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Kubagawa H, Mahmoudi Aliabadi P, Al-Qaisi K, Jani PK, Honjo K, Izui S, Radbruch A, Melchers F. Functions of IgM fc receptor (FcµR) related to autoimmunity. Autoimmunity 2024; 57:2323563. [PMID: 38465789 DOI: 10.1080/08916934.2024.2323563] [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: 10/29/2023] [Accepted: 02/20/2024] [Indexed: 03/12/2024]
Abstract
Unlike Fc receptors for switched immunoglobulin (Ig) isotypes, Fc receptor for IgM (FcµR) is selectively expressed by lymphocytes. The ablation of the FcµR gene in mice impairs B cell tolerance as evidenced by concomitant production of autoantibodies of IgM and IgG isotypes. In this essay, we reiterate the autoimmune phenotypes observed in mutant mice, ie IgM homeostasis, dysregulated humoral immune responses including autoantibodies, and Mott cell formation. We also propose the potential phenotypes in individuals with FCMR deficiency and the model for FcµR-mediated regulation of self-reactive B cells.
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Affiliation(s)
| | | | | | - Peter K Jani
- Deutsches Rheuma-Forschungszentrum Berlin, Berlin, Germany
| | - Kazuhito Honjo
- Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Shozo Izui
- Department of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | | | - Fritz Melchers
- Deutsches Rheuma-Forschungszentrum Berlin, Berlin, Germany
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2
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Hasegawa H, Wang S, Kast E, Chou HT, Kaur M, Janlaor T, Mostafavi M, Wang YL, Li P. Understanding the biosynthesis of human IgM SAM-6 through a combinatorial expression of mutant subunits that affect product assembly and secretion. PLoS One 2024; 19:e0291568. [PMID: 38848420 PMCID: PMC11161108 DOI: 10.1371/journal.pone.0291568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 05/06/2024] [Indexed: 06/09/2024] Open
Abstract
Polymeric IgMs are secreted from plasma cells abundantly despite their structural complexity and intricate multimerization steps. To gain insights into IgM's assembly mechanics that underwrite such high-level secretion, we characterized the biosynthetic process of a natural human IgM, SAM-6, using a heterologous HEK293(6E) cell platform that allowed the production of IgMs both in hexameric and pentameric forms in a controlled fashion. By creating a series of mutant subunits that differentially disrupt secretion, folding, and specific inter-chain disulfide bond formation, we assessed their effects on various aspects of IgM biosynthesis in 57 different subunit chain combinations, both in hexameric and pentameric formats. The mutations caused a spectrum of changes in steady-state subcellular subunit distribution, ER-associated inclusion body formation, intracellular subunit detergent solubility, covalent assembly, secreted IgM product quality, and secretion output. Some mutations produced differential effects on product quality depending on whether the mutation was introduced to hexameric IgM or pentameric IgM. Through this systematic combinatorial approach, we consolidate diverse overlapping knowledge on IgM biosynthesis for both hexamers and pentamers, while unexpectedly revealing that the loss of certain inter-chain disulfide bonds, including the one between μHC and λLC, is tolerated in polymeric IgM assembly and secretion. The findings highlight the differential roles of underlying non-covalent protein-protein interactions in hexamers and pentamers when orchestrating the initial subunit interactions and maintaining the polymeric IgM product integrity during ER quality control steps, secretory pathway trafficking, and secretion.
