101
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Mishra S, Sinha S. Immunoinformatics and modeling perspective of T cell epitope-based cancer immunotherapy: a holistic picture. J Biomol Struct Dyn 2010; 27:293-306. [PMID: 19795913 DOI: 10.1080/07391102.2009.10507317] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cancer immunotherapy is fast gaining global attention with its unique position as a potential therapy showing promise in cancer prevention and cure. It utilizes the natural system of immunity as opposed to chemotherapy and radiotherapy that utilize chemical drugs and radiation, respectively. Cancer immunotherapy essentially involves treatment and/or prevention with vaccines in the form of peptide vaccines (T and B cell epitopes), DNA vaccines and vaccination using whole tumor cells, dendritic cells, viral vectors, antibodies and adoptive transfer of T cells to harness the body's own immune system towards the targeting of cancer cells for destruction. Given the time, cost and labor involved in the vaccine discovery and development, researchers have evinced interest in the novel field of immunoinformatics to cut down the escalation of these critical resources. Immunoinformatics is a relatively new buzzword in the scientific circuit that is showing its potential and delivering on its promise in expediting the development of effective cancer immunotherapeutic agents. This review attempts to present a holistic picture of our race against cancer and time using the science and technology of immunoinformatics and molecular modeling in T cell epitope-based cancer immunotherapy. It also attempts to showcase some problem areas as well as novel ones waiting to be explored where development of novel immunoinformatics tools and simulations in the context of cancer immunotherapy would be highly welcome.
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Affiliation(s)
- Seema Mishra
- National Institute of Biologicals, Ministry of Health and Family Welfare, A-32 Sector 62, Noida, U. P., India.
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102
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Infantes S, Lorente E, Barnea E, Beer I, Cragnolini JJ, García R, Lasala F, Jiménez M, Admon A, López D. Multiple, non-conserved, internal viral ligands naturally presented by HLA-B27 in human respiratory syncytial virus-infected cells. Mol Cell Proteomics 2010; 9:1533-9. [PMID: 20081153 DOI: 10.1074/mcp.m900508-mcp200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cytotoxic T lymphocyte (CTL)-mediated death of virus-infected cells requires prior recognition of short viral peptide antigens that are presented by human leukocyte antigen (HLA) class I molecules on the surface of infected cells. The CTL response is critical for the clearance of human respiratory syncytial virus (HRSV) infection. Using mass spectrometry analysis of complex HLA-bound peptide pools isolated from large amounts of HRSV-infected cells, we identified nine naturally processed HLA-B27 ligands. The isolated peptides are derived from six internal, not envelope, proteins of the infective virus. The sequences of most of these ligands are not conserved between different HRSV strains, suggesting a mechanism to explain recurrent infection with virus of different HRSV antigenic subgroups. In addition, these nine ligands represent a significant fraction of the proteome of this virus, which is monitored by the same HLA class I allele. These data have implications for vaccine development as well as for analysis of the CTL response.
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Affiliation(s)
- Susana Infantes
- Unidad de Protemica, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain
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103
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Perreault C. The Origin and Role of MHC Class I-Associated Self-Peptides. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 92:41-60. [DOI: 10.1016/s1877-1173(10)92003-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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104
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Abstract
For the nervous system to translate experience into memory and behavior, lasting structural change at synapses must occur. This requirement is clearly evident during critical periods of activity-dependent neural development, and accumulating evidence has established a surprising role for the major histocompatibility complex class I (MHCI) proteins in this process.
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Affiliation(s)
- Carla J Shatz
- Bio-X and Departments of Biology and Neurobiology, James H. Clark Center, 318 Campus Drive W1.1, Stanford University, Stanford CA 94305-5437, USA.
