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Lee S, Park B, Kang K, Ahn K. Redox-regulated export of the major histocompatibility complex class I-peptide complexes from the endoplasmic reticulum. Mol Biol Cell 2009; 20:3285-94. [PMID: 19477919 DOI: 10.1091/mbc.e09-03-0238] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
In contrast to the fairly well-characterized mechanism of assembly of MHC class I-peptide complexes, the disassembly mechanism by which peptide-loaded MHC class I molecules are released from the peptide-loading complex and exit the endoplasmic reticulum (ER) is poorly understood. Optimal peptide binding by MHC class I molecules is assumed to be sufficient for triggering exit of peptide-filled MHC class I molecules from the ER. We now show that protein disulfide isomerase (PDI) controls MHC class I disassembly by regulating dissociation of the tapasin-ERp57 disulfide conjugate. PDI acts as a peptide-dependent molecular switch; in the peptide-bound state, it binds to tapasin and ERp57 and induces dissociation of the tapasin-ERp57 conjugate. In the peptide-free state, PDI is incompetent to bind to tapasin or ERp57 and fails to dissociate the tapasin-ERp57 conjugates, resulting in ER retention of MHC class I molecules. Thus, our results indicate that even after optimal peptide loading, MHC class I disassembly does not occur by default but, rather, is a regulated process involving PDI-mediated interactions within the peptide-loading complex.
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Affiliation(s)
- Sungwook Lee
- National Creative Research Center for Antigen Presentation, Department of Biological Sciences, Seoul National University, Seoul 151-747, Korea
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52
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Kim Y, Kang K, Kim I, Lee YJ, Oh C, Ryoo J, Jeong E, Ahn K. Molecular mechanisms of MHC class I-antigen processing: redox considerations. Antioxid Redox Signal 2009; 11:907-36. [PMID: 19178136 DOI: 10.1089/ars.2008.2316] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Major histocompatibility complex (MHC) class I molecules present antigenic peptides to the cell surface for screening by CD8(+) T cells. A number of ER-resident chaperones assist the assembly of peptides onto MHC class I molecules, a process that can be divided into several steps. Early folding of the MHC class I heavy chain is followed by its association with beta(2)-microglobulin (beta(2)m). The MHC class I heavy chain-beta(2)m heterodimer is incorporated into the peptide-loading complex, leading to peptide loading, release of the peptide-filled MHC class I molecules from the peptide-loading complex, and exit of the complete MHC class I complex from the ER. Because proper antigen presentation is vital for normal immune responses, the assembly of MHC class I molecules requires tight regulation. Emerging evidence indicates that thiol-based redox regulation plays critical roles in MHC class I-restricted antigen processing and presentation, establishing an unexpected link between redox biology and antigen processing. We review the influences of redox regulation on antigen processing and presentation. Because redox signaling pathways are a rich source of validated drug targets, newly discovered redox biology-mediated mechanisms of antigen processing may facilitate the development of more selective and therapeutic drugs or vaccines against immune diseases.
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Affiliation(s)
- Youngkyun Kim
- National Creative Research Center for Antigen Presentation, Department of Biological Sciences, Seoul National University, Seoul, South Korea
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53
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Sohn YH, Cha CH, Kim MH, Ko SY, Oh HB. [Experience on identification of cross-reactive group specificity performed by anti-human globulin panel reactive antibody tests]. Korean J Lab Med 2008; 28:362-70. [PMID: 18971617 DOI: 10.3343/kjlm.2008.28.5.362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Panel reactive antibody (PRA) is to screen and identify HLA antibody. Majority of antibody specificities in high-PRA are directed against cross reactive group (CREG). Thus, this study was to know the advantage of identifying CREG specificity and whether antibody specificities are changed according to CREG classification. METHODS HLA class I antibodies were identified from 159 sera from 108 patients in Asan Medical Center, who had shown more than 5% PRA by anti-human globulin (AHG)-complement-dependent cytotoxicity (CDC). Tail analysis-based computer program was developed to identify specificities, applying both Rodey (R-ABC) and Takemoto (T-ABC) classification. The results were also compared with those obtained when without CREG application (ABC). RESULTS Among 151 cases in which HLA specificities was identified, the frequency of CREG specificity was 22.5% in R-ABC and 27.2% in T-ABC. Eleven cases showed CREG specificities only in one classification. However, the individual antigen specificities in one hand were all included in the CREG identified in the other hand. CREG specificities in samples with PRA >50% (60%) were more frequently identified than those in samples with PRA < or =50% (9%) (in R-ABC, P<0.0001). Without applying CREG to interpretation, specificity was not identified in 9 cases. CONCLUSIONS Application of CREG enhanced the rate of antibody identification. Antibody specificities of those cases where CREG specificities were different between Rodey and Takemoto classifications were almost the same when compared at the individual antigen level. Therefore, it was thought that it makes no difference to use any one of these two classifications in interpreting PRA.
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Affiliation(s)
- Yong-Hak Sohn
- Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea
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54
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Schaefer MR, Williams M, Kulpa DA, Blakely PK, Yaffee AQ, Collins KL. A novel trafficking signal within the HLA-C cytoplasmic tail allows regulated expression upon differentiation of macrophages. THE JOURNAL OF IMMUNOLOGY 2008; 180:7804-17. [PMID: 18523244 DOI: 10.4049/jimmunol.180.12.7804] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
MHC class I molecules (MHC-I) present peptides to CTLs. In addition, HLA-C allotypes are recognized by killer cell Ig-like receptors (KIR) found on NK cells and effector CTLs. Compared with other classical MHC-I allotypes, HLA-C has low cell surface expression and an altered intracellular trafficking pattern. We present evidence that this results from effects of both the extracellular domain and the cytoplasmic tail. Notably, we demonstrate that the cytoplasmic tail contains a dihydrophobic (LI) internalization and lysosomal targeting signal that is partially attenuated by an aspartic acid residue (DXSLI). In addition, we provide evidence that this signal is specifically inhibited by hypophosphorylation of the adjacent serine residue upon macrophage differentiation and that this allows high HLA-C expression in this cell type. We propose that tightly regulated HLA-C surface expression facilitates immune surveillance and allows HLA-C to serve a specialized role in macrophages.
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Affiliation(s)
- Malinda R Schaefer
- Graduate Program Immunology, University of Michigan, Ann Arbor, MI 48109, USA
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55
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Detecting and monitoring human leukocyte antigen-specific antibodies. Hum Immunol 2008; 69:591-604. [PMID: 18692106 DOI: 10.1016/j.humimm.2008.06.013] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2008] [Revised: 06/16/2008] [Accepted: 06/17/2008] [Indexed: 01/26/2023]
Abstract
Renewed awareness of the relevance of HLA-specific antibodies to transplantation and the development of protocols to reduce or eliminate sensitization have made monitoring of antibodies and accurate interpretation of test results increasingly important. Here we review the various tests available and provide guidelines for the development of monitoring protocols.
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56
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Neefjes J. Determining protein transport to the plasma membrane. CURRENT PROTOCOLS IN CELL BIOLOGY 2008; Chapter 15:Unit 15.4. [PMID: 18228331 DOI: 10.1002/0471143030.cb1504s05] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Many integral membrane proteins synthesized in the endoplasmic reticulum ultimately arrive at the cell surface to contact the cell environment. During transit through the Golgi and trans-Golgi network, proteins acquire post-translational modifications that can be used to track the appearance of such modified proteins at the cell surface. Cellular proteins can be treated with enzymes-e.g., sialidase or protease-or antibodies, or biotinylated to identify molecules that have reached the cell surface. Some proteins first enter the endocytic pathway before appearing at the cell surface; this is detected by treating the cells at 4 degrees and 37 degrees C. Analysis of the number of sialic acids on proteins of cells treated at 4 degrees C identifies proteins resident at the cell surface, while cells treated at 37 degrees C internalize the sialidase, which can then act with proteins in the endocytic compartments.
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Affiliation(s)
- J Neefjes
- The Netherlands Cancer Institute, Amsterdam, The Netherlands
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57
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Kim MH, Choi SE, Oh HB. Human Leukocyte Antigen Typing Proficiency Surveys in Korea, 2005-2006. Ann Lab Med 2007; 27:442-50. [DOI: 10.3343/kjlm.2007.27.6.442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Myeong-Hee Kim
- Department of Laboratory Medicine, Asan Medical Center and University of Ulsan College of Medicine, Seoul, Korea
| | - Sung-Eun Choi
- Department of Laboratory Medicine, Asan Medical Center and University of Ulsan College of Medicine, Seoul, Korea
| | - Heung-Bum Oh
- Department of Laboratory Medicine, Asan Medical Center and University of Ulsan College of Medicine, Seoul, Korea
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Sibilio L, Martayan A, Setini A, Monaco EL, Tremante E, Butler RH, Giacomini P. A single bottleneck in HLA-C assembly. J Biol Chem 2007; 283:1267-1274. [PMID: 17956861 DOI: 10.1074/jbc.m708068200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Poor assembly of class I major histocompatibility HLA-C heavy chains results in their intracellular accumulation in two forms: free of and associated with their light chain subunit (beta(2)-microglobulin). Both intermediates are retained in the endoplasmic reticulum by promiscuous and HLA-dedicated chaperones and are poorly associated with peptide antigens. In this study, the eight serologically defined HLA-C alleles and the interlocus recombinant HLA-B46 allele (sharing the HLA-C-specific motif KYRV at residues 66-76 of the alpha1-domain alpha-helix) were compared with a large series of HLA-B and HLA-A alleles. Pulse-labeling experiments with HLA-C transfectants and HLA homozygous cell lines demonstrated that KYRV alleles accumulate as free heavy chains because of both poor assembly and post-assembly instability. Reactivity with antibodies to mapped linear epitopes, co-immunoprecipitation experiments, and molecular dynamics simulation studies additionally showed that the KYRV motif confers association to the HLA-dedicated chaperones TAP and tapasin as well as reduced plasticity and unfolding in the peptide-binding groove. Finally, in vitro assembly experiments in cell extracts of the T2 and 721.220 mutant cell lines demonstrated that HLA-Cw1 retains the ability to form a peptide-receptive interface despite a lack of TAP and functional tapasin, respectively. In the context of the available literature, these results indicate that a single locus-specific biosynthetic bottleneck renders HLA-C peptide-selective (rather than peptide-unreceptive) and a preferential natural killer cell ligand.