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Affiliation(s)
- Haruki Hasegawa
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
| | - Songyu Wang
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
| | - Eddie Kast
- Molecular Analytics, Department of Biologic Therapeutic Discovery, Amgen Inc., South San Francisco, CA, United States of America
| | - Hui-Ting Chou
- Structural Biology, Department of Small Molecule Therapeutic Discovery, Amgen Inc., South San Francisco, CA, United States of America
| | - Mehma Kaur
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
| | - Tanakorn Janlaor
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
| | - Mina Mostafavi
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
| | - Yi-Ling Wang
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
| | - Peng Li
- Discovery Protein Science, Department of Large Molecule Discovery and Research Data Science, Amgen Inc., South San Francisco, CA, United States of America
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Martínez-Aracil A, Polanco-Alonso D, Stayerman C, Miguel C, Pérez de Nanclares G. Colonic adenomatous polyp with florid presence of monoclonal lambda Russell bodies: Case report and etiopathogenic hypothesis. REVISTA ESPANOLA DE PATOLOGIA : PUBLICACION OFICIAL DE LA SOCIEDAD ESPANOLA DE ANATOMIA PATOLOGICA Y DE LA SOCIEDAD ESPANOLA DE CITOLOGIA 2024; 57:111-115. [PMID: 38599729 DOI: 10.1016/j.patol.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 06/15/2023] [Accepted: 07/09/2023] [Indexed: 04/12/2024]
Abstract
Russell bodies (RBs) are round eosinophilic intracytoplasmic inclusions formed by condensed immunoglobulins in mature plasma cells, which are called Mott cells. These cells are rarely found in the gastric tract, with even less cases reported in the colorectal region. There are still many questions about this event, as it is still unknown the relationship between the agents reported of increasing the probability of appearance of these cells and the generation of RBs. In this case report we describe the fifth patient presenting an infiltration of Mott cells in a colorectal polyp, being the second case with a monoclonal origin without a neoplastic cause, and the first one monoclonal for lambda. A comparison with previously similar reported cases is also done, and a possible etiopathogenic hypothesis proposed.
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Affiliation(s)
- Adriano Martínez-Aracil
- Pathology Service, Bioaraba Research Health Institute, Araba University Hospital, Vitoria-Gasteiz, Alava, Spain
| | - Diego Polanco-Alonso
- Molecular (Epi)Genetic Lab, Bioaraba Research Health Institute, Araba University Hospital, Vitoria-Gasteiz, Alava, Spain
| | - Celina Stayerman
- Laboratorio Technipath-Hospital del Valle, San Pedro Sula, Honduras
| | - Carlos Miguel
- Pathology Service, Bioaraba Research Health Institute, Araba University Hospital, Vitoria-Gasteiz, Alava, Spain
| | - Guiomar Pérez de Nanclares
- Molecular (Epi)Genetic Lab, Bioaraba Research Health Institute, Araba University Hospital, Vitoria-Gasteiz, Alava, Spain.
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Martinovic T, Vidicevic S, Ciric D, Bumbasirevic V, Stanojevic Z, Tasic J, Petricevic S, Isakovic A, Martinovic VC, Drndarevic N, Trajkovic V, Kravic-Stevovic T. The presence of Mott cells in the lymph nodes of rats with experimental autoimmune encephalomyelitis. Histochem Cell Biol 2024; 161:287-295. [PMID: 37952208 DOI: 10.1007/s00418-023-02252-y] [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] [Accepted: 10/25/2023] [Indexed: 11/14/2023]
Abstract
Mott cells are plasma cells that have multiple spherical Russell bodies packed in their cytoplasm. Russell bodies are dilated endoplasmic reticulum cisternae filled with aggregates of immunoglobulins that are neither secreted nor degraded. Mott cells were observed in our study by light and electron microscope in the lymph nodes of rats with experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Mott cells were detected on hematoxylin and eosin (HE)-stained lymph node sections as vacuolated cells with eccentrically positioned nuclei and large number of faint blue spherical inclusions in the cytoplasm. Electron microscopic investigation revealed the presence of Russell bodies of the "medusa" form inside Mott cells in lymph node ultra-thin sections of EAE animals. Mott cells expressed the plasma cell marker CD138 and either kappa or lambda immunoglobulin light chains, indicating their origin from polyclonally activated B cells. Finally, Mott cells were associated with active EAE, as they were not found in the lymph nodes of EAE-resistant Albino Oxford rats. The presence of Russell bodies implies an excessive production of immunoglobulins in EAE, thus further emphasizing the role of B cells, and among them Mott cells, in the pathogenesis of this animal model of multiple sclerosis.
