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Abstract
Systemic lupus erythematosus (SLE) is a typical autoimmune disease with a complex pathogenesis and genetic predisposition. With continued understanding of this disease, it was found that SLE is related to the interferon gene signature. Most studies have emphasized the important role of IFN-α in SLE, but our previous study suggested a nonnegligible role of IFN-γ in SLE. Some scholars previously found that IFN-γ is abnormally elevated as early as before the classification of SLE and before the emergence of autoantibodies and IFN-α. Due to the large overlap between IFN-α and IFN-γ, SLE is mostly characterized by expression of the IFN-α gene after onset. Therefore, the role of IFN-γ in SLE may be underestimated. This article mainly reviews the role of IFN-γ in SLE and focuses on the nonnegligible role of IFN-γ in SLE to gain a more comprehensive understanding of the disease.
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2
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Potential contribution of the immune system to the emergence of renal diseases. Immunol Lett 2022; 248:1-6. [DOI: 10.1016/j.imlet.2022.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 06/04/2022] [Indexed: 11/21/2022]
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3
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Martínez-Sabadell A, Arenas EJ, Arribas J. IFNγ Signaling in Natural and Therapy-Induced Antitumor Responses. Clin Cancer Res 2021; 28:1243-1249. [PMID: 34785585 DOI: 10.1158/1078-0432.ccr-21-3226] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/02/2021] [Accepted: 11/05/2021] [Indexed: 11/16/2022]
Abstract
IFNγ is a cytokine produced by a restricted number of immune cells that acts on every nucleated cell type. Consistent with this remarkably wide spectrum of targets, the effects of IFNγ are highly pleiotropic. On cells of the immune system, IFNγ signaling has generally a pro-inflammatory effect, coordinating the innate and adaptive responses. On nonimmune cells, IFNγ tends to exert the opposite effect; it inhibits cell proliferation, induces cell death, and, in addition, promotes their recognition by the immune system. These effects on the immune and nonimmune compartments play a crucial role during the immunoediting of tumors and, as shown by recent reports, also determine the efficacy of certain immunotherapies. Different therapeutic interventions to target IFNγ signaling are currently under way, and the emerging picture indicates that rewiring IFNγ signaling, disrupted in some cancer cells, may be an efficacious antitumor therapeutic strategy.
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Affiliation(s)
- Alex Martínez-Sabadell
- Preclinical and Translational Research Program, Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain
| | - Enrique J Arenas
- Preclinical and Translational Research Program, Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain.,Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Monforte de Lemos, Madrid, Spain
| | - Joaquín Arribas
- Preclinical and Translational Research Program, Vall d'Hebron Institute of Oncology (VHIO), Barcelona, Spain. .,Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Monforte de Lemos, Madrid, Spain.,Cancer Research Program, Hospital del Mar Medical Research Institute (IMIM), Barcelona, Spain.,Department of Biochemistry and Molecular Biology, Universitat Autónoma de Barcelona, Bellaterra, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
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4
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Forlani G, Shallak M, Celesti F, Accolla RS. Unveiling the Hidden Treasury: CIITA-Driven MHC Class II Expression in Tumor Cells to Dig up the Relevant Repertoire of Tumor Antigens for Optimal Stimulation of Tumor Specific CD4+ T Helper Cells. Cancers (Basel) 2020; 12:cancers12113181. [PMID: 33138029 PMCID: PMC7693840 DOI: 10.3390/cancers12113181] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/21/2020] [Accepted: 10/27/2020] [Indexed: 12/11/2022] Open
Abstract
Despite the recent enthusiasm generated by novel immunotherapeutic approaches against cancer based on immune checkpoint inhibitors, it becomes increasingly clear that single immune-based strategies are not sufficient to defeat the various forms and types of tumors. Within this frame, novel vaccination strategies that are based on optimal stimulation of the key cell governing adaptive immunity, the CD4+ T helper cell, will certainly help in constructing more efficient treatments. In this review, we will focus on this aspect, mainly describing our past and recent contributions that, starting with a rather unorthodox approach, have ended up with the proposition of a new idea for making available an unprecedented extended repertoire of tumor antigens, both in quantitative and qualitative terms, to tumor-specific CD4+ T helper cells. Our approach is based on rendering the very same tumor cells antigen presenting cells for their own tumor antigens by gene transfer of CIITA, the major transcriptional coordinator of MHC class II expression discovered in our laboratory. CIITA-driven MHC class II-expressing tumor cells optimally stimulate in vivo tumor specific MHC class II-restricted CD4 T cells generating specific and long lasting protective immunity against the tumor. We will discuss the mechanism underlying protection and elaborate not only on the applicability of this approach for novel vaccination strategies amenable to clinical setting, but also on the consequence of our discoveries on sedimented immunological dogmas that are related to antigen presentation.
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5
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Burke JD, Young HA. IFN-γ: A cytokine at the right time, is in the right place. Semin Immunol 2019; 43:101280. [PMID: 31221552 DOI: 10.1016/j.smim.2019.05.002] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 05/15/2019] [Indexed: 02/07/2023]
Abstract
Interferon gamma has long been studied as a critical mediator of tumor immunity. In recent years, the complexity of cellular interactions that take place in the tumor microenvironment has become better appreciated in the context of immunotherapy. While checkpoint inhibitors have dramatically improved remission rates in cancer treatment, IFN-γ and related effectors continue to be identified as strong predictors of treatment success. In this review, we provide an overview of the multiple immunosuppressive barriers that IFN-γ has to overcome to eliminate tumors, and potential avenues for modulating the immune response in favor of tumor rejection.
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Affiliation(s)
- J Daniel Burke
- AIDS and Cancer Virus Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA.
| | - Howard A Young
- Laboratory of Experimental Immunology, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA
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6
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Alspach E, Lussier DM, Schreiber RD. Interferon γ and Its Important Roles in Promoting and Inhibiting Spontaneous and Therapeutic Cancer Immunity. Cold Spring Harb Perspect Biol 2019; 11:a028480. [PMID: 29661791 PMCID: PMC6396335 DOI: 10.1101/cshperspect.a028480] [Citation(s) in RCA: 273] [Impact Index Per Article: 54.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Originally identified in studies of cellular resistance to viral infection, interferon (IFN)-γ is now known to represent a distinct member of the IFN family and plays critical roles not only in orchestrating both innate and adaptive immune responses against viruses, bacteria, and tumors, but also in promoting pathologic inflammatory processes. IFN-γ production is largely restricted to T lymphocytes and natural killer (NK) cells and can ultimately lead to the generation of a polarized immune response composed of T helper (Th)1 CD4+ T cells and CD8+ cytolytic T cells. In contrast, the temporally distinct elaboration of IFN-γ in progressively growing tumors also promotes a state of adaptive resistance caused by the up-regulation of inhibitory molecules, such as programmed-death ligand 1 (PD-L1) on tumor cell targets, and additional host cells within the tumor microenvironment. This review focuses on the diverse positive and negative roles of IFN-γ in immune cell activation and differentiation leading to protective immune responses, as well as the paradoxical effects of IFN-γ within the tumor microenvironment that determine the ultimate fate of that tumor in a cancer-bearing individual.
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Affiliation(s)
- Elise Alspach
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Danielle M Lussier
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Robert D Schreiber
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110
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7
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Flint M, Chatterjee P, Lin DL, McMullan LK, Shrivastava-Ranjan P, Bergeron É, Lo MK, Welch SR, Nichol ST, Tai AW, Spiropoulou CF. A genome-wide CRISPR screen identifies N-acetylglucosamine-1-phosphate transferase as a potential antiviral target for Ebola virus. Nat Commun 2019; 10:285. [PMID: 30655525 PMCID: PMC6336797 DOI: 10.1038/s41467-018-08135-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 12/19/2018] [Indexed: 12/28/2022] Open
Abstract
There are no approved therapies for Ebola virus infection. Here, to find potential therapeutic targets, we perform a screen for genes essential for Ebola virus (EBOV) infection. We identify GNPTAB, which encodes the α and β subunits of N-acetylglucosamine-1-phosphate transferase. We show that EBOV infection of a GNPTAB knockout cell line is impaired, and that this is reversed by reconstituting GNPTAB expression. Fibroblasts from patients with mucolipidosis II, a disorder associated with mutations in GNPTAB, are refractory to EBOV, whereas cells from their healthy parents support infection. Impaired infection correlates with loss of the expression of cathepsin B, known to be essential for EBOV entry. GNPTAB activity is dependent upon proteolytic cleavage by the SKI-1/S1P protease. Inhibiting this protease with the small-molecule PF-429242 blocks EBOV entry and infection. Disruption of GNPTAB function may represent a strategy for a host-targeted therapy for EBOV. Genetic screens are important tools to identify host factors associated with viral infections. Here, Flint et al. perform a genome-wide CRISPR screen using infectious Ebola virus (EBOV) and show that the host transferase GNPTAB is required for EBOV infection and a potential target for antiviral therapies
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Affiliation(s)
- Mike Flint
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS G-14, Atlanta, GA, 30329, USA.
| | - Payel Chatterjee
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS G-14, Atlanta, GA, 30329, USA
| | - David L Lin
- Department of Microbiology & Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Laura K McMullan
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS G-14, Atlanta, GA, 30329, USA
| | - Punya Shrivastava-Ranjan
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS G-14, Atlanta, GA, 30329, USA
| | - Éric Bergeron
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS G-14, Atlanta, GA, 30329, USA
| | - Michael K Lo
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS G-14, Atlanta, GA, 30329, USA
| | - Stephen R Welch
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS G-14, Atlanta, GA, 30329, USA
| | - Stuart T Nichol
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS G-14, Atlanta, GA, 30329, USA
| | - Andrew W Tai
- Department of Microbiology & Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.,Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Christina F Spiropoulou
- Viral Special Pathogens Branch, Division of High-Consequence Pathogens and Pathology, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, 1600 Clifton Road, MS G-14, Atlanta, GA, 30329, USA.