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Affiliation(s)
- Leonardo Sibilio
- Laboratory of Immunology, Regina Elena National Cancer Research Institute, Centro della Ricerca Sperimentale, Via delle Messi d'Oro 156, 00158 Rome, Italy
| | - Aline Martayan
- Laboratory of Immunology, Regina Elena National Cancer Research Institute, Centro della Ricerca Sperimentale, Via delle Messi d'Oro 156, 00158 Rome, Italy
| | - Andrea Setini
- Laboratory of Immunology, Regina Elena National Cancer Research Institute, Centro della Ricerca Sperimentale, Via delle Messi d'Oro 156, 00158 Rome, Italy
| | - Elisa Lo Monaco
- Laboratory of Immunology, Regina Elena National Cancer Research Institute, Centro della Ricerca Sperimentale, Via delle Messi d'Oro 156, 00158 Rome, Italy
| | - Elisa Tremante
- Laboratory of Immunology, Regina Elena National Cancer Research Institute, Centro della Ricerca Sperimentale, Via delle Messi d'Oro 156, 00158 Rome, Italy
| | - Richard H Butler
- Cell Biology Institute, Consiglio Nazionale delle Ricerche, Via E. Ramarini 32, 00016 Monterotondo Scalo Rome, Italy
| | - Patrizio Giacomini
- Laboratory of Immunology, Regina Elena National Cancer Research Institute, Centro della Ricerca Sperimentale, Via delle Messi d'Oro 156, 00158 Rome, Italy.
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59
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Tong JC, Zhang ZH, August JT, Brusic V, Tan TW, Ranganathan S. In silico characterization of immunogenic epitopes presented by HLA-Cw*0401. Immunome Res 2007; 3:7. [PMID: 17705876 PMCID: PMC2040137 DOI: 10.1186/1745-7580-3-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2007] [Accepted: 08/20/2007] [Indexed: 11/13/2022] Open
Abstract
Background HLA-C locus products are poorly understood in part due to their low expression at the cell surface. Recent data indicate that these molecules serve as major restriction elements for human immunodeficiency virus type 1 (HIV-1) cytotoxic T lymphocyte (CTL) epitopes. We report here a structure-based technique for the prediction of peptides binding to Cw*0401. The models were rigorously trained, tested and validated using experimentally verified Cw*0401 binding and non-binding peptides obtained from biochemical studies. A new scoring scheme facilitates the identification of immunological hot spots within antigens, based on the sum of predicted binding energies of the top four binders within a window of 30 amino acids. Results High predictivity is achieved when tested on the training (r2 = 0.88, s = 3.56 kJ/mol, q2 = 0.84, spress = 5.18 kJ/mol) and test (AROC = 0.93) datasets. Characterization of the predicted Cw*0401 binding sequences indicate that amino acids at key anchor positions share common physico-chemical properties which correlate well with existing experimental studies. Conclusion The analysis of predicted Cw*0401-binding peptides showed that anchor residues may not be restrictive and the Cw*0401 binding pockets may possibly accommodate a wide variety of peptides with common physico-chemical properties. The potential Cw*0401-specific T-cell epitope repertoires for HIV-1 p24gag and gp160gag glycoproteins are well distributed throughout both glycoproteins, with thirteen and nine immunological hot spots for HIV-1 p24gag and gp160gag glycoproteins respectively. These findings provide new insights into HLA-C peptide selectivity, indicating that pre-selection of candidate HLA-C peptides may occur at the TAP level, prior to peptide loading in the endoplasmic reticulum.
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Affiliation(s)
- Joo Chuan Tong
- Institute for Infocomm Research, 21 Heng Mui Keng Terrace, 119613, Singapore
| | - Zong Hong Zhang
- Institute for Infocomm Research, 21 Heng Mui Keng Terrace, 119613, Singapore
| | - J Thomas August
- Department of Pharmacology and Molecular Sciences, John Hopkins University School of Medicine, Baltimore, MD, USA
| | - Vladimir Brusic
- Cancer Vaccine Center, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Tin Wee Tan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, 117597, Singapore
| | - Shoba Ranganathan
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, 117597, Singapore
- Department of Chemistry and Biomolecular Sciences & Biotechnology Research Institute, Macquarie University, NSW 2109, Australia
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60
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Cabrera CM. The Double Role of the Endoplasmic Reticulum Chaperone Tapasin in Peptide Optimization of HLA Class I Molecules. Scand J Immunol 2007; 65:487-93. [PMID: 17523940 DOI: 10.1111/j.1365-3083.2007.01934.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: 11/29/2022]
Abstract
During the assembly of the HLA class I molecules with peptides in the peptide-loading complex, a series of transient interactions are made with ER-resident chaperones. These interactions culminate in the trafficking of the HLA class I molecules to the cell surface and presentation of peptides to CD8(+) T lymphocytes. Within the peptide-loading complex, the glycoprotein tapasin exhibits a relevant function. This immunoglobulin (Ig) superfamily member in the endoplasmic reticulum membrane tethers empty HLA class I molecules to the transporter associated with antigen-processing (TAP) proteins. This review will address the current concepts regarding the double role that tapasin plays in the peptide optimization and surface expression of the HLA class I molecules.
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Affiliation(s)
- C M Cabrera
- Stem Cell Bank of Andalucia (Spanish Central Node), Hospital Universitario Virgen de las Nieves, Granada, Spain.
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61
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Aptsiauri N, Cabrera T, Garcia-Lora A, Lopez-Nevot MA, Ruiz-Cabello F, Garrido F. MHC Class I Antigens and Immune Surveillance in Transformed Cells. INTERNATIONAL REVIEW OF CYTOLOGY 2007; 256:139-89. [PMID: 17241907 DOI: 10.1016/s0074-7696(07)56005-5] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
MHC class I antigens play a crucial role in the interaction of tumor cells with the host immune system, in particular, in the presentation of peptides as tumor-associated antigens to cytotoxic lymphocytes (CTLs) and in the regulation of cytolytic activity of natural killer (NK) cells. In this review we discuss the role of MHC class I antigens in the recognition and elimination of transformed cells and in the generation of tumor immune escape routes when MHC class I losses occur in tumors. The different altered MHC class I phenotypes and their distribution in different human tumors are the main topic of this review. In addition, molecular defects that underlie MHC alterations in transformed cells are also described in detail. Future research directions in this field are also discussed, including the laboratory analysis of tumor MHC class I-negative variants and the possible restoration of MHC class I expression.
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Affiliation(s)
- Natalia Aptsiauri
- Servicio de Análisis Clínicos, Hospital Universitario Virgen de las Nieves, Granada, Spain
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62
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Reits EA, Hodge JW, Herberts CA, Groothuis TA, Chakraborty M, Wansley EK, Camphausen K, Luiten RM, de Ru AH, Neijssen J, Griekspoor A, Mesman E, Verreck FA, Spits H, Schlom J, van Veelen P, Neefjes JJ. Radiation modulates the peptide repertoire, enhances MHC class I expression, and induces successful antitumor immunotherapy. ACTA ACUST UNITED AC 2006; 203:1259-71. [PMID: 16636135 PMCID: PMC3212727 DOI: 10.1084/jem.20052494] [Citation(s) in RCA: 1266] [Impact Index Per Article: 70.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Radiotherapy is one of the most successful cancer therapies. Here the effect of irradiation on antigen presentation by MHC class I molecules was studied. Cell surface expression of MHC class I molecules was increased for many days in a radiation dose-dependent manner as a consequence of three responses. Initially, enhanced degradation of existing proteins occurred which resulted in an increased intracellular peptide pool. Subsequently, enhanced translation due to activation of the mammalian target of rapamycin pathway resulted in increased peptide production, antigen presentation, as well as cytotoxic T lymphocyte recognition of irradiated cells. In addition, novel proteins were made in response to gamma-irradiation, resulting in new peptides presented by MHC class I molecules, which were recognized by cytotoxic T cells. We show that immunotherapy is successful in eradicating a murine colon adenocarcinoma only when preceded by radiotherapy of the tumor tissue. Our findings indicate that directed radiotherapy can improve the efficacy of tumor immunotherapy.
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Affiliation(s)
- Eric A Reits
- Division of Tumor Biology, The Netherlands Cancer Institute, 1066 CX, Amsterdam, The Netherlands
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63
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Herberts CA, Neijssen JJ, de Haan J, Janssen L, Drijfhout JW, Reits EA, Neefjes JJ. Cutting Edge: HLA-B27 Acquires Many N-Terminal Dibasic Peptides: Coupling Cytosolic Peptide Stability to Antigen Presentation. THE JOURNAL OF IMMUNOLOGY 2006; 176:2697-701. [PMID: 16493024 DOI: 10.4049/jimmunol.176.5.2697] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ag presentation by MHC class I is a highly inefficient process because cytosolic peptidases destroy most peptides after proteasomal generation. Various mechanisms shape the MHC class I peptidome. We define a new one: intracellular peptide stability. Peptides with two N-terminal basic amino acids are more stable than other peptides. Such peptides should be overrepresented in the peptidome of MHC class I-associated peptides. HLA-B27 binding peptides use anchor residue R at P2 and, although most amino acids are allowed, particular amino acids are overrepresented at P1, including R and K. We show that such N-terminal dibasic peptides are indeed more efficiently presented by HLA-B27. This suggests that HLA-B27 can present peptides from Ags present in fewer copies than required for successful peptide generation for other MHC class I molecules.