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Affiliation(s)
- Tamara Martinovic
- Institute of Histology and Embryology, Faculty of Medicine, University of Belgrade, Višegradska 26, 11000, Belgrade, Serbia
| | - Sasenka Vidicevic
- Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Darko Ciric
- Institute of Histology and Embryology, Faculty of Medicine, University of Belgrade, Višegradska 26, 11000, Belgrade, Serbia.
| | - Vladimir Bumbasirevic
- Institute of Histology and Embryology, Faculty of Medicine, University of Belgrade, Višegradska 26, 11000, Belgrade, Serbia
- Serbian Academy of Sciences and Arts, Belgrade, Serbia
| | - Zeljka Stanojevic
- Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Jelena Tasic
- Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Sasa Petricevic
- Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Aleksandra Isakovic
- Institute of Medical and Clinical Biochemistry, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | | | | | - Vladimir Trajkovic
- Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
| | - Tamara Kravic-Stevovic
- Institute of Histology and Embryology, Faculty of Medicine, University of Belgrade, Višegradska 26, 11000, Belgrade, Serbia
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5
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Mahmoudi Aliabadi P, Al-Qaisi K, Jani PK, Honjo K, Klemm U, Lee KH, Baumgarth N, Radbruch A, Melchers F, Kubagawa H. Enhanced Mott cell formation linked with IgM Fc receptor (FcμR) deficiency. Eur J Immunol 2023; 53:e2250315. [PMID: 37098762 DOI: 10.1002/eji.202250315] [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: 12/06/2022] [Revised: 03/31/2023] [Accepted: 04/25/2023] [Indexed: 04/27/2023]
Abstract
In previous studies, Mott cells, an unusual form of plasma cells containing Ig-inclusion bodies, were frequently observed in peripheral lymphoid tissues in our IgM Fc receptor (FcμR)-deficient (KO) mouse strain. Because of discrepancies in the reported phenotypes of different Fcmr KO mouse strains, we here examined two additional available mutant strains and confirmed that such enhanced Mott-cell formation was a general phenomenon associated with FcμR deficiency. Splenic B cells from Fcmr KO mice clearly generated more Mott cells than those from WT mice when stimulated in vitro with LPS alone or a B-1, but not B-2, activation cocktail. Nucleotide sequence analysis of the Ig variable regions of a single IgMλ+ Mott-hybridoma clone developed from splenic B-1 B cells of Fcmr KO mice revealed the near (VH) or complete (Vλ) identity with the corresponding germline gene segments and the addition of six or five nucleotides at the VH/DH and DH/JH junctions, respectively. Transduction of an FcμR cDNA into the Mott hybridoma significantly reduced cells containing IgM-inclusion bodies with a concomitant increase in IgM secretion, leading to secreted IgM binding to FcμR expressed on Mott transductants. These findings suggest a regulatory role of FcμR in the formation of Mott cells and IgM-inclusion bodies.
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Affiliation(s)
| | - Khlowd Al-Qaisi
- Humoral Immune Regulation, Deutsches Rheuma-Forschungszentrum (DRFZ), Berlin, Germany
| | - Peter K Jani
- Lymphocyte Development, Deutsches Rheuma-Forschungszentrum (DRFZ), Berlin, Germany
| | - Kazuhito Honjo
- Department of Medicine, School of Medicine, University of Alabama, Birmingham, USA
| | - Uwe Klemm
- Experimental Animals, Max Planck Institute for Infectious Biology, Berlin, Germany
| | - Kyeong-Hee Lee
- Inflammation Research Group, Institute of Clinical Chemistry, Hannover Medical School, Hanover, Germany
| | - Nicole Baumgarth
- Department of Molecular Microbiology and immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
| | - Andreas Radbruch
- Department of Cell Biology, Deutsches Rheuma-Forschungszentrum, DRFZ), Berlin, Germany
| | - Fritz Melchers
- Lymphocyte Development, Deutsches Rheuma-Forschungszentrum (DRFZ), Berlin, Germany
| | - Hiromi Kubagawa
- Humoral Immune Regulation, Deutsches Rheuma-Forschungszentrum (DRFZ), Berlin, Germany
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6
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Kuroki K, Williams N, Cook JL. Histologic evidence for a humoral immune response in synovitis associated with cranial cruciate ligament disease in dogs. Vet Surg 2021; 50:1032-1041. [PMID: 33769592 DOI: 10.1111/vsu.13600] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 12/11/2020] [Accepted: 01/03/2021] [Indexed: 12/12/2022]
Abstract