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8
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Abstract
The ability of B lymphocytes to capture external antigens (Ag) and present them as peptide fragments, loaded on major histocompatibility complex (MHC) class II molecules, to CD4+ T cells is a crucial part of the adaptive immune response. This allows for T-B cooperation, a cellular communication that is required for B cells to develop into germinal centers (GC) and form mature high affinity antibody producing cells and to further develop B cell memory. MHC class II antigen presentation by B lymphocytes is a multistep process involving (1) Recognition and capture of external Ag by B lymphocytes through their B cell receptor (BCR), (2) Ag processing, which comprises the degradation of Ag in internal compartments within the B cell and loading of the corresponding peptide fragments on MHC class II molecules, and (3) Presentation of MHCII-peptide complexes to CD4+ T cells. Here, we describe how to study the biochemical and morphological changes that occur in B lymphocytes at these three major levels.
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9
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Abstract
Neuromyelitis optica (NMO) is a rare, disabling, sometimes fatal central nervous system inflammatory demyelinating disease that is associated with antibodies ("NMO IgG") that target the water channel protein aquaporin-4 (AQP4) expressed on astrocytes. There is considerable interest in identifying environmental triggers that may elicit production of NMO IgG by AQP4-reactive B cells. Although NMO is considered principally a humoral autoimmune disease, antibodies of NMO IgG are IgG1, a T-cell-dependent immunoglobulin subclass, indicating that AQP4-reactive T cells have a pivotal role in NMO pathogenesis. When AQP4-specific proliferative T cells were first identified in patients with NMO it was discovered that T cells recognizing the dominant AQP4 T-cell epitope exhibited a T helper 17 (Th17) phenotype and displayed cross-reactivity to a homologous peptide sequence within a protein of Clostridium perfringens, a commensal bacterium found in human gut flora. The initial analysis of gut microbiota in NMO demonstrated that, in comparison to healthy controls (HC) and patients with multiple sclerosis, the microbiome of NMO is distinct. Remarkably, C. perfringens was the second most significantly enriched taxon in NMO, and among bacteria identified at the species level, C. perfringens was the one most highly associated with NMO. Those discoveries, along with evidence that certain Clostridia in the gut can regulate the balance between regulatory T cells and Th17 cells, indicate that gut microbiota, and possibly C. perfringens itself, could participate in NMO pathogenesis. Collectively, the evidence linking microbiota to humoral and cellular immunity in NMO underscores the importance for further investigating this relationship.
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Affiliation(s)
- Scott S Zamvil
- Department of Neurology, University of California, San Francisco, CA, USA.
- Program in Immunology, University of California, San Francisco, CA, USA.
| | - Collin M Spencer
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Sergio E Baranzini
- Department of Neurology, University of California, San Francisco, CA, USA
| | - Bruce A C Cree
- Department of Neurology, University of California, San Francisco, CA, USA
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10
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Fang T, Van Elssen CHMJ, Duarte JN, Guzman JS, Chahal JS, Ling J, Ploegh HL. Targeted antigen delivery by an anti-class II MHC VHH elicits focused αMUC1(Tn) immunity. Chem Sci 2017; 8:5591-5597. [PMID: 28970938 PMCID: PMC5618788 DOI: 10.1039/c7sc00446j] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 05/23/2017] [Indexed: 12/21/2022] Open
Abstract
Unusual patterns of glycosylation on the surface of transformed cells contribute to immune modulation and metastasis of malignant tumors. Active immunization against them requires effective antigen presentation, which is complicated by a lack of access to tumor-specific posttranslational modifications through standard genetic approaches and by the low efficiency of passive antigen sampling. We found that antigen targeted to antigen presenting cells via class II MHC products can elicit a robust immune response against MUC1(Tn) bearing a defined tumor-associated glycoform, Tn. The two-component vaccine construct was prepared by sortase-mediated protein ligation of a synthetic MUC1(Tn) fragment to a class II MHC-binding single-domain antibody fragment (VHH7) as targeting moiety. We show that VHH7 targets antigen presenting cells in vivo, and when conjugated to MUC1(Tn) can elicit a strong αMUC1(Tn) immune response in mice. The resulting sera preferentially recognized the MUC1 epitope with the tumor-associated carbohydrate antigen Tn and were capable of killing cancer cells in a complement-mediated cytotoxicity assay. Immunoglobulin isotype analysis and cytokine release assays suggested a favorable Th1 response. A single boost 12 months after primary immunization triggered a recall response of the same quality, suggesting that long-term αMUC1(Tn) memory had been achieved.
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Affiliation(s)
- Tao Fang
- Whitehead Institute for Biomedical Research , 9 Cambridge Center , Cambridge , MA 02142 , USA .
| | | | - Joao N Duarte
- Whitehead Institute for Biomedical Research , 9 Cambridge Center , Cambridge , MA 02142 , USA .
| | - Jonathan S Guzman
- Whitehead Institute for Biomedical Research , 9 Cambridge Center , Cambridge , MA 02142 , USA .
- Department of Biology , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA
| | - Jasdave S Chahal
- Whitehead Institute for Biomedical Research , 9 Cambridge Center , Cambridge , MA 02142 , USA .
| | - Jingjing Ling
- Whitehead Institute for Biomedical Research , 9 Cambridge Center , Cambridge , MA 02142 , USA .
- Department of Chemistry , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA
| | - Hidde L Ploegh
- Whitehead Institute for Biomedical Research , 9 Cambridge Center , Cambridge , MA 02142 , USA .
- Department of Biology , Massachusetts Institute of Technology , Cambridge , MA 02139 , USA
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11
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Rawal L, Panwar D, Ali S. Intermolecular Interactions Between DMα and DMβ Proteins in BuLA‐DM Complex of Water Buffalo
Bubalus bubalis. J Cell Biochem 2017; 118:4254-4266. [DOI: 10.1002/jcb.26075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/14/2017] [Indexed: 01/26/2023]
Affiliation(s)
- Leena Rawal
- Molecular Genetics LaboratoryNational Institute of ImmunologyAruna Asaf Ali MargDelhi‐110067India
| | - Deepak Panwar
- Molecular Genetics LaboratoryNational Institute of ImmunologyAruna Asaf Ali MargDelhi‐110067India
- Department of ZoologyUniversity of DelhiDelhi‐110007India
| | - Sher Ali
- Molecular Genetics LaboratoryNational Institute of ImmunologyAruna Asaf Ali MargDelhi‐110067India
- Centre for Interdisciplinary Research in Basic SciencesJamia Millia IslamiaDelhi‐110025India
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12
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Ohigashi I, Kozai M, Takahama Y. Development and developmental potential of cortical thymic epithelial cells. Immunol Rev 2016; 271:10-22. [DOI: 10.1111/imr.12404] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Izumi Ohigashi
- Division of Experimental Immunology; Institute for Genome Research; University of Tokushima; Tokushima Japan
| | - Mina Kozai
- Division of Experimental Immunology; Institute for Genome Research; University of Tokushima; Tokushima Japan
| | - Yousuke Takahama
- Division of Experimental Immunology; Institute for Genome Research; University of Tokushima; Tokushima Japan
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13
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Baldwin KM, Ehrenberg PK, Geretz A, Prentice HA, Nitayaphan S, Rerks-Ngarm S, Kaewkungwal J, Pitisuttithum P, O'Connell RJ, Kim JH, Thomas R. HLA class II diversity in HIV-1 uninfected individuals from the placebo arm of the RV144 Thai vaccine efficacy trial. ACTA ACUST UNITED AC 2015; 85:117-26. [PMID: 25626602 DOI: 10.1111/tan.12507] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 11/11/2014] [Accepted: 12/13/2014] [Indexed: 11/29/2022]
Abstract
The RV144 HIV vaccine trial in Thailand elicited antibody responses to the envelope of HIV-1, which correlated significantly with the risk of HIV-1 acquisition. Human leukocyte antigen (HLA) class II molecules are essential in antigen presentation to CD4 T cells for activation of B cells to produce antibodies. We genotyped the classical HLA-DRB1, DQB1, and DPB1 genes in 450 individuals from the placebo arm of the RV144 study to determine the background allele and haplotype frequencies of these genes in this cohort. High-resolution 4 and 6-digit class II HLA typing data was generated using sequencing-based methods. The observed diversity for the HLA loci was 33 HLA-DRB1, 15 HLA-DQB1, and 26 HLA-DPB1 alleles. Common alleles with frequencies greater than 10% were DRB1*07:01, DRB1*09:01, DRB1*12:02, DRB1*15:02, DQB1*02:01/02, DQB1*03:01, DQB1*03:03, DQB1*05:01, DQB1*05:02, DPB1*04:01:01, DPB1*05:01:01, and DPB1*13:01:01. We identified 28 rare alleles with frequencies of less than 1% in the Thai individuals. Ambiguity for HLA-DPB1*28:01 in exon 2 was resolved to DPB1*296:01 by next-generation sequencing of all exons. Multi-locus haplotypes including HLA class I and II loci were reported in this study. This is the first comprehensive report of allele and haplotype frequencies of all three HLA class II genes from a Thai population. A high-resolution genotyping method such as next-generation sequencing avoids missing rare alleles and resolves ambiguous calls. The HLA class II genotyping data generated in this study will be beneficial not only for future disease association/vaccine efficacy studies related to the RV144 study, but also for similar studies in other diseases in the Thai population, as well as population genetics and transplantation studies.