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105
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Kawahara M, York IA, Hearn A, Farfan D, Rock KL. Analysis of the role of tripeptidyl peptidase II in MHC class I antigen presentation in vivo. THE JOURNAL OF IMMUNOLOGY 2009; 183:6069-77. [PMID: 19841172 DOI: 10.4049/jimmunol.0803564] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Previous experiments using enzyme inhibitors and RNA interference in cell lysates and cultured cells have suggested that tripeptidyl peptidase II (TPPII) plays a role in creating and destroying MHC class I-presented peptides. However, its precise contribution to these processes has been controversial. To elucidate the importance of TPPII in MHC class I Ag presentation, we analyzed TPPII-deficient gene-trapped mice and cell lines from these animals. In these mice, the expression level of TPPII was reduced by >90% compared with wild-type mice. Thymocytes from TPPII gene-trapped mice displayed more MHC class I on the cell surface, suggesting that TPPII normally limits Ag presentation by destroying peptides overall. TPPII gene-trapped mice responded as well as did wild-type mice to four epitopes from lymphocytic choriomeningitis virus. The processing and presentation of peptide precursors with long N-terminal extensions in TPPII gene-trapped embryonic fibroblasts was modestly reduced, but in vivo immunization with recombinant lentiviral or vaccinia virus vectors revealed that such peptide precursors induced an equivalent CD8 T cell response in wild-type and TPPII-deficient mice. These data indicate that while TPPII contributes to the trimming of peptides with very long N-terminal extensions, TPPII is not essential for generating most MHC class I-presented peptides or for stimulating CTL responses to several Ags in vivo.
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Affiliation(s)
- Masahiro Kawahara
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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106
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Schnurr M, Orban M, Robson NC, Shin A, Braley H, Airey D, Cebon J, Maraskovsky E, Endres S. ISCOMATRIX adjuvant induces efficient cross-presentation of tumor antigen by dendritic cells via rapid cytosolic antigen delivery and processing via tripeptidyl peptidase II. THE JOURNAL OF IMMUNOLOGY 2009; 182:1253-9. [PMID: 19155470 DOI: 10.4049/jimmunol.182.3.1253] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cancer vaccines aim to induce antitumor CTL responses, which require cross-presentation of tumor Ag to CTLs by dendritic cells (DCs). Adjuvants that facilitate cross-presentation of vaccine Ag are therefore key for inducing antitumor immunity. We previously reported that human DCs could not efficiently cross-present the full-length cancer/testis Ag NY-ESO-1 to CTL unless formulated as either an immune complex (NY-ESO-1/IC) or with ISCOMATRIX adjuvant. We now demonstrate that NY-ESO-1/ICs induce cross-presentation of HLA-A2- and HLA-Cw3-restricted epitopes via a proteasome-dependent pathway. In contrast, cross-presentation of NY-ESO-1/ISCOMATRIX vaccine was proteasome independent and required the cytosolic protease tripeptidyl peptidase II. Trafficking studies revealed that uptake of ICs and ISCOMATRIX vaccine by DCs occurred via endocytosis with delivery to lysosomes. Interestingly, ICs were retained in lysosomes, whereas ISCOMATRIX adjuvant induced rapid Ag translocation into the cytosol. Ag translocation was dependent on endosomal acidification and IL-4-driven differentiation of monocytes into DCs. This study demonstrates that Ag formulation determines Ag processing and supports a role for tripeptidyl peptidase II in cross-presentation of CTL epitopes restricted to diverse HLA alleles.
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Affiliation(s)
- Max Schnurr
- Department of Internal Medicine, Universityof Munich, Munich, Germany.
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107
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Immunity and the regulation of protein synthesis: surprising connections. Curr Opin Immunol 2009; 21:70-7. [PMID: 19328667 DOI: 10.1016/j.coi.2009.03.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 03/03/2009] [Accepted: 03/09/2009] [Indexed: 11/27/2022]
Abstract
The plasticity that is needed by the cell to respond to rapid changes in its environment cannot only be provided by means of transcriptional regulation, which generally confers on cells a set of stable properties. Alternatively, the control of mRNA translation allows the cell to modulate rapidly and over short period of time its gene expression program, without invoking the slower nuclear pathways for mRNA synthesis and transport. Several recent findings indicate that regulation of translation affects directly antigen presentation, cytokine production, as well as the survival of dendritic cells. I describe here some of the regulatory mechanisms that control translation in response to microbial products or cytokine exposure and their contribution to the overall immune response.