OBJECTIVE To investigate histopathological features of synovium from dogs with cranial cruciate ligament disease (CCLD) to seek mechanisms of osteoarthritis (OA) associated with CCLD. STUDY DESIGN Retrospective, single-institution case series. ANIMALS Thirty client-owned dogs. METHODS Synovial biopsies (n = 30) obtained from stifles with CCLD were assessed by using two synovitis histopathology grading systems (Krenn and Hospital for Special Surgery [HSS]). The Krenn synovitis score was interpreted as "no synovitis," "low-grade," or "high-grade," while inflammatory subtype (low, mixed, or high) was determined by a computational algorithm within the HSS system. Comparison of synovitis scores was based on degree of CCL rupture and presence of meniscal tears. RESULTS Histopathological changes and synovitis scores were similar regardless of degree of rupture (partial n = 5, complete n = 25) or presence of meniscal injury (n = 12) and were characterized by hyperplastic and lymphoplasmacytic synovitis with increased vascularity (30/30) and the presence of hemosiderin deposits (28/30), binucleated plasma cells (28/30), mucoid change (25/30), and Mott cells (16/30). Thirteen (43%) specimens were consistent with high-grade synovitis according to the Krenn system, while 11 (37%) specimens fit into the high-inflammatory subtype with the HSS system. CONCLUSION Synovitis associated with canine CCLD in this study population was lymphoplasmacytic and was often highly inflammatory, with the presence of cells pertaining to humoral immunity. Humoral immune responses may play key roles in the synovitis associated with CCLD. CLINICAL SIGNIFICANCE Modulation of biological factors that provoke humoral immune responses may mitigate symptoms of OA that persist and progress even after surgical treatment of CCLD in dogs.
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Affiliation(s)
- Keiichi Kuroki
- Thompson Laboratory for Regenerative Orthopaedics, University of Missouri, Columbia, Missouri, USA.,Department of Veterinary Pathobiology, Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Ned Williams
- Eastern Carolina Veterinary Referral, Wilmington, North Carolina, USA
| | - James L Cook
- Thompson Laboratory for Regenerative Orthopaedics, University of Missouri, Columbia, Missouri, USA.,Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri, USA
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7
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Ligand-promoted protein folding by biased kinetic partitioning. Nat Chem Biol 2017; 13:369-371. [PMID: 28218913 PMCID: PMC5362304 DOI: 10.1038/nchembio.2303] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 12/12/2016] [Indexed: 01/03/2023]
Abstract
Protein folding in cells occurs in the presence of high concentrations of endogenous binding partners, and exogenous binding partners have been exploited as pharmacological chaperones. A combined mathematical modeling and experimental approach shows that a ligand improves the folding of a destabilized protein by biasing the kinetic partitioning between folding and alternative fates (aggregation or degradation). Computationally predicted inhibition of test protein aggregation and degradation as a function of ligand concentration are validated by experiments in two disparate cellular systems.
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8
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Roles of N-glycans in the polymerization-dependent aggregation of mutant Ig-μ chains in the early secretory pathway. Sci Rep 2017; 7:41815. [PMID: 28157181 PMCID: PMC5291101 DOI: 10.1038/srep41815] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 12/28/2016] [Indexed: 02/07/2023] Open
Abstract
The polymeric structure of secretory IgM allows efficient antigen binding and complement fixation. The available structural models place the N-glycans bound to asparagines 402 and 563 of Ig-μ chains within a densely packed core of native IgM. These glycans are found in the high mannose state also in secreted IgM, suggesting that polymerization hinders them to Golgi processing enzymes. Their absence alters polymerization. Here we investigate their role following the fate of aggregation-prone mutant μ chains lacking the Cμ1 domain (μ∆). Our data reveal that μ∆ lacking 563 glycans (μ∆5) form larger intracellular aggregates than μ∆ and are not secreted. Like μ∆, they sequester ERGIC-53, a lectin previously shown to promote polymerization. In contrast, μ∆ lacking 402 glycans (μ∆4) remain detergent soluble and accumulate in the ER, as does a double mutant devoid of both (μ∆4–5). These results suggest that the two C-terminal Ig-μ glycans shape the polymerization-dependent aggregation by engaging lectins and acting as spacers in the alignment of individual IgM subunits in native polymers.