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Affiliation(s)
- K M Baldwin
- U.S. Military HIV Research Program, Walter Reed Army Institute of Research, Silver Spring, MD, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, USA
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14
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Yuseff MI, Lennon-Duménil AM. B Cells use Conserved Polarity Cues to Regulate Their Antigen Processing and Presentation Functions. Front Immunol 2015; 6:251. [PMID: 26074919 PMCID: PMC4445385 DOI: 10.3389/fimmu.2015.00251] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 05/07/2015] [Indexed: 11/13/2022] Open
Abstract
The ability of B cells to produce high-affinity antibodies and to establish immunological memory in response to a wide range of pathogenic antigens is an essential part of the adaptive immune response. The initial step that triggers a humoral immune response involves the acquisition of antigens by B cells via their surface immunoglobulin, the B cell receptor (BCR). BCR-engaged antigens are transported into specialized lysosomal compartments where proteolysis and production of MHC class II-peptide complexes occur, a process referred to as antigen processing. Expression of MHC class II complexes at the B cell surface allows them to interact with T cells and to receive their help to become fully activated. In this review, we describe how B cells rely on conserved cell polarity mechanisms to coordinate local proteolytic secretion and mechanical forces at the B cell synapse enabling them to efficiently acquire and present extracellular antigens. We foresee that the mechanisms that dictate B cell activation can be used to tune B cell responses in the context of autoimmune diseases and cancer.
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Affiliation(s)
- Maria-Isabel Yuseff
- Department of Cellular and Molecular Biology, Pontificia Universidad Católica de Chile , Santiago , Chile
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15
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BoseDasgupta S, Pieters J. Striking the Right Balance Determines TB or Not TB. Front Immunol 2014; 5:455. [PMID: 25339950 PMCID: PMC4189424 DOI: 10.3389/fimmu.2014.00455] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 09/06/2014] [Indexed: 12/11/2022] Open
Abstract
Mycobacterium tuberculosis continues to be one of the most successful pathogens on earth. Upon inhalation of M. tuberculosis by a healthy individual, the host immune system will attempt to eliminate these pathogens using a combination of immune defense strategies. These include the recruitment of macrophages and other phagocytes to the site of infection, production of cytokines that enhance the microbicidal capacity of the macrophages, as well as the activation of distinct subsets of leukocytes that work in concert to fight the infection. However, being as successful as it is, M. tuberculosis has evolved numerous strategies to subvert host immunity at virtual every level. As a consequence, one third of the world inhabitants carry M. tuberculosis, and tuberculosis continuous to cause disease in more than 8 million people with deadly consequences in well over 1 million patients each year. In this review, we discuss several of the strategies that M. tuberculosis employs to circumvent host immunity, as well as describe some of the mechanisms that the host uses to counter such subversive strategies. As for many other infectious diseases, the ultimate outcome is usually defined by the relative strength of the virulence strategies employed by the tubercle bacillus versus the arsenal of immune defense mechanisms of the infected host.
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Affiliation(s)
| | - Jean Pieters
- Biozentrum, University of Basel , Basel , Switzerland
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16
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Fortin JS, Cloutier M, Thibodeau J. Exposing the Specific Roles of the Invariant Chain Isoforms in Shaping the MHC Class II Peptidome. Front Immunol 2013; 4:443. [PMID: 24379812 PMCID: PMC3861868 DOI: 10.3389/fimmu.2013.00443] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 11/26/2013] [Indexed: 11/26/2022] Open
Abstract
The peptide repertoire (peptidome) associated with MHC class II molecules (MHCIIs) is influenced by the polymorphic nature of the peptide binding groove but also by cell-intrinsic factors. The invariant chain (Ii) chaperones MHCIIs, affecting their folding and trafficking. Recent discoveries relating to Ii functions have provided insights as to how it edits the MHCII peptidome. In humans, the Ii gene encodes four different isoforms for which structure-function analyses have highlighted common properties but also some non-redundant roles. Another layer of complexity arises from the fact that Ii heterotrimerizes, a characteristic that has the potential to affect the maturation of associated MHCIIs in many different ways, depending on the isoform combinations. Here, we emphasize the peptide editing properties of Ii and discuss the impact of the various isoforms on the MHCII peptidome.
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Affiliation(s)
- Jean-Simon Fortin
- Laboratoire d'Immunologie Moléculaire, Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal , Montréal, QC , Canada
| | - Maryse Cloutier
- Laboratoire d'Immunologie Moléculaire, Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal , Montréal, QC , Canada
| | - Jacques Thibodeau
- Laboratoire d'Immunologie Moléculaire, Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal , Montréal, QC , Canada
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17
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Yuseff MI, Pierobon P, Reversat A, Lennon-Duménil AM. How B cells capture, process and present antigens: a crucial role for cell polarity. Nat Rev Immunol 2013; 13:475-86. [PMID: 23797063 DOI: 10.1038/nri3469] [Citation(s) in RCA: 199] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
B cells are key components of the adaptive immune response. Their differentiation into either specific memory B cells or antibody-secreting plasma cells is a consequence of activation steps that involve the processing and presentation of antigens. The engagement of B cell receptors by surface-tethered antigens leads to the formation of an immunological synapse that coordinates cell signalling events and that promotes antigen uptake for presentation on MHC class II molecules. In this Review, we discuss membrane trafficking and the associated molecular mechanisms that are involved in antigen extraction and processing at the B cell synapse, and we highlight how B cells use cell polarity to coordinate the complex events that ultimately lead to efficient humoral responses.
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18
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Manoury B. Proteases: essential actors in processing antigens and intracellular toll-like receptors. Front Immunol 2013; 4:299. [PMID: 24065969 PMCID: PMC3781364 DOI: 10.3389/fimmu.2013.00299] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 09/09/2013] [Indexed: 01/28/2023] Open
Abstract
MHC class II molecules expressed by professional antigen presenting cells (pAPCs) such as macrophages, B cells, and dendritic cells (DCs) play a fundamental role in presenting peptides to CD4+ T cells. However, to elicit CD4+-T cells immunity, pAPCs need an additional signal, which can be delivered by toll-like receptors (TLRs) molecules. TLRs recognize microbial patterns and are critical in initiating immune responses. Proteases, which provide peptide ligands for the MHC class II antigenic presentation pathway, were recently shown to cleave and activate intracellular TLRs in endosomal compartments. Here, I give an overview on the individual roles of the most well studied proteases in both antigen and TLRs processing.
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Affiliation(s)
- Bénédicte Manoury
- Institut National de la Santé et de le Recherche Médicale, Unité 1013, Université Paris Descartes, Sorbonne Paris Cité, Faculté de médecine , Paris , France
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19
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Hoze E, Tsaban L, Maman Y, Louzoun Y. Predictor for the effect of amino acid composition on CD4+ T cell epitopes preprocessing. J Immunol Methods 2013; 391:163-73. [PMID: 23481624 DOI: 10.1016/j.jim.2013.02.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2012] [Revised: 02/17/2013] [Accepted: 02/17/2013] [Indexed: 11/28/2022]
Abstract
Predictive tools for all levels of CD8+ T cell epitopes processing have reached a maturation level. Good prediction algorithms have been developed for proteasomal cleavage, TAP and MHC class I peptide binding. The same cannot be said of CD4+ T cell epitopes. While multiple algorithms of varying accuracy have been proposed for MHC class II peptide binding, the preprocessing of CD4+ T cell epitopes is still lacking a good prediction algorithm. CD4+ T cell epitopes generation includes several stages, not all which are well-defined. We here group these stages to produce a generic preprocessing stage predictor for the cleavage processes preceding the presentation of epitopes to CD4+ T cell. The predictor is learnt using a combination of in vitro cleavage experiments and observed naturally processed MHC class II binding peptides. The properties of the predictor highlight the effect of different factors on CD4+ T cell epitopes preprocessing. The most important factor emerging from the predictor is the secondary structure of the cleaved region in the protein. The effect of the secondary structure is expected since CD4+ T cell epitopes are not denatured before cleavage. A website developed based on this predictor is available at: http://peptibase.cs.biu.ac.il/PepCleave_cd4/.