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Affiliation(s)
- Carla A Herberts
- Division of Tumor Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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64
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Groothuis T, Neefjes J. The Ins and Outs of Intracellular Peptides and Antigen Presentation by MHC Class I Molecules. Curr Top Microbiol Immunol 2006; 300:127-48. [PMID: 16573239 DOI: 10.1007/3-540-28007-3_6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
MHC class I molecules present small intracellular generated fragments to the outside surveying immune system. This is the result of a series of biochemical processes involving biosynthesis, degradation, translocation, intracellular transport, diffusion, and many more. Critical intermediates and end products of this cascade of events are peptides. The peptides are generated by the proteasome, degraded by peptidases unless transported into the ER where another peptidase and MHC class I molecules are waiting. Unless peptides bind to MHC class I molecules, they are released from the ER and enter the cytoplasm by a system resembling the ERAD pathway in many aspects. The cycle of peptides over the ER membrane with the proteasome at the input site and peptidases or MHC class I molecules on the output site are central in the MHC class I antigen presentation pathway and this review.
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Affiliation(s)
- T Groothuis
- Division of Tumor Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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65
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Hansen TH, Lybarger L, Yu L, Mitaksov V, Fremont DH. Recognition of open conformers of classical MHC by chaperones and monoclonal antibodies. Immunol Rev 2005; 207:100-11. [PMID: 16181330 DOI: 10.1111/j.0105-2896.2005.00315.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
There is considerable evidence that the conformation and stability of class I and class II major histocompatibility complex (MHC) proteins is dependent upon high-affinity peptide ligation, but structural data for an empty MHC protein unfortunately is lacking. However, several monoclonal antibodies (mAbs) that specifically detect open MHC conformers have been characterized, and they provide insights into the changes associated with peptide loading and unloading. Here, the structural changes make the argument that certain of these open conformer-specific mAbs recognize analogous MHC segments as the molecular chaperones tapasin and DM. MHC residues located in regions flanking the peptide-terminal anchoring pockets have been implicated in both chaperone and monoclonal antibody binding. Indeed, we propose these regions serve as peptide-binding hinges that are uniquely accessible in open MHC.
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Affiliation(s)
- Ted H Hansen
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA.
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66
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Groothuis TAM, Griekspoor AC, Neijssen JJ, Herberts CA, Neefjes JJ. MHC class I alleles and their exploration of the antigen-processing machinery. Immunol Rev 2005; 207:60-76. [PMID: 16181327 DOI: 10.1111/j.0105-2896.2005.00305.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
At the cell surface, major histocompatibility complex (MHC) class I molecules present fragments of intracellular antigens to the immune system. This is the end result of a cascade of events initiated by multiple steps of proteolysis. Only a small part of the fragments escapes degradation by interacting with the peptide transporter associated with antigen presentation and is translocated into the endoplasmic reticulum lumen for binding to MHC class I molecules. Subsequently, these newly formed complexes can be transported to the plasma membrane for presentation. Every step in this process confers specificity and determines the ultimate result: presentation of only few fragments from a given antigen. Here, we introduce the players in the antigen processing and presentation cascade and describe their specificity and allelic variation. We highlight MHC class I alleles, which are not only different in sequence but also use different aspects of the antigen presentation pathway to their advantage: peptide acquaintance.
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Affiliation(s)
- Tom A M Groothuis
- Division of Tumour Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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67
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Tourdot S, Nejmeddine M, Powis SJ, Gould KG. Different MHC class I heavy chains compete with each other for folding independently of beta 2-microglobulin and peptide. THE JOURNAL OF IMMUNOLOGY 2005; 174:925-33. [PMID: 15634915 DOI: 10.4049/jimmunol.174.2.925] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We reported previously that different MHC class I molecules can compete with each other for cell surface expression in F(1) hybrid and MHC class I transgenic mice. In this study, we show that the competition also occurs in transfected cell lines, and investigate the mechanism. Cell surface expression of an endogenous class I molecule in Chinese hamster ovary (CHO) cells was strongly down-regulated when the mouse K(d) class I H chain was introduced by transfection. The competition occurred only after K(d) protein translation, not at the level of RNA, and localization studies of a CHO class I-GFP fusion showed that the presence of K(d) caused retention of the hamster class I molecule in the endoplasmic reticulum. The competition was not for beta(2)-microglobulin, because a single chain version of K(d) that included mouse beta(2)-microglobulin also had a similar effect. The competition was not for association with TAP and loading with peptide, because a mutant form of the K(d) class I H chain, not able to associate with TAP, caused the same down-regulation of hamster class I expression. Moreover, K(d) expression led to a similar level of competition in TAP2-negative CHO cells. Competition for cell surface expression was also found between different mouse class I H chains in transfected mouse cells, and this competition prevented association of the H chain with beta(2)-microglobulin. These unexpected new findings show that different class I H chains compete with each other at an early stage of the intracellular assembly pathway, independently of beta(2)-microglobulin and peptide.
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Affiliation(s)
- Sophie Tourdot
- Department of Immunology, Wright-Fleming Institute, Imperial College London, London, United Kingdom
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68
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van Eijkeren MA, Roovers JP, Oorschot V, Geuze HJ. Overall major histocompatibility complex class I expression is not downregulated in cervix cancer, as detected by immunoelectron microscopy. Int J Gynecol Cancer 2004; 14:317-21. [PMID: 15086732 DOI: 10.1111/j.1048-891x.2004.014216.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Downregulation of major histocompatibility complex (MHC) class I molecules in cervix cancer has been proposed as a mechanism for cancer cells to escape immunodetection. By means of light microscopic immunohistochemistry, it has been shown that in 20-70% of cervix cancers MHC class I is downregulated. We have reinvestigated this phenomenon by quantitative immunogold analysis of MHC class I labeling on the plasma membrane of cervix epithelial cells in ten human squamous cancers and ten normal human cervices. We have not found a statistically significant difference in MHC class I expression between normal and cancer cells. The difference with published light microscopic data probably reflects the higher morphologic resolution and quantifiable immunoreactivity of the immunoelectron microscopy.
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Affiliation(s)
- M A van Eijkeren
- Department of Obstetrics and Gynecology, University Medical Center, PO Box 85500, 3508 GA Utrecht, The Netherlands.
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69
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Yewdell JW, Reits E, Neefjes J. Making sense of mass destruction: quantitating MHC class I antigen presentation. Nat Rev Immunol 2004; 3:952-61. [PMID: 14647477 DOI: 10.1038/nri1250] [Citation(s) in RCA: 310] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Jonathan W Yewdell
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-0440, USA
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70
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Furman MH, Loureiro J, Ploegh HL, Tortorella D. Ubiquitinylation of the cytosolic domain of a type I membrane protein is not required to initiate its dislocation from the endoplasmic reticulum. J Biol Chem 2003; 278:34804-11. [PMID: 12832421 DOI: 10.1074/jbc.m300913200] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human cytomegalovirus US2 and US11 target newly synthesized class I major histocompatibility complex (MHC) heavy chains for rapid degradation by the proteasome through a process termed dislocation. The presence of US2 induces the formation of class I MHC heavy chain conjugates of increased molecular weight that are recognized by a conformation-specific monoclonal antibody, W6/32, suggesting that these class I MHC molecules retain their proper tertiary structure. These conjugates are properly folded glycosylated heavy chains modified by attachment of an estimated one, two, and three ubiquitin molecules. The folded ubiquitinated class I MHC heavy chains are not observed in control cells or in cells transfected with US11, suggesting that US2 targets class I MHC heavy chains for dislocation in a manner distinct from that used by US11. This is further supported by the fact that US2 and US11 show different requirements in terms of the conformation of the heavy chain molecule. Although ubiquitin conjugation may occur on the cytosolic tail of the class I MHC molecule, replacement of lysines in the cytosolic tail of heavy chains with arginine does not prevent their degradation by US2. In an in vitro system that recapitulates US2-mediated dislocation, heavy chains that lack these lysines still occur in an ubiquitin-modified form, but in the soluble (cytoplasmic) fraction. Such ubiquitin conjugation can only occur on the class I MHC lumenal domain and is likely to take place once class I MHC heavy chains have been discharged from the endoplasmic reticulum. We conclude that ubiquitinylation of class I MHC heavy chain is not required during the initial step of the US2-mediated dislocation reaction.
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Affiliation(s)
- Margo H Furman
- Harvard Medical School, Department of Pathology, Boston, Massachusetts 02115, USA
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71
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Paulsson K, Wang P. Chaperones and folding of MHC class I molecules in the endoplasmic reticulum. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1641:1-12. [PMID: 12788224 DOI: 10.1016/s0167-4889(03)00048-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In this review we discuss the influence of chaperones on the general phenomena of folding as well as on the specific folding of an individual protein, MHC class I. MHC class I maturation is a highly sophisticated process in which the folding machinery of the endoplasmic reticulum (ER) is heavily involved. Understanding the MHC class I maturation per se is important since peptides loaded onto MHC class I molecules are the base for antigen presentation generating immune responses against virus, intracellular bacteria as well as tumours. This review discusses the early stages of MHC class I maturation regarding BiP and calnexin association, and differences in MHC class I heavy chain (HC) interaction with calnexin and calreticulin are highlighted. Late stage MHC class I maturation with focus on the dedicated chaperone tapasin is also discussed.
