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Rodríguez-Zhurbenko N, Hernández AM. The role of B-1 cells in cancer progression and anti-tumor immunity. Front Immunol 2024; 15:1363176. [PMID: 38629061 PMCID: PMC11019000 DOI: 10.3389/fimmu.2024.1363176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 03/14/2024] [Indexed: 04/19/2024] Open
Abstract
In recent years, in addition to the well-established role of T cells in controlling or promoting tumor growth, a new wave of research has demonstrated the active involvement of B cells in tumor immunity. B-cell subsets with distinct phenotypes and functions play various roles in tumor progression. Plasma cells and activated B cells have been linked to improved clinical outcomes in several types of cancer, whereas regulatory B cells have been associated with disease progression. However, we are only beginning to understand the role of a particular innate subset of B cells, referred to as B-1 cells, in cancer. Here, we summarize the characteristics of B-1 cells and review their ability to infiltrate tumors. We also describe the potential mechanisms through which B-1 cells suppress anti-tumor immune responses and promote tumor progression. Additionally, we highlight recent studies on the protective anti-tumor function of B-1 cells in both mouse models and humans. Understanding the functions of B-1 cells in tumor immunity could pave the way for designing more effective cancer immunotherapies.
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Affiliation(s)
- Nely Rodríguez-Zhurbenko
- Immunobiology Department, Immunology and Immunotherapy Division, Center of Molecular Immunology, Habana, Cuba
| | - Ana M. Hernández
- Applied Genetics Group, Department of Biochemistry, Faculty of Biology, University of Habana, Habana, Cuba
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2
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Zhang T, Yu-Jing L, Ma T. Role of regulation of PD-1 and PD-L1 expression in sepsis. Front Immunol 2023; 14:1029438. [PMID: 36969168 PMCID: PMC10035551 DOI: 10.3389/fimmu.2023.1029438] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Accepted: 02/27/2023] [Indexed: 03/11/2023] Open
Abstract
Long term immunosuppression is problematic during sepsis. The PD-1 and PD-L1 immune checkpoint proteins have potent immunosuppressive functions. Recent studies have revealed several features of PD-1 and PD-L1 and their roles in sepsis. Here, we summarize the overall findings of PD-1 and PD-L1 by first reviewing the biological features of PD-1 and PD-L1 and then discussing the mechanisms that control the expression of PD-1 and PD-L1. We then review the functions of PD-1 and PD-L1 in physiological settings and further discuss PD-1 and PD-L1 in sepsis, including their involvement in several sepsis-related processes and their potential therapeutic relevance in sepsis. In general, PD-1 and PD-L1 have critical roles in sepsis, indicating that their regulation may be a potential therapeutic target for sepsis.
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Affiliation(s)
- Teng Zhang
- Department of General Surgery, Tianjin Medical University General Hospital, Tianjin, China
| | - Li Yu-Jing
- Department of Neurology, Tianjin Medical University General Hospital, Tianjin, China
| | - Tao Ma
- Department of General Surgery, Tianjin Medical University General Hospital, Tianjin, China
- *Correspondence: Tao Ma,
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3
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Almishri W, Davis RP, Shaheen AA, Altonsy MO, Jenne CN, Swain MG. The Antidepressant Mirtazapine Rapidly Shifts Hepatic B Cell Populations and Functional Cytokine Signatures in the Mouse. Front Immunol 2021; 12:622537. [PMID: 33841403 PMCID: PMC8027111 DOI: 10.3389/fimmu.2021.622537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 03/08/2021] [Indexed: 01/17/2023] Open
Abstract
Introduction B cells are important regulators of both adaptive and innate immunity. The normal liver contains significant numbers of B cells, and their numbers increase dramatically in immune-mediated liver diseases. Our previous observations suggest a hepatoprotective effect of the antidepressant mirtazapine in human and experimental immune-mediated liver disease. Therefore, we performed a series of experiments to determine the impact of mirtazapine treatment on hepatic B cell homeostasis, as reflected by B cell number, trafficking and phenotype using flow cytometry (FCM) and intravital microscopy (IVM) analysis. Mirtazapine treatment rapidly induced a significant reduction in total hepatic B cell numbers, paralleled by a compositional shift in the predominant hepatic B cell subtype from B2 to B1. This shift in hepatic B cells induced by mirtazapine treatment was associated with a striking increase in total hepatic levels of the chemokine CXCL10, and increased production of CXCL10 by hepatic macrophages and dendritic cells. Furthermore, mirtazapine treatment led to an upregulation of CXCR3, the cognate chemokine receptor for CXCL10, on hepatic B cells that remained in the liver post-mirtazapine. A significant role for CXCR3 in the hepatic retention of B cells post-mirtazapine was confirmed using CXCR3 receptor blockade. In addition, B cells remaining in the liver post-mirtazapine produced lower amounts of the proinflammatory Th1-like cytokines IFNγ, TNFα, and IL-6, and increased amounts of the Th2-like cytokine IL-4, after stimulation in vitro. Conclusion Mirtazapine treatment rapidly alters hepatic B cell populations, enhancing hepatic retention of CXCR3-expressing innate-like B cells that generate a more anti-inflammatory cytokine profile. Mirtazapine-induced hepatic B cell shifts could potentially represent a novel therapeutic approach to immune-mediated liver diseases characterized by B cell driven pathology.