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Affiliation(s)
- Ehud Hoze
- Department of Mathematics, Bar Ilan University, Ramat Gan 52900, Israel
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20
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Yuseff MI, Lennon-Dumenil AM. Studying MHC class II presentation of immobilized antigen by B lymphocytes. Methods Mol Biol 2013; 960:529-543. [PMID: 23329512 DOI: 10.1007/978-1-62703-218-6_39] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
The ability of B lymphocytes to capture external antigens (Ag) and present them as peptide fragments, loaded on Major Histocompatibility complex (MHC) class II molecules, to CD4(+) T cells is a crucial part of the adaptive immune response. This allows T-B cooperation, a cellular communication that is required for B cells to develop into germinal centers (GC) and form mature high-affinity antibody producing cells and to further develop B cell memory. MHC class II antigen presentation by B lymphocytes is a multistep process involving (1) Recognition and capture of external Ag by B lymphocytes through their B cell receptor (BCR); (2) Ag processing, which comprises the degradation of Ag in internal compartments within the B cell and loading of the corresponding peptide fragments on MHC class II molecules and (3) Presentation of MHC II-peptide complexes to CD4(+) T cells. Here, we describe how to study MHC class II antigen presentation by B lymphocytes at these three major levels.
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Affiliation(s)
- M I Yuseff
- Institut Curie, Inserm U932, Paris, France
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21
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Caza TN, Talaber G, Perl A. Metabolic regulation of organelle homeostasis in lupus T cells. Clin Immunol 2012; 144:200-13. [PMID: 22836085 PMCID: PMC3423541 DOI: 10.1016/j.clim.2012.07.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 07/03/2012] [Indexed: 12/23/2022]
Abstract
Abnormal T-cell signaling and activation are characteristic features in systemic lupus erythematosus (SLE). Lupus T cells are shifted toward an over-activated state, important signaling pathways are rewired, and signaling molecules are replaced. Disturbances in metabolic and organelle homeostasis, importantly within the mitochondrial, endosomal, and autophagosomal compartments, underlie the changes in signal transduction. Mitochondrial hyperpolarization, enhanced endosomal recycling, and dysregulated autophagy are hallmarks of pathologic organelle homeostasis in SLE. This review is focused on the metabolic checkpoints of endosomal traffic that control immunological synapse formation and mitophagy and may thus serve as targets for treatment in SLE.
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Affiliation(s)
- Tiffany N Caza
- Department of Medicine, State University of New York Upstate Medical University, Syracuse, 13210, USA
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22
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Yu B, Morales JF, O'Rourke SM, Tatsuno GP, Berman PW. Glycoform and net charge heterogeneity in gp120 immunogens used in HIV vaccine trials. PLoS One 2012; 7:e43903. [PMID: 22928048 PMCID: PMC3425498 DOI: 10.1371/journal.pone.0043903] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 07/27/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The RV144 clinical trial showed for the first time that vaccination could provide modest but significant protection from HIV-1 infection. To understand the protective response, and to improve upon the vaccine's efficacy, it is important to define the structure of the immunogens used in the prime/boost regimen. Here we examined the heterogeneity in net charge, attributable to glycoform variation, of the gp120 immunogens contained in the AIDSVAX B/E vaccine. METHODOLOGY/PRINCIPAL FINDINGS Isoelectric focusing and glycosidase digestion were used to assess variation in net charge of the gp120s contained in the AIDSVAX B/E vaccine used in the RV144 trial. We observed 16 variants of MN-rgp120 and 24 variants of A244-rgp120. Glycoform variation in gp120 produced in Chinese hamster ovary cells was compared to glycoform variation in gp120 produced in the 293F human embryonic kidney cell line, often used for neutralization assays. We found that gp120 variants produced in CHO cells were distinctly more acidic than gp120 variants produced in 293 cells. The effect of glycoform heterogeneity on antigenicity was assessed using monoclonal antibodies. The broadly neutralizing PG9 MAb bound to A244-rgp120, but not to MN-rgp120, whether produced in CHO or in 293. However, PG9 was able to bind with high affinity to MN-rgp120 and A244-rgp120 produced in 293 cells deficient in N-acetylglucosaminyltransferase I. CONCLUSIONS/SIGNIFICANCE MN- and A244-rgp120 used in the RV144 trial exhibited extensive heterogeneity in net charge due to variation in sialic acid-containing glycoforms. These differences were cell line-dependent, affected the antigenicity of recombinant envelope proteins, and may affect assays used to measure neutralization. These studies, together with recent reports documenting broadly neutralizing antibodies directed against carbohydrate epitopes of gp120, suggest that glycoform variation is a key variable to be considered in the production and evaluation of subunit vaccines designed to prevent HIV infection.
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Affiliation(s)
- Bin Yu
- Department of Biomolecular Engineering, Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Javier F. Morales
- Department of Biomolecular Engineering, Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Sara M. O'Rourke
- Department of Biomolecular Engineering, Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Gwen P. Tatsuno
- Department of Biomolecular Engineering, Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Phillip W. Berman
- Department of Biomolecular Engineering, Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
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23
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Gengenbacher M, Kaufmann SHE. Mycobacterium tuberculosis: success through dormancy. FEMS Microbiol Rev 2012; 36:514-32. [PMID: 22320122 PMCID: PMC3319523 DOI: 10.1111/j.1574-6976.2012.00331.x] [Citation(s) in RCA: 464] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 12/22/2011] [Accepted: 01/31/2012] [Indexed: 01/21/2023] Open
Abstract
Tuberculosis (TB) remains a major health threat, killing nearly 2 million individuals around this globe, annually. The only vaccine, developed almost a century ago, provides limited protection only during childhood. After decades without the introduction of new antibiotics, several candidates are currently undergoing clinical investigation. Curing TB requires prolonged combination of chemotherapy with several drugs. Moreover, monitoring the success of therapy is questionable owing to the lack of reliable biomarkers. To substantially improve the situation, a detailed understanding of the cross-talk between human host and the pathogen Mycobacterium tuberculosis (Mtb) is vital. Principally, the enormous success of Mtb is based on three capacities: first, reprogramming of macrophages after primary infection/phagocytosis to prevent its own destruction; second, initiating the formation of well-organized granulomas, comprising different immune cells to create a confined environment for the host-pathogen standoff; third, the capability to shut down its own central metabolism, terminate replication, and thereby transit into a stage of dormancy rendering itself extremely resistant to host defense and drug treatment. Here, we review the molecular mechanisms underlying these processes, draw conclusions in a working model of mycobacterial dormancy, and highlight gaps in our understanding to be addressed in future research.
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Affiliation(s)
- Martin Gengenbacher
- Max Planck Institute for Infection Biology, Department of Immunology Charitéplatz 1, 10117 Berlin, Germany
| | - Stefan H. E. Kaufmann
- Max Planck Institute for Infection Biology, Department of Immunology Charitéplatz 1, 10117 Berlin, Germany
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24
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Kumar R, Tuen M, Li H, Tse DB, Hioe CE. Improving immunogenicity of HIV-1 envelope gp120 by glycan removal and immune complex formation. Vaccine 2011; 29:9064-74. [PMID: 21945958 DOI: 10.1016/j.vaccine.2011.09.057] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 08/18/2011] [Accepted: 09/02/2011] [Indexed: 11/18/2022]
Abstract
HIV-1 envelope (Env) gp120 is an important target for neutralizing antibody (Ab) responses against the virus; however, developing gp120 vaccines that elicit potent and broad neutralizing Abs has proven to be a formidable challenge. Previously, removal of an N-linked glycan at residue 448 by an N to Q mutation (N448Q) has been found to enhance the in vitro antigenicity of neutralizing epitopes in the V3 loop. In this study the mutated gp120 was first compared with wild type gp120 for immunogenicity in mice using a DNA prime and protein boost immunization regimen. The N448Q mutant did not elicit higher titers of anti-gp120 serum Abs and failed to generate anti-V3 Abs. The sera also had no virus-neutralizing activity, even though the mutant induced higher levels of lymphoproliferation and cytokine production. Subsequently, the N448Q mutant was used to construct an immune complex vaccine with the anti-CD4 binding site monoclonal antibody (mAb) 654. The N448Q/654 complex stimulated comparably high levels of serum Abs to gp120 and V3 as the wild type complex. However, Abs against the C1 and C2 regions in the gp120 core were more elevated. Importantly, the mutant complex also elicited higher titers of neutralizing Abs activity than the wild type counterpart. Similar results were achieved with a complex made with gp120 bearing an N448E mutation, confirming the importance of the N448-linked glycan in modulating gp120 immunogenicity. Neutralizing activity was directed to V3 and other undefined neutralizing epitopes. Improved immunogenicity of the immune complexes correlated with alterations in exposure of V3 and other Ab epitopes and their stability against proteases. These data demonstrate the advantage of combining site-specific N-glycan removal and immune complex formation as a novel vaccine strategy to improve immunogenicity of targeted Ab epitopes on critical regions of HIV-1 gp120.