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Affiliation(s)
- Kajsa Paulsson
- The Institution of Tumour Immunology, Lund University, BMC I12, S-223 62, Lund, Sweden.
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72
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Tourdot S, Gould KG. Competition between MHC class I alleles for cell surface expression alters CTL responses to influenza A virus. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:5615-21. [PMID: 12421940 DOI: 10.4049/jimmunol.169.10.5615] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mammalian cells express up to six different MHC class I alleles, many of which differ in terms of their interaction with components of the Ag presentation pathway and level of cell surface expression. However, it is often assumed in Ag presentation studies that class I alleles function independently of each other. We have compared cell surface expression levels and function of MHC class I molecules in F(1) hybrid mice with those in the homozygous parental strains. The level of cell surface expression of certain alleles in F(1) mice differed significantly from 50% of that found on the same cell type in the corresponding parental strain, suggesting allele-specific competition for cell surface expression, and not expression solely according to gene dosage. The strongest effect was observed in H-2(b) x H-2(k) F(1) mice, in which the H-2(b) class I molecules dominated over the H-2(k) class I molecules. The magnitude of H-2(k)-restricted CTL responses to influenza A virus infection was similar in the F(1) hybrid and parental H-2(k) mice. However, in H-2(k) mice expressing a K(b) transgene, cell surface levels of the endogenous class I molecules were down-regulated to a greater degree than in F(1) hybrid mice, and H-2(k)-restricted CTL responses against influenza A virus were greatly reduced, although the CTL repertoire was apparently present. Therefore, certain MHC class I molecules compete with each other for cell surface expression, and the resulting low cell surface expression of specific alleles can lead to a severe reduction in the ability to generate a CTL response.
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MESH Headings
- Alleles
- Animals
- Binding, Competitive/genetics
- Binding, Competitive/immunology
- Cell Membrane/genetics
- Cell Membrane/immunology
- Cell Membrane/metabolism
- Crosses, Genetic
- Cytotoxicity, Immunologic/genetics
- Dose-Response Relationship, Immunologic
- Down-Regulation/genetics
- Down-Regulation/immunology
- Female
- Gene Dosage
- Gene Expression Regulation/immunology
- H-2 Antigens/biosynthesis
- H-2 Antigens/genetics
- Histocompatibility Antigen H-2D
- Histocompatibility Antigens Class I/biosynthesis
- Histocompatibility Antigens Class I/genetics
- Influenza A virus/immunology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mice, Transgenic
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
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Affiliation(s)
- Sophie Tourdot
- Department of Immunology, Faculty of Medicine, Imperial College of Science, Technology and Medicine, Norfolk Place, London W2 1PG, UK
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73
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Grommé M, Neefjes J. Antigen degradation or presentation by MHC class I molecules via classical and non-classical pathways. Mol Immunol 2002; 39:181-202. [PMID: 12200050 DOI: 10.1016/s0161-5890(02)00101-3] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Major histocompatibility complex (MHC) class I molecules usually present endogenous peptides at the cell surface. This is the result of a cascade of events involving various dedicated proteins like the peptide transporter associated with antigen processing (TAP) and the ER chaperone tapasin. However, alternative ways for class I peptide loading exist which may be highly relevant in a process called cross-priming. Both pathways are described here in detail. One major difference between these pathways is that the proteases involved in the generation of peptides are different. How proteases and peptidases influence peptide generation and degradation will be discussed. These processes determine the amount of peptides available for TAP translocation and class I binding and ultimately the immune response.
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Affiliation(s)
- Monique Grommé
- Division of Tumor Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
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74
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Abstract
The association of HLA-B27 with ankylosing spondylitis and other spondyloarthropathies ranks among the strongest between any HLA antigen and a human disease. Yet, in spite of intense research and advanced knowledge of the biochemistry and biology of major histocompatibility complex molecules, the mechanism of this association remains unknown. This review attempts a critical assessment of current pathogenetic hypotheses from evidence concerning the epidemiology of HLA-B27 association with disease, its peptide-binding specificity, and other aspects of the molecular biology and immunology of this molecule.
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Affiliation(s)
- M Ramos
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Facultad de Ciencias, Madrid, Spain
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75
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Abstract
MHC class I antigen presentation refers to the co-ordinated activities of many intracellular pathways that promote the cell surface appearance of MHC class I/beta2m heterodimers loaded with a spectrum of self or foreign peptides. These MHC class I peptide complexes form ligands for CD8 positive T cells and NK cells. MHC class I heterodimers are loaded within the endoplasmic reticulum (ER) with peptides derived from intracellular proteins. Alternatively, MHC class I molecules may be loaded with peptides derived from extracellular proteins in a process called MHC class I cross presentation. This pathway is less well defined but can overlap those pathways operating in classical MHC class I presentation and has recently been reviewed elsewhere (1). This review will address the current concepts regarding the intracellular assembly of MHC class I molecules with their peptide cargo within the ER and their subsequent progress to the cell surface.
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Affiliation(s)
- A Williams
- Cancer Sciences Division, University of Southampton School of Medicine, UK
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76
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Kavanagh DG, Gold MC, Wagner M, Koszinowski UH, Hill AB. The multiple immune-evasion genes of murine cytomegalovirus are not redundant: m4 and m152 inhibit antigen presentation in a complementary and cooperative fashion. J Exp Med 2001; 194:967-78. [PMID: 11581318 PMCID: PMC2193484 DOI: 10.1084/jem.194.7.967] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Both human cytomegaloviruses (HCMVs) and murine cytomegaloviruses (MCMVs) encode multiple genes that interfere with antigen presentation by major histocompatibility complex (MHC) class I, and thus protect infected targets from lysis by virus-specific cytotoxic T lymphocytes (CTLs). HCMV has been shown to encode four such genes and MCMV to encode two. MCMV m152 blocks the export of class I from a pre-Golgi compartment, and MCMV m6 directs class I to the lysosome for degradation. A third MCMV gene, m4, encodes a glycoprotein which is expressed at the cell surface in association with class I. Here we here show that m4 is a CTL-evasion gene which, unlike previously described immune-evasion genes, inhibited CTLs without blocking class I surface expression. m152 was necessary to block antigen presentation to both K(b)- and D(b)-restricted CTL clones, while m4 was necessary to block presentation only to K(b)-restricted clones. m152 caused complete retention of D(b), but only partial retention of K(b), in a pre-Golgi compartment. Thus, while m152 effectively inhibited D(b)-restricted CTLs, m4 was required to completely inhibit K(b)-restricted CTLs. We propose that cytomegaloviruses encode multiple immune-evasion genes in order to cope with the diversity of class I molecules in outbred host populations.
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Affiliation(s)
- Daniel G. Kavanagh
- Department of Molecular Microbiology and Immunology, Oregon Health Sciences University, Portland, Oregon 97201
| | - Marielle C. Gold
- Department of Molecular Microbiology and Immunology, Oregon Health Sciences University, Portland, Oregon 97201
| | - Markus Wagner
- Max von Pettenkofer Institut, D-81377 Munich, Germany
| | | | - Ann B. Hill
- Department of Molecular Microbiology and Immunology, Oregon Health Sciences University, Portland, Oregon 97201
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77
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Chersi A, Garzillo C, Butler RH, Tanigaki N. Allele- and temperature-dependency of in vitro HLA class I assembly. Hum Immunol 2001; 62:858-68. [PMID: 11476909 DOI: 10.1016/s0198-8859(01)00273-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Allelic variations of in vitro HLA class I assembly have been investigated in both the absence and the presence of binding peptides by flow cytometry using human leukocyte antigen (HLA) class I alpha chains isolated by alkali treatment from cultured HLA homozygous B cells and polystyrene beads coated with anti-HLA class I alpha chain antibodies specific to the C-terminal segment (anti-HLA class I beads). The specificity of assembly was temperature dependent, while the stability of the assembled complex depended on the bound peptide. The efficiency of assembly was allele dependent and primarily ruled by the binding affinity of alpha chains with beta(2)m. Thus, an allele hierarchy could be defined for the binding of HLA-B alpha chain with beta(2)-microglobulin: B7, B18 > B35, B62 > B27, B51. Allele and temperature dependency was found in HLA class I reassembly on acid treated B cells. The HLA class I proteins, reassembled with specific single peptides, could be efficiently transferred to anti-HLA class I beads. These findings would be used to produce microspheres coupled at high surface density with oriented single-peptide loaded HLA class I molecules and also to improve the preparation efficiency of HLA class I tetramers by the use of site-specific biotinylation.
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Affiliation(s)
- A Chersi
- Regina Elena Institute for Cancer Research, Rome, Italy
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78
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Fernández MA, Ruiz-Cabello F, Oliva MR, Cabrera T, Jimenez P, López Nevot MA, Garrido F. Beta2-microglobulin gene mutation is not a common mechanism of HLA class I total loss in human tumors. INTERNATIONAL JOURNAL OF CLINICAL & LABORATORY RESEARCH 2001; 30:87-92. [PMID: 11043502 DOI: 10.1007/bf02874164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
One hundred and sixty-two tumor samples were analyzed for HLA class I expression using immunohistological techniques. HLA class I total loss (phenotype no. I) was detected in 31 cases (19%), comprising 20 colorectal, 3 laryngeal, and 2 bladder carcinomas and 6 melanomas. Twenty-one cases were selected for molecular analysis due to a higher proportion of tumor cells versus stroma cells (75%). We investigated whether beta2-microglobulin mutation was responsible for HLA downregulation. Single-strand conformation polymorphism and sequencing analysis of DNA samples was performed. Alterations were detected only in melanomas M78 (a point mutation in the initiation ATG sequence), M79 (a mutation in codon 31 producing a stop codon), and M34 (a TTCT deletion introducing a termination codon signal). We found no beta2-microglobulin gene mutation in the other 18 samples. Loss of heterozygosity in 15q close to the beta2-microglobulin gene was found in 5 cases. We conclude that HLA class I total loss can frequently occur without beta2-microglobulin gene mutations.