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Affiliation(s)
- Wagdi Almishri
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, AB, Canada.,Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.,Department of Pathology and Clinical Pathology, Faculty of Veterinary Medicine, University of Tripoli, Tripoli, Libya
| | - Rachelle P Davis
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, AB, Canada.,Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Abdel-Aziz Shaheen
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, AB, Canada
| | - Mohammed O Altonsy
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, AB, Canada.,Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.,Department of Zoology, Faculty of Science, Sohag University, Sohag, Egypt
| | - Craig N Jenne
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, AB, Canada.,Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Mark G Swain
- Department of Microbiology, Immunology, and Infectious Diseases, University of Calgary, Calgary, AB, Canada.,Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.,Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, AB, Canada
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4
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Daly CA, Spurrier MA, Jennings-Gee JE, Haas KM. B Cell Subsets Differentially Contribute to the T Cell-Independent Memory Pool. THE JOURNAL OF IMMUNOLOGY 2020; 205:2362-2374. [PMID: 32978280 DOI: 10.4049/jimmunol.1901453] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 08/28/2020] [Indexed: 01/27/2023]
Abstract
The roles distinct B cell subsets play in clonal expansion, isotype switching, and memory B cell differentiation in response to T cell-independent type 2 Ags (TI-2 Ags) has been understudied. Using sorted B cells from VHB1-8 knock-in mice, we evaluated B-1b, marginal zone, and follicular B cell responses to the TI-2 Ag, NP-Ficoll. All subsets extensively divided in response to NP-Ficoll. Nonetheless, B-1b cells exhibited significantly increased IgG switching and differentiation into Ab-secreting cells (ASC)-a finding that coincided with increased AgR signaling capacity and Blimp1 expression by B-1b cells. All subsets formed memory cells and expressed markers previously identified for T cell-dependent memory B cells, including CD80, PDL2, and CD73, although B-1b cells generated the greatest number of memory cells with higher frequencies of IgG- and CD80-expressing cells. Despite memory formation, secondary immunization 4 wk after primary immunization did not increase NP-specific IgG. However, boosting occurred in B-1b cell-recipient mice when IgG levels declined. CD80+ memory B-1b cells divided, class switched, and differentiated into ASC in response to Ag in vivo, but this was inhibited in the presence of NP-specific IgG. Furthermore, CD80 blockade significantly increased memory B-1b cell division and differentiation to ASC upon Ag restimulation. Collectively, these findings demonstrate B-1b, marginal zone B, and follicular B subsets significantly contribute to the TI-2 Ag-specific memory B cell pool. In particular, we show B-1b cells generate a functional CD80-regulated memory population that can be stimulated to divide and differentiate into ASC upon Ag re-encounter when Ag-specific IgG levels decline.
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Affiliation(s)
- Christina A Daly
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - M Ariel Spurrier
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Jamie E Jennings-Gee
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Karen M Haas
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157
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5
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The regulators of BCR signaling during B cell activation. BLOOD SCIENCE 2019; 1:119-129. [PMID: 35402811 PMCID: PMC8975005 DOI: 10.1097/bs9.0000000000000026] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Accepted: 07/25/2019] [Indexed: 11/26/2022] Open
Abstract
B lymphocytes produce antibodies under the stimulation of specific antigens, thereby exerting an immune effect. B cells identify antigens by their surface B cell receptor (BCR), which upon stimulation, directs the cell to activate and differentiate into antibody generating plasma cells. Activation of B cells via their BCRs involves signaling pathways that are tightly controlled by various regulators. In this review, we will discuss three major BCR mediated signaling pathways (the PLC-γ2 pathway, PI3K pathway and MAPK pathway) and related regulators, which were roughly divided into positive, negative and mutual-balanced regulators, and the specific regulators of the specific signaling pathway based on regulatory effects.
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Ledov VA, Golovina ME, Markina AA, Knirel YA, L'vov VL, Kovalchuk AL, Aparin PG. Highly homogenous tri-acylated S-LPS acts as a novel clinically applicable vaccine against Shigella flexneri 2a infection. Vaccine 2019; 37:1062-1072. [PMID: 30670300 DOI: 10.1016/j.vaccine.2018.12.067] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 12/08/2018] [Accepted: 12/30/2018] [Indexed: 12/24/2022]
Abstract
Shigellosis, a major cause of diarrhea worldwide, exhibits high morbidity and mortality in children. Specificity of Shigella immunity is determined by the structure of the main protective O-antigen polysaccharide component incorporated into the lipopolysaccharide (LPS) molecule. Endotoxicity, however, precludes LPS clinical use. Thus, there is still no vaccine against the most prevalent shigellosis species (serotype S. flexneri 2a), despite ongoing efforts focused on inducing serotype-specific immunity. As LPS is highly heterogenous, we hypothesized that more homogenous pools of LPS might be less toxic. We developed a method to generate a homogenous S. flexneri 2a LPS subfraction, Ac3-S-LPS, containing long chain O-specific polysaccharide (S-LPS) and mainly tri-acylated lipid A, with no penta- and hexa-acylated, and rare tetra-acylated lipid A. Ac3-S-LPS had dramatically reduced pyrogenicity and protected guinea pigs from shigellosis. In volunteers, 50 µg of injected Ac3-S-LPS vaccine was safe, with low pyrogenicity, no severe and few minor adverse events, and did not induce pro-inflammatory cytokines. In spite of the profound lipid A modification, the vaccine induced a prevalence of IgG and IgA antibodies. Thus, we have developed the first safe immunogenic LPS-based vaccine candidate for human administration. Homogenous underacetylated LPSs may also be useful for treating other LPS-driven human diseases. Clinical trial registry: http://grls.rosminzdrav.ru/.
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Affiliation(s)
- Vladimir A Ledov
- Laboratory of Carbohydrate Vaccines, National Research Center-Institute of Immunology, Federal Medical Biological Agency of Russia, 24, Kashirskoe Shosse, Moscow 115478, Russia
| | - Marina E Golovina
- Laboratory of Carbohydrate Vaccines, National Research Center-Institute of Immunology, Federal Medical Biological Agency of Russia, 24, Kashirskoe Shosse, Moscow 115478, Russia
| | - Anna A Markina
- Laboratory of Carbohydrate Vaccines, National Research Center-Institute of Immunology, Federal Medical Biological Agency of Russia, 24, Kashirskoe Shosse, Moscow 115478, Russia
| | - Yuriy A Knirel
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47, Leninsky Prospect, Moscow 117913, Russia
| | - Vyacheslav L L'vov
- Laboratory of Preparative Biochemistry, National Research Center-Institute of Immunology, Federal Medical Biological Agency of Russia, 24, Kashirskoe Shosse, Moscow 115478, Russia
| | - Alexander L Kovalchuk
- The Virology and Cellular Immunology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, NIH, Rockville, MD 20852, United States
| | - Petr G Aparin
- Laboratory of Carbohydrate Vaccines, National Research Center-Institute of Immunology, Federal Medical Biological Agency of Russia, 24, Kashirskoe Shosse, Moscow 115478, Russia.