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108
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Ebert LM, Liu YC, Clements CS, Robson NC, Jackson HM, Markby JL, Dimopoulos N, Tan BS, Luescher IF, Davis ID, Rossjohn J, Cebon J, Purcell AW, Chen W. A long, naturally presented immunodominant epitope from NY-ESO-1 tumor antigen: implications for cancer vaccine design. Cancer Res 2009; 69:1046-54. [PMID: 19176376 DOI: 10.1158/0008-5472.can-08-2926] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The tumor antigen NY-ESO-1 is a promising cancer vaccine target. We describe here a novel HLA-B7-restricted NY-ESO-1 epitope, encompassing amino acids 60-72 (APRGPHGGAASGL), which is naturally presented by melanoma cells. The tumor epitope bound to HLA-B7 by bulging outward from the peptide-binding cleft. This bulged epitope was not an impediment to T-cell recognition, however, because four of six HLA-B7(+) melanoma patients vaccinated with NY-ESO-1 ISCOMATRIX vaccine generated a potent T-cell response to this determinant. Moreover, the response to this epitope was immunodominant in three of these patients and, unlike the T-cell responses to bulged HLA class I viral epitopes, the responding T cells possessed a remarkably broad TCR repertoire. Interestingly, HLA-B7(+) melanoma patients who did not receive the NY-ESO-1 ISCOMATRIX vaccine rarely generated a spontaneous T-cell response to this cryptic epitope, suggesting a lack of priming of such T cells in the natural anti-NY-ESO-1 response, which may be corrected by vaccination. Together, our results reveal several surprising aspects of antitumor immunity and have implications for cancer vaccine design.
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Affiliation(s)
- Lisa M Ebert
- Ludwig Institute for Cancer Research, Melbourne Centre for Clinical Sciences, Austin Health, Heidelberg, Victoria, Australia
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109
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Kanaseki T, Shastri N. Endoplasmic reticulum aminopeptidase associated with antigen processing regulates quality of processed peptides presented by MHC class I molecules. THE JOURNAL OF IMMUNOLOGY 2009; 181:6275-82. [PMID: 18941218 DOI: 10.4049/jimmunol.181.9.6275] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Effective immune surveillance by CD8 T cells depends on the presentation of diverse peptides by MHC class I (pMHC I) molecules on the cell surface. The pMHC I repertoire is shaped in the endoplasmic reticulum (ER) by the ER aminopeptidase associated with Ag processing (ERAAP). The ERAAP activity is required for producing peptides of appropriate length for generating optimal pMHC I. Paradoxically, ERAAP also inhibits generation of certain peptides such as the SVL9 (SSVVGVWYL) peptide encoded by the H13(a) histocompatibility gene and presented by D(b) MHC by an unknown mechanism. In this study, we show that the presentation of the SVL9-D(b) complex is inhibited when other peptides compete for binding D(b). Conversely, improving the binding of SVL9 peptide to D(b) suppresses the inhibition. Interestingly, the inhibitory effect of competitor peptides is observed only when ERAAP is expressed in the same cells. Thus, ERAAP, in concert with MHC I molecules, regulates the quality of processed peptides presented on the cell surface.