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Affiliation(s)
- Rajnish Kumar
- New York University School of Medicine, Department of Pathology, New York, NY 10016, USA
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25
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Porter GW, Yi W, Denzin LK. TLR agonists downregulate H2-O in CD8alpha- dendritic cells. THE JOURNAL OF IMMUNOLOGY 2011; 187:4151-60. [PMID: 21918198 DOI: 10.4049/jimmunol.1003137] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Peptide loading of MHC class II (MHCII) molecules is catalyzed by the nonclassical MHCII-related molecule H2-M. H2-O, another MHCII-like molecule, associates with H2-M and modulates H2-M function. The MHCII presentation pathway is tightly regulated in dendritic cells (DCs), yet how the key modulators of MHCII presentation, H2-M and H2-O, are affected in different DC subsets in response to maturation is unknown. In this study, we show that H2-O is markedly downregulated in vivo in mouse CD8α(-) DCs in response to a broad array of TLR agonists. In contrast, CD8α(+) DCs only modestly downregulated H2-O in response to TLR agonists. H2-M levels were slightly downmodulated in both CD8α(-) and CD8α(+) DCs. As a consequence, H2-M/H2-O ratios significantly increased for CD8α(-) but not for CD8α(+) DCs. The TLR-mediated downregulation was DC specific, as B cells did not show significant H2-O and H2-M downregulation. TLR4 signaling was required to mediate DC H2-O downregulation in response to LPS. Finally, our studies showed that the mechanism of H2-O downregulation was likely due to direct protein degradation of H2-O as well as downregulation of H2-O mRNA levels. The differential H2-O and H2-M modulation after DC maturation supports the proposed roles of CD8α(-) DCs in initiating CD4-restricted immune responses by optimal MHCII presentation and of CD8α(+) DCs in promoting immune tolerance via presentation of low levels of MHCII-peptide.
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Affiliation(s)
- Gavin W Porter
- Immunology Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
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26
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Blank F, Gerber P, Rothen-Rutishauser B, Sakulkhu U, Salaklang J, De Peyer K, Gehr P, Nicod LP, Hofmann H, Geiser T, Petri-Fink A, Von Garnier C. Biomedical nanoparticles modulate specific CD4+ T cell stimulation by inhibition of antigen processing in dendritic cells. Nanotoxicology 2011; 5:606-21. [PMID: 21231795 DOI: 10.3109/17435390.2010.541293] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Understanding how nanoparticles may affect immune responses is an essential prerequisite to developing novel clinical applications. To investigate nanoparticle-dependent outcomes on immune responses, dendritic cells (DCs) were treated with model biomedical poly(vinylalcohol)-coated super-paramagnetic iron oxide nanoparticles (PVA-SPIONs). PVA-SPIONs uptake by human monocyte-derived DCs (MDDCs) was analyzed by flow cytometry (FACS) and advanced imaging techniques. Viability, activation, function, and stimulatory capacity of MDDCs were assessed by FACS and an in vitro CD4+ T cell assay. PVA-SPION uptake was dose-dependent, decreased by lipopolysaccharide (LPS)-induced MDDC maturation at higher particle concentrations, and was inhibited by cytochalasin D pre-treatment. PVA-SPIONs did not alter surface marker expression (CD80, CD83, CD86, myeloid/plasmacytoid DC markers) or antigen-uptake, but decreased the capacity of MDDCs to process antigen, stimulate CD4+ T cells, and induce cytokines. The decreased antigen processing and CD4+ T cell stimulation capability of MDDCs following PVA-SPION treatment suggests that MDDCs may revert to a more functionally immature state following particle exposure.
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Affiliation(s)
- Fabian Blank
- Department of Clinical Research , Division of Pulmonology, Bern University Hospital, Bern, Switzerland
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27
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Ishizaki T, Erickson A, Kuric E, Shamloo M, Hara-Nishimura I, Inácio ARL, Wieloch T, Ruscher K. The asparaginyl endopeptidase legumain after experimental stroke. J Cereb Blood Flow Metab 2010; 30:1756-66. [PMID: 20234379 PMCID: PMC3023405 DOI: 10.1038/jcbfm.2010.39] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Various proteases in the brain contribute to ischemic brain injury. We investigated the involvement of the asparaginyl endopeptidase legumain after experimental stroke. On the basis of gene array studies and in situ hybridizations, we observed an increase of legumain expression in the peri-infarct area of rats after transient occlusion of the middle cerebral artery (MCAO) for 120 mins with a maximum expression at 24 and 48 h. Immunohistochemical analyses revealed the expression of legumain in Iba1(+) microglial cells and glial fibrillary acidic protein-positive astrocytes of the peri-infarct area in mice after MCAO. Post-stroke recovery was also studied in aged legumain-deficient mice (45 to 58 weeks old). Legumain-deficient mice did not show any differences in physiologic parameters compared with respective littermates before, during MCAO (45 mins), and the subsequent recovery period of 8 days. Moreover, legumain deficiency had no effect on mortality, infarct volume, and the neurologic deficit determined by the rotating pole test, a standardized grip strength test, and the pole test. However, a reduced number of invading CD74(+) cells in the ischemic hemisphere indicates an involvement in post-stroke inflammation. We conclude that legumain is not essential for the functional deficit after MCAO but may be involved in mechanisms of immune cell invasion.
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Affiliation(s)
- Taku Ishizaki
- Department of Clinical Sciences, Wallenberg Neuroscience Center, University of Lund, Sweden
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28
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Demirel O, Bangert I, Tampé R, Abele R. Tuning the cellular trafficking of the lysosomal peptide transporter TAPL by its N-terminal domain. Traffic 2010; 11:383-93. [PMID: 20377823 DOI: 10.1111/j.1600-0854.2009.01021.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The homodimeric ATP-binding cassette (ABC) transport complex TAPL (transporter associated with antigen processing-like, ABCB9) translocates a broad spectrum of peptides from the cytosol into the lumen of lysosomes. The presence of an extra N-terminal transmembrane domain (TMD0) lacking any sequence homology to known proteins distinguishes TAPL from most other ABC transporters of its subfamily. By dissecting TAPL, we could assign distinct functions to the core complex and TMD0. The core-TAPL complex, composed of six predicted transmembrane helices and a nucleotide-binding domain, is sufficient for peptide transport, showing that the core transport complex is correctly targeted to and assembled in the membrane. Strikingly, in contrast to the full-length transporter, the core translocation complex is targeted preferentially to the plasma membrane. However, TMD0 alone, comprising a putative four transmembrane helix bundle, traffics to lysosomes. Upon coexpression, TMD0 forms a stable non-covalently linked complex with the core translocation machinery and guides core-TAPL into lysosomal compartments. Therefore, TMD0 represents a unique domain, which folds independently and encodes the information for lysosomal targeting. These outcomes are discussed in respect of trafficking, folding and function of TAPL.
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Affiliation(s)
- Ozlem Demirel
- Institute of Biochemistry, Biocenter, Goethe-University Frankfurt, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany
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29
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Al-Alwan M, Hou S, Zhang TT, Makondo K, Marshall AJ. Bam32/DAPP1 promotes B cell adhesion and formation of polarized conjugates with T cells. THE JOURNAL OF IMMUNOLOGY 2010; 184:6961-9. [PMID: 20495066 DOI: 10.4049/jimmunol.0904176] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
B cell Ag receptors function in both signaling activation of Ag-specific cells and in collecting specific Ag for presentation to T lymphocytes. Signaling via PI3K is required for BCR-mediated activation and Ag presentation functions; however, the relevant downstream targets of PI3K in B cells are incompletely defined. In this study, we have investigated the roles of the PI3K effector molecule Bam32/DAPP1 in BCR signaling and BCR-mediated Ag presentation functions. In mouse primary B cells, Bam32 was required for efficient activation of the GTPase Rac1 and downstream signaling to JNK, but not activation of BLNK, phospholipase C gamma2, or calcium responses. Consistent with a role of this adaptor in Rac-mediated cytoskeletal rearrangement, Bam32 was required for BCR-induced cell adhesion and spreading responses on ICAM-1 or fibronectin-coated surfaces. The function of Bam32 in promoting Rac activation and adhesion required tyrosine 139, a known site of phosphorylation by Lyn kinase. After BCR crosslinking by Ag, Bam32-deficient B cells are able to carry out the initial steps of Ag endocytosis and processing, but show diminished ability to form Ag-specific conjugates with T cells and polarize F-actin at the B-T interface. As a result, Bam32-deficient B cells were unable to efficiently activate Ag-specific T cells. Together, these results indicate that Bam32 serves to integrate PI3K and Src kinase signaling to promote Rac-dependent B cell adhesive interactions important for Ag presentation function.
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Affiliation(s)
- Monther Al-Alwan
- Department of Immunology, University of Manitoba, Winnipeg, Manitoba, Canada
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30
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van Luijn MM, van den Ancker W, Chamuleau MED, Ossenkoppele GJ, van Ham SM, van de Loosdrecht AA. Impaired antigen presentation in neoplasia: basic mechanisms and implications for acute myeloid leukemia. Immunotherapy 2010; 2:85-97. [DOI: 10.2217/imt.09.84] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
During onset, treatment and progression of acute myeloid leukemia (AML), inadequate immune responses against certain myeloid leukemic blasts might be associated with the occurrence of minimal residual disease and subsequent relapse. Several studies on this subject have demonstrated that, in general, solid tumor cells are able to avoid CD8+ cytotoxic T-cell recognition by downregulating HLA class I-restricted presentation of tumor-associated antigens. In tumor cells that can express HLA class II molecules, such as myeloid leukemic blasts, abnormalities in the processing pathways of endogenous antigens could also result in impaired HLA class II-restricted tumor-associated antigen presentation to CD4+ T helper cells. More insight into impaired tumor-associated antigen presentation by myeloid leukemic blasts could explain their escape from immune recognition and might be crucial for selecting appropriate strategies to improve whole-cell or dendritic cell-based tumor vaccine efficacy in the treatment of AML patients.