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7
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PD-1 immunobiology in systemic lupus erythematosus. J Autoimmun 2018; 97:1-9. [PMID: 30396745 DOI: 10.1016/j.jaut.2018.10.025] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 10/22/2018] [Accepted: 10/28/2018] [Indexed: 01/22/2023]
Abstract
Programmed death (PD)-1 receptors and their ligands have been identified in the pathogenesis and development of systemic lupus erythematosus (SLE). Two key pathways, toll-like receptor and type I interferon, are significant to SLE pathogenesis and modulate the expression of PD-1 and the ligands (PD-L1, PD-L2) through activation of NF-κB and/or STAT1. These cell signals are regulated by tyrosine kinase (Tyro, Axl, Mer) receptors (TAMs) that are aberrantly activated in SLE. STAT1 and NF-κB also exhibit crosstalk with the aryl hydrocarbon receptor (AHR). Ligands to AHR are identified in SLE etiology and pathogenesis. These ligands also regulate the activity of the Epstein-Barr virus (EBV), which is an identified factor in SLE and PD-1 immunobiology. AHR is important in the maintenance of immune tolerance and the development of distinct immune subsets, highlighting a potential role of AHR in PD-1 immunobiology. Understanding the functions of AHR ligands as well as AHR crosstalk with STAT1, NF-κB, and EBV may provide insight into disease development, the PD-1 axis and immunotherapies that target PD-1 and its ligand, PD-L1.
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8
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Haas KM, Johnson KL, Phipps JP, Do C. CD22 Promotes B-1b Cell Responses to T Cell-Independent Type 2 Antigens. THE JOURNAL OF IMMUNOLOGY 2018; 200:1671-1681. [PMID: 29374074 DOI: 10.4049/jimmunol.1701578] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 12/27/2017] [Indexed: 01/12/2023]
Abstract
CD22 (Siglec-2) is a critical regulator of B cell activation and survival. CD22-/- mice generate significantly impaired Ab responses to T cell-independent type 2 (TI-2) Ags, including haptenated Ficoll and pneumococcal polysaccharides, Ags that elicit poor T cell help and activate BCR signaling via multivalent epitope crosslinking. This has been proposed to be due to impaired marginal zone (MZ) B cell development/maintenance in CD22-/- mice. However, mice expressing a mutant form of CD22 unable to bind sialic acid ligands generated normal TI-2 Ab responses, despite significantly reduced MZ B cells. Moreover, mice treated with CD22 ligand-binding blocking mAbs, which deplete MZ B cells, had little effect on TI-2 Ab responses. We therefore investigated the effects of CD22 deficiency on B-1b cells, an innate-like B cell population that plays a key role in TI-2 Ab responses. B-1b cells from CD22-/- mice had impaired BCR-induced proliferation and significantly increased intracellular Ca2+ concentration responses following BCR crosslinking. Ag-specific B-1b cell expansion and plasmablast differentiation following TI-2 Ag immunization was significantly impaired in CD22-/- mice, consistent with reduced TI-2 Ab responses. We generated CD22-/- mice with reduced CD19 levels (CD22-/-CD19+/-) to test the hypothesis that augmented B-1b cell BCR signaling in CD22-/- mice contributes to impaired TI-2 Ab responses. BCR-induced proliferation and intracellular Ca2+ concentration responses were normalized in CD22-/-CD19+/- B-1b cells. Consistent with this, TI-2 Ag-specific B-1b cell expansion, plasmablast differentiation, survival, and Ab responses were rescued in CD22-/-CD19+/- mice. Thus, CD22 plays a critical role in regulating TI-2 Ab responses through regulating B-1b cell signaling thresholds.
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Affiliation(s)
- Karen M Haas
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Kristen L Johnson
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - James P Phipps
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Cardinal Do
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157
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9
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The Role of Liver Sinusoidal Endothelial Cells in Induction of Carbohydrate Reactive B Cells Tolerance Through the Programmed Death 1/Programmed Death Ligand 1 Pathway. Transplantation 2015; 99:2325-36. [PMID: 26247556 DOI: 10.1097/tp.0000000000000831] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND A spontaneous tolerance of B cells responding to blood group antigens frequently develops in ABO-incompatible pediatric liver transplantation (LT). Liver sinusoidal endothelial cells (LSECs), which exclusively express blood group antigens in the liver, possess a capacity to induce alloantigen-specific tolerance. In this study, we elucidated the role of LSECs in the tolerance induction of blood group antigen-reactive B cells after ABO-incompatible LT using mice that lack galactose-α(1,3)galactose (Gal) epitopes resembling blood group carbohydrate antigens. METHODS Using adoptive transfer of LSECs from wild type (WT) C57BL/6J mice to congenic α1,3-galactosyltransferase gene knockout (GalT) mice, we established orthotropic GalT → GalT LSEC chimera mice. Anti-Gal Ab (antibody) production was evaluated after immunization of GalT → GalT LSEC chimera mice with Gal rabbit RBC. RESULTS Adoptive transfer of LSECs isolated from WT GalT mice via the portal vein resulted in persistent engraftment of Gal LSECs in congenic GalT mouse livers. Only when GalT mice were splenectomized before LSEC inoculation, the GalT → GalT LSEC chimera lost the ability to produce anti-Gal Abs. The administration of blocking monoclonal Abs (mAbs) against programmed death ligand 1 to the splenectomized GalT → GalT LSEC chimera resulted in the recovery of anti-Gal Ab production. CONCLUSIONS These findings suggest that LSECs take a part in tolerization of immature but not mature B cells specifically for Gal. Furthermore, the programmed death 1/programmed death ligand 1 pathway likely plays a crucial role in the mechanisms underlying spontaneous tolerization of B cells responding to ABO-blood group antigens in LT.