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Affiliation(s)
- Takayuki Kanaseki
- Division of Immunology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA
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110
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Evnouchidou I, Momburg F, Papakyriakou A, Chroni A, Leondiadis L, Chang SC, Goldberg AL, Stratikos E. The internal sequence of the peptide-substrate determines its N-terminus trimming by ERAP1. PLoS One 2008; 3:e3658. [PMID: 18987748 PMCID: PMC2573961 DOI: 10.1371/journal.pone.0003658] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 10/20/2008] [Indexed: 11/26/2022] Open
Abstract
Background Endoplasmic reticulum aminopeptidase 1 (ERAP1) trims N-terminally extended antigenic peptide precursors down to mature antigenic peptides for presentation by major histocompatibility complex (MHC) class I molecules. ERAP1 has unique properties for an aminopeptidase being able to trim peptides in vitro based on their length and the nature of their C-termini. Methodology/Principal Findings In an effort to better understand the molecular mechanism that ERAP1 uses to trim peptides, we systematically analyzed the enzyme's substrate preferences using collections of peptide substrates. We discovered strong internal sequence preferences of peptide N-terminus trimming by ERAP1. Preferences were only found for positively charged or hydrophobic residues resulting to trimming rate changes by up to 100 fold for single residue substitutions and more than 40,000 fold for multiple residue substitutions for peptides with identical N-termini. Molecular modelling of ERAP1 revealed a large internal cavity that carries a strong negative electrostatic potential and is large enough to accommodate peptides adjacent to the enzyme's active site. This model can readily account for the strong preference for positively charged side chains. Conclusions/Significance To our knowledge no other aminopeptidase has been described to have such strong preferences for internal residues so distal to the N-terminus. Overall, our findings indicate that the internal sequence of the peptide can affect its trimming by ERAP1 as much as the peptide's length and C-terminus. We therefore propose that ERAP1 recognizes the full length of its peptide-substrate and not just the N- and C- termini. It is possible that ERAP1 trimming preferences influence the rate of generation and the composition of antigenic peptides in vivo.
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Affiliation(s)
- Irini Evnouchidou
- National Centre for Scientific Research “Demokritos”, IRRP, Aghia Paraskevi, Greece
| | - Frank Momburg
- Department of Molecular Immunology, German Cancer Research Centre, (DKFZ), Heidelberg, Germany
| | - Athanasios Papakyriakou
- Institute of Physical Chemistry, National Centre for Scientific Research “Demokritos”, Aghia Paraskevi, Greece
| | - Angeliki Chroni
- National Centre for Scientific Research “Demokritos”, Institute of Biology, Aghia Paraskevi, Greece
| | - Leondios Leondiadis
- National Centre for Scientific Research “Demokritos”, IRRP, Aghia Paraskevi, Greece
| | - Shih-Chung Chang
- Institute of Microbiology and Biochemistry, Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Alfred L. Goldberg
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Efstratios Stratikos
- National Centre for Scientific Research “Demokritos”, IRRP, Aghia Paraskevi, Greece
- * E-mail:
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111
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Starck SR, Ow Y, Jiang V, Tokuyama M, Rivera M, Qi X, Roberts RW, Shastri N. A distinct translation initiation mechanism generates cryptic peptides for immune surveillance. PLoS One 2008; 3:e3460. [PMID: 18941630 PMCID: PMC2565129 DOI: 10.1371/journal.pone.0003460] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2008] [Accepted: 09/29/2008] [Indexed: 12/04/2022] Open
Abstract
MHC class I molecules present a comprehensive mixture of peptides on the cell surface for immune surveillance. The peptides represent the intracellular protein milieu produced by translation of endogenous mRNAs. Unexpectedly, the peptides are encoded not only in conventional AUG initiated translational reading frames but also in alternative cryptic reading frames. Here, we analyzed how ribosomes recognize and use cryptic initiation codons in the mRNA. We find that translation initiation complexes assemble at non-AUG codons but differ from canonical AUG initiation in response to specific inhibitors acting within the peptidyl transferase and decoding centers of the ribosome. Thus, cryptic translation at non-AUG start codons can utilize a distinct initiation mechanism which could be differentially regulated to provide peptides for immune surveillance.
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Affiliation(s)
- Shelley R. Starck
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Yongkai Ow
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Vivian Jiang
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Maria Tokuyama
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Mark Rivera
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
| | - Xin Qi
- Howard Hughes Medical Institute and Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Richard W. Roberts
- Department of Chemistry, Chemical Engineering, and Biology, University of Southern California, Los Angeles, California, United States of America
| | - Nilabh Shastri
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California, Berkeley, California, United States of America
- * E-mail:
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112
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Berkers CR, de Jong A, Ovaa H, Rodenko B. Transpeptidation and reverse proteolysis and their consequences for immunity. Int J Biochem Cell Biol 2008; 41:66-71. [PMID: 18817889 DOI: 10.1016/j.biocel.2008.08.036] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 08/29/2008] [Accepted: 08/29/2008] [Indexed: 11/27/2022]
Abstract
Reverse proteolysis and transpeptidation lead to the generation of polypeptide sequences that cannot be inferred directly from genome sequences as they are post-translational phenomena. These phenomena have so far received little attention although the physiological consequences may reach far. The protease-mediated synthesis of several immunodominant MHC class I antigens was recently reported, underscoring its importance to immunity. Reverse proteolytic and transpeptidation mechanisms as well as conditions that favor successful protease-catalyzed synthetic events are discussed here.
