1
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Shimizu T, Sun L, Ohnishi K. Influence of pre-B cell receptor deficiency on the immunoglobulin repertoires in peripheral blood B cells before and after immunization. Mol Immunol 2024; 166:87-100. [PMID: 38271880 DOI: 10.1016/j.molimm.2024.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Revised: 11/17/2023] [Accepted: 01/03/2024] [Indexed: 01/27/2024]
Abstract
During B cell development, pre-B cell receptor (pre-BCR), comprising the immunoglobulin heavy chain (HC) and surrogate light chain (SLC), plays a crucial role. The expression of pre-BCR serves as a certification of HC quality, confirming its ability to associate with the SLC and light chain (LC). In mice lacking SLC, the absence of this quality control mechanism leads to a distorted repertoire of HCs in the spleen and bone marrow. In this study, we conducted a comparative analysis of the immunoglobulin gene repertoire in peripheral blood cells of both wild-type mice and pre-BCR-deficient mice. Our findings reveal differences not only in the μ HC repertoire but also in the α HC and κ LC repertoires of the pre-BCR-deficient mice. These results suggest that the pre-BCR-mediated quality check of HC influences the selection of class-switched HC and LC repertoires. To further explore the impact of pre-BCR deficiency, we immunized these mice with thymus-dependent antigens and compared the antigen-responding repertoires. Our observations indicate that the affinity maturation pathways remain consistent between wild-type mice and pre-BCR-deficient mice, albeit with variations in the degree of maturation.
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Affiliation(s)
- Takeyuki Shimizu
- Department of Immunology, Kochi Medical School, Kochi University, Nankoku, Kochi 783-8505, Japan.
| | - Lin Sun
- Department of Immunology, National Institute of Infectious Diseases, Shinjuku, Tokyo 162-8640, Japan
| | - Kazuo Ohnishi
- Department of Immunology, National Institute of Infectious Diseases, Shinjuku, Tokyo 162-8640, Japan
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2
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Wang H, Huang Y, Xu C. Charging CAR by electrostatic power. Immunol Rev 2023; 320:138-146. [PMID: 37366589 DOI: 10.1111/imr.13232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 06/13/2023] [Indexed: 06/28/2023]
Abstract
Chimeric antigen receptor (CAR)-T cell therapy has emerged as a promising approach for cancer treatment. CAR is a synthetic immune receptor that recognizes tumor antigen and activates T cells through multiple signaling pathways. However, the current CAR design is not as robust as T cell receptor (TCR), a natural antigen receptor with high sensitivity and efficiency. TCR signaling relies on specific molecular interactions, and thus electrostatic force, the major force of molecular interactions, play critical roles. Understanding how electrostatic charge regulates TCR/CAR signaling events will facilitate the development of next-generation T cell therapies. This review summarizes recent findings on the roles of electrostatic interactions in both natural and synthetic immune receptor signaling, specifically that in CAR clustering and effector molecule recruitments, and highlights potential strategies for engineering CAR-T cell therapy by leveraging charge-based interactions.
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Affiliation(s)
- Haopeng Wang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Shanghai Clinical Research and Trial Center, Shanghai, China
| | - Yuwei Huang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Lingang Laboratory, Shanghai, China
| | - Chenqi Xu
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
- School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China
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3
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Mamidi MK, Huang J, Honjo K, Li R, Tabengwa EM, Neeli I, Randall NL, Ponnuchetty MV, Radic M, Leu CM, Davis RS. FCRL1 immunoregulation in B cell development and malignancy. Front Immunol 2023; 14:1251127. [PMID: 37822931 PMCID: PMC10562807 DOI: 10.3389/fimmu.2023.1251127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/01/2023] [Indexed: 10/13/2023] Open
Abstract
Immunotherapeutic targeting of surface regulatory proteins and pharmacologic inhibition of critical signaling pathways has dramatically shifted our approach to the care of individuals with B cell malignancies. This evolution in therapy reflects the central role of the B cell receptor (BCR) signaling complex and its co-receptors in the pathogenesis of B lineage leukemias and lymphomas. Members of the Fc receptor-like gene family (FCRL1-6) encode cell surface receptors with complex tyrosine-based regulation that are preferentially expressed by B cells. Among them, FCRL1 expression peaks on naïve and memory B cells and is unique in terms of its intracellular co-activation potential. Recent studies in human and mouse models indicate that FCRL1 contributes to the formation of the BCR signalosome, modulates B cell signaling, and promotes humoral responses. Progress in understanding its regulatory properties, along with evidence for its over-expression by mature B cell leukemias and lymphomas, collectively imply important yet unmet opportunities for FCRL1 in B cell development and transformation. Here we review recent advances in FCRL1 biology and highlight its emerging significance as a promising biomarker and therapeutic target in B cell lymphoproliferative disorders.
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Affiliation(s)
- Murali K. Mamidi
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Jifeng Huang
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Kazuhito Honjo
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ran Li
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Edlue M. Tabengwa
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Indira Neeli
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Nar’asha L. Randall
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Manasa V. Ponnuchetty
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Marko Radic
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Chuen-Miin Leu
- Institute of Microbiology and Immunology, National Yang Ming ChiaoTung University, Taipei, Taiwan
| | - Randall S. Davis
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Departments of Microbiology, and Biochemistry & Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, United States
- O’Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, United States
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4
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Tuning charge density of chimeric antigen receptor optimizes tonic signaling and CAR-T cell fitness. Cell Res 2023; 33:341-354. [PMID: 36882513 PMCID: PMC10156745 DOI: 10.1038/s41422-023-00789-0] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 02/10/2023] [Indexed: 03/09/2023] Open
Abstract
Tonic signaling of chimeric antigen receptor (CAR), i.e., the spontaneous CAR activation in the absence of tumor antigen stimulation, is considered to be a pivotal event controlling CAR-T efficacy. However, the molecular mechanism underlying the spontaneous CAR signals remains elusive. Here, we unveil that positively charged patches (PCPs) on the surface of the CAR antigen-binding domain mediate CAR clustering and result in CAR tonic signaling. For CARs with high tonic signaling (e.g., GD2.CAR and CSPG4.CAR), reducing PCPs on CARs or boosting ionic strength in the culture medium during ex vivo CAR-T cell expansion minimizes spontaneous CAR activation and alleviates CAR-T cell exhaustion. In contrast, introducing PCPs into the CAR with weak tonic signaling, such as CD19.CAR, results in improved in vivo persistence and superior antitumor function. These results demonstrate that CAR tonic signaling is induced and maintained by PCP-mediated CAR clustering. Notably, the mutations we generated to alter the PCPs maintain the antigen-binding affinity and specificity of the CAR. Therefore, our findings suggest that the rational tuning of PCPs to optimize tonic signaling and in vivo fitness of CAR-T cells is a promising design strategy for the next-generation CAR.
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5
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Zhang T, Zhang M, Yang L, Gao L, Sun W. Potential targeted therapy based on deep insight into the relationship between the pulmonary microbiota and immune regulation in lung fibrosis. Front Immunol 2023; 14:1032355. [PMID: 36761779 PMCID: PMC9904240 DOI: 10.3389/fimmu.2023.1032355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 01/09/2023] [Indexed: 01/26/2023] Open
Abstract
Pulmonary fibrosis is an irreversible disease, and its mechanism is unclear. The lung is a vital organ connecting the respiratory tract and the outside world. The changes in lung microbiota affect the progress of lung fibrosis. The latest research showed that lung microbiota differs in healthy people, including idiopathic pulmonary fibrosis (IPF) and acute exacerbation-idiopathic pulmonary fibrosis (AE-IPF). How to regulate the lung microbiota and whether the potential regulatory mechanism can become a necessary targeted treatment of IPF are unclear. Some studies showed that immune response and lung microbiota balance and maintain lung homeostasis. However, unbalanced lung homeostasis stimulates the immune response. The subsequent biological effects are closely related to lung fibrosis. Core fucosylation (CF), a significant protein functional modification, affects the lung microbiota. CF regulates immune protein modifications by regulating key inflammatory factors and signaling pathways generated after immune response. The treatment of immune regulation, such as antibiotic treatment, vitamin D supplementation, and exosome micro-RNAs, has achieved an initial effect in clearing the inflammatory storm induced by an immune response. Based on the above, the highlight of this review is clarifying the relationship between pulmonary microbiota and immune regulation and identifying the correlation between the two, the impact on pulmonary fibrosis, and potential therapeutic targets.
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Affiliation(s)
- Tao Zhang
- School of Medicine, Nankai University, Tianjin, China
| | - Min Zhang
- Department of Geriatric Endocrinology, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, Chengdu, China
| | - Liqing Yang
- Department of Respiratory and Critical Care Medicine, Sichuan Provincial People's Hospital, Chengdu, China
| | - Lingyun Gao
- Sichuan Provincial People's Hospital, Sichuan Academy of Medical Sciences, Chengdu, China,Medical College, University of Electronic Science and Technology, Chengdu, China,Guanghan People's Hospital, Guanghan, China,*Correspondence: Wei Sun, ; Lingyun Gao,
| | - Wei Sun
- Department of Respiratory and Critical Care Medicine, Sichuan Provincial People's Hospital, Chengdu, China,Medical College, University of Electronic Science and Technology, Chengdu, China,*Correspondence: Wei Sun, ; Lingyun Gao,
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Kerketta R, Erasmus MF, Wilson BS, Halasz AM, Edwards JS. Spatial Stochastic Model of the Pre-B Cell Receptor. IEEE/ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS 2023; 20:683-693. [PMID: 35482702 PMCID: PMC10123485 DOI: 10.1109/tcbb.2022.3166149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Survival and proliferation of immature B lymphocytes requires expression and tonic signaling of the pre-B cell receptor (pre-BCR). This low level, ligand-independent signaling is likely achieved through frequent, but short-lived, homo interactions. Tonic signaling is also central in the pathology of precursor B acute lymphoblastic leukemia (B-ALL). In order to understand how repeated, transient events can lead to sustained signaling and to assess the impact of receptor accumulation induced by the membrane landscape, we developed a spatial stochastic model of receptor aggregation and downstream signaling events. Our rule- and agent-based model builds on previous mature BCR signaling models and incorporates novel parameters derived from single particle tracking of pre-BCR on surfaces of two different B-ALL cell lines, 697 and Nalm6. Live cell tracking of receptors on the two cell lines revealed characteristic differences in their dimer dissociation rates and diffusion coefficients. We report here that these differences affect pre-BCR aggregation and consequent signal initiation events. Receptors on Nalm6 cells, which have a lower off-rate and lower diffusion coefficient, more frequently form higher order oligomers than pre-BCR on 697 cells, resulting in higher levels of downstream phosphorylation in the Nalm6 cell line.