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10
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Abstract
B-1 cells comprise subpopulations of B lymphocytes in mice that display developmental, phenotypic, and functional characteristics that are distinct from those of conventional B cell populations (B-2 cells). Despite the known importance of murine B-1a (CD5(+) ) and B-1b (CD5(-) ) cells in the production of natural antibodies and rapid antigen-specific humoral responses to infection, evidence for B-1 cells in primates, including humans, is very limited. Identifying these cells in humans proves challenging given the limited number of cells that can be obtained from sites expected to harbor increased frequencies of these cells (i.e., peritoneal and pleural cavities) and the need to perform functional analyses on these cells, which, in the case of B-1b cells, must be carried out in vivo. My laboratory has used cynomolgus macaques and African green monkeys to bypass these limitations and to identify and extensively analyze primate B cell populations with the phenotypic and functional characteristics of mouse B-1a and B-1b cells. Our results reveal striking similarities between primate and murine B-1 cells, including a conserved functional role for primate B-1b-like cells in immunity to T cell-independent type 2 antigens.
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Affiliation(s)
- Karen M Haas
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, North Carolina
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11
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McKay JT, Egan RP, Yammani RD, Chen L, Shin T, Yagita H, Haas KM. PD-1 suppresses protective immunity to Streptococcus pneumoniae through a B cell-intrinsic mechanism. THE JOURNAL OF IMMUNOLOGY 2015; 194:2289-99. [PMID: 25624454 DOI: 10.4049/jimmunol.1401673] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Despite the emergence of the programmed cell death 1 (PD-1):PD-1 ligand (PD-L) regulatory axis as a promising target for treating multiple human diseases, remarkably little is known about how this pathway regulates responses to extracellular bacterial infections. We found that PD-1(-/-) mice, as well as wild-type mice treated with a PD-1 blocking Ab, exhibited significantly increased survival against lethal Streptococcus pneumoniae infection following either priming with low-dose pneumococcal respiratory infection or S. pneumoniae-capsular polysaccharide immunization. Enhanced survival in mice with disrupted PD-1:PD-L interactions was explained by significantly increased proliferation, isotype switching, and IgG production by pneumococcal capsule-specific B cells. Both PD-L, B7-H1 and B7-DC, contributed to PD-1-mediated suppression of protective capsule-specific IgG. Importantly, PD-1 was induced on capsule-specific B cells and suppressed IgG production and protection against pneumococcal infection in a B cell-intrinsic manner. To our knowledge, these results provide the first demonstration of a physiologic role for B cell-intrinsic PD-1 expression in vivo. In summary, our study reveals that B cell-expressed PD-1 plays a central role in regulating protection against S. pneumoniae, and thereby represents a promising target for bolstering immunity to encapsulated bacteria.
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Affiliation(s)
- Jerome T McKay
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Ryan P Egan
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Rama D Yammani
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157
| | - Lieping Chen
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06519
| | - Tahiro Shin
- Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229; and
| | - Hideo Yagita
- Department of Immunology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
| | - Karen M Haas
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157;
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12
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Yammani RD, Leyva MA, Jennings RN, Haas KM. C4 Deficiency is a predisposing factor for Streptococcus pneumoniae-induced autoantibody production. THE JOURNAL OF IMMUNOLOGY 2014; 193:5434-43. [PMID: 25339671 DOI: 10.4049/jimmunol.1401462] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Reductions in C4 levels may predispose individuals to infection with encapsulated bacteria as well as autoimmunity. In this study, we examined the role C4 has in protection against Streptococcus pneumoniae-induced autoimmunity. Mild respiratory infection with serotype 19F pneumococci selectively induced systemic anti-dsDNA IgA production in naive C4(-/-) mice, but not in C3(-/-) or wild-type mice. Systemic challenge with virulent serotype 3 pneumococci also induced anti-dsDNA IgA production in immune C4(-/-) mice. Remarkably, pneumococcal polysaccharide (PPS) vaccination alone induced C4(-/-) mice to produce increased anti-dsDNA IgA levels that were maintained in some mice for months. These effects were most pronounced in female C4(-/-) mice. Importantly, immunization-induced increases in anti-dsDNA IgA levels were strongly associated with increased IgA deposition in kidneys. Cross-reactivity between pneumococcal Ags and dsDNA played a partial role in the induction of anti-dsDNA IgA, but a major role for PPS-associated TLR2 agonists was also revealed. Administration of the TLR2/4 antagonist, OxPAPC, at the time of PPS immunization completely blocked the production of anti-dsDNA IgA in C4(-/-) mice without suppressing PPS-specific Ab production. The TLR2 agonist, Pam3CSK4, similarly induced anti-dsDNA IgA production in C4(-/-) mice, which OxPAPC also prevented. LPS, a TLR4 agonist, had no effect. Pam3CSK4, but not LPS, also induced dsDNA-specific IgA production by C4(-/-) splenic IgA(+) B cells in vitro, indicating that TLR2 agonists can stimulate autoantibody production via B cell-intrinsic mechanisms. Collectively, our results show an important role for C4 in suppressing autoantibody production elicited by cross-reactive Ags and TLR2 agonists associated with S. pneumoniae.
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Affiliation(s)
- Rama D Yammani
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27101
| | - Marcela A Leyva
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27101
| | - Ryan N Jennings
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27101
| | - Karen M Haas
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27101
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Abreu MT, Carvalheiro H, Rodrigues-Sousa T, Domingos A, Segorbe-Luis A, Rodrigues-Santos P, Souto-Carneiro MM. Alterations in the peripheral blood B cell subpopulations of multidrug-resistant tuberculosis patients. Clin Exp Med 2013; 14:423-9. [PMID: 24068613 DOI: 10.1007/s10238-013-0258-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Accepted: 09/02/2013] [Indexed: 01/09/2023]
Abstract
The function of B cells in the immune response against Mycobacterium tuberculosis (Mtb) is still regarded as secondary, although major findings in mouse models of tuberculosis (TB) support their participation as regulators and antibody producers. However, studies in cohorts of TB or multidrug-resistant TB (MDR-TB) patients have failed to clearly identify changes in the circulating B cell pool. Therefore, in the present study we aimed at identifying alterations in the different B cell subpopulations in peripheral blood samples of HIV-negative pulmonary MDR-TB patients when compared to healthy donors. The data show, for the first time, that MDR-TB patients, similarly to what has been observed in other chronic inflammatory diseases, have a much lower frequency of peripheral blood unswitched IgD(+)CD27(+) memory B cells. Equally novel are the findings that in MDR-TB patients there is a reduction in the circulating plasma cell pool and that in MDR-TB there is an increased frequency of circulating type 1 transitional IgD(+)CD38(++), CD69(+) and TLR9(+) B cells. These results document disease-related shifts in peripheral blood B cell subsets in MDR-TB and suggest that such changes should be taken into account when designing new strategies to boost the cellular and humoral immune response against Mtb.