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9
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Sano T, Takai Y, Anayama H, Watanabe T, Fukuda R. Accumulation of Mott cells in the spleen in a CB6F1-Tg rasH2 mouse. J Toxicol Pathol 2016; 29:265-268. [PMID: 27821912 PMCID: PMC5097970 DOI: 10.1293/tox.2016-0023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/30/2016] [Indexed: 11/19/2022] Open
Abstract
Mott cells are a variant form of plasma cells in humans and laboratory animals. This report describes the morphological characteristics of Mott cells observed in a 33-week-old female CB6F1-Tg rasH2 mouse. Microscopically, a large number of round cells with abundant eosinophilic globules, which were variable in size, were observed in the spleen and were densely distributed in the red pulp adjacent to the marginal zone. A few similar cells were present in the submandibular lymph node and bone marrow. Neither systemic nor local chronic inflammatory changes were seen in this animal. These cells were positive for mouse immunoglobulins. Ultrastructurally, the dilated rough endoplasmic reticulum had a homogenous substances with an intermediate electron density. On the basis of the above findings, these cells were identified as Mott cells. The present lesion is thought to be a spontaneous lesion, an unusual appearance of Mott cells without any associated pathological conditions.
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Affiliation(s)
- Tomoya Sano
- Drug Safety Research Laboratories, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Yuichi Takai
- Drug Safety Research Laboratories, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Hisashi Anayama
- Drug Safety Research Laboratories, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Takeshi Watanabe
- Drug Safety Research Laboratories, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Ryo Fukuda
- Drug Safety Research Laboratories, Takeda Pharmaceutical Company Limited, 26-1 Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
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10
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Honjo K, Kubagawa Y, Suzuki Y, Takagi M, Ohno H, Bucy RP, Izui S, Kubagawa H. Enhanced auto-antibody production and Mott cell formation in FcμR-deficient autoimmune mice. Int Immunol 2014; 26:659-72. [PMID: 24994818 DOI: 10.1093/intimm/dxu070] [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] [Indexed: 11/12/2022] Open
Abstract
The IgM-Fc receptor (FcμR) is involved in IgM homeostasis as evidenced by increased pre-immune serum IgM and natural auto-antibodies of both IgM and IgG isotypes in Fcmr-deficient C57BL/6 (B6) mice. To determine the impact of Fcmr-ablation on autoimmunity, we introduced the Fcmr null mutation onto the Fas-deficient autoimmune-prone B6.MRL Fas (lpr/lpr) mouse background (B6/lpr). Both IgM and IgG auto-antibodies against dsDNA or chromatin appeared earlier in FcμR(-) B6/lpr than FcμR(+) B6/lpr mice, but this difference became less pronounced with age. Splenic B2 cells, which were 2-fold elevated in FcμR(+) B6/lpr mice, were reduced to normal B6 levels in FcμR(-) B6/lpr mice, whereas splenic B1 cells were comparable in both groups of B6/lpr mice. By contrast, marginal zone (MZ) B cells were markedly reduced in FcμR(-) B6/lpr mice compared with either FcμR(+) B6/lpr or wild type (WT) B6 mice. This reduction appeared to result from rapid differentiation of MZ B cells into plasma cells in the absence of FcμR, as IgM antibody to a Smith (Sm) antigen, to which MZ B cells are known to preferentially respond, was greatly increased in both groups (B6/lpr and B6) of FcμR(-) mice compared with FcμR(+) B6/lpr or B6 mice. Mott cells, aberrant plasma cells with intra-cytoplasmic inclusions, were also increased in the absence of FcμR. Despite these abnormalities, the severity of renal pathology and function and survival were all indistinguishable between FcμR(-) and FcμR(+) B6/lpr mice. Collectively, these findings suggest that FcμR plays important roles in the regulation of auto-antibody production, Mott cell formation and the differentiation of MZ B cells into plasma cells in B6.MRL Fas (lpr/lpr) mice.
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Affiliation(s)
- Kazuhito Honjo
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yoshiki Kubagawa
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yusuke Suzuki
- Department of Internal Medicine, Division of Nephrology, Juntendo University School of Medicine, Tokyo 113-8421, Japan
| | - Miyuki Takagi
- Department of Internal Medicine, Division of Nephrology, Juntendo University School of Medicine, Tokyo 113-8421, Japan
| | - Hiroshi Ohno
- Laboratory for Intestinal Ecosystem, RIKEN Center for Integrative Medical Sciences, Yokohama 230-0045, Japan
| | - R Pat Bucy
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Shozo Izui
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva 4, Switzerland
| | - Hiromi Kubagawa
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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11
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Serum free immunoglobulin light chain evaluation as a marker of impact from intraclonal heterogeneity on myeloma outcome. Blood 2014; 123:3414-9. [DOI: 10.1182/blood-2013-12-542662] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Key Points
The type of antibody secreted at relapse can serve as a marker of clonal heterogeneity. It is important to monitor for serum FLC in the suspicion of clinical relapse to ensure that FLC relapse is not missed.