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Affiliation(s)
- Celia R Berkers
- Division of Cellular Biochemistry, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
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113
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114
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A detailed analysis of the murine TAP transporter substrate specificity. PLoS One 2008; 3:e2402. [PMID: 18545702 PMCID: PMC2408963 DOI: 10.1371/journal.pone.0002402] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Accepted: 04/26/2008] [Indexed: 01/06/2023] Open
Abstract
Background The transporter associated with antigen processing (TAP) supplies cytosolic peptides into the endoplasmic reticulum for binding to major histocompatibility complex (MHC) class I molecules. Its specificity therefore influences the repertoire of peptides presented by MHC molecules. Compared to human TAP, murine TAP's binding specificity has not been characterized as well, even though murine systems are widely used for basic studies of antigen processing and presentation. Methodology/Principal Findings We performed a detailed experimental analysis of murine TAP binding specificity by measuring the binding affinities of 323 peptides. Based on this experimental data, a computational model of murine TAP specificity was constructed. The model was compared to previously generated data on human and murine TAP specificities. In addition, the murine TAP specificities for known epitopes and random peptides were predicted and compared to assess the impact of murine TAP selectivity on epitope selection. Conclusions/Significance Comparisons to a previously constructed model of human TAP specificity confirms the well-established differences for peptide substrates with positively charged C-termini. In addition these comparisons show that several residues at the N-terminus of peptides which strongly influence binding to human TAP showed little effect on binding to murine TAP, and that the overall influence of the aminoterminal residues on peptide affinity for murine TAP is much lower than for the human transporter. Murine TAP also partly prefers different hydrophobic amino acids than human TAP in the carboxyterminal position. These species-dependent differences in specificity determined in vitro are shown to correlate with the epitope repertoire recognized in vivo. The quantitative model of binding specificity of murine TAP developed herein should be useful for interpreting epitope mapping and immunogenicity data obtained in humanized mouse models.
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115
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Bortfeldt R, Schindler S, Szafranski K, Schuster S, Holste D. Comparative analysis of sequence features involved in the recognition of tandem splice sites. BMC Genomics 2008; 9:202. [PMID: 18447903 PMCID: PMC2423196 DOI: 10.1186/1471-2164-9-202] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Accepted: 04/30/2008] [Indexed: 01/05/2023] Open
Abstract
Background The splicing of pre-mRNAs is conspicuously often variable and produces multiple alternatively spliced (AS) isoforms that encode different messages from one gene locus. Computational studies uncovered a class of highly similar isoforms, which were related to tandem 5'-splice sites (5'ss) and 3'-splice sites (3'ss), yet with very sparse anecdotal evidence in experimental studies. To compare the types and levels of alternative tandem splice site exons occurring in different human organ systems and cell types, and to study known sequence features involved in the recognition and distinction of neighboring splice sites, we performed large-scale, stringent alignments of cDNA sequences and ESTs to the human and mouse genomes, followed by experimental validation. Results We analyzed alternative 5'ss exons (A5Es) and alternative 3'ss exons (A3Es), derived from transcript sequences that were aligned to assembled genome sequences to infer patterns of AS occurring in several thousands of genes. Comparing the levels of overlapping (tandem) and non-overlapping (competitive) A5Es and A3Es, a clear preference of isoforms was seen for tandem acceptors and donors, with four nucleotides and three to six nucleotides long exon extensions, respectively. A subset of inferred A5E tandem exons was selected and experimentally validated. With the focus on A5Es, we investigated their transcript coverage, sequence conservation and base-paring to U1 snRNA, proximal and distal splice site classification, candidate motifs for cis-regulatory activity, and compared A5Es with A3Es, constitutive and pseudo-exons, in H. sapiens and M. musculus. The results reveal a small but authentic enriched set of tandem splice site preference, with specific distances between proximal and distal 5'ss (3'ss), which showed a marked dichotomy between the levels of in- and out-of-frame splicing for A5Es and A3Es, respectively, identified a number of candidate NMD targets, and allowed a rough estimation of a number of undetected tandem donors based on splice site information. Conclusion This comparative study distinguishes tandem 5'ss and 3'ss, with three to six nucleotides long extensions, as having unusually high proportions of AS, experimentally validates tandem donors in a panel of different human tissues, highlights the dichotomy in the types of AS occurring at tandem splice sites, and elucidates that human alternative exons spliced at overlapping 5'ss posses features of typical splice variants that could well be beneficial for the cell.