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Affiliation(s)
- Marvin M van Luijn
- VU Institute for Cancer & Immunology, Cancer Center Amsterdam, VU University Medical Center, Department of Hematology, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
- Department of Immunopathology, Sanquin Research & Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Willemijn van den Ancker
- VU Institute for Cancer & Immunology, Cancer Center Amsterdam, VU University Medical Center, Department of Hematology, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Martine ED Chamuleau
- VU Institute for Cancer & Immunology, Cancer Center Amsterdam, VU University Medical Center, Department of Hematology, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Gert J Ossenkoppele
- VU Institute for Cancer & Immunology, Cancer Center Amsterdam, VU University Medical Center, Department of Hematology, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - S Marieke van Ham
- Department of Immunopathology, Sanquin Research & Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, The Netherlands
| | - Arjan A van de Loosdrecht
- VU Institute for Cancer & Immunology, Cancer Center Amsterdam, VU University Medical Center, Department of Hematology, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
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31
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Protease cleavage sites in HIV-1 gp120 recognized by antigen processing enzymes are conserved and located at receptor binding sites. J Virol 2009; 84:1513-26. [PMID: 19939935 DOI: 10.1128/jvi.01765-09] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The identification of vaccine immunogens able to elicit broadly neutralizing antibodies (bNAbs) is a major goal in HIV vaccine research. Although it has been possible to produce recombinant envelope glycoproteins able to adsorb bNAbs from HIV-positive sera, immunization with these proteins has failed to elicit antibody responses effective against clinical isolates of HIV-1. Thus, the epitopes recognized by bNAbs are present on recombinant proteins, but they are not immunogenic. These results led us to consider the possibility that changes in the pattern of antigen processing might alter the immune response to the envelope glycoprotein to better elicit protective immunity. In these studies, we have defined protease cleavage sites on HIV gp120 recognized by three major human proteases (cathepsins L, S, and D) important for antigen processing and presentation. Remarkably, six of the eight sites identified in gp120 were highly conserved and clustered in regions of the molecule associated with receptor binding and/or the binding of neutralizing antibodies. These results suggested that HIV may have evolved to take advantage of major histocompatibility complex (MHC) class II antigen processing enzymes in order to evade or direct the antiviral immune response.
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32
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Walsh MD, Dent OF, Young JP, Wright CM, Barker MA, Leggett BA, Bokey L, Chapuis PH, Jass JR, Macdonald GA. HLA-DR expression is associated with better prognosis in sporadic Australian clinicopathological Stage C colorectal cancers. Int J Cancer 2009; 125:1231-7. [PMID: 19462453 DOI: 10.1002/ijc.24484] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Predicting patient outcome for colorectal carcinoma (CRC) with lymph node but not distant metastases remains challenging. Various prognostic markers have been identified including microsatellite instability (MSI) and possibly expression of the MHC Class II protein, HLA-DR. About 15% of sporadic CRC exhibits MSI associated with methylation of the DNA mismatch repair gene hMLH1 promoter. In addition, a significant proportion of unselected CRC demonstrates expression of HLA-DR. We sought to examine the relationship between HLA-DR expression, MSI status and prognosis in sporadic Australian Clinicopathological (ACP) Stage C CRC. Two hundred seventy consecutive patients with sporadic ACP Stage C CRC were treated at Concord Repatriation General Hospital between 1986 and 1992. None of these patients received adjuvant chemotherapy and all were followed for a minimum of 5 years or until death. DNA was extracted from paraffin sections and MSI status determined by PCR. HLA-DR expression was determined immunohistochemically using an antibody against the HLA-DR alpha chain. MSI status could be assigned in 235 cases: 176 CRCs (74.9%) were microsatellite stable, whereas 23 (9.8%) had high levels of MSI (MSI-H) and 36 (15.3%) had low levels of MSI (MSI-L). HLA-DR expression by CRC cells was seen in 148 (60.1%) cases and correlated with the presence of tumor-infiltrating lymphocytes (p = 0.0005) and peritumoral lymphocytes (p = 0.003), but not other clinicopathological features or MSI status. HLA-DR-positive CRCs were strongly associated with better patient outcome (p < 0.0001).
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Affiliation(s)
- Michael D Walsh
- Queensland Institute of Medical Research, Herston, Australia
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33
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Boes M, Stoppelenburg AJ, Sillé FCM. Endosomal processing for antigen presentation mediated by CD1 and Class I major histocompatibility complex: roads to display or destruction. Immunology 2009; 127:163-70. [PMID: 19476512 DOI: 10.1111/j.1365-2567.2009.03078.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The presentation of antigen in a form that can be recognized by T lymphocytes of the immune system requires antigen processing and association of antigen-derived fragments with molecules encoded by the major histocompatibility complex (MHC) locus or by the CD1 locus. Much emphasis on antigen processing and presentation in the last decades has focused on what we consider 'conventional routes' of antigen processing and presentation, whereby extracellular antigens are processed for presentation via Class II MHC complexes and cytosolic antigens are presented as peptide-Class I MHC complexes. We here highlight two other pathways in myeloid dendritic cells, those of lipid antigen presentation in association with CD1 and of peptide cross-presentation via Class I MHC complexes. Some pathogens evade immune recognition through inhibition of antigen presentation of phagosomal origin. Deviations in endosomal antigen processing and presentation are also seen in individuals suffering from glycosphingolipid lysosomal lipid storage diseases. We summarize recent developments in the endosomal antigen processing and presentation pathway, for display as lipid-CD1 complexes to natural killer T cells and as peptide-Class I MHC complexes to CD8 T cells.
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Affiliation(s)
- Marianne Boes
- Department of Pediatric Immunology, University Medical Center Utrecht, Wilhelmina Children's Hospital, the Netherlands.
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Affiliation(s)
- Adam C Berger
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
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35
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Abstract
The stimulation of a tumour-specific T-cell response has several theoretical advantages over other forms of cancer treatment. First, T cells can home in to antigen-expressing tumour deposits no matter where they are located in the body-even in deep tissue beds. Additionally, T cells can continue to proliferate in response to immunogenic proteins expressed in cancer until all the tumour cells are eradicated. Finally, immunological memory can be generated, allowing for eradication of antigen-bearing tumours if they reoccur. We will highlight two direct methods of stimulating tumour-specific T-cell immunity: active immunisation with cancer vaccines and infusion of competent T cells via adoptive T-cell treatment. Preclinical and clinical studies have shown that modulation of the tumour microenvironment to support the immune response is as important as stimulation of the most appropriate effector T cells. The future of T-cell immunity stimulation to treat cancer will need combination approaches focused on both the tumour and the T cell.
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Affiliation(s)
- Mary L Disis
- Center for Translational Medicine in Women's Health, Tumor Vaccine Group, University of Washington, Seattle, WA, USA
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36
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Pieters J. Mycobacterium tuberculosis and the macrophage: maintaining a balance. Cell Host Microbe 2008; 3:399-407. [PMID: 18541216 DOI: 10.1016/j.chom.2008.05.006] [Citation(s) in RCA: 338] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 05/19/2008] [Accepted: 05/19/2008] [Indexed: 01/03/2023]
Abstract
Mycobacterium tuberculosis is a highly efficient pathogen, killing millions of infected people annually. The capacity of M. tuberculosis to survive and cause disease is strongly correlated to their ability to escape immune defense mechanisms. In particular, M. tuberculosis has the remarkable capacity to survive within the hostile environment of the macrophage. Understanding M. tuberculosis virulence strategies will not only define novel targets for drug development but will also help to uncover previously unknown signaling pathways related to the host's response to M. tuberculosis infection.
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Affiliation(s)
- Jean Pieters
- Biozentrum, University of Basel, Klingelbergstrasse 50, 4056 Basel, Switzerland.
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Sun PD, Boyington JC. Overview of protein folds in the immune system. ACTA ACUST UNITED AC 2008; Appendix 1:Appendix 1N. [PMID: 18432648 DOI: 10.1002/0471142735.ima01ns44] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The rapid advancement of X-ray crystallography and nuclear magnetic resonance techniques in recent years has resulted in the solution of macromolecular structures at an unprecedented rate. This review aims at providing a comprehensive description of structures and folds related to the function of the immune system. Focus is placed on immunologically relevant proteins such as immunoreceptors and major histocompatibility complexes. Information is also provided regarding protein structure data banks.
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Affiliation(s)
- P D Sun
- National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland, USA
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Khor B, Makar RS. Toward a Molecular Explanation for Cross-presentation of Antigens to the Immune System. Transfus Med Rev 2008; 22:188-201. [DOI: 10.1016/j.tmrv.2008.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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39
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Zavasnik-Bergant T, Turk B. Cysteine proteases: destruction ability versus immunomodulation capacity in immune cells. Biol Chem 2008; 388:1141-9. [PMID: 17976006 DOI: 10.1515/bc.2007.144] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cysteine proteases (cathepsins) play a pivotal role in various physiological processes, as well as in several diseases. In the immune response, maturation of major histocompatibility class II (MHC II) molecules and processing of antigens for further presentation by MHC II is tightly linked to the enzymes of the endosomal/lysosomal system, of which cysteine proteases constitute a major proportion. Furthermore, the process of autophagy provides access for cytosolic antigens to proteolysis by lysosomal cathepsins and subsequent MHC II presentation. Other specific functions of proteolytic enzymes associated with the immune response, such as activation of granzymes by cathepsin C in T-lymphocytes, are introduced and covered in this review.