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7
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Ott JA, Haakenson JK, Kelly AR, Christian C, Criscitiello MF, Smider VV. Evolution of surrogate light chain in tetrapods and the relationship between lengths of CDR H3 and VpreB tails. Front Immunol 2022; 13:1001134. [PMID: 36311706 PMCID: PMC9614664 DOI: 10.3389/fimmu.2022.1001134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 09/20/2022] [Indexed: 12/05/2022] Open
Abstract
In the mammalian immune system, the surrogate light chain (SLC) shapes the antibody repertoire during B cell development by serving as a checkpoint for production of functional heavy chains (HC). Structural studies indicate that tail regions of VpreB contact and cover the third complementarity-determining region of the HC (CDR H3). However, some species, particularly bovines, have CDR H3 regions that may not be compatible with this HC-SLC interaction model. With immense structural and genetic diversity in antibody repertoires across species, we evaluated the genetic origins and sequence features of surrogate light chain components. We examined tetrapod genomes for evidence of conserved gene synteny to determine the evolutionary origin of VpreB1, VpreB2, and IGLL1, as well as VpreB3 and pre-T cell receptor alpha (PTCRA) genes. We found the genes for the SLC components (VpreB1, VpreB2, and IGLL1) only in eutherian mammals. However, genes for PTCRA occurred in all amniote groups and genes for VpreB3 occurred in all tetrapod groups, and these genes were highly conserved. Additionally, we found evidence of a new VpreB gene in non-mammalian tetrapods that is similar to the VpreB2 gene of eutherian mammals, suggesting VpreB2 may have appeared earlier in tetrapod evolution and may be a precursor to traditional VpreB2 genes in higher vertebrates. Among eutherian mammals, sequence conservation between VpreB1 and VpreB2 was low for all groups except rabbits and rodents, where VpreB2 was nearly identical to VpreB1 and did not share conserved synteny with VpreB2 of other species. VpreB2 of rabbits and rodents likely represents a duplicated variant of VpreB1 and is distinct from the VpreB2 of other mammals. Thus, rabbits and rodents have two variants of VpreB1 (VpreB1-1 and VpreB1-2) but no VpreB2. Sequence analysis of VpreB tail regions indicated differences in sequence content, charge, and length; where repertoire data was available, we observed a significant relationship between VpreB2 tail length and maximum DH length. We posit that SLC components co-evolved with immunoglobulin HC to accommodate the repertoire - particularly CDR H3 length and structure, and perhaps highly unusual HC (like ultralong HC of cattle) may bypass this developmental checkpoint altogether.
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Affiliation(s)
- Jeannine A. Ott
- Comparative Immunogenetics Lab, Department of Veterinary Pathobiology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
| | - Jeremy K. Haakenson
- Applied Biomedical Science Institute, San Diego, CA, United States
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - Abigail R. Kelly
- Applied Biomedical Science Institute, San Diego, CA, United States
| | - Claire Christian
- Comparative Immunogenetics Lab, Department of Veterinary Pathobiology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
| | - Michael F. Criscitiello
- Comparative Immunogenetics Lab, Department of Veterinary Pathobiology, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
| | - Vaughn V. Smider
- Applied Biomedical Science Institute, San Diego, CA, United States
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
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8
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Ullah H, Zhang B, Sharma NK, McCrea PD, Srivastava Y. In-silico probing of AML related RUNX1 cancer-associated missense mutations: Predicted relationships to DNA binding and drug interactions. Front Mol Biosci 2022; 9:981020. [PMID: 36090034 PMCID: PMC9454315 DOI: 10.3389/fmolb.2022.981020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 07/19/2022] [Indexed: 11/24/2022] Open
Abstract
The molecular consequences of cancer associated mutations in Acute myeloid leukemia (AML) linked factors are not very well understood. Here, we interrogated the COSMIC database for missense mutations associated with the RUNX1 protein, that is frequently mis-regulated in AML, where we sought to identify recurrently mutated positions at the DNA-interacting interface. Indeed, six of the mutated residues, out of a total 417 residues examined within the DNA binding domain, evidenced reduced DNA association in in silico predictions. Further, given the prominence of RUNX1’s compromised function in AML, we asked the question if the mutations themselves might alter RUNX1’s interaction (off-target) with known FDA-approved drug molecules, including three currently used in treating AML. We identified several AML-associated mutations in RUNX1 that were calculated to enhance RUNX1’s interaction with specific drugs. Specifically, we retrieved data from the COSMIC database for cancer-associated mutations of RUNX1 by using R package “data.table” and “ggplot2” modules. In the presence of DNA and/or drug, we used docking scores and energetics of the complexes as tools to evaluate predicted interaction strengths with RUNX1. For example, we performed predictions of drug binding pockets involving Enasidenib, Giltertinib, and Midostaurin (AML associated), as well as ten different published cancer associated drug compounds. Docking of wild type RUNX1 with these 13 different cancer-associated drugs indicates that wild-type RUNX1 has a lower efficiency of binding while RUNX1 mutants R142K, D171N, R174Q, P176H, and R177Q suggested higher affinity of drug association. Literature evidence support our prediction and suggests the mutation R174Q affects RUNX1 DNA binding and could lead to compromised function. We conclude that specific RUNX1 mutations that lessen DNA binding facilitate the binding of a number of tested drug molecules. Further, we propose that molecular modeling and docking studies for RUNX1 in the presence of DNA and/or drugs enables evaluation of the potential impact of RUNX1 cancer associated mutations in AML.
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Affiliation(s)
- Hanif Ullah
- Guangxi Key Laboratory for Genomics and Personalized Medicine, Guangxi Collaborative Innovation Center for Genomics and Personalized Medicine, Guangxi Medical University, Nanning, China
- Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Baoyun Zhang
- Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Narendra Kumar Sharma
- Department of Bioscience and Biotechnology, Banasthali Vidyapith, Banasthali, Tonk, Rajasthan, India
| | - Pierre D. McCrea
- University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Yogesh Srivastava
- University of Chinese Academy of Sciences, Beijing, China
- Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, TX, United States
- Genome Regulation Laboratory; Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
- *Correspondence: Yogesh Srivastava,
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Nguyen K, Alsaati N, Le Coz C, Romberg N. Genetic obstacles to developing and tolerizing human B cells. WIREs Mech Dis 2022; 14:e1554. [DOI: 10.1002/wsbm.1554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/17/2022] [Accepted: 02/19/2022] [Indexed: 11/11/2022]
Affiliation(s)
- Kim Nguyen
- Division of Immunology and Allergy Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Nouf Alsaati
- Division of Immunology and Allergy Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Carole Le Coz
- Division of Immunology and Allergy Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Neil Romberg
- Division of Immunology and Allergy Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Department of Pediatrics, Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania USA
- Institute for Immunology University of Pennsylvania Philadelphia Pennsylvania USA
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10
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Sun Y, Li X, Wang T, Li W. Core Fucosylation Regulates the Function of Pre-BCR, BCR and IgG in Humoral Immunity. Front Immunol 2022; 13:844427. [PMID: 35401499 PMCID: PMC8990897 DOI: 10.3389/fimmu.2022.844427] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 02/25/2022] [Indexed: 11/20/2022] Open
Abstract
Most of the membrane molecules involved in immune response are glycosylated. N-glycans linked to asparagine (Asn) of immune molecules contribute to the protein conformation, surface expression, stability, and antigenicity. Core fucosylation catalyzed by core fucosyltransferase (FUT8) is the most common post-translational modification. Core fucosylation is essential for evoking a proper immune response, which this review aims to communicate. First, FUT8 deficiency suppressed the interaction between μHC and λ5 during pre-BCR assembly is given. Second, we described the effects of core fucosylation in B cell signal transduction via BCR. Third, we investigated the role of core fucosylation in the interaction between helper T (TH) cells and B cells. Finally, we showed the role of FUT8 on the biological function of IgG. In this review, we discussed recent insights into the sites where core fucosylation is critical for humoral immune responses.
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Affiliation(s)
- Yuhan Sun
- College of Basic Medical Science, Dalian Medical University, Dalian, China
- Division of Regulatory Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Pharmaceutical University, Sendai, Japan
| | - Xueying Li
- Research Institute for Microbial Diseases and World Premier International Immunology Frontier Research Center, Osaka University, Suita, Japan
| | - Tiantong Wang
- College of Basic Medical Science, Dalian Medical University, Dalian, China
| | - Wenzhe Li
- College of Basic Medical Science, Dalian Medical University, Dalian, China
- *Correspondence: Wenzhe Li,
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Lee J, Rho JH, Roehrl MH, Wang JY. Dermatan Sulfate Is a Potential Regulator of IgH via Interactions With Pre-BCR, GTF2I, and BiP ER Complex in Pre-B Lymphoblasts. Front Immunol 2021; 12:680212. [PMID: 34113352 PMCID: PMC8185350 DOI: 10.3389/fimmu.2021.680212] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/05/2021] [Indexed: 12/11/2022] Open
Abstract
Dermatan sulfate (DS) and autoantigen (autoAg) complexes are capable of stimulating autoreactive CD5+ B1 cells. We examined the activity of DS on CD5+ pre-B lymphoblast NFS-25 cells. CD19, CD5, CD72, PI3K, and Fas possess varying degrees of DS affinity. The three pre-BCR components, Ig heavy chain mu (IgH), VpreB, and lambda 5, display differential DS affinities, with IgH having the strongest affinity. DS attaches to NFS-25 cells, gradually accumulates in the ER, and eventually localizes to the nucleus. DS and IgH co-localize on the cell surface and in the ER. DS associates strongly with 17 ER proteins (e.g., BiP/Grp78, Grp94, Hsp90ab1, Ganab, Vcp, Canx, Kpnb1, Prkcsh, Pdia3), which points to an IgH-associated multiprotein complex in the ER. In addition, DS interacts with nuclear proteins (Ncl, Xrcc6, Prmt5, Eftud2, Supt16h) and Lck. We also discovered that DS binds GTF2I, a required gene transcription factor at the IgH locus. These findings support DS as a potential regulator of IgH in pre-B cells at protein and gene levels. We propose a (DS•autoAg)-autoBCR dual signal model in which an autoBCR is engaged by both autoAg and DS, and, once internalized, DS recruits a cascade of molecules that may help avert apoptosis and steer autoreactive B cell fate. Through its affinity with autoAgs and its control of IgH, DS emerges as a potential key player in the development of autoreactive B cells and autoimmunity.
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Affiliation(s)
- Jongmin Lee
- Department of Molecular and Cell Biology, Boston University School of Dental Medicine, Boston, MA, United States
| | - Jung-hyun Rho
- MP Biomedicals New Zealand Limited, Auckland, New Zealand
| | - Michael H. Roehrl
- Department of Pathology and Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, United States
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Do PC, Nguyen TH, Vo UHM, Le L. iBRAB: In silico based-designed broad-spectrum Fab against H1N1 influenza A virus. PLoS One 2020; 15:e0239112. [PMID: 33382708 PMCID: PMC7774956 DOI: 10.1371/journal.pone.0239112] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 12/15/2020] [Indexed: 11/19/2022] Open
Abstract
Influenza virus A is a significant agent involved in the outbreak of worldwide epidemics, causing millions of fatalities around the world by respiratory diseases and seasonal illness. Many projects had been conducting to investigate recovered infected patients for therapeutic vaccines that have broad-spectrum activity. With the aid of the computational approach in biology, the designation for a vaccine model is more accessible. We developed an in silico protocol called iBRAB to design a broad-reactive Fab on a wide range of influenza A virus. The Fab model was constructed based on sequences and structures of available broad-spectrum Abs or Fabs against a wide range of H1N1 influenza A virus. As a result, the proposed Fab model followed iBRAB has good binding affinity over 27 selected HA of different strains of H1 influenza A virus, including wild-type and mutated ones. The examination also took by computational tools to fasten the procedure. This protocol could be applied for a fast-designed therapeutic vaccine against different types of threats.