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Affiliation(s)
- Ralf Bortfeldt
- Department of Bioinformatics, Friedrich-Schiller University, Ernst-Abbe-Platz 2, D-07743 Jena, Germany.
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116
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Hawkins OE, Vangundy RS, Eckerd AM, Bardet W, Buchli R, Weidanz JA, Hildebrand WH. Identification of breast cancer peptide epitopes presented by HLA-A*0201. J Proteome Res 2008; 7:1445-57. [PMID: 18345606 DOI: 10.1021/pr700761w] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cellular immune mechanisms detect and destroy cancerous and infected cells via the human leukocyte antigen (HLA) class I molecules that present peptides of intracellular origin on the surface of all nucleated cells. The identification of novel, tumor-specific epitopes is a critical step in the development of immunotherapeutics for breast cancer. To directly identify peptide epitopes unique to cancerous cells, secreted human class I HLA molecules (sHLA) were constructed by deletion of the transmembrane and cytoplasmic domain of HLA A*0201. The resulting sHLA-A*0201 was transferred and expressed in breast cancer cell lines MCF-7, MDA-MB-231, and BT-20 as well as in the immortal, nontumorigenic cell line MCF10A. Stable transfectants were seeded into bioreactors for production of > 25 mg of sHLA-A*0201. Peptides eluted from affinity purified sHLA were analyzed by mass spectroscopy. Comparative analysis of HLA-A*0201 peptides revealed 5 previously uncharacterized epitopes uniquely presented on breast cancer cells. These peptides were derived from intracellular proteins with either well-defined or putative roles in breast cancer development and progression: Cyclin Dependent Kinase 2 (Cdk2), Ornithine Decarboxylase (ODC1), Kinetochore Associated 2 (KNTC2 or HEC1), Macrophage Migration Inhibitory Factor (MIF), and Exosome Component 6 (EXOSC6). Cellular recognition of the MIF, KNTC2, EXOSC6, and Cdk2 peptides by circulating CD8+ cells was demonstrated by tetramer staining and IFN-gamma ELISPOT. The identification and characterization of peptides unique to the class I of breast cancer cells provide putative targets for the development of immune diagnostic tools and therapeutics.
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Affiliation(s)
- Oriana E Hawkins
- University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, Pure Protein, LLC, Oklahoma City, Oklahoma 73104, USA
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117
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Grotenbreg GM, Roan NR, Guillen E, Meijers R, Wang JH, Bell GW, Starnbach MN, Ploegh HL. Discovery of CD8+ T cell epitopes in Chlamydia trachomatis infection through use of caged class I MHC tetramers. Proc Natl Acad Sci U S A 2008; 105:3831-6. [PMID: 18245382 PMCID: PMC2268777 DOI: 10.1073/pnas.0711504105] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Indexed: 11/18/2022] Open
Abstract
Class I MHC tetramers allow direct phenotypic identification of CD8(+) T cell populations, but their production remains laborious. A peptide exchange strategy that employs class I MHC products loaded with conditional ligands (caged MHC molecules) provides a fast and straightforward method to obtain diverse arrays of class I MHC tetramers and facilitates CD8(+) T cell epitope discovery. Here, we describe the development of photocleavable analogs of the FAPGNYPAL (SV9) epitope that bind H-2K(b) and H-2D(b) with full retention of their structural and functional integrity. We ranked all possible H-2K(b) octameric and H-2D(b) nonameric epitopes that span the genome of Chlamydia trachomatis and prepared MHC tetramers from approximately 2,000 of the highest scoring peptides by replacement of the SV9 analog with the peptide of choice. The resulting 2,000-member class I MHC tetramer array allowed the discovery of two variants of an epitope derived from polymorphic membrane protein I (PmpI) and an assessment of the kinetics of emergence and the effector function of the corresponding CD8(+) T cells.