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Affiliation(s)
- Mónica T Abreu
- Center for Neuroscience and Cell Biology, University of Coimbra, Largo Marques de Pombal, 3004-517, Coimbra, Portugal
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Donius LR, Orlando CM, Weis JJ, Weis JH. Generation of a novel Cr2 gene allele by homologous recombination that abrogates production of Cr2 but is sufficient for expression of Cr1. Immunobiology 2013; 219:53-63. [PMID: 24012440 DOI: 10.1016/j.imbio.2013.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 08/01/2013] [Indexed: 11/17/2022]
Abstract
The enhancing effects of the complement system for humoral immunity have primarily focused upon the recognition of complement-bound foreign antigens by a co-receptor complex of the antigen-specific B cell receptor (BCR) and complement receptor 2 (Cr2). In vivo experiments using Cr2 gene deficient mice (which lack the expression of both the Cr1 and Cr2 proteins) do demonstrate depressed humoral responses to immunization but cannot be used to define specific contributions of the singular Cr1 or Cr2 proteins on B cell functions. To study the effect of a Cr2 deficiency in a Cr1 sufficient environment we created a mouse line in which the alternative splice site required for the expression of the Cr2 isoform was removed. This mouse line, Cr2KO, still expressed Cr1 on B cells but was deficient for the full length Cr2 protein. Surprisingly a new alternative splice within the Cr2 gene created a truncated product that encoded a novel protein termed iCr2 that was expressed on the surface of the cells. The Cr2KO mouse thus provides a new model system for the analysis of Cr1 and Cr2 functions in the immune response of the mouse.
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Affiliation(s)
- Luke R Donius
- Division of Microbiology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, United States
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Haas KM, Blevins MW, High KP, Pang B, Swords WE, Yammani RD. Aging promotes B-1b cell responses to native, but not protein-conjugated, pneumococcal polysaccharides: implications for vaccine protection in older adults. J Infect Dis 2013; 209:87-97. [PMID: 23964109 DOI: 10.1093/infdis/jit442] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The efficacy of different vaccines in protecting elderly individuals against Streptococcus pneumoniae infections is not clear. In the current study, aged mice (22-25 months old) exhibited significantly increased susceptibility to respiratory infection with serotype 3 S. pneumoniae relative to younger adult mice, regardless of whether mice were naive or immunized with native pneumococcal polysaccharide (PPS; Pneumovax23) or protein-PPS conjugate (Prevnar-13) vaccines. Nonetheless, Pneumovax-immunized aged mice developed limited bacteremia following respiratory challenge and exhibited significantly increased survival following systemic challenge relative to Prevnar-immune aged mice and young mice that had received either vaccine. This was explained by >10-fold increases in PPS-specific immunoglobulin G (IgG) levels in Pneumovax-immunized aged mice relative to other groups. Remarkably, PPS3-specific B-cell expansion, IgG switching, plasmablast differentiation, and spleen and bone marrow antibody-secreting cell frequencies were 10-fold higher in aged mice following Pneumovax immunization relative to young mice, due to significantly increased B-1b cell participation. In summary, this study highlights (1) the need to devise strategies to enhance respiratory immunity in aged populations, (2) the diverse responses young and aged populations generate to Pneumovax vs Prevnar vaccines, and (3) the potential value of exploiting B-1b cell responses in aged individuals for increased vaccine efficacy.
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Donius LR, Handy JM, Weis JJ, Weis JH. Optimal germinal center B cell activation and T-dependent antibody responses require expression of the mouse complement receptor Cr1. THE JOURNAL OF IMMUNOLOGY 2013; 191:434-47. [PMID: 23733878 DOI: 10.4049/jimmunol.1203176] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Follicular dendritic cells (FDCs) and complement receptor (Cr)1 and complement receptor (Cr)2 are important for the generation of humoral immunity. Cr1/2 expression on B cells and FDCs was shown to provide a secondary signal for B cell activation, to facilitate transport of Ag in immune follicles, and to enhance retention of immune complexes by FDCs. We show in this study that murine B cells predominantly express the Cr2 product from the Cr2 gene, whereas FDCs almost exclusively express the Cr1 isoform generated from the Cr2 gene. To define the specific role of Cr1, we created an animal that maintains normal cell-restricted expression of Cr2 but does not express Cr1. Cr1-deficient (Cr1KO) mice develop normal B1 and B2 immature and mature B cell subsets and have normal levels of naive serum Abs but altered levels of natural Abs. Immunization of the Cr1KO animal demonstrates deficient Ab responses to T-dependent, but not T-independent, Ags. Germinal centers from the immunized Cr1KO animal possess a deficiency in activated B cells, similar to that seen for animals lacking both Cr1 and Cr2 or C3. Finally, animals lacking only Cr1 respond similarly to wild-type animals to infections with Streptococcus pneumoniae, a pathogen to which animals lacking C3 or both Cr1 and Cr2 are particularly sensitive. Altogether, these data suggest that the production of Cr1, primarily by FDCs, is critical in the generation of appropriately activated B cells of the germinal center and the generation of mature Ab responses.