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MESH Headings
- Amino Acid Sequence
- Antibodies, Viral/chemistry
- Antibodies, Viral/genetics
- Antigens, Viral/chemistry
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Binding Sites
- Computer Simulation
- Drug Design
- Hemagglutinin Glycoproteins, Influenza Virus/chemistry
- Hemagglutinin Glycoproteins, Influenza Virus/genetics
- Hemagglutinin Glycoproteins, Influenza Virus/immunology
- Humans
- Immunoglobulin Fab Fragments/chemistry
- Immunoglobulin Fab Fragments/genetics
- Influenza A Virus, H1N1 Subtype/immunology
- Influenza Vaccines/administration & dosage
- Influenza Vaccines/biosynthesis
- Influenza, Human/immunology
- Influenza, Human/prevention & control
- Influenza, Human/virology
- Molecular Docking Simulation
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Interaction Domains and Motifs
- Sequence Alignment
- Sequence Homology, Amino Acid
- Thermodynamics
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Affiliation(s)
- Phuc-Chau Do
- School of Biotechnology, International University, Thu Duc District, Hochiminh City, Vietnam
- Vietnam National University Ho Chi Minh City, Thu Duc District, Hochiminh City, Vietnam
| | - Trung H. Nguyen
- School of Biotechnology, International University, Thu Duc District, Hochiminh City, Vietnam
- Vietnam National University Ho Chi Minh City, Thu Duc District, Hochiminh City, Vietnam
| | - Uyen H. M. Vo
- School of Biotechnology, International University, Thu Duc District, Hochiminh City, Vietnam
- Vietnam National University Ho Chi Minh City, Thu Duc District, Hochiminh City, Vietnam
| | - Ly Le
- School of Biotechnology, International University, Thu Duc District, Hochiminh City, Vietnam
- Vietnam National University Ho Chi Minh City, Thu Duc District, Hochiminh City, Vietnam
- Vingroup Big Data Institute, Hai Ba Trung District, Ha Noi, Vietnam
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13
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Conditional antibody expression to avoid central B cell deletion in humanized HIV-1 vaccine mouse models. Proc Natl Acad Sci U S A 2020; 117:7929-7940. [PMID: 32209668 DOI: 10.1073/pnas.1921996117] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
HIV-1 vaccine development aims to elicit broadly neutralizing antibodies (bnAbs) against diverse viral strains. In some HIV-1-infected individuals, bnAbs evolved from precursor antibodies through affinity maturation. To induce bnAbs, a vaccine must mediate a similar antibody maturation process. One way to test a vaccine is to immunize mouse models that express human bnAb precursors and assess whether the vaccine can convert precursor antibodies into bnAbs. A major problem with such mouse models is that bnAb expression often hinders B cell development. Such developmental blocks may be attributed to the unusual properties of bnAb variable regions, such as poly-reactivity and long antigen-binding loops, which are usually under negative selection during primary B cell development. To address this problem, we devised a method to circumvent such B cell developmental blocks by expressing bnAbs conditionally in mature B cells. We validated this method by expressing the unmutated common ancestor (UCA) of the human VRC26 bnAb in transgenic mice. Constitutive expression of the VRC26UCA led to developmental arrest of B cell progenitors in bone marrow; poly-reactivity of the VRC26UCA and poor pairing of the VRC26UCA heavy chain with the mouse surrogate light chain may contribute to this phenotype. The conditional expression strategy bypassed the impediment to VRC26UCA B cell development, enabling the expression of VRC26UCA in mature B cells. This approach should be generally applicable for expressing other bnAbs that are under negative selection during B cell development.
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14
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de Barrios O, Meler A, Parra M. MYC's Fine Line Between B Cell Development and Malignancy. Cells 2020; 9:E523. [PMID: 32102485 PMCID: PMC7072781 DOI: 10.3390/cells9020523] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 12/12/2022] Open
Abstract
The transcription factor MYC is transiently expressed during B lymphocyte development, and its correct modulation is essential in defined developmental transitions. Although temporary downregulation of MYC is essential at specific points, basal levels of expression are maintained, and its protein levels are not completely silenced until the B cell becomes fully differentiated into a plasma cell or a memory B cell. MYC has been described as a proto-oncogene that is closely involved in many cancers, including leukemia and lymphoma. Aberrant expression of MYC protein in these hematological malignancies results in an uncontrolled rate of proliferation and, thereby, a blockade of the differentiation process. MYC is not activated by mutations in the coding sequence, and, as reviewed here, its overexpression in leukemia and lymphoma is mainly caused by gene amplification, chromosomal translocations, and aberrant regulation of its transcription. This review provides a thorough overview of the role of MYC in the developmental steps of B cells, and of how it performs its essential function in an oncogenic context, highlighting the importance of appropriate MYC regulation circuitry.
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Affiliation(s)
| | | | - Maribel Parra
- Lymphocyte Development and Disease Group, Josep Carreras Leukaemia Research Institute, IJC Building, Campus ICO-Germans Trias i Pujol, Ctra de Can Ruti, 08916 Barcelona, Spain (A.M.)
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15
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Honjo K, Won WJ, King RG, Ianov L, Crossman DK, Easlick JL, Shakhmatov MA, Khass M, Vale AM, Stephan RP, Li R, Davis RS. Fc Receptor-Like 6 (FCRL6) Discloses Progenitor B Cell Heterogeneity That Correlates With Pre-BCR Dependent and Independent Pathways of Natural Antibody Selection. Front Immunol 2020; 11:82. [PMID: 32117244 PMCID: PMC7033751 DOI: 10.3389/fimmu.2020.00082] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 01/13/2020] [Indexed: 11/24/2022] Open
Abstract
B-1a cells produce "natural" antibodies (Abs) to neutralize pathogens and clear neo self-antigens, but the fundamental selection mechanisms that shape their polyreactive repertoires are poorly understood. Here, we identified a B cell progenitor subset defined by Fc receptor-like 6 (FCRL6) expression, harboring innate-like defense, migration, and differentiation properties conducive for natural Ab generation. Compared to FCRL6- pro B cells, the repressed mitotic, DNA damage repair, and signaling activity of FCRL6+ progenitors, yielded VH repertoires with biased distal Ighv segment accessibility, constrained diversity, and hydrophobic and charged CDR-H3 sequences. Beyond nascent autoreactivity, VH11 productivity, which predominates phosphatidylcholine-specific B-1a B cell receptors (BCRs), was higher for FCRL6+ cells as was pre-BCR formation, which was required for Myc induction and VH11, but not VH12, B-1a development. Thus, FCRL6 revealed unexpected heterogeneity in the developmental origins, regulation, and selection of natural Abs at the pre-BCR checkpoint with implications for autoimmunity and lymphoproliferative disorders.
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MESH Headings
- Animals
- Antibodies/immunology
- Antibodies/metabolism
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Female
- Humans
- Immunoglobulin Heavy Chains/genetics
- Immunoglobulin Heavy Chains/immunology
- Immunoglobulin Variable Region/genetics
- Immunoglobulin Variable Region/immunology
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Phosphatidylcholines/immunology
- Phosphatidylcholines/metabolism
- Precursor Cells, B-Lymphoid/immunology
- Precursor Cells, B-Lymphoid/metabolism
- Receptors, Antigen, B-Cell/genetics
- Receptors, Antigen, B-Cell/immunology
- Receptors, Antigen, B-Cell/metabolism
- Receptors, Fc/genetics
- Receptors, Fc/immunology
- Receptors, Fc/metabolism
- Signal Transduction/genetics
- Signal Transduction/immunology
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Affiliation(s)
- Kazuhito Honjo
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Woong-Jai Won
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Rodney G. King
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Lara Ianov
- Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL, United States
| | - David K. Crossman
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Juliet L. Easlick
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mikhail A. Shakhmatov
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Mohamed Khass
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Genetic Engineering and Biotechnology Division, National Research Center, Cairo, Egypt
| | - Andre M. Vale
- Program in Immunobiology, Carlos Chagas Filho Institute of Biophysics, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil
| | - Robert P. Stephan
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ran Li
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Randall S. Davis
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, United States
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, AL, United States
- Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, United States
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16
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Zehentmeier S, Pereira JP. Cell circuits and niches controlling B cell development. Immunol Rev 2020; 289:142-157. [PMID: 30977190 DOI: 10.1111/imr.12749] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 02/06/2023]
Abstract
Studies over the last decade uncovered overlapping niches for hematopoietic stem cells (HSCs), multipotent progenitor cells, common lymphoid progenitors, and early B cell progenitors. HSC and lymphoid niches are predominantly composed by mesenchymal progenitor cells (MPCs) and by a small subset of endothelial cells. Niche cells create specialized microenvironments through the concomitant production of short-range acting cell-fate determining cytokines such as interleukin (IL)-7 and stem cell factor and the potent chemoattractant C-X-C motif chemokine ligand 12. This type of cellular organization allows for the cross-talk between hematopoietic stem and progenitor cells with niche cells, such that niche cell activity can be regulated by the quality and quantity of hematopoietic progenitors being produced. For example, preleukemic B cell progenitors and preB acute lymphoblastic leukemias interact directly with MPCs, and downregulate IL-7 expression and the production of non-leukemic lymphoid cells. In this review, we discuss a novel model of B cell development that is centered on cellular circuits formed between B cell progenitors and lymphopoietic niches.
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Affiliation(s)
- Sandra Zehentmeier
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut
| | - João P Pereira
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut
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17
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Spangler JB, Moraga I, Jude KM, Savvides CS, Garcia KC. A strategy for the selection of monovalent antibodies that span protein dimer interfaces. J Biol Chem 2019; 294:13876-13886. [PMID: 31387945 PMCID: PMC6755802 DOI: 10.1074/jbc.ra119.009213] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/15/2019] [Indexed: 11/06/2022] Open
Abstract
Ligand-induced dimerization is the predominant mechanism through which secreted proteins activate cell surface receptors to transmit essential biological signals. Cytokines are a large class of soluble proteins that dimerize transmembrane receptors into precise signaling topologies, but there is a need for alternative, engineerable ligand scaffolds that specifically recognize and stabilize these protein interactions. Recombinant antibodies can potentially serve as robust and versatile platforms for cytokine complex stabilization, and their specificity allows for tunable modulation of dimerization equilibrium. Here, we devised an evolutionary strategy to isolate monovalent antibody fragments that bridge together two different receptor subunits in a cytokine-receptor complex, precisely as the receptors are disposed in their natural signaling orientations. To do this, we screened a naive antibody library against a stabilized ligand-receptor ternary complex that acted as a "molecular cast" of the natural receptor dimer conformation. Our selections elicited "stapler" single-chain variable fragments (scFvs) of antibodies that specifically engage the interleukin-4 receptor heterodimer. The 3.1 Å resolution crystal structure of one such stapler revealed that, as intended, this scFv recognizes a composite epitope between the two receptors as they are positioned in the complex. Extending our approach, we evolved a stapler scFv that specifically binds to and stabilizes the interface between the interleukin-2 cytokine and one of its receptor subunits, leading to a 15-fold enhancement in interaction affinity. This demonstration that scFvs can be selected to recognize epitopes that span protein interfaces presents new opportunities to engineer structurally defined antibodies for a broad range of research and therapeutic applications.