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12
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One siRNA pool targeting the λ constant region stops λ light-chain production and causes terminal endoplasmic reticulum stress. Blood 2014; 123:3440-51. [DOI: 10.1182/blood-2013-10-535187] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Key PointsImmunoglobulin light-chain and antibody production by plasma cells is significantly reduced by siRNA for the light-chain constant region. In plasma cells making intact antibodies, knockdown of light chains can cause terminal ER stress because of unpaired heavy chains.
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13
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Reinhart D, Sommeregger W, Debreczeny M, Gludovacz E, Kunert R. In search of expression bottlenecks in recombinant CHO cell lines--a case study. Appl Microbiol Biotechnol 2014; 98:5959-65. [PMID: 24557570 DOI: 10.1007/s00253-014-5584-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 01/28/2014] [Accepted: 01/29/2014] [Indexed: 01/23/2023]
Abstract
The efficient production of recombinant proteins such as antibodies typically involves the screening of an extravagant number of clones in order to finally select a stable and high-producing cell line. Thereby, the underlying principles of a powerful protein machinery, but also potential expression limitations, often remain poorly understood. To shed more light on this topic, we applied several different techniques to investigate a previously generated cell line (4B3-IgA), which expressed recombinant immunoglobulin A (IgA) with an unusually low specific productivity. Results were compared to the host cell line and to another recombinant CHO cell line (3D6-IgA) expressing another IgA that binds to an overlapping epitope. The low specific productivity of clone 4B3-IgA could not be explained by GCN or mRNA levels, but insufficiencies in protein maturation and/or secretion were determined. Despite the presence of free light chain polypeptides, they occasionally failed to associate with their heavy chain partners. Consequently, heavy chains were misassembled and accumulated to form intracellular aggregates, so-called Russell bodies. These protein deposits evoked the expression of increased amounts of ER-resident chaperones to combat the induced stress. Despite bottlenecks in protein processing, the cells' quality checkpoints remained intact, and predominantly correctly processed IgA was exported into the culture medium. The results of our study demonstrated that recombinant protein expression was impaired by heavy chain aggregation despite the presence of a disposable light chain and revealed elevated chaperone formation in combination with limited antibody assembly. Our studies suggest that the primary amino acid sequence and consequently the resulting structure of an expressed protein need to be considered as a factor influencing a cell's productivity.
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Affiliation(s)
- David Reinhart
- Vienna Institute of BioTechnology, Department of Biotechnology, University of Natural Resources and Life Sciences, Muthgasse 11, 1190, Vienna, Austria,
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14
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Aggregates, crystals, gels, and amyloids: intracellular and extracellular phenotypes at the crossroads of immunoglobulin physicochemical property and cell physiology. Int J Cell Biol 2013; 2013:604867. [PMID: 23533417 PMCID: PMC3603282 DOI: 10.1155/2013/604867] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 01/27/2013] [Indexed: 12/20/2022] Open
Abstract
Recombinant immunoglobulins comprise an important class of human therapeutics. Although specific immunoglobulins can be purposefully raised against desired antigen targets by various methods, identifying an immunoglobulin clone that simultaneously possesses potent therapeutic activities and desirable manufacturing-related attributes often turns out to be challenging. The variable domains of individual immunoglobulins primarily define the unique antigen specificities and binding affinities inherent to each clone. The primary sequence of the variable domains also specifies the unique physicochemical properties that modulate various aspects of individual immunoglobulin life cycle, starting from the biosynthetic steps in the endoplasmic reticulum, secretory pathway trafficking, secretion, and the fate in the extracellular space and in the endosome-lysosome system. Because of the diverse repertoire of immunoglobulin physicochemical properties, some immunoglobulin clones' intrinsic properties may manifest as intriguing cellular phenotypes, unusual solution behaviors, and serious pathologic outcomes that are of scientific and clinical importance. To gain renewed insights into identifying manufacturable therapeutic antibodies, this paper catalogs important intracellular and extracellular phenotypes induced by various subsets of immunoglobulin clones occupying different niches of diverse physicochemical repertoire space. Both intrinsic and extrinsic factors that make certain immunoglobulin clones desirable or undesirable for large-scale manufacturing and therapeutic use are summarized.