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Affiliation(s)
- M A Fernández
- Servicio de Análisis Clínicos, Hospital Universitario Virgen de las Nieves, Universidad de Granada, Spain
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79
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Agrawal S, Kishore MC. MHC class I gene expression and regulation. JOURNAL OF HEMATOTHERAPY & STEM CELL RESEARCH 2000; 9:795-812. [PMID: 11177592 DOI: 10.1089/152581600750062237] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Major histocompatibility complex (MHC) is a conglomerate of genes that play an important role in recognition of self and nonself. These genes are under tight control. In this review we have discussed the transcription processes regulating MHC gene expression. Various biological or chemical modulators can modulate MHC gene expression. The promoter region of class I genes can be activated through several pathways. Hence, these genes are not typical "domestic" genes. Extensive studies on regulation of MHC class I expression, using transfection techniques and transgenic animal models, have resulted in identification of various cis-acting sequences involved in positive and negative regulation of class I genes. Work is in progress to identify the transacting proteins that bind to these sites and to delineate the mechanisms that regulate constitutive and inducible expression of class I genes in normal and diseased cells. It has been seen that various biological molecules (IFN, GM-CSF, IL-2) and other chemicals up-regulate the MHC expression. If the exact mechanisms are known by which the expression of class I genes is up regulated, the efforts can be made to balance the beneficial and toxic effects of biological molecules with one another, which may facilitate the use of combination of these molecules in subpharmacological doses (to eliminate toxicity) for early and better management of neoplastic diseases, as it is well-known that during malignancy MHC gene expression is down-regulated. In the future, the use of transgenic and knockout mice will be useful in acquiring a better understanding, which may further help in cancer therapy.
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Affiliation(s)
- S Agrawal
- Department of Medical Genetics, Samjay Gandhi Post Graduate Institute of Medical Sciences, Raebareli Road, Lucknow-226014, India.
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80
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Kaufman J. The simple chicken major histocompatibility complex: life and death in the face of pathogens and vaccines. Philos Trans R Soc Lond B Biol Sci 2000; 355:1077-84. [PMID: 11186309 PMCID: PMC1692814 DOI: 10.1098/rstb.2000.0645] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In contrast to the major histocompatibility complex (MHC) of well-studied mammals such as humans and mice, the particular haplotype of the B-F/B-L region of the chicken B locus determines life and death in response to certain infectious pathogens as well as to certain vaccines. We found that the B-F/B-L region is much smaller and simpler than the typical mammalian MHC, with an important difference being the expression of a single class I gene at a high level of RNA and protein. The peptide-binding specificity of this dominantly expressed class I molecule in different haplotypes correlates with resistance to tumours caused by Rous sarcoma virus, while the cell-surface expression level correlates with susceptibility to tumours caused by Marek's disease virus. A similar story is developing with class II beta genes and response to killed viral vaccines. This apparently suicidal strategy of single dominantly expressed class I and class II molecules may be due to coevolution between genes within the compact chicken MHC.
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Affiliation(s)
- J Kaufman
- Institute for Animal Health, Compton, Berkshire, UK.
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81
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King A, Burrows TD, Hiby SE, Bowen JM, Joseph S, Verma S, Lim PB, Gardner L, Le Bouteiller P, Ziegler A, Uchanska-Ziegler B, Loke YW. Surface expression of HLA-C antigen by human extravillous trophoblast. Placenta 2000; 21:376-87. [PMID: 10833373 DOI: 10.1053/plac.1999.0496] [Citation(s) in RCA: 198] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this paper definitive evidence that the classical class I product, HLA-C, is expressed on the surface of normal trophoblast cells is provided. HLA-C transcripts were sequenced from cDNA isolated from first trimester trophoblast cells obtained by flow cytometric sorting. Both paternal and maternal alleles were transcribed. HLA-C proteins were demonstrated by biochemical analysis and found on the cell surface in association with beta(2)-microglobulin. Upregulation of cell surface HLA-C but not HLA-G expression after interferon (IFN)-gamma treatment was demonstrated by flow cytometric analysis. Immunohistology has confirmed HLA-C is expressed by all extravillous subpopulations in vivo. The question of whether trophoblast HLA-C molecules interact with decidual NK cells expressing killer Ig-like receptors (KIR) has also been addressed. Our results demonstrate that extravillous trophoblast expresses at least two HLA class I molecules, HLA-G and HLA-C on the cell surface.
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MESH Headings
- Adult
- Antigens, Surface/biosynthesis
- Antigens, Surface/genetics
- Choriocarcinoma/metabolism
- Cytotoxicity Tests, Immunologic
- Electrophoresis, Polyacrylamide Gel
- Female
- Flow Cytometry
- Fluorescent Antibody Technique, Indirect
- HLA Antigens/biosynthesis
- HLA-C Antigens/biosynthesis
- HLA-C Antigens/genetics
- HLA-G Antigens
- Histocompatibility Antigens Class I/biosynthesis
- Humans
- Interferon-gamma/pharmacology
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Pregnancy
- RNA, Messenger/biosynthesis
- Receptors, Immunologic/immunology
- Receptors, Immunologic/metabolism
- Receptors, KIR
- Receptors, KIR2DL1
- Recombinant Proteins/immunology
- Recombinant Proteins/metabolism
- Trophoblasts/drug effects
- Trophoblasts/metabolism
- Tumor Cells, Cultured
- Up-Regulation
- beta 2-Microglobulin/metabolism
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Affiliation(s)
- A King
- Research Group in Human Reproductive Immunobiology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.
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82
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Hansen T, Balendiran G, Solheim J, Ostrov D, Nathenson S. Structural features of MHC class I molecules that might facilitate alternative pathways of presentation. IMMUNOLOGY TODAY 2000; 21:83-8. [PMID: 10652466 DOI: 10.1016/s0167-5699(98)01426-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Comparisons of the structures of different mouse MHC class I molecules define how polymorphic residues determine the unique structural motif and atomic anchoring of their bound peptides. Here, Ted Hansen and colleagues speculate that quantitative differences in how class I molecules interact with peptide, beta2-microglobulin and molecular chaperones that facilitate peptide loading might determine their relative participation in different pathways of antigen presentation.
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Affiliation(s)
- T Hansen
- Washington University School of Medicine, St Louis, MO 63110, USA.
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83
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Wainwright SD, Biro PA, Holmes CH. HLA-F is a predominantly empty, intracellular, TAP-associated MHC class Ib protein with a restricted expression pattern. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:319-28. [PMID: 10605026 DOI: 10.4049/jimmunol.164.1.319] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
HLA-F is currently the most enigmatic of the human MHC-encoded class Ib genes. We have investigated the expression of HLA-F using a specific Ab raised against a synthetic peptide corresponding to amino acids 61-84 in the alpha1 domain of the predicted HLA-F protein. HLA-F is expressed as a beta2-microglobulin-associated, 42-kDa protein that shows a restricted tissue distribution. To date, we have detected this product only in peripheral blood B cells, B cell lines, and tissues containing B cells, in particular adult tonsil and fetal liver, a major site of B cell development. Thermostability assays suggest that HLA-F is expressed as an empty heterodimer devoid of peptide. Consistent with this, studies using endoglycosidase-H and cell surface immunoprecipitations also indicate that the overwhelming majority of HLA-F contains an immature oligosaccharide component and is expressed inside the cell. We have found that IFN-gamma treatment induces expression of HLA-F mRNA and HLA-F protein, but that this does not result in concomitant cell surface expression. HLA-F associates with at least two components of the conventional class I assembly pathway, calreticulin and TAP. The unusual characteristics of the predicted peptide-binding groove together with the predominantly intracellular localization raise the possibility that HLA-F may be capable of binding only a restricted set of peptides.
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Affiliation(s)
- S D Wainwright
- Department of Clinical Medicine, Division of Obstetrics and Gynaecology, University of Bristol, St. Michael's Hospital, United Kingdom
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84
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Mear JP, Schreiber KL, Münz C, Zhu X, Stevanović S, Rammensee HG, Rowland-Jones SL, Colbert RA. Misfolding of HLA-B27 as a Result of Its B Pocket Suggests a Novel Mechanism for Its Role in Susceptibility to Spondyloarthropathies. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.12.6665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
The MHC class I protein HLA-B27 is strongly associated with susceptibility to spondyloarthropathies and can cause arthritis when expressed in rats and mice, implying a direct role in disease pathogenesis. A prominent hypothesis to explain this role suggests that the unique peptide binding specificity of HLA-B27 confers an ability to present arthritogenic peptides. The B pocket, a region of the peptide binding groove that is an important determinant of allele-specific peptide binding, is thought to be critical for arthritogenicity. However, this hypothesis remains unproven. We show that in addition to its role in peptide selection, the B pocket causes a portion of the pool of assembling HLA-B27 heavy chains in the endoplasmic reticulum to misfold, resulting in their degradation in the cytosol. The misfolding phenotype is corrected by replacing the HLA-B27 B pocket with one from HLA-A2. Our results suggest an alternative to the arthritogenic peptide hypothesis. Misfolding and its consequences, rather than allele-specific peptide presentation, may underlie the strong link between the HLA-B27 B pocket and susceptibility to spondyloarthropathies.