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Affiliation(s)
- Jamie B Spangler
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94305 .,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305.,Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305.,Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21218.,Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218
| | - Ignacio Moraga
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94305.,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305.,Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305
| | - Kevin M Jude
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94305.,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305.,Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305
| | - Christina S Savvides
- Department of Biology, Stanford University School of Medicine, Stanford, California 94305
| | - K Christopher Garcia
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California 94305 .,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305.,Department of Structural Biology, Stanford University School of Medicine, Stanford, California 94305
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18
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Marques AT, Anjo SI, Bhide M, Varela Coelho A, Manadas B, Lecchi C, Grilli G, Ceciliani F. Changes in the intestinal mucosal proteome of turkeys (Meleagris gallopavo) infected with haemorrhagic enteritis virus. Vet Immunol Immunopathol 2019; 213:109880. [PMID: 31307669 DOI: 10.1016/j.vetimm.2019.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 06/04/2019] [Accepted: 06/07/2019] [Indexed: 10/26/2022]
Abstract
Haemorrhagic enteritis (HE) is a viral disease affecting intestinal integrity and barrier function in turkey (Meleagris gallopavo) and resulting in a significant economic loss. Sequential Windowed Acquisition of All Theoretical Fragment Ion Mass Spectra (SWATH-MS) was applied to identify crucial proteins involved in HE infection. A total of 938 proteins were identified and used to generate a reference library for SWATH-MS analysis. In total, 523 proteins were reliably quantified, and 64 proteins were found to be differentially expressed, including 49 up-regulated and 15 down-regulated proteins between healthy and HE-affected intestinal mucosa. Functional analysis suggested that these proteins were involved in the following categories of cellular pathways and metabolisms: 1) energy pathways; 2) intestine lipid and amino acid metabolism; 3) oxidative stress; 4) intestinal immune response. Major findings of this study demonstrated that natural HE infection is related to the changes in abundance of several proteins involved in cell-intrinsic immune defense against viral invasion, systemic inflammation, modulation of excessive inflammation, B and T cell development and function and antigen presentation. mRNA quantitative expression demonstrated that most of the proteins involved in innate immunity that were found to be differentially abundant were produced by intestinal mucosa, suggesting its direct involvement in immune defences against HE infection.
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Affiliation(s)
- Andreia Tomás Marques
- Università degli Studi di Milano, Department of Veterinary Medicine, Via Celoria 10, 20133, Milano, Italy
| | - Sandra I Anjo
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, Faculdade de Medicina, Pólo I, 1° andar, 3004-504, Coimbra, Portugal; Faculty of Sciences and Technology, University of Coimbra, Universidade de Coimbra - Pólo II, Rua Sílvio Lima, 3030-790, Coimbra, Portugal
| | - Mangesh Bhide
- Laboratory of Biomedical Microbiology and Immunology, University of Veterinary Medicine and Pharmacy, Komenskeho 73 Kosice, Slovakia
| | - Ana Varela Coelho
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Bruno Manadas
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Rua Larga, Faculdade de Medicina, Pólo I, 1° andar, 3004-504, Coimbra, Portugal
| | - Cristina Lecchi
- Università degli Studi di Milano, Department of Veterinary Medicine, Via Celoria 10, 20133, Milano, Italy
| | - Guido Grilli
- Università degli Studi di Milano, Department of Veterinary Medicine, Via Celoria 10, 20133, Milano, Italy
| | - Fabrizio Ceciliani
- Università degli Studi di Milano, Department of Veterinary Medicine, Via Celoria 10, 20133, Milano, Italy.
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19
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Khass M, Vale AM, Burrows PD, Schroeder HW. The sequences encoded by immunoglobulin diversity (D H ) gene segments play key roles in controlling B-cell development, antigen-binding site diversity, and antibody production. Immunol Rev 2019; 284:106-119. [PMID: 29944758 DOI: 10.1111/imr.12669] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Although at first glance the diversity of the immunoglobulin repertoire appears random, there are a number of mechanisms that act to constrain diversity. For example, key mechanisms controlling the diversity of the third complementarity determining region of the immunoglobulin heavy chain (CDR-H3) include natural selection of germline diversity (DH ) gene segment sequence and somatic selection upon passage through successive B-cell developmental checkpoints. To test the role of DH gene segment sequence, we generated a panel of mice limited to the use of a single germline or frameshifted DH gene segment. Specific individual amino acids within core DH gene segment sequence heavily influenced the absolute numbers of developing and mature B-cell subsets, antibody production, epitope recognition, protection against pathogen challenge, and susceptibility to the production of autoreactive antibodies. At the tip of the antigen-binding loop (PDB position 101) in CDR-H3, both natural (germline) and somatic selection favored tyrosine while disfavoring the presence of hydrophobic amino acids. Enrichment for arginine in CDR-H3 appeared to broaden recognition of epitopes of varying hydrophobicity, but led to diminished binding intensity and an increased likelihood of generating potentially pathogenic dsDNA-binding autoreactive antibodies. The phenotype of altering the sequence of the DH was recessive for T-independent antibody production, but dominant for T-cell-dependent responses. Our work suggests that the antibody repertoire is structured, with the sequence of individual DH selected by evolution to preferentially generate an apparently preferred category of antigen-binding sites. The result of this structured approach appears to be a repertoire that has been adapted, or optimized, to produce protective antibodies for a wide range of pathogen epitopes while reducing the likelihood of generating autoreactive specificities.
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Affiliation(s)
- Mohamed Khass
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.,Division of Genetic Engineering and Biotechnology, National Research Center, Cairo, Egypt
| | - Andre M Vale
- Program in Immunobiology, Laboratory of Lymphocyte Biology, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Peter D Burrows
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Harry W Schroeder
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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20
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Winkler TH, Mårtensson IL. The Role of the Pre-B Cell Receptor in B Cell Development, Repertoire Selection, and Tolerance. Front Immunol 2018; 9:2423. [PMID: 30498490 PMCID: PMC6249383 DOI: 10.3389/fimmu.2018.02423] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/01/2018] [Indexed: 11/18/2022] Open
Abstract
Around four decades ago, it had been observed that there were cell lines as well as cells in the fetal liver that expressed antibody μ heavy (μH) chains in the apparent absence of bona fide light chains. It was thus possible that these cells expressed another molecule(s), that assembled with μH chains. The ensuing studies led to the discovery of the pre-B cell receptor (pre-BCR), which is assembled from Ig μH and surrogate light (SL) chains, together with the signaling molecules Igα and β. It is expressed on a fraction of pro-B (pre-BI) cells and most large pre-B(II) cells, and has been implicated in IgH chain allelic exclusion and down-regulation of the recombination machinery, assessment of the expressed μH chains and shaping the IgH repertoire, transition from the pro-B to pre-B stage, pre-B cell expansion, and cessation.
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Affiliation(s)
- Thomas H Winkler
- Chair of Genetics, Department of Biology, Nikolaus-Fiebiger-Center for Molecular Medicine, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Inga-Lill Mårtensson
- Department of Rheumatology and Inflammation Research, Institute of Medicine, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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21
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Fahl SP, Daamen AR, Crittenden RB, Bender TP. c-Myb Coordinates Survival and the Expression of Genes That Are Critical for the Pre-BCR Checkpoint. THE JOURNAL OF IMMUNOLOGY 2018; 200:3450-3463. [PMID: 29654210 DOI: 10.4049/jimmunol.1302303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 03/13/2018] [Indexed: 11/19/2022]
Abstract
The c-Myb transcription factor is required for adult hematopoiesis, yet little is known about c-Myb function during lineage-specific differentiation due to the embryonic lethality of Myb-null mutations. We previously used tissue-specific inactivation of the murine Myb locus to demonstrate that c-Myb is required for differentiation to the pro-B cell stage, survival during the pro-B cell stage, and the pro-B to pre-B cell transition during B lymphopoiesis. However, few downstream mediators of c-Myb-regulated function have been identified. We demonstrate that c-Myb regulates the intrinsic survival of CD19+ pro-B cells in the absence of IL-7 by repressing expression of the proapoptotic proteins Bmf and Bim and that levels of Bmf and Bim mRNA are further repressed by IL-7 signaling in pro-B cells. c-Myb regulates two crucial components of the IL-7 signaling pathway: the IL-7Rα-chain and the negative regulator SOCS3 in CD19+ pro-B cells. Bypassing IL-7R signaling through constitutive activation of Stat5b largely rescues survival of c-Myb-deficient pro-B cells, whereas constitutively active Akt is much less effective. However, rescue of pro-B cell survival is not sufficient to rescue proliferation of pro-B cells or the pro-B to small pre-B cell transition, and we further demonstrate that c-Myb-deficient large pre-B cells are hypoproliferative. Analysis of genes crucial for the pre-BCR checkpoint demonstrates that, in addition to IL-7Rα, the genes encoding λ5, cyclin D3, and CXCR4 are downregulated in the absence of c-Myb, and λ5 is a direct c-Myb target. Thus, c-Myb coordinates survival with the expression of genes that are required during the pre-BCR checkpoint.
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Affiliation(s)
- Shawn P Fahl
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia Health System, Charlottesville, VA 22908; and
| | - Andrea R Daamen
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia Health System, Charlottesville, VA 22908; and
| | - Rowena B Crittenden
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia Health System, Charlottesville, VA 22908; and
| | - Timothy P Bender
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia Health System, Charlottesville, VA 22908; and .,Beirne B. Carter Center for Immunology Research, University of Virginia Health System, Charlottesville, VA 22908
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22
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Yamagata N, Chen X, Zhou J, Li J, Du X, Xu B. Enzymatic self-assembly of an immunoreceptor tyrosine-based inhibitory motif (ITIM). Org Biomol Chem 2017; 15:5689-5692. [PMID: 28675212 DOI: 10.1039/c7ob01074e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Here we show the first example of an immunoreceptor tyrosine-based inhibitory motif (ITIM), LYYYYL, as well as its enantiomeric or retro-inverso peptide, to self-assemble in water via enzyme-instructed self-assembly. Upon enzymatic dephosphorylation, the phosphohexapeptides become hexapeptides, which self-assemble in water to result in supramolecular hydrogels. This work illustrates a new approach to design bioinspired soft materials from a less explored, but important pool of immunomodulatory peptides.
