    PubMed Central

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

    2015-01-01

    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. PMID:25742773

  10. Intrinsic Toll-like receptor signalling drives regulatory function in B cells.

    PubMed

    Shen, Ping; Lampropoulou, Vicky; Stervbo, Ulrik; Hilgenberg, Ellen; Ries, Stefanie; Mecqinion, Aurelie; Fillatreau, Simon

    2013-01-01

    B cells can contribute to immunity through production of antibodies, presentation of antigen to T cells, and secretion of cytokines. B cell activation can result in various outcomes for the host. In general B cell responses are beneficial during infections, and deleterious during autoimmune diseases. However, B cells can also limit host defence against pathogens, and protect from autoimmune pathologies. B cells can therefore act both as drivers and as regulators of immunity. Understanding how these opposite functions are mediated shall stimulate the elaboration of novel approaches for manipulating the immune system. B cells might acquire distinct functional properties depending on their mode of activation. Antigen-specific B cell responses require triggering of B cell receptor (BCR) by antigen, and provision of helper signals by T cells. B cells also express various innate immune receptors, and can directly respond to microbial products. Here, we discuss how intrinsic signalling via Toll-like receptors contributes to the suppressive functions of B cells during autoimmune and infectious diseases.

  11. B cells in chronic obstructive pulmonary disease: moving to center stage

    PubMed Central

    Polverino, Francesca; Seys, Leen J. M.; Bracke, Ken R.

    2016-01-01

    Chronic inflammatory responses in the lungs contribute to the development and progression of chronic obstructive pulmonary disease (COPD). Although research studies focused initially on the contributions of the innate immune system to the pathogenesis of COPD, more recent studies have implicated adaptive immune responses in COPD. In particular, studies have demonstrated increases in B cell counts and increases in the number and size of B cell-rich lymphoid follicles in COPD lungs that correlate directly with COPD severity. There are also increases in lung levels of mediators that promote B cell maturation, activation, and survival in COPD patients. B cell products such as autoantibodies directed against lung cells, components of cells, and extracellular matrix proteins are also present in COPD lungs. These autoantibodies may contribute to lung inflammation and injury in COPD patients, in part, by forming immune complexes that activate complement components. Studies of B cell-deficient mice and human COPD patients have linked B cells most strongly to the emphysema phenotype. However, B cells have protective activities during acute exacerbations of COPD by promoting adaptive immune responses that contribute to host defense against pathogens. This review outlines the evidence that links B cells and B cell-rich lymphoid follicles to the pathogenesis of COPD and the mechanisms involved. It also reviews the potential and limitations of B cells as therapeutic targets to slow the progression of human COPD. PMID:27542809

  12. B cells in chronic obstructive pulmonary disease: moving to center stage.

    PubMed

    Polverino, Francesca; Seys, Leen J M; Bracke, Ken R; Owen, Caroline A

    2016-10-01

    Chronic inflammatory responses in the lungs contribute to the development and progression of chronic obstructive pulmonary disease (COPD). Although research studies focused initially on the contributions of the innate immune system to the pathogenesis of COPD, more recent studies have implicated adaptive immune responses in COPD. In particular, studies have demonstrated increases in B cell counts and increases in the number and size of B cell-rich lymphoid follicles in COPD lungs that correlate directly with COPD severity. There are also increases in lung levels of mediators that promote B cell maturation, activation, and survival in COPD patients. B cell products such as autoantibodies directed against lung cells, components of cells, and extracellular matrix proteins are also present in COPD lungs. These autoantibodies may contribute to lung inflammation and injury in COPD patients, in part, by forming immune complexes that activate complement components. Studies of B cell-deficient mice and human COPD patients have linked B cells most strongly to the emphysema phenotype. However, B cells have protective activities during acute exacerbations of COPD by promoting adaptive immune responses that contribute to host defense against pathogens. This review outlines the evidence that links B cells and B cell-rich lymphoid follicles to the pathogenesis of COPD and the mechanisms involved. It also reviews the potential and limitations of B cells as therapeutic targets to slow the progression of human COPD. Copyright © 2016 the American Physiological Society.

  13. 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

  14. 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.

  15. 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