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Affiliation(s)
- John P. Mear
- *William S. Rowe Division of Rheumatology, Children’s Hospital Medical Center, Cincinnati, OH 45229
| | - Kathy L. Schreiber
- *William S. Rowe Division of Rheumatology, Children’s Hospital Medical Center, Cincinnati, OH 45229
| | - Christian Münz
- †Department of Immunology, Institute of Cell Biology, Eberhard-Karls-Universität Tubingen, Tubingen, Germany; and
| | - Xiaoming Zhu
- *William S. Rowe Division of Rheumatology, Children’s Hospital Medical Center, Cincinnati, OH 45229
| | - Stefan Stevanović
- †Department of Immunology, Institute of Cell Biology, Eberhard-Karls-Universität Tubingen, Tubingen, Germany; and
| | - Hans-Georg Rammensee
- †Department of Immunology, Institute of Cell Biology, Eberhard-Karls-Universität Tubingen, Tubingen, Germany; and
| | - Sarah L. Rowland-Jones
- ‡Nuffield Department of Clinical Medicine and Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Robert A. Colbert
- *William S. Rowe Division of Rheumatology, Children’s Hospital Medical Center, Cincinnati, OH 45229
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85
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Demaria S, DeVito-Haynes LD, Salter RD, Burlingham WJ, Bushkin Y. Peptide-conformed beta2m-free class I heavy chains are intermediates in generation of soluble HLA by the membrane-bound metalloproteinase. Hum Immunol 1999; 60:1216-26. [PMID: 10626735 DOI: 10.1016/s0198-8859(99)00113-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Molecular mechanisms of soluble HLA-release by a membrane-bound metalloproteinase (MPase) are not defined. We have investigated the possibility that certain beta2-microglobulin (beta2m)-free heavy chains (HC) retain peptide-induced conformations before and after the cleavage by using mutant HLA-A2.242K HC with reduced affinity for beta2m. We show that dissociation of HC/beta2m complexes on the surface of C1R lymphoblastoid cells generates both conformed and non-conformed beta2m-free HC recognized by conformation-dependent antibodies. Conformed HC, having bound the HLA-A2-specific peptide HTLV-1 tax 11-19, can retain their proper conformations after dissociation of beta2m. Further, conformed and non-conformed surface beta2m-free HC are cleaved by the MPase, and some released HC preserve their conformations. Exogenous beta2m binds only to conformed HC, and protects them from cleavage as effectively as the MPase inhibitor BB-2116. We propose that soluble HLA-release requires generation of peptide-conformed beta2m-free HC intermediates on the cell surface, which are then cleaved by the MPase and in solution may reassociate with beta2m. Given the role of soluble HLA in the indirect allorecognition, the activity of this MPase may be important in transplant rejection.
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Affiliation(s)
- S Demaria
- Laboratory of Molecular Immunology, Public Health Research Institute, New York, NY 10016, USA
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86
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Lauvau G, Gubler B, Cohen H, Daniel S, Caillat-Zucman S, van Endert PM. Tapasin enhances assembly of transporters associated with antigen processing-dependent and -independent peptides with HLA-A2 and HLA-B27 expressed in insect cells. J Biol Chem 1999; 274:31349-58. [PMID: 10531335 DOI: 10.1074/jbc.274.44.31349] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Assembly of HLA class I-peptide complexes is assisted by multiple proteins that associate with HLA molecules in loading complexes. These include the housekeeping chaperones calnexin and calreticulin and two essential proteins, the transporters associated with antigen processing (TAP) for peptide supply, and the protein tapasin which is thought to act as a specialized chaperone. We dissected functional effects of processing cofactors by co-expressing in insect cells various combinations of the human proteins HLA-A2, HLA-B27, beta(2)-microglobulin, TAP, calnexin, calreticulin, and tapasin. Stability at 37 degrees C and surface expression of class I dimers correlated closely in baculovirus-infected Sf9 cells, suggesting that these cells retain empty dimers in the endoplasmic reticulum. Both HLA molecules form substantial quantities of stable complexes with insect cell-produced peptide pools. These pools are TAP-selected cytosolic peptides for HLA-B27 but endoplasmic reticulum-derived, i.e. TAP-independent peptides for HLA-A2. This discrepancy may be due to peptide selection by human TAP which is much better adapted to the HLA-B27 than to the HLA-A2 ligand preferences. HLA class I assembly with peptides from TAP-dependent and -independent pools was enhanced strongly by tapasin. Thus, tapasin acts as a chaperone and/or peptide editor that facilitates assembly of peptides with HLA class I molecules independently of mediating their interaction with TAP and/or retention in the endoplasmic reticulum.
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Affiliation(s)
- G Lauvau
- INSERM Unité 25, Hôpital Necker, 161 rue de Sèvres, 75743 Paris, France
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87
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Grommé M, Uytdehaag FG, Janssen H, Calafat J, van Binnendijk RS, Kenter MJ, Tulp A, Verwoerd D, Neefjes J. Recycling MHC class I molecules and endosomal peptide loading. Proc Natl Acad Sci U S A 1999; 96:10326-31. [PMID: 10468607 PMCID: PMC17887 DOI: 10.1073/pnas.96.18.10326] [Citation(s) in RCA: 219] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
MHC class I molecules usually present peptides derived from endogenous antigens that are bound in the endoplasmic reticulum. Loading of exogenous antigens on class I molecules, e.g., in cross-priming, sometimes occurs, but the intracellular location where interaction between the antigenic fragment and class I takes place is unclear. Here we show that measles virus F protein can be presented by class I in transporters associated with antigen processing-independent, NH(4)Cl-sensitive manner, suggesting that class I molecules are able to interact and bind antigen in acidic compartments, like class II molecules. Studies on intracellular transport of green fluorescent protein-tagged class I molecules in living cells confirmed that a small fraction of class I molecules indeed enters classical MHC class II compartments (MIICs) and is transported in MIICs back to the plasma membrane. Fractionation studies show that class I complexes in MIICs contain peptides. The pH in MIIC (around 5.0) is such that efficient peptide exchange can occur. We thus present evidence for a pathway for class I loading that is shared with class II molecules.
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Affiliation(s)
- M Grommé
- Department of Tumor Biology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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88
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Andersen MH, Søndergaard I, Zeuthen J, Elliott T, Haurum JS. An assay for peptide binding to HLA-Cw*0102. TISSUE ANTIGENS 1999; 54:185-90. [PMID: 10488746 DOI: 10.1034/j.1399-0039.1999.540210.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The assembly assay for peptide binding to class I major histocompatibility complex (MHC) molecules is based on the ability of peptides to stabilize MHC class I molecules synthesized by transporter associated with antigen processing (TAP)-deficient cell. The TAP-deficient cell line T2 has previously been used in the assembly assay to analyze peptide binding to HLA-A*0201 and -B*5101. In this study, we have extended this technique to assay for peptides binding to endogenous HLA-Cw*0102 molecules. We have analyzed the peptide binding of 20 peptides with primary anchor motifs for HLA-Cw*0102. One-third of the peptides analyzed bound with high affinity, half of the peptides examined did not bind, whereas the remaining peptides displayed intermediate binding activity. Interest in HLA-C molecules has increased significantly in recent years, since it has been shown that HLA-C molecules both can present peptides to cytotoxic T lymphocytes (CTL) and in addition are able to inhibit natural killer (NK)-mediated lysis.
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Affiliation(s)
- M H Andersen
- Department of Tumor Cell Biology, Danish Cancer Society, Copenhagen.
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89
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Martayan A, Fraioli R, Giorda E, Setini A, Ciccarelli G, Delfino L, Ferrara GB, Giacomini P. Biosynthesis of HLA-C heavy chains in melanoma cells with multiple defects in the expression of HLA-A, -B, -C molecules. Br J Cancer 1999; 80:639-49. [PMID: 10360639 PMCID: PMC2362293 DOI: 10.1038/sj.bjc.6690405] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Recent investigations have shown that malignant transformation may down-regulate the expression of class I HLA molecules, beta2-microglobulin (beta2m) and members of the antigen-processing machinery. In the present study, we HLA-genotyped and identified at a biochemical level the three (HLA-A25, -B8, -Cw7) class I alleles expressed by the previously described [D'Urso CM et al (1992) J Clin Invest 87: 284-292] beta2m-defective human melanoma FO-1 cell line and tested their ability to interact with calnexin, calreticulin and the TAP (transporter associated with antigen processing) complex. All these alleles were found to bind calnexin, but not calreticulin or the poorly expressed TAP complex, both in parental and beta2m-transfected FO-1 cells, demonstrating a complex defect of class I expression in FO-1 cells. In these conditions, Cw7 heavy chains interacted with calnexin more strongly than A25 and B8, and preferentially accumulated in the endoplasmic reticulum, in both a calnexin-associated and a calnexin-free form. In addition, they could be transported to the cell surface at low levels even in the absence of beta2m, without undergoing terminal glycosylation. These results establish a parallel between HLA-C and the murine Db and Ld molecules which have been found to be surface expressed and functional in beta2m-defective cells. They also demonstrate distinctive features of HLA-C molecules. We propose that the accumulation of several assembly intermediates of HLA-C might favour the binding of peptide antigens not readily bound by HLA-A and -B molecules in neoplastic cells with suboptimal class I expression.