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Affiliation(s)
- Natsuko Yamagata
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, USA.
| | - Xiaoyi Chen
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, USA.
| | - Jie Zhou
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, USA.
| | - Jie Li
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, USA.
| | - Xuewen Du
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, USA.
| | - Bing Xu
- Department of Chemistry, Brandeis University, 415 South Street, Waltham, Massachusetts 02454, USA.
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23
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Lim VY, Zehentmeier S, Fistonich C, Pereira JP. A Chemoattractant-Guided Walk Through Lymphopoiesis: From Hematopoietic Stem Cells to Mature B Lymphocytes. Adv Immunol 2017; 134:47-88. [PMID: 28413023 DOI: 10.1016/bs.ai.2017.02.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
B lymphocytes develop from hematopoietic stem cells (HSCs) in specialized bone marrow niches composed of rare mesenchymal lineage stem/progenitor cells (MSPCs) and sinusoidal endothelial cells. These niches are defined by function and location: MSPCs are mostly perisinusoidal cells that together with a small subset of sinusoidal endothelial cells express stem cell factor, interleukin-7 (IL-7), IL-15, and the highest amounts of CXCL12 in bone marrow. Though rare, MSPCs are morphologically heterogeneous, highly reticular, and form a vast cellular network in the bone marrow parenchyma capable of interacting with large numbers of hematopoietic cells. HSCs, downstream multipotent progenitor cells, and common lymphoid progenitor cells utilize CXCR4 to fine-tune access to critical short-range growth factors provided by MSPCs for their long-term maintenance and/or multilineage differentiation. In later stages, developing B lymphocytes use CXCR4 to navigate the bone marrow parenchyma, and predominantly cannabinoid receptor-2 for positioning within bone marrow sinusoids, prior to being released into peripheral blood circulation. In the final stages of differentiation, transitional B cells migrate to the spleen where they preferentially undergo further rounds of differentiation until selection into the mature B cell pool occurs. This bottleneck purges up to 97% of all developing B cells in a peripheral selection process that is heavily controlled not only by the intensity of BCR signaling and access to BAFF but also by the proper functioning of the B cell motility machinery.
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Affiliation(s)
- Vivian Y Lim
- Yale University School of Medicine, New Haven, CT, United States
| | | | - Chris Fistonich
- Yale University School of Medicine, New Haven, CT, United States
| | - João P Pereira
- Yale University School of Medicine, New Haven, CT, United States.
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24
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Polyspecificity of Anti-lipid A Antibodies and Its Relevance to the Development of Autoimmunity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 966:181-202. [PMID: 28887790 DOI: 10.1007/5584_2017_94] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The process of natural selection favours germ-line gene segments that encode CDRs that have the ability to recognize a range of structurally related antigens. This presents an immunological advantage to the host, as it can confer protection against a common pathogen and still cope with new or changing antigens. Cross-reactive and polyspecific antibodies also play a central role in autoimmune responses, and a link has been shown to exist between auto-reactive B cells and certain bacterial infections. Bacterial DNA, lipids, and carbohydrates have been implicated in the progression of autoimmune diseases such as systemic lupus erythematosus. As well, reports of anti-lipid A antibody polyspecificity towards single-stranded DNA together with the observed sequence homology amongst isolated auto- and anti-lipid A antibodies has prompted further study of this phenomenon. Though the lipid A epitope appears cryptic during Gram-negative bacterial infection, there have been several reported instances of lipid A-specific antibodies isolated from human sera, some of which have exhibited polyspecificity for single stranded DNA. In such cases, the breakdown of negative selection through polyspecificity can have the unfortunate consequence of autoimmune disease. This review summarizes current knowledge regarding such antibodies and emphasizes the features of S1-15, A6, and S55-5, anti-lipid A antibodies whose structures were recently determined by X-ray crystallography.
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25
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Erasmus MF, Matlawska-Wasowska K, Kinjyo I, Mahajan A, Winter SS, Xu L, Horowitz M, Lidke DS, Wilson BS. Dynamic pre-BCR homodimers fine-tune autonomous survival signals in B cell precursor acute lymphoblastic leukemia. Sci Signal 2016; 9:ra116. [PMID: 27899526 DOI: 10.1126/scisignal.aaf3949] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The pre-B cell receptor (pre-BCR) is an immature form of the BCR critical for early B lymphocyte development. It is composed of the membrane-bound immunoglobulin (Ig) heavy chain, surrogate light chain components, and the signaling subunits Igα and Igβ. We developed monovalent quantum dot (QD)-labeled probes specific for Igβ to study the behavior of pre-BCRs engaged in autonomous, ligand-independent signaling in live B cells. Single-particle tracking revealed that QD-labeled pre-BCRs engaged in transient, but frequent, homotypic interactions. Receptor motion was correlated at short separation distances, consistent with the formation of dimers and higher-order oligomers. Repeated encounters between diffusing pre-BCRs appeared to reflect transient co-confinement in plasma membrane domains. In human B cell precursor acute lymphoblastic leukemia (BCP-ALL) cells, we showed that frequent, short-lived, homotypic pre-BCR interactions stimulated survival signals, including expression of BCL6, which encodes a transcriptional repressor. These survival signals were blocked by inhibitory monovalent antigen-binding antibody fragments (Fabs) specific for the surrogate light chain components of the pre-BCR or by inhibitors of the tyrosine kinases Lyn and Syk. For comparison, we evaluated pre-BCR aggregation mediated by dimeric galectin-1, which has binding sites for carbohydrate and for the surrogate light chain λ5 component. Galectin-1 binding resulted in the formation of large, highly immobile pre-BCR aggregates, which was partially relieved by the addition of lactose to prevent the cross-linking of galectin-BCR complexes to other glycosylated membrane components. Analysis of the pre-BCR and its signaling partners suggested that they could be potential targets for combination therapy in BCP-ALL.
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Affiliation(s)
- M Frank Erasmus
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.,UNM Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Ksenia Matlawska-Wasowska
- UNM Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.,Department of Pediatrics, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Ichiko Kinjyo
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.,UNM Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Avanika Mahajan
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.,UNM Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Stuart S Winter
- UNM Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.,Department of Pediatrics, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Li Xu
- Sea Lane Biotechnologies, 2450 Bayshore Parkway, Mountain View, CA 94043, USA
| | - Michael Horowitz
- Sea Lane Biotechnologies, 2450 Bayshore Parkway, Mountain View, CA 94043, USA
| | - Diane S Lidke
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA.,UNM Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
| | - Bridget S Wilson
- Department of Pathology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA. .,UNM Comprehensive Cancer Center, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, USA
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26
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Budzko L, Marcinkowska-Swojak M, Jackowiak P, Kozlowski P, Figlerowicz M. Copy number variation of genes involved in the hepatitis C virus-human interactome. Sci Rep 2016; 6:31340. [PMID: 27510840 PMCID: PMC4980658 DOI: 10.1038/srep31340] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 07/18/2016] [Indexed: 02/06/2023] Open
Abstract
Copy number variation (CNV) is a newly discovered form of intra-species genetic polymorphism that is defined as deletions or duplications of genome segments ranging from 1 kbp to several Mbp. CNV accounts for the majority of the genetic variation observed in humans (CNV regions cover more than 10% of the human genome); therefore, it may significantly influence both the phenotype and susceptibility to various diseases. Unfortunately, the impact of CNV on a number of diseases, including hepatitis C virus (HCV) infection, remains largely unexplored. Here, we analyzed 421 human genes encoding proteins that have been shown to interact with HCV proteins or genomic RNA (proteins from the HCV-human interactome). We found that 19 of the 421 candidate genes are located in putative CNV regions. For all of these genes, copy numbers were determined for European, Asiatic and African populations using the multiplex ligation-dependent amplification (MLPA) method. As a result, we identified 4 genes, IGLL1, MLLT4, PDPK1, PPP1R13L, for which the CN-genotype ranged from 1 to 6. All of these genes are involved in host-virus interaction; thus, their polymorphism has a potential impact on the development of HCV infection and/or therapy outcome.
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Affiliation(s)
- Lucyna Budzko
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
| | | | - Paulina Jackowiak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Poznan, Poland
| | - Piotr Kozlowski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Poznan, Poland
| | - Marek Figlerowicz
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, Poland
- Institute of Computing Science, Poznan University of Technology, Poznan, Poland
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27
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Khass M, Blackburn T, Burrows PD, Walter MR, Capriotti E, Schroeder HW. VpreB serves as an invariant surrogate antigen for selecting immunoglobulin antigen-binding sites. Sci Immunol 2016; 1:aaf6628. [PMID: 28217764 PMCID: PMC5315267 DOI: 10.1126/sciimmunol.aaf6628] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Developmental checkpoints eliminate B cells synthesizing defective immunoglobulin heavy (HC) and light (LC) chains. The first checkpoint tests for formation of a VpreB/λ5/µHC-containing preB-cell receptor (preBCR) and predicts whether µHCs will bind conventional LCs to form membrane IgM. VpreB and λ5 also create a sensing site that interacts with µHC antigen-binding region CDR-H3, but whether it plays a role in immunoglobulin repertoire selection and function is unknown. On a position-by-position basis, we analyzed the amino acid content of CDR-H3s from H chains cloned from living and apoptotic preB cells and from IgG:Antigen structures. Using a panel of DH gene-targeted mice, we show that progressively reducing CDR-H3 tyrosine content increasingly impairs preBCR checkpoint passage. Counting from cysteine at Framework 3 position 96, we found that VpreB particularly selects for tyrosine at CDR-H3 position 101, and that Y101 also binds antigen in IgG:Antigen structures. VpreB thus acts as an early invariant antigen. It selects for particular CDR-H3 amino acids and shapes the specificity of the IgG humoral response. This helps explain why some neutralizing antibodies against pathogens are readily produced while others are rare.
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Affiliation(s)
- Mohamed Khass
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL
- Division of Genetic Engineering, National Research Center of Egypt, Cairo, Egypt
| | - Tessa Blackburn
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL
| | - Peter D Burrows
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL
| | - Mark R. Walter
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL
| | - Emidio Capriotti
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL
- Institute for Mathematical Modeling of Biological Systems, Department of Biology, University of Düsseldorf, Düsseldorf, Germany
| | - Harry W Schroeder
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL
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28
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Köhrer S, Havranek O, Seyfried F, Hurtz C, Coffey GP, Kim E, Hacken ET, Jäger U, Vanura K, O’Brien S, Thomas DA, Kantarjian H, Ghosh D, Wang Z, Zhang M, Ma W, Jumaa H, Debatin KM, Müschen M, Meyer LH, Davis RE, Burger JA. Pre-BCR signaling in precursor B-cell acute lymphoblastic leukemia regulates PI3K/AKT, FOXO1 and MYC, and can be targeted by SYK inhibition. Leukemia 2016; 30:1246-54. [PMID: 26847027 PMCID: PMC5459356 DOI: 10.1038/leu.2016.9] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 11/20/2015] [Accepted: 12/23/2015] [Indexed: 12/11/2022]
Abstract
Precursor-B-cell receptor (pre-BCR) signaling and spleen tyrosine kinase (SYK) recently were introduced as therapeutic targets for patients with B-cell acute lymphoblastic leukemia (B-ALL), but the importance of this pathway in B-ALL subsets and mechanism of downstream signaling have not fully been elucidated. Here, we provide new detailed insight into the mechanism of pre-BCR signaling in B-ALL. We compared the effects of pharmacological and genetic disruption of pre-BCR signaling in vitro and in mouse models for B-ALL, demonstrating exquisite dependency of pre-BCR(+) B-ALL, but not other B-ALL subsets, on this signaling pathway. We demonstrate that SYK, PI3K/AKT, FOXO1 and MYC are important downstream mediators of pre-BCR signaling in B-ALL. Furthermore, we define a characteristic immune phenotype and gene expression signature of pre-BCR(+) ALL to distinguish them from other B-ALL subsets. These data provide comprehensive new insight into pre-BCR signaling in B-ALL and corroborate pre-BCR signaling and SYK as promising new therapeutic targets in pre-BCR(+) B-ALL.