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Affiliation(s)
- Luke R Donius
- Division of Cell Biology and Immunology, Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
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17
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Marginal zone B cells: virtues of innate-like antibody-producing lymphocytes. Nat Rev Immunol 2013; 13:118-32. [PMID: 23348416 DOI: 10.1038/nri3383] [Citation(s) in RCA: 528] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Protective responses to microorganisms involve the nonspecific but rapid defence mechanisms of the innate immune system, followed by the specific but slow defence mechanisms of the adaptive immune system. Located as sentinels at the interface between the circulation and lymphoid tissue, splenic marginal zone B cells rapidly respond to blood-borne antigens by adopting 'crossover' defensive strategies that blur the conventional boundaries of innate and adaptive immunity. This Review discusses how marginal zone B cells function as innate-like lymphocytes that mount rapid antibody responses to both T cell-dependent and T cell-independent antigens. These responses require the integration of activation signals from germline-encoded and somatically recombined receptors for microorganisms with helper signals from effector cells of the innate and adaptive immune systems.
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Yammani RD, Haas KM. Primate B-1 cells generate antigen-specific B cell responses to T cell-independent type 2 antigens. THE JOURNAL OF IMMUNOLOGY 2013; 190:3100-8. [PMID: 23455507 DOI: 10.4049/jimmunol.1203058] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Ab responses to T cell-independent type 2 (TI-2) Ags, such as bacterial capsular polysaccharides, are critical for host defense. In mice, B-1b cells expressing a CD11b(+)FSC(hi)CD21(lo/-)CD19(hi) phenotype play a key role in producing Abs against TI-2 Ags. In primates, a distinct IgM(+)CD27(+) "memory" B cell population is thought to generate TI-2 Ab responses, and evidence for a B-1b-like cell population participating in these responses is lacking. In this article, we demonstrate that nonhuman primates (NHPs; African green monkeys and cynomolgus macaques) harbor serosal B cells expressing a CD11b(+)FSC(hi)CD21(lo/-)CD80(+/-)CD19(hi) phenotype, constitutively active Stat3, and increased reactivity with phosphorylcholine, similar to murine peritoneal B-1a and B-1b cell populations. Like what is observed for murine B-1b cells, NHP CD11b(+)FSC(hi)CD21(lo/-)CD19(hi) B cells dominate the Ag-specific B cell response and Ab production against the TI-2 Ag trinitrophenyl-Ficoll. Although Ag-specific IgM(+) B cells expressing CD27 were not detected prior to immunization, Ag-specific CD11b(+)CD19(hi) B cells expressed and maintained an IgM(+)IgD(lo)CD27(+)CD80(+) phenotype following immunization. Thus, the murine and NHP B cell populations responding to trinitrophenyl-Ficoll are highly similar, with the main exception being that Ag-specific NHP B-1-like cells express CD27 following TI-2 Ag encounter. Therefore, murine B-1b and primate IgM(+)CD27(+) "memory" B cell subsets proposed to produce TI-2 Ab responses may be highly related, if not identical. Overall, these data not only support that B-1-like cells are present in NHPs but also provide evidence that these cells perform the same functions attributed to murine B-1b cells.
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Affiliation(s)
- Rama D Yammani
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27101, USA
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Bodhankar S, Galipeau D, Vandenbark AA, Offner H. PD-1 Interaction with PD-L1 but not PD-L2 on B-cells Mediates Protective Effects of Estrogen against EAE. ACTA ACUST UNITED AC 2013; 4:143. [PMID: 24009988 DOI: 10.4172/2155-9899.1000143] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Increased remissions in multiple sclerosis (MS) during late pregnancy may result from high levels of sex steroids such as estrogen and estriol. Estrogen (E2=17β-estradiol) protects against experimental autoimmune encephalomyelitis (EAE), but the cellular basis for E2-induced protection remains unclear. Treatment with relatively low doses of E2 can protect against clinical and histological signs of MOG-35-55 induced EAE through mechanisms involving the PD-1 coinhibitory pathway and B-cells. The current study evaluated the contribution of PD-1 ligands, PD-L1 and PD-L2, on B-cells in E2-mediated protection against EAE in WT, PD-L1-/- and PD-L2-/- mice. Unlike PD-L2-/- mice that were fully protected against EAE after E2 treatment, E2-implanted PD-L1-/- mice were fully susceptible to EAE, with increased numbers of proliferating Th1/Th17 cells in the periphery and severe cellular infiltration and demyelination in the CNS. Moreover, transfer of B-cells from MOG-immunized PD-L1-/- or PD-L2-/- donors into E2-preconditioned B-cell deficient μMT-/- recipient mice revealed significantly reduced E2-mediated protection against EAE in recipients of PD-L1-/- B-cells, but near-complete protection in recipients of PD-L2-/- B-cells. We conclude that PD-1 interaction with PD-L1 but not PD-L2 on B-cells is crucial for E2-mediated protection in EAE and that strategies that enhance PD-1/PD-L1 interactions might potentiate E2 treatment effects in MS.
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Affiliation(s)
- Sheetal Bodhankar
- Neuroimmunology Research, Portland VA Medical Center, Portland, OR, USA ; Department of Neurology, Oregon Health & Science University, Portland, OR, USA
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Haas KM. Programmed cell death 1 suppresses B-1b cell expansion and long-lived IgG production in response to T cell-independent type 2 antigens. THE JOURNAL OF IMMUNOLOGY 2011; 187:5183-95. [PMID: 22003198 DOI: 10.4049/jimmunol.1101990] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
B-1b cells play a key role in producing Abs against T cell-independent type 2 Ags. However, the factors regulating Ab production by this unique B cell subset are not well understood. In this study, a detailed analysis of the B cell response to 2,4,6-trinitrophenol (TNP)-Ficoll was performed using normal mice. TNP-Ficoll delivered i.p. or i.v. induced rapid Ag-specific B-1b cell activation, expansion, isotype switching, and plasmablast/plasma cell differentiation. Ag-specific B-1b cell numbers peaked at day 5 and then gradually declined in the spleen but remained elevated in the peritoneal cavity beyond 40 d postimmunization. In addition to expressing CD43, CD44, and CD86, Ag-activated B-1b cells transiently expressed programmed cell death 1 (PD-1), which functionally suppressed BCR-induced B-1b cell in vitro proliferation when additional costimulatory signals were lacking. Inhibiting PD-1:PD-1 ligand interactions during TNP-Ficoll immunization significantly enhanced Ag-specific B-1b cell expansion and the frequency of IgG isotype switching and plasmablast/plasma cell differentiation. Remarkably, PD-1 mAb blockade during the first week following immunization resulted in significantly increased numbers of both splenic and bone marrow Ag-specific IgG3-secreting cells, but not IgM-secreting cells, at both early (day 5) and late (week 6) time points. Moreover, Ag-specific serum IgG3 levels, as well as IgG2c, IgG2b, and IgA levels, remained significantly elevated in PD-1 mAb-treated mice relative to control Ab-treated mice for ≥6 wk postimmunization. Thus, PD-1:PD-1 ligand interactions occurring shortly after initial T cell-independent type 2 Ag encounter play a critical role in suppressing Ag-specific B-1b cell expansion and the development of long-term IgG-producing bone marrow and spleen cells.