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Stoops J, Byrd S, Hasegawa H. Russell body inducing threshold depends on the variable domain sequences of individual human IgG clones and the cellular protein homeostasis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1643-57. [PMID: 22728328 DOI: 10.1016/j.bbamcr.2012.06.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 06/12/2012] [Accepted: 06/13/2012] [Indexed: 01/05/2023]
Abstract
Russell bodies are intracellular aggregates of immunoglobulins. Although the mechanism of Russell body biogenesis has been extensively studied by using truncated mutant heavy chains, the importance of the variable domain sequences in this process and in immunoglobulin biosynthesis remains largely unknown. Using a panel of structurally and functionally normal human immunoglobulin Gs, we show that individual immunoglobulin G clones possess distinctive Russell body inducing propensities that can surface differently under normal and abnormal cellular conditions. Russell body inducing predisposition unique to each immunoglobulin G clone was corroborated by the intrinsic physicochemical properties encoded in the heavy chain variable domain/light chain variable domain sequence combinations that define each immunoglobulin G clone. While the sequence based intrinsic factors predispose certain immunoglobulin G clones to be more prone to induce Russell bodies, extrinsic factors such as stressful cell culture conditions also play roles in unmasking Russell body propensity from immunoglobulin G clones that are normally refractory to developing Russell bodies. By taking advantage of heterologous expression systems, we dissected the roles of individual subunit chains in Russell body formation and examined the effect of non-cognate subunit chain pair co-expression on Russell body forming propensity. The results suggest that the properties embedded in the variable domain of individual light chain clones and their compatibility with the partnering heavy chain variable domain sequences underscore the efficiency of immunoglobulin G biosynthesis, the threshold for Russell body induction, and the level of immunoglobulin G secretion. We propose that an interplay between the unique properties encoded in variable domain sequences and the state of protein homeostasis determines whether an immunoglobulin G expressing cell will develop the Russell body phenotype in a dynamic cellular setting.
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Affiliation(s)
- Janelle Stoops
- Department of Therapeutic Discovery, Amgen Inc., Seattle, WA 98119, USA
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Drayson MT. Using single protein biomarkers to predict health and disease in diverse patient populations: a new role for assessment of immunoglobulin free light chains. Mayo Clin Proc 2012; 87:505-7. [PMID: 22677069 PMCID: PMC3498045 DOI: 10.1016/j.mayocp.2012.04.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 04/26/2012] [Indexed: 10/28/2022]
Affiliation(s)
- Mark T. Drayson
- Correspondence: Address to Mark T. Drayson, MD, PhD, Clinical Immunology Service, University of Birmingham Medical School, Edgbaston B15 2TT, England
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Lopera D, Naranjo TW, Cruz OG, Restrepo A, Cano LE, Lenzi HL. Structural and topographic dynamics of pulmonary histopathology and local cytokine profiles in Paracoccidioides brasiliensis conidia-infected mice. PLoS Negl Trop Dis 2011; 5:e1232. [PMID: 21765962 PMCID: PMC3134433 DOI: 10.1371/journal.pntd.0001232] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 05/25/2011] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Paracoccidioidomycosis (PCM), an endemic systemic mycosis caused by the fungus Paracoccidioides brasiliensis (Pb), usually results in severe lung damage in patients. METHODS AND FINDINGS Considering the difficulties to sequentially study the infection in humans, this work was done in mice inoculated intranasally with infective Pb-conidia. Lungs of control and Pb-infected mice were studied after 2-hours, 4, 8, 12 and 16-weeks post-infection (p.i) in order to define histopathologic patterns of pulmonary lesions, multiplex-cytokine profiles and their dynamics during the course of this mycosis. Besides the nodular/granulomatous lesions previously informed, results revealed additional non-formerly described lung abnormalities, such as periarterial sheath inflammation and pseudotumoral masses. The following chronologic stages occurring during the course of the experimental infection were defined: Stage one (2-hours p.i): mild septal infiltration composed by neutrophils and macrophages accompanied by an intense "cytokine burst" represented