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Affiliation(s)
- Stefan Köhrer
- Department of Leukemia, Unit 428, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
| | - Ondrej Havranek
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
| | - Felix Seyfried
- Ulm University Medical Center, Department of Pediatrics and Adolescent Medicine, Ulm, Germany
| | - Christian Hurtz
- Department of Laboratory Medicine, University of California, San Francisco, CA 94143
| | | | - Ekaterina Kim
- Department of Leukemia, Unit 428, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
| | - Elisa ten Hacken
- Department of Leukemia, Unit 428, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
| | - Ulrich Jäger
- Department of Internal Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Vienna, Austria
| | - Katrina Vanura
- Department of Internal Medicine I, Division of Hematology and Hemostaseology, Medical University of Vienna, Vienna, Austria
| | - Susan O’Brien
- Department of Leukemia, Unit 428, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
| | - Deborah A. Thomas
- Department of Leukemia, Unit 428, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
| | - Hagop Kantarjian
- Department of Leukemia, Unit 428, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
| | - Dipanjan Ghosh
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
| | - Zhiqiang Wang
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
| | - Min Zhang
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
| | - Wencai Ma
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
| | - Hassan Jumaa
- Ulm University, Department of Immunology, Ulm, Germany
| | - Klaus-Michael Debatin
- Ulm University Medical Center, Department of Pediatrics and Adolescent Medicine, Ulm, Germany
| | - Markus Müschen
- Department of Laboratory Medicine, University of California, San Francisco, CA 94143
| | - Lüder H. Meyer
- Ulm University Medical Center, Department of Pediatrics and Adolescent Medicine, Ulm, Germany
| | - R. Eric Davis
- Department of Lymphoma/Myeloma, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
| | - Jan A. Burger
- Department of Leukemia, Unit 428, The University of Texas MD Anderson Cancer Center, Houston, Texas, United States, 77030
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29
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Übelhart R, Jumaa H. Autoreactivity and the positive selection of B cells. Eur J Immunol 2015; 45:2971-7. [DOI: 10.1002/eji.201444622] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 07/08/2015] [Accepted: 08/13/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Rudolf Übelhart
- Institute of Immunology; University Hospital Ulm; Ulm Germany
| | - Hassan Jumaa
- Institute of Immunology; University Hospital Ulm; Ulm Germany
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30
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Assembly, organization and regulation of cell-surface receptors by lectin–glycan complexes. Biochem J 2015; 469:1-16. [DOI: 10.1042/bj20150461] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Galectins are a family of β-galactoside-binding lectins carrying at least one consensus sequence in the carbohydrate-recognition domain. Properties of glycosylated ligands, such as N- and O-glycan branching, LacNAc (N-acetyl-lactosamine) content and the balance of α2,3- and α2,6-linked sialic acid dramatically influence galectin binding to a preferential set of counter-receptors. The presentation of specific glycans in galectin-binding partners is also critical, as proper orientation and clustering of oligosaccharide ligands on multiple carbohydrate side chains increase the binding avidity of galectins for particular glycosylated receptors. When galectins are released from the cells, they typically concentrate on the cell surface and the local matrix, raising their local concentration. Thus galectins can form their own multimers in the extracellular milieu, which in turn cross-link glycoconjugates on the cell surface generating galectin–glycan complexes that modulate intracellular signalling pathways, thus regulating cellular processes such as apoptosis, proliferation, migration and angiogenesis. Subtle changes in receptor expression, rates of protein synthesis, activities of Golgi enzymes, metabolite concentrations supporting glycan biosynthesis, density of glycans, strength of protein–protein interactions at the plasma membrane and stoichiometry may modify galectin–glycan complexes. Although galectins are key contributors to the formation of these extended glycan complexes leading to promotion of receptor segregation/clustering, and inhibition of receptor internalization by surface retention, when these complexes are disrupted, some galectins, particularly galectin-3 and -4, showed the ability to drive clathrin-independent mechanisms of endocytosis. In the present review, we summarize the data available on the assembly, hierarchical organization and regulation of conspicuous galectin–glycan complexes, and their implications in health and disease.
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Abstract
During early stages of development, precursor B lymphocytes express a characteristic type of antigen receptor known as the pre-B-cell receptor (pre-BCR). This receptor differs from conventional BCRs in that it possesses a germ line-encoded surrogate light chain (SLC), which is associated with the signal transduction machinery via heavy chain (HC) proteins that have been generated by productive rearrangement of the immunoglobulin HC genes. The pre-BCR marks a key step of B-cell commitment, as it activates the B-cell-specific signaling cascade and mediates the selection, expansion, and differentiation of cells expressing a productively rearranged HC protein. Another difference between the pre-BCR and conventional BCR might be the initial event that triggers receptor activation, as the pre-BCR is activated in the absence of external ligands, while conventional BCRs require antigen for activation. Nonetheless, the pre-BCR downstream signaling cascade is largely similar to that of the BCR suggesting that the characteristic LC of the pre-BCR mediates important receptor interactions thereby providing distinctive, germ line-encoded features to the pre-BCR. In fact, the SLC enables the pre-BCR to act as a surrogate autoreactive receptor. Here, we outline the structure and function of the pre-BCR and how the autonomous signaling capacity might be a direct consequence of pre-BCR assembly. In addition to its role in early B-cell development, we discuss how the ordered activation of downstream signaling cascades enables the pre-BCR to activate seemingly opposing cellular programs such as proliferation and differentiation.
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32
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Feige MJ, Buchner J. Principles and engineering of antibody folding and assembly. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2014; 1844:2024-2031. [PMID: 24931831 DOI: 10.1016/j.bbapap.2014.06.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/04/2014] [Accepted: 06/06/2014] [Indexed: 11/20/2022]
Abstract
Antibodies are uniquely suited to serve essential roles in the human immune defense as they combine several specific functions in one hetero-oligomeric protein. Their constant regions activate effector functions and their variable domains provide a stable framework that allows incorporation of highly diverse loop sequences. The combination of non-germline DNA recombination and mutation together with heavy and light chain assembly allows developing variable regions that specifically recognize essentially any antigen they may encounter. However, this diversity also requires tailor-made mechanisms to guarantee that folding and association of antibodies is carefully this diversity also requires tailor-made mechanisms to guarantee that folding and association of antibodies is carefully controlled before the protein is secreted from a plasma cell. Accordingly, the generic immunoglobulin fold β-barrel structure of antibody domains has been fine-tuned during evolution to fit the different requirements. Work over the past decades has identified important aspects of the folding and assembly of antibody domains and chains revealing domain specific variations of a general scheme. The most striking is the folding of an intrinsically disordered antibody domain in the context of its partner domain as the basis for antibody assembly and its control on the molecular level in the cell. These insights have not only allowed a better understanding of the antibody folding process but also provide a wealth of opportunities for rational optimization of antibody molecules. In this review, we summarize current concepts of antibody folding and assembly and discuss how they can be utilized to engineer antibodies with improved performance for different applications. This article is part of a Special Issue entitled: Recent advances in the molecular engineering of antibodies.
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Affiliation(s)
- Matthias J Feige
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis 38105, TN, USA.
| | - Johannes Buchner
- CIPSM at the Department of Chemistry, Technische Universität München, 85748 Garching, Germany.
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33
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Hamel KM, Mandal M, Karki S, Clark MR. Balancing Proliferation with Igκ Recombination during B-lymphopoiesis. Front Immunol 2014; 5:139. [PMID: 24765092 PMCID: PMC3980108 DOI: 10.3389/fimmu.2014.00139] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 03/19/2014] [Indexed: 12/13/2022] Open
Abstract
The essential events of B-cell development are the stochastic and sequential rearrangement of immunoglobulin heavy (Igμ) and then light chain (Igκ followed by Igλ) loci. The counterpoint to recombination is proliferation, which both maintains populations of pro-B cells undergoing Igμ recombination and expands the pool of pre-B cells expressing the Igμ protein available for subsequent Igκ recombination. Proliferation and recombination must be segregated into distinct and mutually exclusive developmental stages. Failure to do so risks aberrant gene translocation and leukemic transformation. Recent studies have demonstrated that proliferation and recombination are each affected by different and antagonistic receptors. The IL-7 receptor drives proliferation while the pre-B-cell antigen receptor, which contains Igμ and surrogate light chain, enhances Igκ accessibility and recombination. Remarkably, the principal downstream proliferative effectors of the IL-7R, STAT5 and cyclin D3, directly repress Igκ accessibility through very divergent yet complementary mechanisms. Conversely, the pre-B-cell receptor represses cyclin D3 leading to cell cycle exit and enhanced Igκ accessibility. These studies reveal how cell fate decisions can be directed and reinforced at each developmental transition by single receptors. Furthermore, they identify novel mechanisms of Igκ repression that have implications for gene regulation in general.