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Affiliation(s)
| | | | - Eduardo Guillen
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02139
| | - Rob Meijers
- Medicine
- Laboratory of Immunology, Department of Medical Oncology, Dana–Farber Cancer Institute, Boston, MA 02115
| | - Jia-huai Wang
- Pediatrics, and
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115; and
- Laboratory of Immunology, Department of Medical Oncology, Dana–Farber Cancer Institute, Boston, MA 02115
| | - George W. Bell
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02139
| | | | - Hidde L. Ploegh
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02139
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118
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Firat E, Huai J, Saveanu L, Gaedicke S, Aichele P, Eichmann K, van Endert P, Niedermann G. Analysis of direct and cross-presentation of antigens in TPPII knockout mice. THE JOURNAL OF IMMUNOLOGY 2008; 179:8137-45. [PMID: 18056356 DOI: 10.4049/jimmunol.179.12.8137] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Tripeptidyl peptidase II (TPPII) is an oligopeptidase forming giant complexes in the cytosol that have high exo-, but also, endoproteolytic activity. Immunohistochemically, the complexes appear as distinct foci in the cytosol. In part controversial biochemical and functional studies have suggested that TPPII contributes, on the one hand, positively to Ag processing by generating epitope carboxyl termini or by trimming epitope precursors, and, on the other, negatively by destroying potentially antigenic peptides. To clarify which of these roles is predominant, we generated and analyzed TPPII-deficient mice. Cell surface levels of MHC class I peptide complexes tended to be increased on most cell types of these mice. Although presentation of three individual epitopes derived from lymphocytic choriomeningitis virus was not elevated on TPPII-/- cells, that of the immunodominant OVA epitope SIINFEKL was significantly enhanced. Consistent with this, degradation of a synthetic peptide corresponding to the OVA epitope and of another corresponding to a precursor thereof, both being proteasomally generated OVA fragments, was delayed in TPPII-deficient cytosolic extracts. In addition, dendritic cell cross-presentation of phagocytosed OVA and of OVA internalized as an immune complex was increased to about the same level as direct presentation of the Ag. The data suggest a moderate, predominantly destructive role of TPPII in class I Ag processing, in line with our finding that TPPII is not induced by IFN-gamma, which up-regulates numerous, predominantly constructive components of the Ag processing and presentation machinery.
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Affiliation(s)
- Elke Firat
- Clinic for Radiotherapy, University Hospital of Freiburg, Freiburg, Germany
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119
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Roth G, Freund S, Möhrle B, Wöllner K, Brünjes J, Gauglitz G, Wiesmüller KH, Jung G. Ubiquitin binds to a short peptide segment of hydrolase UCH-L3: a study by FCS, RIfS, ITC and NMR. Chembiochem 2008; 8:323-31. [PMID: 17211910 DOI: 10.1002/cbic.200600254] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Screening for small peptidic affinity tags for the detection of ubiquitin and ubiquitinated proteins yielded the dodecapeptide amide DPDELRFNAIAL-NH(2) as a specific ubiquitin-interacting ligand. A peptide collection--based on crystal structures with ubiquitin-interacting proteins--was designed and confirmed by sequence comparison of ubiquitin-interacting motifs. Four independent physical detection methods demonstrated that the peptide binds to monomeric ubiquitin with an affinity of about 10 muM and with fast on and off rates. Fluorescence correlation spectroscopy with fluorescent peptides showed specific interaction with ubiquitin. Reflectometric interference spectroscopy with surface-immobilized peptides and isothermal calorimetry measurements confirmed the specific binding of ubiquitin and fast rate constants. (1)H,(15)N heteronuclear NMR localised the interaction site across the beta sheet of ubiquitin. The peptide aligns well with the ubiquitin-interacting motif and represents a lead structure for the rational design of high-affinity tags for targeting ubiquitinated protein in vitro and in vivo.