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Affiliation(s)
- A Martayan
- Laboratory of Immunology, Regina Elena Institute CRS, Rome, Italy
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90
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Abstract
Despite a strong cytotoxic T-lymphocyte (CTL) response directed against viral antigens, untreated individuals infected with the human immunodeficiency virus (HIV-1) develop AIDS. We have found that primary T cells infected with HIV-1 downregulate surface MHC class I antigens and are resistant to lysis by HLA-A2-restricted CTL clones. In contrast, cells infected with an HIV-1 in which the nef gene is disrupted are sensitive to CTLs in an MHC and peptide-specific manner. In primary T cells HLA-A2 antigens are downmodulated more dramatically than total MHC class I antigens, suggesting that nef selectively downmodulates certain MHC class I antigens. In support of this, studies on cells expressing individual MHC class I alleles have revealed that nef does not downmodulate HLA-C and HLA-E antigens. This selective downmodulation allows infected cells to maintain resistance to certain natural killer cells that lyse infected cells expressing low levels of MHC class I antigens. Downmodulation of MHC class I HLA-A2 antigens occurs not only in primary T cells, but also in B and astrocytoma cell lines. No effect of other HIV-1 accessory proteins such as vpu and vpr was observed. Thus Nef is a protein that may promote escape of HIV-1 from immune surveillance.
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Affiliation(s)
- K L Collins
- Department of Medicine, University of Michigan, Ann Arbor, USA
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91
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Borowski A, van Valen F, Ulbrecht M, Weiss EH, Blasczyk R, Jürgens H, Göbel U, Schneider EM. Monomorphic HLA class I-(non-A, non-B) expression on Ewing's tumor cell lines, modulation by TNF-alpha and IFN-gamma. Immunobiology 1999; 200:1-20. [PMID: 10084692 DOI: 10.1016/s0171-2985(99)80029-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
In this study, the expression of polymorphic and non-polymorphic MHC antigens in Ewing's tumor (ET) cells was examined by surface staining, Western blots and transcriptional analysis. Cell lines derived from Ewing's tumors largely lack polymorphic HLA class Ia antigens of both the HLA-A and the HLA-B loci but binding of monomorphic HLA antibodies indicates significant expression of HLA-C locus antigens and/or HLA class Ib molecules. HLA Ib molecules encoded by the HLA-E, -F or -G loci with a molecular mass of less than 44 kDa were not detected in lysates of either constitutive or TNF-alpha plus IFN-gamma treated ET cells. Two representative ET cell lines with either detectable HLA-A, -B antigens (A673) or absolutely non-detectable HLA-A, -B antigens (SK-ES-1) were further subjected to transcriptional analysis. A673 mRNA hybridized with HLA-A, -B, -C and HLA-E-specific probes in Northern blots. By contrast, mRNA specific for HLA-A, -B, -C was negative in SK-ES-1 but TNF-alpha plus IFN-gamma reconstituted HLA-A, -B, -C transcription in this cell line. HLA-E was transcribed in A673 but not in SK-ES-1. Combining mRNA and surface expression of HLA class Ia molecules results in a highly variable pattern of defective HLA class I expression in this type of neuroectodermal tumor. The involvement of the ET-specific fusion transcript EWS/Fli-1 in modulating the HLA-A and -B locus antigens is likely to occur by the upregulation of c-myc in these tumors. The exceptionally constant expression of HLA-C or some other non-A, non-B antigens (reactive with defined monoclonal antibodies) implies important consequences on tumor-cell resistance against specific CTL and NK activity in vivo.
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Affiliation(s)
- A Borowski
- Immunological Laboratory, Institute of Hemostaseology and Transfusion-Medicine, Düsseldorf University, Germany
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92
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Kość A, Dubis J, Wojciechowska I, Maćkiewicz Z, Gorczyca W, Myc A, Kupryszewski G, Mańczak M, Myc P, Kuśnierczyk P. Studies on binding of HIV-1 p24gag peptide to HLA-Cw3+ cells. Immunol Lett 1998; 64:57-62. [PMID: 9870655 DOI: 10.1016/s0165-2478(98)00079-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Human major histocompatibility complex class I antigens, HLA-C, are expressed on the cell surface at approximately a tenfold lower level than HLA-A and -B. We hypothesized that the expression of HLA-C is limited by the quantity of high affinity peptides which bind to these molecules, thus allowing only a small fraction of HLA-C molecules to be transported and/or to remain stable on the cell surface. If this assumption is correct, then the addition of exogenous peptide should increase cell surface HLA-C expression. To verify the hypothesis, we pulsed lymphoblastoid cell line PAJ (HLA-Cw3+) with synthetic HIV-1 p24gag 145-152 peptide, known to be presented to T-lymphocytes by HLA-Cw3 molecule. PAJ (HLA-Cw3+) cells bound approximately two times more of the peptide than HAJ (HLA-Cw3-), and four times more than 500/C9 (HLA-Cw3-) cells. Accordingly, overnight pulsing of PAJ cells with the p24gag 145-152 peptide caused an increase in class I HLA expression detected on the cell surface by flow cytofluorimetric analysis with anti-HLA-B,C monoclonal antibodies but not by anti-HLA-A antibody. In contrast, HLA-Cw3- cells treated in the same manner did not show any increase of HLA class I expression. Our data suggest that low concentration of high affinity peptides within the cell may be one of the factors limiting cell surface expression of HLA-C molecules.
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Affiliation(s)
- A Kość
- Laboratory of Immunogenetics, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw
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93
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Pepperl S, Benninger-Döring G, Modrow S, Wolf H, Jilg W. Immediate-early transactivator Rta of Epstein-Barr virus (EBV) shows multiple epitopes recognized by EBV-specific cytotoxic T lymphocytes. J Virol 1998; 72:8644-9. [PMID: 9765404 PMCID: PMC110276 DOI: 10.1128/jvi.72.11.8644-8649.1998] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We analyzed the immediate-early transactivator Rta of Epstein-Barr virus (EBV) for its role as a target for specific cytotoxic T lymphocytes (CTL). Panels of overlapping peptides covering the entire amino acid sequence of Rta were synthesized and used to induce and analyze specific CTL responses in EBV-positive donors. Using peptide-pulsed target cells, we found nine different CTL epitopes that are distributed over the entire protein sequence. One epitope restricted by HLA-A24 could be mapped to the decameric sequence DYCNVLNKEF between amino acid positions 28 and 37 of the Rta protein. A second epitope could be assigned to the same region of Rta (residues 25 to 39) and was shown to be restricted by HLA-B18. Another, minimal epitope could be mapped to the nonameric sequence ATIGTAMYK between amino acid positions 134 and 142; this peptide was restricted by HLA-A11. Another four epitopes were proven to be restricted by HLA-A2, -A3, -B61, and -Cw4 and were located between Rta residues 225 and 239, 145 and 159, 529 and 543, and 393 and 407, respectively. For two other epitopes, only the location within the Rta protein is known so far (residues 121 to 135 and 441 to 455); their exact HLA restriction patterns have not yet been identified. Using target cells infected with recombinant vaccinia virus containing the gene for Rta, we showed that six of eight Rta-specific CTL lines recognized the corresponding peptides also after endogenous processing. These data suggest that Rta comprises an important target for EBV-specific cellular cytotoxicity. Together with recent findings of other immediate-early and early proteins also acting as CTL targets, they reveal the role of proteins of the lytic cycle in the immune recognition of EBV-infected cells.
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Affiliation(s)
- S Pepperl
- Institut für Medizinische Mikrobiologie und Hygiene, Universität Regensburg, D-93053 Regensburg, Germany
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94
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Cabrera T, Collado A, Fernandez MA, Ferron A, Sancho J, Ruiz-Cabello F, Garrido F. High frequency of altered HLA class I phenotypes in invasive colorectal carcinomas. TISSUE ANTIGENS 1998; 52:114-23. [PMID: 9756399 DOI: 10.1111/j.1399-0039.1998.tb02274.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We analyzed the expression of HLA class I antigens in 78 tumor tissue samples obtained from patients diagnosed as having colorectal carcinomas. A broad panel of mAbs defining HLA monomorphic, locus-specific and allele-specific determinants was used. In addition, an antibody defining HLA-C locus-specific determinant (L31) was also tested. Previous reports on these tumors indicated HLA class I losses of 30 to 40%. At least 73% of the patients in the present study had a detectable HLA class I alteration. These altered HLA phenotypes were classified as total HLA loss (18%) (phenotype I); HLA-A locus-specific loss (9%) (phenotype IIIa); HLA-B locus-specific loss (8%) (phenotype IIIb); HLA-A and B locus losses (2%) and HLA allelic losses (36%) (phenotype IV). We found no HLA-C locus losses. Autologous peripheral blood lymphocyte HLA class I typing was always necessary to define phenotype IV. We also studied the CD3 zeta chain in tumor tissues to correlate possible changes in the CD3 signal transduction pathway with HLA alterations. The CD3 ratio was frequently altered, but this alteration could not be correlated with tumor HLA phenotypes. The high frequency of HLA class I losses in colorectal carcinomas suggests that this finding is a widespread phenomenon and may be required to escape T-cell recognition. It remains to be determined whether HLA expression is "normal" in the rest of the 27% of our patients.