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Affiliation(s)
- Tina Zavasnik-Bergant
- Department of Biochemistry, Molecular and Structural Biology, Jozef Stefan Institute, SI-1000, Ljubljana, Slovenia
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40
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Mellman I. Private Lives: Reflections and Challenges in Understanding the Cell Biology of the Immune System. Science 2007; 317:625-7. [PMID: 17673653 DOI: 10.1126/science.1142955] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The immune system comprises a variety of cell types whose activities must be carefully regulated to act as a coherent unit for the purpose of host defense. To perform their autonomous functions, immune cells must rely on the same basic organizational features that apply to all cells, although immune cells often exhibit remarkable degrees of specialization and adaptation. The study of these specializations has lagged behind advances in understanding the immune response and cell biology individually. As a result, there are great opportunities, but also great challenges, for new conceptual discoveries by taking a more cell-biological approach to probing the function of the immune system.
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Affiliation(s)
- Ira Mellman
- Department of Research Oncology, Genentech, 1 DNA Way, Mail Stop 212, South San Francisco, CA 94080-4990, USA.
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41
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Vascotto F, Lankar D, Faure-André G, Vargas P, Diaz J, Le Roux D, Yuseff MI, Sibarita JB, Boes M, Raposo G, Mougneau E, Glaichenhaus N, Bonnerot C, Manoury B, Lennon-Duménil AM. The actin-based motor protein myosin II regulates MHC class II trafficking and BCR-driven antigen presentation. ACTA ACUST UNITED AC 2007; 176:1007-19. [PMID: 17389233 PMCID: PMC2064085 DOI: 10.1083/jcb.200611147] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Antigen (Ag) capture and presentation onto major histocompatibility complex (MHC) class II molecules by B lymphocytes is mediated by their surface Ag receptor (B cell receptor [BCR]). Therefore, the transport of vesicles that carry MHC class II and BCR–Ag complexes must be coordinated for them to converge for processing. In this study, we identify the actin-associated motor protein myosin II as being essential for this process. Myosin II is activated upon BCR engagement and associates with MHC class II–invariant chain complexes. Myosin II inhibition or depletion compromises the convergence and concentration of MHC class II and BCR–Ag complexes into lysosomes devoted to Ag processing. Accordingly, the formation of MHC class II–peptides and subsequent CD4 T cell activation are impaired in cells lacking myosin II activity. Therefore, myosin II emerges as a key motor protein in BCR-driven Ag processing and presentation.
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Affiliation(s)
- Fulvia Vascotto
- Institut National de la Santé et de la Recherche Medicale Unité 653, Unité Mixte de Recherche 144 Institut Curie, 75005 Paris, France
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42
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Mimura Y, Mimura-Kimura Y, Doores K, Golgher D, Davis BG, Dwek RA, Rudd PM, Elliott T. Folding of an MHC class II-restricted tumor antigen controls its antigenicity via MHC-guided processing. Proc Natl Acad Sci U S A 2007; 104:5983-8. [PMID: 17389359 PMCID: PMC1851603 DOI: 10.1073/pnas.0701307104] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Indexed: 11/18/2022] Open
Abstract
CD4(+) and CD8(+) T cell responses to endogenous retroviral envelope glycoprotein gp90 generate protective immunity to murine colon carcinoma CT26. A panel of I-A(d)-restricted T cell hybridomas recognize gp90 synthesized by CT26 cells but not by other gp90-expressing tumors. Here we report that antigenicity resides in an incompletely folded form of gp90 that is unique to CT26. In contrast to more compact forms of gp90 that are present in other tumors, this open conformer is captured by recycling I-A(d) on antigen-presenting cells and is processed intracellularly. Thus, gp90 acquires immunodominance via MHC-guided processing, and the generation of an MHC class II-restricted response can be controlled by the intracellular folding environment of antigen-expressing cells.
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Affiliation(s)
- Yusuke Mimura
- *Cancer Sciences Division, School of Medicine, Southampton General Hospital, University of Southampton, Tremona Road, Southampton SO16 6YD, United Kingdom
- Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX 1 3QU, United Kingdom; and
| | - Yuka Mimura-Kimura
- Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX 1 3QU, United Kingdom; and
| | - Katie Doores
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Denise Golgher
- *Cancer Sciences Division, School of Medicine, Southampton General Hospital, University of Southampton, Tremona Road, Southampton SO16 6YD, United Kingdom
| | - Benjamin G. Davis
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Raymond A. Dwek
- Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX 1 3QU, United Kingdom; and
| | - Pauline M. Rudd
- Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX 1 3QU, United Kingdom; and
| | - Tim Elliott
- *Cancer Sciences Division, School of Medicine, Southampton General Hospital, University of Southampton, Tremona Road, Southampton SO16 6YD, United Kingdom
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Burster T, Beck A, Poeschel S, Øren A, Baechle D, Reich M, Roetzschke O, Falk K, Boehm BO, Youssef S, Kalbacher H, Overkleeft H, Tolosa E, Driessen C. Interferon-gamma regulates cathepsin G activity in microglia-derived lysosomes and controls the proteolytic processing of myelin basic protein in vitro. Immunology 2007; 121:82-93. [PMID: 17302735 PMCID: PMC2265925 DOI: 10.1111/j.1365-2567.2007.02540.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
The serine protease cathepsin (Cat) G dominates the proteolytic processing of the multiple sclerosis (MS)-associated autoantigen myelin basic protein (MBP) in lysosomes from primary human B cells and dendritic cells. This is in contrast to B-lymphoblastoid cell lines, where the asparagine endopeptidase (AEP) is responsible for this task. We have analysed microglia-derived lysosomal proteases for their ability to process MBP in vitro. In lysosomes derived from primary murine microglia, CatD, CatS, AEP and CatG were involved in the processing of MBP. Interestingly, when microglia were treated with interferon-gamma to mimic a T helper type 1-biased cytokine milieu in MS, CatG was drastically down-regulated, in contrast to CatS, CatB, CatL, CatD or AEP. This resulted in significantly increased stability of MBP and a selective lack of CatG-derived proteolytic fragments; however, it did not affect the gross pattern of MBP processing. Inhibition of serine proteases eliminated the processing differences between lysosomal extracts from resting microglia compared to interferon-stimulated microglia. Thus, the cytokine environment modulates lysosomal proteases in microglia by a selective down-regulation of CatG, leading to decreased MBP-processing by microglia-derived lysosomal proteases in vitro.
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Affiliation(s)
- Timo Burster
- Department of Medicine II, University of Tübingen, Germany.
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44
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Fallas JL, Yi W, Draghi NA, O'Rourke HM, Denzin LK. Expression Patterns of H2-O in Mouse B Cells and Dendritic Cells Correlate with Cell Function. THE JOURNAL OF IMMUNOLOGY 2007; 178:1488-97. [PMID: 17237397 DOI: 10.4049/jimmunol.178.3.1488] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In the endosomes of APCs, the MHC class II-like molecule H2-M catalyzes the exchange of class II-associated invariant chain peptides (CLIP) for antigenic peptides. H2-O is another class II-like molecule that modulates the peptide exchange activity of H2-M. Although the expression pattern of H2-O in mice has not been fully evaluated, H2-O is expressed by thymic epithelial cells, B cells, and dendritic cells (DCs). In this study, we investigated H2-O, H2-M, and I-A(b)-CLIP expression patterns in B cell subsets during B cell development and activation. H2-O was first detected in the transitional 1 B cell subset and high levels were maintained in marginal zone and follicular B cells. H2-O levels were down-regulated specifically in germinal center B cells. Unexpectedly, we found that mouse B cells may have a pool of H2-O that is not associated with H2-M. Additionally, we further evaluate H2-O and H2-M interactions in mouse DCs, as well as H2-O expression in bone marrow-derived DCs. We also evaluated H2-O, H2-M, I-A(b), and I-A(b)-CLIP expression in splenic DC subsets, in which H2-O expression levels varied among the splenic DC subsets. Although it has previously been shown that H2-O modifies the peptide repertoire, H2-O expression did not alter DC presentation of a number of endogenous and exogenous Ags. Our further characterization of H2-O expression in DCs, as well as the identification of a potential free pool of H2-O in mouse splenic B cells, suggest that H2-O may have a yet to be elucidated role in immune responses.