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Affiliation(s)
- Karen M Haas
- Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
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Kanswal S, Katsenelson N, Allman W, Uslu K, Blake MS, Akkoyunlu M. Suppressive effect of bacterial polysaccharides on BAFF system is responsible for their poor immunogenicity. THE JOURNAL OF IMMUNOLOGY 2011; 186:2430-43. [PMID: 21248261 DOI: 10.4049/jimmunol.1002976] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Capsular polysaccharides of encapsulated bacteria are weakly immunogenic T cell-independent type 2 (TI-2) Ags. Recent findings suggest that BAFF system molecules have a critical role in the development of Ab responses against TI-2 Ags. In this study, we investigated the effect of bacterial polysaccharides on B cell responses to BAFF and a proliferation-inducing ligand (APRIL). We determined that B cells exposed to meningococcal type C polysaccharide (MCPS) or group B Streptococcus serotype V (GBS-V) were unresponsive to BAFF- and APRIL-induced Ig secretion. Moreover, MCPS and GBS-V strongly downregulated transmembrane activator and calcium-modulator and cyclophilin ligand interactor, the BAFF and APRIL receptor that is responsible for Ab development against TI-2 Ags. Interestingly, (4-hydroxy-3-nitrophenyl)acetyl-Ficoll (NP-Ficoll), a prototype TI-2 Ag, did not manifest a suppressive effect on B cells. Paradoxically, whereas GBS-V and MCPS inhibited IFN-γ-induced BAFF production from dendritic cells, NP-Ficoll strongly increased BAFF secretion. TLR 9 agonist CpG deoxyoligonucleotide (ODN) was able to reverse the MCPS-mediated transmembrane activator and calcium-modulator and cyclophilin ligand interactor suppression but could not rescue the Ig secretion in BAFF- or APRIL-stimulated B cells. In support of these in vitro observations, it was observed that CpG ODN could help augment the Ab response against NP in mice immunized with a CpG ODN-containing NP-Ficoll vaccine but exhibited only marginal adjuvant activity for MCPS vaccine. Collectively, these results suggest a mechanism for the weak immunogenicity of bacterial polysaccharides and explain the previously observed differences between bacterial polysaccharide and NP-Ficoll immunogenicity.
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Affiliation(s)
- Sunita Kanswal
- Laboratory of Bacterial Polysaccharides, Division of Bacterial Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, US Food and Drug Administration, Bethesda, MD 20852, USA
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Woods KM, Pope MR, Hoffman SM, Fleming SD. CR2+ marginal zone B cell production of pathogenic natural antibodies is C3 independent. THE JOURNAL OF IMMUNOLOGY 2010; 186:1755-62. [PMID: 21187447 DOI: 10.4049/jimmunol.1002059] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Intestinal ischemia-reperfusion (IR)-induced damage requires complement receptor 2 (CR2) for generation of the appropriate natural Ab repertoire. Pathogenic Abs recognize neoantigens on the ischemic tissue, activate complement, and induce intestinal damage. Because C3 cleavage products act as ligands for CR2, we hypothesized that CR2(hi) marginal zone B cells (MZBs) require C3 for generation of the pathogenic Abs. To explore the ability of splenic CR2(+) B cells to generate the damaging Ab repertoire, we adoptively transferred either MZBs or follicular B cells (FOBs) from C57BL/6 or Cr2(-/-) mice into Rag-1(-/-) mice. Adoptive transfer of wild type CR2(hi) MZBs but not CR2(lo) FOBs induced significant damage, C3 deposition, and inflammation in response to IR. In contrast, similarly treated Rag-1(-/-) mice reconstituted with either Cr2(-/-) MZB/B1 B cells (B1Bs) or FOBs lacked significant intestinal damage and displayed limited complement activation. To determine whether C3 cleavage products are critical in CR2-dependent Ab production, we evaluated the ability of the natural Ab repertoire of C3(-/-) mice to induce damage in response to IR. Infusion of C3(-/-) serum into Cr2(-/-) mice restored IR-induced tissue damage. Furthermore, Rag-1(-/-) mice sustained significant damage after infusion of Abs from C3(-/-) but not Cr2(-/-) mice. Finally, adoptive transfer of MZBs from C3(-/-) mice into Rag-1(-/-) mice resulted in significant tissue damage and inflammation. These data indicate that CR2 expression on MZBs is sufficient to induce the appropriate Abs required for IR-induced tissue damage and that C3 is not critical for generation of the pathogenic Abs.