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Affiliation(s)
- T Cabrera
- Departamento de Análisis Clínicos, Hospital Universitario Virgen de las Nieves, Granada, Spain
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95
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Zarling AL, Lee DR. Conversion of a human immunodeficiency virus cytotoxic T lymphocyte epitope into a high affinity HLA-Cw3 ligand. Hum Immunol 1998; 59:472-82. [PMID: 9712350 DOI: 10.1016/s0198-8859(98)00053-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
To elucidate the residues important for the binding of peptides to HLA-Cw3, a substitutional analysis of two HLA-Cw*0304-binding peptides was performed. The optimal registry and length for a Cw3-restricted epitope from HIV-1 p24gag was determined to be a nonamer, p24gag 144-152. Substituted analogs of this nonamer peptide revealed that substitutions at position 3 (P3) and the carboxyl-terminal P9 were inhibitory to binding, while certain substitutions at the amino-terminal P1 or P2 increased binding significantly. Substituted analogs of another Cw3-restricted peptide, the Cw3 consensus peptide, which binds to HLA-Cw*0304 with a 1,000-fold higher affinity and with a greater stability than the HIV p24gag nonamer revealed that the P1, P2, P6, and P9 residues play important roles in the ligand's binding to Cw*0304. The incorporation of the amino-terminal P1 and P2 residues from the Cw3 consensus peptide into the HIV p24gag 144-152 peptide created a hybrid peptide with profoundly enhanced affinity for and stability with Cw*0304. Collectively, these findings provide a clear insight into how peptides interact with HLA-Cw3 and how high affinity Cw3 ligands can be constructed.
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Affiliation(s)
- A L Zarling
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia 65212, USA
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96
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Tortorella D, Story CM, Huppa JB, Wiertz EJ, Jones TR, Bacik I, Bennink JR, Yewdell JW, Ploegh HL. Dislocation of type I membrane proteins from the ER to the cytosol is sensitive to changes in redox potential. J Cell Biol 1998; 142:365-76. [PMID: 9679137 PMCID: PMC2133060 DOI: 10.1083/jcb.142.2.365] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/1997] [Revised: 05/28/1998] [Indexed: 02/08/2023] Open
Abstract
The human cytomegalovirus (HCMV) gene products US2 and US11 dislocate major histocompatibility class I heavy chains from the ER and target them for proteasomal degradation in the cytosol. The dislocation reaction is inhibited by agents that affect intracellular redox potential and/or free thiol status, such as diamide and N-ethylmaleimide. Subcellular fractionation experiments indicate that this inhibition occurs at the stage of discharge from the ER into the cytosol. The T cell receptor alpha (TCR alpha) chain is also degraded by a similar set of reactions, yet in a manner independent of virally encoded gene products. Diamide and N-ethylmaleimide likewise inhibit the dislocation of the full-length TCR alpha chain from the ER, as well as a truncated, mutant version of TCR alpha chain that lacks cysteine residues. Cytosolic destruction of glycosylated, ER-resident type I membrane proteins, therefore, requires maintenance of a proper redox potential for the initial step of removal of the substrate from the ER environment.
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Affiliation(s)
- D Tortorella
- Harvard Medical School, Department of Pathology, Boston, Massachusetts 02115, USA
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97
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Daniel S, Brusic V, Caillat-Zucman S, Petrovsky N, Harrison L, Riganelli D, Sinigaglia F, Gallazzi F, Hammer J, van Endert PM. Relationship Between Peptide Selectivities of Human Transporters Associated with Antigen Processing and HLA Class I Molecules. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.2.617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Efficiency of presentation of a peptide epitope by a MHC class I molecule depends on two parameters: its binding to the MHC molecule and its generation by intracellular Ag processing. In contrast to the former parameter, the mechanisms underlying peptide selection in Ag processing are poorly understood. Peptide translocation by the TAP transporter is required for presentation of most epitopes and may modulate peptide supply to MHC class I molecules. To study the role of human TAP for peptide presentation by individual HLA class I molecules, we generated artificial neural networks capable of predicting the affinity of TAP for random sequence 9-mer peptides. Using neural network-based predictions of TAP affinity, we found that peptides eluted from three different HLA class I molecules had higher TAP affinities than control peptides with equal binding affinities for the same HLA class I molecules, suggesting that human TAP may contribute to epitope selection. In simulated TAP binding experiments with 408 HLA class I binding peptides, HLA class I molecules differed significantly with respect to TAP affinities of their ligands. As a result, some class I molecules, especially HLA-B27, may be particularly efficient in presentation of cytosolic peptides with low concentrations, while most class I molecules may predominantly present abundant cytosolic peptides.
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Affiliation(s)
- Soizic Daniel
- *Institut National de la Santé et de la Recherche Médicale, Unité 25, Paris, France
| | - Vladimir Brusic
- †The Walter and Eliza Hall Institute, Royal Melbourne Hospital, Victoria, Australia
| | - Sophie Caillat-Zucman
- *Institut National de la Santé et de la Recherche Médicale, Unité 25, Paris, France
| | - Nicolai Petrovsky
- †The Walter and Eliza Hall Institute, Royal Melbourne Hospital, Victoria, Australia
| | - Leonard Harrison
- †The Walter and Eliza Hall Institute, Royal Melbourne Hospital, Victoria, Australia
| | - Daniela Riganelli
- ‡Istituto di Medicina Interna, Università di Perugia, Perugia, Italy; and
| | | | | | | | - Peter M. van Endert
- *Institut National de la Santé et de la Recherche Médicale, Unité 25, Paris, France
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98
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Bouvier M, Wiley DC. Structural characterization of a soluble and partially folded class I major histocompatibility heavy chain/beta 2m heterodimer. NATURE STRUCTURAL BIOLOGY 1998; 5:377-84. [PMID: 9587000 DOI: 10.1038/nsb0598-377] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Class I major histocompatibility (MHC) heavy chain (HC) must fold and assemble with beta 2 microglobulin (beta 2m) prior to binding peptides in the endoplasmic reticulum (ER). Each of these events is mediated by association with chaperones and other proteins and is an essential requirement for the maturation and normal cell surface expression of stable class I MHC-peptide complexes. Here we describe the biochemical and structural characterization of a soluble HC (B*0702)/beta 2m heterodimer, apparently free of peptide. Results suggest that the peptide binding domains (alpha 1 and alpha 2) of this folding intermediate are unstable and possess many of the properties ascribed to the molten globule state. The partially folded state of the HC/beta 2m heterodimer is consistent with the suggestion that it is stabilized by chaperones and other proteins in the ER. This soluble intermediate may be useful for studying protein-assisted folding and peptide binding of class I MHC molecules.
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Affiliation(s)
- M Bouvier
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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99
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Wainwright SD, Simpson KL, Holmes CH. Calreticulin associates with non-HLA-A,-B class I proteins in the human choriocarcinoma cell lines JEG-3 and BeWo. Immunol Suppl 1998; 93:437-45. [PMID: 9640257 PMCID: PMC1364095 DOI: 10.1046/j.1365-2567.1998.00439.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Human placental trophoblast expresses as unusual repertoire of major histocompatibility complex (MHC) class I products that appears to reflect the unique role of this epithelium in mediating feto-maternal relations during pregnancy. Trophoblast is devoid of human leucocyte antigen (HLA)-A,-B antigens but can express one or more non-HLA-A,-B class I proteins. The human choriocarcinoma cell lines JEG-3, BeWo and JAR are widely used as models to study trophoblast. During attempts to isolate non-HLA-A,-B class I from JEG-3 and BeWo by immunoaffinity chromatography using a monoclonal antibody to beta 2-microglobulin we observed a 55,000 MW protein co-purifying with class I. N-terminal amino acid sequencing and immunoblotting using a specific antiserum identified this product as calreticulin, a molecule recently shown to be involved in the assembly of classical class I in human B-lymphoblastoid cells. In our hands JEG-3 and BeWo were found to express 45,000 MW non-HLA-A,-B class I proteins while the 40,000 MW HLA-G product was identified only in JEG-3. Our data suggest that calreticulin associates with non-HLA-A,-B class I heterodimers and with free 45,000 MW non-HLA-A,-B class I H chains in JEG-3. JAR was found to be devoid of detectable class I H chains but contained beta 2-microglobulin and calreticulin. However, calreticulin-beta 2-microglobulin complexes were not detected in JAR. Calreticulin and class I were apparently co-localized within the endoplasmic reticulum of JEG-3 cells whereas only class I was expressed at the cell surface. These studies demonstrate that calreticulin is associated with non-HLA-A,-B class I products in human choriocarcinoma cells.
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Affiliation(s)
- S D Wainwright
- University of Bristol, Department of Clinical Medicine, St. Michael's Hospital, UK
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100
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Braud VM, Allan DS, Wilson D, McMichael AJ. TAP- and tapasin-dependent HLA-E surface expression correlates with the binding of an MHC class I leader peptide. Curr Biol 1998; 8:1-10. [PMID: 9427624 DOI: 10.1016/s0960-9822(98)70014-4] [Citation(s) in RCA: 216] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The human major histocompatibility complex (MHC) class lb molecule HLA-E is transcribed in most tissues but little is known about its localisation within the cell. We have recently shown that HLA-E binds signal-sequence-derived peptides from human MHC class I molecules in vitro. RESULTS Using a newly characterised antibody recognising HLA-E, we show that HLA-E is expressed at the cell surface. We demonstrate that HLA-E surface expression is correlated with the presence of MHC class I molecules which provide suitable leader sequence peptides capable of binding to HLA-E. Further studies on the interaction of HLA-E with molecules in the endoplasmic reticulum revealed that HLA-E associates with the transporter associated with antigen processing (TAP) and calreticulin, and that HLA-E expression is TAP-dependent and tapasin-dependent. In addition, HLA-E dissociates from TAP upon binding of MHC class I leader sequence peptides. CONCLUSION These experiments establish that surface expression of HLA-E is regulated by the binding of a restricted pool of peptides from the leader sequence of MHC class I molecules. The correlation between HLA-E and MHC class I surface expression might be relevant to the function of HLA-E. Our results also show that, although these HLA-E binding peptides are derived from signal sequences, they may be released back into the cytosol and subsequently translocated by the TAP complex and loaded onto HLA-E molecules.
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Affiliation(s)
- V M Braud
- Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, OX3 9DS, UK.
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