by significant increases in IL-1α, IL-1β, IL-4, IL-5, IL-6, IL-10, IL12p70, IL-13, IL-17, Eotaxin, G-CSF, MCP1, MIP1α, GM-CSF, IFN-γ, MIP1β and TNFα levels. Stage two (4-weeks p.i): presence of nodules, evidence of incipient periarterial- and intense but disperse parenchymal- inflammation, abnormalities that continued to be accompanied by hyper-secretion of those cytokines and chemokines mentioned in the first stage of infection. Stages three and four (8 and 12-weeks p.i.): fungal proliferation, inflammation and collagenesis reached their highest intensity with particular involvement of the periarterial space. Paradoxically, lung cytokines and chemokines were down-regulated with significant decreases in IL-2,IL-3,IL-5,IL-9,IL-13,IL-15,GM-CSF,IFN-γ,MIP1β and TNFα. Stage five (16-weeks p.i.): inflammation decreased becoming limited to the pseudotumoral masses and was accompanied by a "silent" cytokine response, except for PDGF, MIG, RANTES and IL12p40 which remained up-regulated for the duration of the experiment. CONCLUSIONS Results of this study identified both classic and novel patterns corresponding to histopathologic and immunologic responses occurring during the course of experimental PCM.
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Affiliation(s)
- Damaris Lopera
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas, Medellín, Colombia
| | - Tonny W. Naranjo
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas, Medellín, Colombia
- School of Health Sciences, Universidad Pontificia Bolivarina, Medellín, Colombia
| | - Oswaldo G. Cruz
- Programa de Computação Científica, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Angela Restrepo
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas, Medellín, Colombia
| | - Luz Elena Cano
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas, Medellín, Colombia
- School of Health Sciences, Universidad Pontificia Bolivarina, Medellín, Colombia
- Microbiology School, Universidad de Antioquia, Medellín, Colombia
| | - Henrique Leonel Lenzi
- Laboratory of Pathology, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
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Abstract
Heavy chain diseases (HCDs) are B-cell proliferative disorders characterized by the production of monoclonal, incomplete, immunoglobulin (Ig) heavy chains (HCs) without associated light chains (LCs). These abnormal HCs are produced as a consequence of HC gene alterations in the neoplastic B cells. HC gene alterations will also impact on surface HC, which is part of the B-cell receptor (BCR), a crucial player in lymphocyte activation by antigen. The selective advantage conferred to mutant cells by abnormal BCR without an antigen-binding domain may be explained by activation of ligand-independent signaling, in analogy to what has been shown for mutated oncogenic growth factor receptors. Here we review data obtained from mouse models showing abnormal, constitutive activity of HCD-BCR, and we discuss the possible mechanism involved, namely, aberrant spontaneous self-aggregation. This self-aggregation might occur as a consequence of escape from the chaperone immunoglobulin binding protein (BiP) and from the anti-aggregation effect of LC association. The concept of misfolding-induced signaling elaborated here may extend to other pathologies termed conformational diseases.
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Corcos D. Immunoglobulin transport in the absence of light chains. Trends Biochem Sci 2010; 35:593; author reply 594. [PMID: 20728360 DOI: 10.1016/j.tibs.2010.07.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 07/26/2010] [Accepted: 07/27/2010] [Indexed: 10/19/2022]
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Physiology and pathology of proteostasis in the early secretory compartment. Semin Cell Dev Biol 2010; 21:520-5. [PMID: 20178856 DOI: 10.1016/j.semcdb.2010.02.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 02/15/2010] [Indexed: 10/19/2022]
Abstract
The endoplasmic reticulum (ER), the port of entry for proteins into the secretory pathway, is a multifunctional organelle emerging as a central integrator of numerous signalling pathways. The mechanisms that control proteostasis are integral part of this signalling network, providing cues for morphological and functional cell remodelling, proliferation, inflammation and cell death. The complexity of ER responses is exploited during physiological and pathological tissue development, cell differentiation and lifespan control. This essay outlines some of the mechanisms that link proteostasis within the early secretory compartment to signalling in development and disease.
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