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Affiliation(s)
- Jennifer L Fallas
- Cell Biology and Genetics Program, Weill Graduate School of Medical Sciences of Cornell University, New York, NY 10021, USA
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45
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Gadola SD, Silk JD, Jeans A, Illarionov PA, Salio M, Besra GS, Dwek R, Butters TD, Platt FM, Cerundolo V. Impaired selection of invariant natural killer T cells in diverse mouse models of glycosphingolipid lysosomal storage diseases. ACTA ACUST UNITED AC 2006; 203:2293-303. [PMID: 16982810 PMCID: PMC2118110 DOI: 10.1084/jem.20060921] [Citation(s) in RCA: 115] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Glycolipid ligands for invariant natural killer T cells (iNKT cells) are loaded onto CD1d molecules in the late endosome/lysosome. Accumulation of glycosphingolipids (GSLs) in lysosomal storage diseases could potentially influence endogenous and exogenous lipid loading and/or presentation and, thus, affect iNKT cell selection or function. The percentages and frequency of iNKT cells were reduced in multiple mouse models of lysosomal GSL storage disease, irrespective of the specific genetic defect or lipid species stored. Reduced numbers of iNKT cells resulted in the absence of cytokine production in response to alpha-galactosylceramide (alpha-GalCer) and reduced iNKT cell-mediated lysis of wild-type targets loaded with alpha-GalCer. The reduction in iNKT cells did not result from defective expression of CD1d or a lack of antigen-presenting cells. Although H-2 restricted CD4(+) T cell responses were generally unaffected, processing of a lysosome-dependent analogue of alpha-GalCer was impaired in all the strains of mice tested. These data suggest that GSL storage may result in alterations in thymic selection of iNKT cells caused by impaired presentation of selecting ligands.
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Affiliation(s)
- Stephan D Gadola
- Weatherall Institute of Molecular Medicine, Tumour Immunology Group, John Radcliffe Hospital, Oxford OX3 9DS, England, UK
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46
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Major AS, Joyce S, Van Kaer L. Lipid metabolism, atherogenesis and CD1-restricted antigen presentation. Trends Mol Med 2006; 12:270-8. [PMID: 16651026 DOI: 10.1016/j.molmed.2006.04.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2006] [Revised: 03/15/2006] [Accepted: 04/13/2006] [Indexed: 11/29/2022]
Abstract
CD1 molecules are a family of major histocompatibility complex (MHC)-related glycoproteins that present lipid and glycolipid antigens to T cells. Interestingly, it has been demonstrated that CD1d-restricted T cells have a pathogenic role in atherosclerosis. Recent studies suggest an association between the cellular machinery that loads CD1 molecules with glycolipids and several key proteins in lipid metabolism. These proteins include the sphingolipid activator proteins (SAPs), microsomal triglyceride transfer protein (MTP) and apolipoprotein E (apoE). MTP and SAPs seem to be crucial for loading CD1d with lipids in the endoplasmic reticulum and endosomal compartments, respectively, whereas apoE facilitates efficient uptake and delivery of exogenous lipid antigens to CD1d in endosomal compartments. These studies reveal new and unexpected relationships between lipid metabolism and antigen presentation by CD1 molecules. Targeting this pathway of immune activation might have therapeutic potential for the treatment of chronic inflammatory diseases.
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Affiliation(s)
- Amy S Major
- Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University School of Medicine, 2220 Pierce Avenue, Room 383, Preston Research Building, Nashville, TN 37232, USA.
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47
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Nanda NK, Bikoff EK. DM peptide-editing function leads to immunodominance in CD4 T cell responses in vivo. THE JOURNAL OF IMMUNOLOGY 2006; 175:6473-80. [PMID: 16272301 DOI: 10.4049/jimmunol.175.10.6473] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
DM functions as a peptide editor for MHC class II-bound peptides. We examined the hypothesis that DM peptide editing plays a key role in focusing the in vivo CD4 T cell responses against complex pathogens and protein Ags to only one, or at most a few, immunodominant peptides. Most CD4 T cells elicited in the wild-type BALB/c (H-2d) mice infected with Leishmania major predominantly recognize a single epitope 158-173 within Leishmania homologue of activated receptor for c-kinase (LACK), as is the case when these mice are immunized with rLACK. Using DM-deficient (DM-/-) H-2d mice, we now show that in the absence of DM, the in vivo CD4 T cell responses to rLACK are skewed away from the immunodominant epitopes and are diversified to include two novel epitopes (LACK 33-48 and 261-276). DM-/- B10.BR (H-2k) mice showed similar results. These results constitute the first demonstration of the role of DM peptide editing in sculpting the specificity and immunodominance in in vivo CD4 T cell responses.
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Affiliation(s)
- Navreet K Nanda
- Departments of Microbiology and Immunology, and Oncology, Lombardi Cancer Center, Georgetown University Medical Center, Washington DC 20057, USA.
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48
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Ranella A, Vassiliadis S, Mastora C, Valentina M, Dionyssopoulou E, Athanassakis I. Constitutive intracellular expression of human leukocyte antigen (HLA)-DO and HLA-DR but not HLA-DM in trophoblast cells. Hum Immunol 2005; 66:43-55. [PMID: 15620461 DOI: 10.1016/j.humimm.2004.10.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 10/05/2004] [Accepted: 10/07/2004] [Indexed: 11/19/2022]
Abstract
The nonclassic human leukocyte antigen (HLA)-DM molecules have been proved to positively regulate antigen presentation in classic antigen-presenting cells, whereas in B lymphocytes HLA-DO have been identified as negative regulators of the process. The present report examines whether the negative expression of classic class II molecules in trophoblasts implies negative regulation by HLA-DO. It was revealed by immunofluorescence, confocal microscopy, and subcellular fractionation techniques that human trophoblasts, although not expressing any surface HLA-DR antigens, constitutively express intracellular HLA-DR, HLA-DO, and CD74, but not HLA-DM. Administration of interferon-gamma to the cell culture increased HLA-DR and CD74, induced HLA-DM, but did not alter the expression of HLA-DO and induced HLA-DR release from the cells. These results were confirmed by reverse transcriptase-polymerase chain reaction analysis except that HLA-DM mRNA was detected in control cells, indicating a posttranscriptional regulation. Under the same experimental conditions, human monocytes/macrophages were not expressing intracellular HLA-DO while exhibiting significant levels of HLA-DR, HLA-DM, and CD74. The results presented here reveal for the first time expression of HLA-DO in trophoblasts, which can be of great importance in maintaining the class II-negative state in these cells and consequently protecting the fetus from maternal immune attack.
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Affiliation(s)
- Anthi Ranella
- Department of Biology, Laboratory of Immunology, University of Crete, Heraklion, Crete, Greece
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49
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Iannello A, Debbeche O, Martin E, Attalah LH, Samarani S, Ahmad A. Viral strategies for evading antiviral cellular immune responses of the host. J Leukoc Biol 2005; 79:16-35. [PMID: 16204622 DOI: 10.1189/jlb.0705397] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The host invariably responds to infecting viruses by activating its innate immune system and mounting virus-specific humoral and cellular immune responses. These responses are aimed at controlling viral replication and eliminating the infecting virus from the host. However, viruses have evolved numerous strategies to counter and evade host's antiviral responses. Providing specific examples from the published literature, we discuss in this review article various strategies that viruses have developed to evade antiviral cellular responses of the host. Unraveling these viral strategies allows a better understanding of the host-pathogen interactions and their coevolution. This knowledge is important for identifying novel molecular targets for developing antiviral reagents. Finally, it may also help devise new knowledge-based strategies for developing antiviral vaccines.
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Affiliation(s)
- Alexandre Iannello
- Ste-Justine Hospital Research Center, Department of Microbiology and Immunology, University of Montreal, Quebec, Canada
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50
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Azar GA, Sékaly RP, Thibodeau J. A defective viral superantigen-presenting phenotype in HLA-DR transfectants is corrected by CIITA. THE JOURNAL OF IMMUNOLOGY 2005; 174:7548-57. [PMID: 15944254 DOI: 10.4049/jimmunol.174.12.7548] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Activation of T lymphocytes by mouse mammary tumor virus superantigen (vSAg) requires binding to MHC class II molecules. The subcellular location where functional interactions occur between MHC class II molecules and vSAgs is still a matter of debate. To gain further insight into this issue, we have used human epithelial HeLa cells expressing HLA-DR1. Surprisingly, the human cells were unable to present transfected vSAg7 or vSAg9 to a series of murine T cell hybridomas. The defect is not related to a lack of vSAg processing, because these cells can indirectly activate T cells after coculture in the presence of B lymphocytes. However, after IFN-gamma treatment, the HeLa DR1(+) cells became apt at directly presenting the vSAg. Furthermore, transfection of CIITA was sufficient to restore presentation. Reconstitution experiments demonstrated the necessity of coexpressing HLA-DM and invariant chain (Ii) for efficient vSAg presentation. Interestingly, inclusion of a dileucine motif in the DRbeta cytoplasmic tail bypassed the need for HLA-DM expression and allowed the efficient presentation of vSAg7 in the presence of Ii. A similar trafficking signal was included in vSAg7 by replacing its cytoplasmic tail with the one of Ii. However, sorting of this chimeric Ii/vSAg molecule to the endocytic pathway completely abolished both its indirect and direct presentation. Together, our results suggest that functional vSAgs-DR complexes form after the very late stages of class II maturation, most probably at the cell surface.
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Affiliation(s)
- Georges A Azar
- Laboratoire d'Immunologie Moléculaire, Département de Microbiologie et Immunologie, Faculté de Médecine, Université de Montréal, Hôpital St.-Luc, Montréal, Canada
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