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Affiliation(s)
- Keith M Woods
- Division of Biology, Kansas State University, Manhattan, KS 66506, USA
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Torres J, Tamimi F, Alkhraisat MH, Manchón A, Linares R, Prados-Frutos JC, Hernández G, López Cabarcos E. Platelet-rich plasma may prevent titanium-mesh exposure in alveolar ridge augmentation with anorganic bovine bone. J Clin Periodontol 2010. [PMID: 20796106 DOI: 10.1111/j.1600] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Bone augmentation with the titanium-mesh (Ti-mesh) technique is susceptible to a large rate of complications such as morbidity of bone graft donor site, and mesh exposure to the oral cavity. The purpose of this study was to evaluate the effectiveness of anorganic bovine bone (ABB) in alveolar bone augmentation with the Ti-mesh technique. In addition, we investigated the effect of platelet-rich plasma (PRP) in preventing mesh exposure by using it to cover the Ti-mesh. PATIENTS AND METHODS Patients included in the clinical trial were randomly allocated by a blinded assistant into two groups. The 30 patients recruited for this study underwent 43 alveolar bone augmentation with the Ti-mesh technique using ABB as graft material in all of them. In 15 patients, the Ti-meshes were covered with PRP (PRP group) whereas in the other 15 the Ti-meshes were not (control group). After 6 months, patients were called for clinical, radiographic, and histological evaluation, and implant placement surgery. A total of 97 implants were placed in the augmented bone and their evolution was followed up for a period of 24 months. RESULTS Significant differences were found between the two study groups in terms of complications and bone formation. In the control group, 28.5% of the cases suffered from mesh exposure, while in the PRP group, no exposures were registered. Radiographic analysis revealed that bone augmentation was higher in the PRP group than in the control group. Overall, 97.3% of implants placed in the control group and 100% of those placed in the PRP group were successful during the monitoring period. We suggest that the positive effect of PRP on the Ti-mesh technique is due to its capacity to improve soft tissue healing, thereby protecting the mesh and graft material secured beneath the gingival tissues. CONCLUSIONS Alveolar bone augmentation using ABB alone in the Ti-mesh technique is sufficient for implant rehabilitation. Besides, covering the Ti-meshes with PRP was a determining factor in avoiding mesh exposure. Ti-mesh exposure provoked significant bone loss, but in most cases it did not affect the subsequent placement of implants.
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Affiliation(s)
- Jesús Torres
- Ciencias de la Salud III, Universidad Rey Juan Carlos, Alcorcón, Spain
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Prokopec KE, Rhodiner M, Matt P, Lindqvist U, Kleinau S. Down regulation of Fc and complement receptors on B cells in rheumatoid arthritis. Clin Immunol 2010; 137:322-9. [PMID: 20850384 DOI: 10.1016/j.clim.2010.08.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 07/22/2010] [Accepted: 08/09/2010] [Indexed: 01/08/2023]
Abstract
B cell tolerance is regulated by receptors that modulate B cell receptor signaling, such as Fc gamma receptor IIb (FcγRIIb; CD32b) and complement receptors (CR) 1 and 2. Deficiency in these receptors may contribute to autoimmunity. To address this we have investigated the receptor expression in healthy individuals in comparison with rheumatoid arthritis (RA) patients. In healthy subjects we found that women had overall lower FcγRIIb expression on B cells than men that significantly decreased with age. RA patients had fewer FcγRIIb, CR1 and CR2 positive B cells and decreased receptor expressions compared to healthy subjects. Further, the RA B cells displayed a significantly increased proliferative response when cultured with interleukin-2 in vitro. In summary, the dysregulated B cells in RA are associated with lower FcγRIIb, CR1 and CR2 levels. The reduced FcγRIIb expression on B cells in women may influence the increased frequency of autoimmunity in women.
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Affiliation(s)
- Kajsa E Prokopec
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
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25
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Abstract
Regulatory T cells (Tregs) and the PD-1: PD-ligand (PD-L) pathway are both critical to terminating immune responses. Elimination of either can result in the breakdown of tolerance and the development of autoimmunity. The PD-1: PD-L pathway can thwart self-reactive T cells and protect against autoimmunity in many ways. In this review, we highlight how PD-1 and its ligands defend against potentially pathogenic self-reactive effector T cells by simultaneously harnessing two mechanisms of peripheral tolerance: (i) the promotion of Treg development and function and (ii) the direct inhibition of potentially pathogenic self-reactive T cells that have escaped into the periphery. Treg cells induced by the PD-1 pathway may also assist in maintaining immune homeostasis, keeping the threshold for T-cell activation high enough to safeguard against autoimmunity. PD-L1 expression on non-hematopoietic cells as well as hematopoietic cells endows PD-L1 with the capacity to promote Treg development and enhance Treg function in lymphoid organs and tissues that are targets of autoimmune attack. At sites where transforming growth factor-beta is present (e.g. sites of immune privilege or inflammation), PD-L1 may promote the de novo generation of Tregs. When considering the consequences of uncontrolled immunity, it would be therapeutically advantageous to manipulate Treg development and sustain Treg function. Thus, this review also discusses how the PD-1 pathway regulates a number of autoimmune diseases and the therapeutic potential of PD-1: PD-L modulation.
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Affiliation(s)
- Loise M. Francisco
- Departments of Pathology, Harvard Medical School, Boston, MA, USA
- Brigham & Women’s Hospital, Boston, MA, USA
| | - Peter T. Sage
- Departments of Pathology, Harvard Medical School, Boston, MA, USA
| | - Arlene H. Sharpe
- Departments of Pathology, Harvard Medical School, Boston, MA, USA
- Brigham & Women’s Hospital, Boston, MA, USA
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Tedder TF. Innate and adaptive receptors interact to balance humoral immunity. THE JOURNAL OF IMMUNOLOGY 2010; 184:2231-2. [PMID: 20164432 DOI: 10.4049/jimmunol.1090001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Thomas F Tedder
- Department of Immunology, Box 3010, Duke University Medical Center, Durham, NC 27710, USA.
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Brown KE, Freeman GJ, Wherry EJ, Sharpe AH. Role of PD-1 in regulating acute infections. Curr Opin Immunol 2010; 22:397-401. [PMID: 20427170 DOI: 10.1016/j.coi.2010.03.007] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 02/26/2010] [Accepted: 03/25/2010] [Indexed: 12/25/2022]
Abstract
While the role of PD-1 in inhibiting immunity during chronic infections is well established, its functions during acute infections are much less clear. The PD-1 pathway can dampen CD8 T cell responses during some acute infections and restrain responses by 'helpless' CD8 memory T cells. An emerging role for PD-1 in innate immunity has been revealed by recent studies showing that PD-1 can limit function of DC and macrophages as well as T cell independent B cell responses. Thus, PD-1 can influence adaptive immune responses during acute infections, though precisely how this regulation occurs is only just beginning to be appreciated.
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Affiliation(s)
- Keturah E Brown
- Department of Pathology, Harvard Medical School, Boston, MA 02115, USA
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