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Affiliation(s)
- Keith M Hamel
- Department of Medicine, Section of Rheumatology, Gwen Knapp Center for Lupus and Immunology Research, The University of Chicago , Chicago, IL , USA
| | - Malay Mandal
- Department of Medicine, Section of Rheumatology, Gwen Knapp Center for Lupus and Immunology Research, The University of Chicago , Chicago, IL , USA
| | - Sophiya Karki
- Department of Medicine, Section of Rheumatology, Gwen Knapp Center for Lupus and Immunology Research, The University of Chicago , Chicago, IL , USA
| | - Marcus R Clark
- Department of Medicine, Section of Rheumatology, Gwen Knapp Center for Lupus and Immunology Research, The University of Chicago , Chicago, IL , USA
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34
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Zouali M. Transcriptional and metabolic pre-B cell receptor-mediated checkpoints: implications for autoimmune diseases. Mol Immunol 2014; 62:315-20. [PMID: 24602812 DOI: 10.1016/j.molimm.2014.01.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 01/10/2014] [Accepted: 01/13/2014] [Indexed: 02/01/2023]
Abstract
At the pre-B cell stage of lymphocyte development, immunoglobulin light-chains are not yet produced, and heavy-chains are covalently linked to surrogate light-chains composed of VpreB and λ5 to form the pre-B cell receptor (pre-BCR) in a non-covalent association with signal-transducing modules. Even tough the pre-BCR does not have the potential to bind conventional antigens, accumulating evidence indicates that pre-BCR-mediated checkpoints are important both for negative and positive selection of self-reactivity, and that defects in these regulatory nodes may be associated with autoimmune disease. Thus, the transcription factor BACH2, which represents a susceptibility locus for rheumatoid arthritis, has recently emerged as a crucial mediator of negative selection at a pre-BCR checkpoint. The lysosome-associated protein LAPTM5, which is highly expressed in an animal model of Sjögren's syndrome, plays a role in down-modulation of the pre-BCR. Studies of copy number variation in rheumatoid arthritis suggest that a reduced dosage of the VPREB1 gene is involved in disease pathogenesis. Notably, animal models of autoimmune disease exhibit defects in pre-B to naïve B cell checkpoints. Administration of a pre-BCR ligand, which also plays a role in anergy both in human and murine B lymphocytes, ameliorates disease in experimental models of autoimmunity. Further investigation is required to gain a better insight into the molecular mechanisms of pre-BCR-mediated checkpoints and to determine their relevance to autoimmune diseases.
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Affiliation(s)
- Moncef Zouali
- Inserm, UMR 1132, F-75475 Paris, France; Université Paris Diderot, Sorbone Paris Cité, F-75475 Paris, France.
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35
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Tsuji S, Yamashita M, Kageyama T, Ohtsu T, Suzuki K, Kato S, Akitomi J, Furuichi M, Waga I. Hishot display--a new combinatorial display for obtaining target-recognizing peptides. PLoS One 2014; 8:e83108. [PMID: 24386149 PMCID: PMC3873924 DOI: 10.1371/journal.pone.0083108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 11/08/2013] [Indexed: 11/18/2022] Open
Abstract
Display technologies are procedures used for isolating target-recognizing peptides without using immunized animals. In this study, we describe a new display method, named Hishot display, that uses Escherichia coli and an expression plasmid to isolate target-recognizing peptides. This display method is based on the formation, in bacteria, of complexes between a polyhistidine (His)-tagged peptide including random sequences and the peptide-encoding mRNA including an RNA aptamer against the His-tag. When this system was tested using a sequence encoding His-tagged green fluorescent protein that included an RNA aptamer against the His-tag, the collection of mRNA encoding the protein was dependent on the RNA aptamer. Using this display method and a synthetic library of surrogate single-chain variable fragments consisting of VpreB and Ig heavy-chain variable domains, it was possible to isolate clones that could specifically recognize a particular target (intelectin-1 or tumor necrosis factor-α). These clones were obtained as soluble proteins produced by E. coli, and the purified peptide clones recognizing intelectin-1 could be used as detectors for sandwich enzyme-linked immunosorbent assays. The Hishot display will be a useful method to add to the repertoire of display technologies.
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Affiliation(s)
- Shoutaro Tsuji
- Molecular Diagnostic Project, Kanagawa Cancer Center Research Institute, Yokohama, Japan
- * E-mail:
| | - Makiko Yamashita
- Molecular Diagnostic Project, Kanagawa Cancer Center Research Institute, Yokohama, Japan
| | - Taihei Kageyama
- Molecular Diagnostic Project, Kanagawa Cancer Center Research Institute, Yokohama, Japan
| | - Takashi Ohtsu
- Anticancer Drug Project, Kanagawa Cancer Center Research Institute, Yokohama, Japan
| | - Katsuo Suzuki
- Molecular Diagnostic Project, Kanagawa Cancer Center Research Institute, Yokohama, Japan
| | - Shintaro Kato
- VALWAY Technology Center, NEC Soft Ltd., Tokyo, Japan
| | - Joe Akitomi
- VALWAY Technology Center, NEC Soft Ltd., Tokyo, Japan
| | | | - Iwao Waga
- VALWAY Technology Center, NEC Soft Ltd., Tokyo, Japan
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36
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Abstract
The development and function of B lymphocytes critically depend on the non-germline B-cell antigen receptor (BCR). In addition to the diverse antigen-recognition regions, whose coding sequences are generated by the somatic DNA rearrangement, the variety of the constant domains of the Heavy Chain (HC) portion contributes to the multiplicity of the BCR types. The functions of particular classes of the HC, particularly in the context of the membrane BCR, are not completely understood. The expression of the various classes of the HC correlates with the distinct stages of B-cell development, types of B-cell subsets, and their effector functions. In this chapter, we summarize and discuss the accumulated knowledge on the role of the μ, δ, and γ HC isotypes of the conventional and precursor BCR in B-cell differentiation, selection, and engagement with (auto)antigens.
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Affiliation(s)
- Elena Surova
- Spemann Graduate School of Biology and Medicine (SGBM), Albert Ludwigs University Freiburg, Freiburg, Germany; Department of Molecular immunology, Faculty of Biology, University of Freiburg and Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Hassan Jumaa
- Spemann Graduate School of Biology and Medicine (SGBM), Albert Ludwigs University Freiburg, Freiburg, Germany; Department of Molecular immunology, Faculty of Biology, University of Freiburg and Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Department of Immunology, Ulm University, Ulm, Germany.
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37
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38
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Orchestrating B cell lymphopoiesis through interplay of IL-7 receptor and pre-B cell receptor signalling. Nat Rev Immunol 2013; 14:69-80. [PMID: 24378843 DOI: 10.1038/nri3570] [Citation(s) in RCA: 216] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The development of B cells is dependent on the sequential DNA rearrangement of immunoglobulin loci that encode subunits of the B cell receptor. The pathway navigates a crucial checkpoint that ensures expression of a signalling-competent immunoglobulin heavy chain before commitment to rearrangement and expression of an immunoglobulin light chain. The checkpoint segregates proliferation of pre-B cells from immunoglobulin light chain recombination and their differentiation into B cells. Recent advances have revealed the molecular circuitry that controls two rival signalling systems, namely the interleukin-7 (IL-7) receptor and the pre-B cell receptor, to ensure that proliferation and immunoglobulin recombination are mutually exclusive, thereby maintaining genomic integrity during B cell development.
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39
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Antibodies that bind complex glycosaminoglycans accumulate in the Golgi. Proc Natl Acad Sci U S A 2013; 110:11958-63. [PMID: 23818632 DOI: 10.1073/pnas.1308620110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Light (L) chains that edit anti-DNA heavy (H) chains rescue B-cell development by suppressing DNA binding. However, exceptional editor L chains allow B cells to reach splenic compartments even though their B-cell receptors remain autoreactive. Such incompletely edited B cells express multireactive antibodies that accumulate in the Golgi and are released as insoluble, amyloid-like immune complexes. Here, we examine examples of incomplete editing from the analysis of variable to joining (VJ) gene junction of the variable (Vλx) editor L chain. When paired with the anti-DNA heavy chain, VH56R, the Vλx variants yield antibodies with differing specificities, including glycosaminoglycan reactivity. Our results implicate these specificities in the evasion of receptor editing through intracellular sequestration of IgM and the release of insoluble IgM complexes. Our findings can be extrapolated to human L chains and have implications for understanding a latent component of the Ig repertoire that could exert pathogenic and protective functions.
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Abstract
Sera of camelids contain both conventional heterotetrameric antibodies and unique functional heavy (H)-chain antibodies (HCAbs). The H chain of these homodimeric antibodies consists of one antigen-binding domain, the VHH, and two constant domains. HCAbs fail to incorporate light (L) chains owing to the deletion of the first constant domain and a reshaped surface at the VHH side, which normally associates with L chains in conventional antibodies. The genetic elements composing HCAbs have been identified, but the in vivo generation of these antibodies from their dedicated genes into antigen-specific and affinity-matured bona fide antibodies remains largely underinvestigated. However, the facile identification of antigen-specific VHHs and their beneficial biochemical and economic properties (size, affinity, specificity, stability, production cost) supported by multiple crystal structures have encouraged antibody engineering of these single-domain antibodies for use as a research tool and in biotechnology and medicine.
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Affiliation(s)
- Serge Muyldermans
- Research Group Cellular and Molecular Immunology, Vrije Universiteit Brussel, 1050 Brussels, Belgium.
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Cohen S, Haimovich J, Hollander N. Distinct processing of the pre-B cell receptor and the B cell receptor. Mol Immunol 2012; 54:115-21. [PMID: 23267849 DOI: 10.1016/j.molimm.2012.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 11/04/2012] [Accepted: 11/13/2012] [Indexed: 02/03/2023]
Abstract
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.
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Affiliation(s)
- Sharon Cohen
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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42
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Elantak L, Espeli M, Boned A, Bornet O, Bonzi J, Gauthier L, Feracci M, Roche P, Guerlesquin F, Schiff C. Structural basis for galectin-1-dependent pre-B cell receptor (pre-BCR) activation. J Biol Chem 2012; 287:44703-13. [PMID: 23124203 DOI: 10.1074/jbc.m112.395152] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
During B cell differentiation in the bone marrow, the expression and activation of the pre-B cell receptor (pre-BCR) constitute crucial checkpoints for B cell development. Both constitutive and ligand-dependent pre-BCR activation modes have been described. The pre-BCR constitutes an immunoglobulin heavy chain (Igμ) and a surrogate light chain composed of the invariant λ5 and VpreB proteins. We previously showed that galectin-1 (GAL1), produced by bone marrow stromal cells, is a pre-BCR ligand that induces receptor clustering, leading to efficient pre-BII cell proliferation and differentiation. GAL1 interacts with the pre-BCR via the unique region of λ5 (λ5-UR). Here, we investigated the solution structure of a minimal λ5-UR motif that interacts with GAL1. This motif adopts a stable helical conformation that docks onto a GAL1 hydrophobic surface adjacent to its carbohydrate binding site. We identified key hydrophobic residues from the λ5-UR as crucial for the interaction with GAL1 and for pre-BCR clustering. These residues involved in GAL1-induced pre-BCR activation are different from those essential for autonomous receptor activation. Overall, our results indicate that constitutive and ligand-induced pre-BCR activation could occur in a complementary manner.
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Affiliation(s)
- Latifa Elantak
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, CNRS UMR7255, Aix-Marseille Université, 13402 Marseille cedex 20, France
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43
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Almqvist N, Mårtensson IL. The pre-B cell receptor; selecting for or against autoreactivity. Scand J Immunol 2012; 76:256-62. [PMID: 22909069 DOI: 10.1111/j.1365-3083.2012.02751.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Antibodies represent a crucial component of humoral immunity as protection against invading pathogens, to which they bind and thereby trigger mechanisms that lead to the disposal of the pathogen. Antibodies are assembled from Ig heavy chains (HCs) and light chains (LCs) and are found in both a secreted and a membrane-bound form, termed B cell receptors (BCRs), where the latter allows the 'right' B cell to respond upon recognition of its cognate antigen. The antibody repertoire is almost unlimited because of a process in which germ line V(D)J gene segments, encoding the variable (antigen-binding) region of the antibody HCs and LCs, are recombined. As this process is random, it is apparent that it results in a vast variety of antibodies, those that recognize foreign but also those that recognize self- (auto-) antigens. Control mechanisms are, therefore, in place to ensure that as few autoreactive B cells as possible are allowed to proceed in development. This counter-selection takes place through various mechanisms and at several stages as the cells develop from pre-B cells to antibody-secreting plasma cells. At the first major checkpoint, at the pre-BI to pre-BII cell transition, antibody HCs assemble with the invariant surrogate LC (SLC) forming a pre-BCR. Herein, we will discuss the role of the pre-BCR in the selection at this stage, how a dysfunctional pre-BCR affects selection and its effects on later stages, and whether the pre-BCR selects for or against autoreactivity.
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Affiliation(s)
- N Almqvist
- Department of Rheumatology and Inflammation Research, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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44
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Bednarski JJ, Sleckman BP. Integrated signaling in developing lymphocytes: the role of DNA damage responses. Cell Cycle 2012; 11:4129-34. [PMID: 23032308 DOI: 10.4161/cc.22021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Lymphocyte development occurs in a stepwise progression through distinct developmental stages. This ordered maturation ensures that cells express a single, non-autoreactive antigen receptor, which is the cornerstone of a diverse adaptive immune response. Expression of a mature antigen receptor requires assembly of the antigen receptor genes by the process of V(D)J recombination, a reaction that joins distant gene segments through DNA double-strand break (DSB) intermediates. These physiologic DSBs are generated by the recombinase-activating gene (RAG) -1 and -2 proteins, and their generation is regulated by lymphocyte and developmental stage-specific signals from cytokine receptors and antigen receptor chains. Collectively, these signals ensure that V(D)J recombination of specific antigen receptor genes occurs at discrete developmental stages. Once generated, RAG-induced DSBs activate the ataxia-telangiectasia mutated (ATM) kinase to orchestrate a multifaceted DNA damage response that ensures proper DSB repair. In response to RAG DSBs, ATM also regulates a cell type-specific transcriptional response, and here we discuss how this genetic program integrates with other cellular cues to regulate lymphocyte development.
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Affiliation(s)
- Jeffrey J Bednarski
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO, USA
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Wang X, Parra ZE, Miller RD. A VpreB3 homologue in a marsupial, the gray short-tailed opossum, Monodelphis domestica. Immunogenetics 2012; 64:647-52. [PMID: 22684248 DOI: 10.1007/s00251-012-0626-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Accepted: 05/30/2012] [Indexed: 01/22/2023]
Abstract
A VpreB surrogate light (SL) chain was identified for the first time in a marsupial, the opossum Monodelphis domestica. Comparing the opossum VpreB to homologues from eutherian (placental mammals) and avian species supported the marsupial gene being VpreB3. VpreB3 is a protein that is not known to traffic to the cell surface as part of the pre-B cell receptor. Rather, VpreB3 associates with nascent immunoglobulin chains in the endoplasmic reticulum. Homologues of other known SL chains VpreB1, VpreB2, and λ5, which are found in eutherian mammals, were not found in the opossum genome, nor have they been identified in the genomes of nonmammals. VpreB3 likely evolved from earlier gene duplication, independent of that which generated VpreB1 and VpreB2 in eutherians. The apparent absence of VpreB1, VpreB2, and λ5 in marsupials suggests that an extracellular pre-B cell receptor containing SL chains, as it has been defined in humans and mice, may be unique to eutherian mammals. In contrast, the conservation of VpreB3 in marsupials and its presence in nonmammals is consistent with previous hypotheses that it is playing a more primordial role in B cell development.
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Affiliation(s)
- Xinxin Wang
- Center for Evolutionary & Theoretical Immunology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
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46
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Knoll M, Yanagisawa Y, Simmons S, Engels N, Wienands J, Melchers F, Ohnishi K. The non-Ig parts of the VpreB and λ5 proteins of the surrogate light chain play opposite roles in the surface representation of the precursor B cell receptor. THE JOURNAL OF IMMUNOLOGY 2012; 188:6010-7. [PMID: 22566564 DOI: 10.4049/jimmunol.1200071] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The VpreB and λ5 proteins, together with Igμ-H chains, form precursor BCRs (preBCRs). We established λ5(-/-)/VpreB1(-/-)/VpreB2(-/-) Abelson virus-transformed cell lines and reconstituted these cells with λ5 and VpreB in wild-type form or with a deleted non-Ig part. Whenever preBCRs had the non-Ig part of λ5 deleted, surface deposition was increased, whereas deletion of VpreB non-Ig part decreased it. The levels of phosphorylation of Syk, SLP65, or PLC-γ2, and of Ca(2+) mobilization from intracellular stores, stimulated by μH chain crosslinking Ab were dependent on the levels of surface-bound preBCRs. It appears that VpreB probes the fitness of newly generated VH domains of IgH chains for later pairing with IgL chains, and its non-Ig part fixes the preBCRs on the surface. By contrast, the non-Ig part of λ5 crosslinks preBCRs for downregulation and stimulation.
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Affiliation(s)
- Marko Knoll
- Research Group of Lymphocyte Development, Max Planck Institute for Infection Biology, Berlin 10117, Germany.
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47
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Ekman A, Ilves M, Iivanainen A. B lymphopoiesis is characterized by pre-B cell marker gene expression in fetal cattle and declines in adults. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2012; 37:39-49. [PMID: 22210545 DOI: 10.1016/j.dci.2011.12.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 12/16/2011] [Accepted: 12/19/2011] [Indexed: 05/31/2023]
Abstract
Fetal cattle B-cell development proceeds via a pre-B cell stage that is characterized by the expression of surrogate light chain and recombination activation genes. In this paper, we identify a new member of bovine pre-B lymphocyte genes, VPREB2. Using RT-qPCR, we assess the expression of VPREB2 and three other surrogate light chain genes as well as RAG1 and RAG2 in fetal and adult cattle tissues. The absence of VPREB1, IGLL1, RAG1 and RAG2 expression in adult tissues and the lack of B-lymphoid differentiation in adult bone marrow - OP9 stromal cell co-culture, suggest a decline of B lymphopoiesis in adult cattle. The marked differences in the expression profiles of VPREB2 and VPREB3 in comparison to those of VPREB1, IGLL1 and RAGs suggest that the biological roles of VPREB2 and VPREB3 are unrelated to the pre-B cells.
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Affiliation(s)
- Anna Ekman
- Department of Veterinary Biosciences, University of Helsinki, P.O. Box 66, 00014 Helsinki, Finland
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48
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Herzog S, Jumaa H. Self-recognition and clonal selection: autoreactivity drives the generation of B cells. Curr Opin Immunol 2012; 24:166-72. [PMID: 22398125 DOI: 10.1016/j.coi.2012.02.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 01/19/2012] [Accepted: 02/06/2012] [Indexed: 11/15/2022]
Abstract
The diversity of B cell receptor (BCR) specificities is generated by VDJ recombination of gene segments during early B cell development, a process which bears the risk of producing BCRs that recognize and lead to the destruction of self-structures. Traditional thoughts have mainly focused on how such putatively dangerous specificities are dealt with and in how they contribute to the development of autoimmune diseases. However, a positive or even necessary role of self-recognition during B cell development has rarely been taken into account. Now, considerable data reveal that the pre-B cell receptor (pre-BCR), which marks an important checkpoint during B cell development, acts as a surrogate autoreactive receptor. This review outlines how autoreactivity is necessary for efficient B cell development and how autoreactive receptors drive positive selection, leading to a diverse repertoire of receptor specificities in the mature B cell pool.
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Affiliation(s)
- Sebastian Herzog
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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49
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Bednarski JJ, Sleckman BP. Lymphocyte development: integration of DNA damage response signaling. Adv Immunol 2012; 116:175-204. [PMID: 23063077 DOI: 10.1016/b978-0-12-394300-2.00006-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Lymphocytes traverse functionally discrete stages as they develop into mature B and T cells. This development is directed by cues from a variety of different cell surface receptors. To complete development, all lymphocytes must express a functional nonautoreactive heterodimeric antigen receptor. The genes that encode antigen receptor chains are assembled through the process of V(D)J recombination, a reaction that proceeds through DNA double-stranded break (DSB) intermediates. These DSBs are generated by the RAG endonuclease in G1-phase developing lymphocytes and activate ataxia-telangiectasia mutated (ATM), the kinase that orchestrates cellular DSB responses. The canonical DNA damage response includes cell cycle arrest, DNA break repair, and apoptosis of cells when DSBs are not repaired. However, recent studies have demonstrated that ATM activation in response to RAG DSBs also regulates a transcriptional program including many genes with no known function in canonical DNA damage responses. Rather, these genes have activities that would be important for lymphocyte development. Here, these findings and the broader concept that signals initiated by physiologic DNA DSBs provide cues that regulate cell type-specific processes and functions are discussed.
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Affiliation(s)
- Jeffrey J Bednarski
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
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50
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Li W, Liu Q, Pang Y, Jin J, Wang H, Cao H, Li Z, Wang X, Ma B, Chi Y, Wang R, Kondo A, Gu J, Taniguchi N. Core fucosylation of μ heavy chains regulates assembly and intracellular signaling of precursor B cell receptors. J Biol Chem 2011; 287:2500-8. [PMID: 22084235 DOI: 10.1074/jbc.m111.303123] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
α1,6-Fucosyltransferase (Fut8) knock-out (Fut8(-/-)) mice showed an abnormality in pre-B cell generation. Membrane assembly of pre-BCR is a crucial checkpoint for pre-B cell differentiation and proliferation in both humans and mice. The assembly of pre-BCR on the cell surface was substantially blocked in the Fut8-knockdown pre-B cell line, 70Z/3-KD cells, and then completely restored by re-introduction of the Fut8 gene to 70Z/3-KD (70Z/3-KD-re) cells. Moreover, loss of α1,6-fucosylation (also called core fucosylation) of μHC was associated with the suppression of the interaction between μHC and λ5. In contrast to Fut8(+/+) CD19(+)CD43(-) cells, the subpopulation expressing the μHC·λ5 complex in the Fut8(-/-) CD19(+)CD43(-) cell fraction was decreased. The pre-BCR-mediated tyrosine phosphorylation of CD79a and activation of Btk were attenuated in Fut8-KD cells, and restored in 70Z/3-KD-re cells. The frequency of CD19(low)CD43(-) cells (pre-B cell enriched fraction) was also reduced in Fut8(-/-) bone marrow cells, and then the levels of IgM, IgG, and IgA of 12-week-old Fut8(-/-) mice sera were significantly lower than those of Fut8(+/+) mice. Our results suggest that the core fucosylation of μHC mediates the assembly of pre-BCR to regulate pre-BCR intracellular signaling and pre-B cell proliferation.
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Affiliation(s)
- Wenzhe Li
- Institute of Immunology, College of Life Science and Technology, Dalian University, 10-Xuefu Avenue, Dalian Economical and Technological Development Zone, Liaoning 116622, China.
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