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Affiliation(s)
- Günter Roth
- Institut für Organische Chemie, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany
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120
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121
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Abstract
Heterogeneous intracellular pathways and biochemical mechanisms are responsible for generating the glycoprotein complexes of peptide and major histocompatibility complex that are displayed on the surfaces of antigen-presenting cells for recognition by T lymphocytes. These pathways have a profound influence on the specificity of adaptive immunity and tolerance, as well as the context and consequences of antigen recognition by T cells in the thymus and periphery. The field of antigen processing and presentation has continued to advance since the publication of a focus issue on the topic in Nature Immunology in July 2004. Progress has been made on many fronts, including advances in understanding how proteases, accessory molecules and intracellular pathways influence peptide loading and antigen presentation in various cell types.
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Affiliation(s)
- Peter E Jensen
- Department of Pathology, University of Utah, Salt Lake City, Utah 84112, USA.
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122
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Xiong Z, Liu E, Yan Y, Silver RT, Yang F, Chen IH, Hodge I, Verstovsek S, Segura FJ, Wang H, Prchal J, Yang XF. A novel unconventional antigen MPD5 elicits anti-tumor humoral immune responses in a subset of patients with polycythemia vera. Int J Immunopathol Pharmacol 2007; 20:373-80. [PMID: 17624250 PMCID: PMC2892688 DOI: 10.1177/039463200702000218] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In an effort to define the antigenic mechanism that contributes to beneficial therapeutic outcome in patients with polycythemia vera (PV), we screened a human testis cDNA library with serological cloning derived from sera of three PV patients who had undergone therapeutic-induced remission. As a result, we identified a novel antigen, MPD5, which belongs to the group of cryptic antigens with unconventional genomic intron/exon structure. Moreover, MPD5 elicited IgG antibody responses in a subset of PV patients who had benefited from a variety of therapies--including IFN-alpha, Hydroxyurea, Imatinib mesylate, Anagrelide, and phlebotomy--but not in untreated PV patients or healthy donors, suggesting that MPD5 is a PV-associated, therapy-related antigen. In the granulocytes of PV patients who are responsive to therapy, upregulated MPD5 expression may serve to enhance immune responses. These findings provide new insight into the mechanism underlying regulation of the self-antigen repertoire that elicits anti-tumor immune responses in patients with myeloproliferative diseases, indicating the potential of these self-antigens as targets of novel immunotherapy.
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Affiliation(s)
- Z Xiong
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA
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123
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Archbold JK, Ely LK, Kjer-Nielsen L, Burrows SR, Rossjohn J, McCluskey J, Macdonald WA. T cell allorecognition and MHC restriction--A case of Jekyll and Hyde? Mol Immunol 2007; 45:583-98. [PMID: 17869342 DOI: 10.1016/j.molimm.2006.05.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Accepted: 05/19/2006] [Indexed: 01/14/2023]
Abstract
A great paradox in cellular immunology is how T cell allorecognition exists at high frequencies (up to 10%) despite the stringent requirements of discriminating 'self' from 'non-self' imposed by MHC restriction. Thus, in tissue transplantation, a substantial proportion of the recipient's T cells will have the ability to recognize the graft and instigate an immune response against the transplanted tissue, ultimately resulting in graft rejection--a manifestation of T cell alloreactivity. Transplantation of human organs and lymphoid cells as treatment for otherwise life-threatening diseases has become a more routine medical procedure making this problem of great importance. Immunologists have gained important insights into the mechanisms of T cell alloreactivity from cytotoxic T cell assays, affinity-avidity studies, and crystal structures of peptide-MHC (pMHC) molecules and T cell receptors (TCRs) both alone and in complex. Despite the clinical significance of alloreactivity, the crystal structure of an alloreactive human TCR in complex with both cognate pMHC and an allogeneic pMHC complex has yet to be determined. This review highlights some of the important findings from studies characterizing the way in which alloreactive T cell receptors and pMHC molecules interact in an attempt to resolve this great irony of the cellular immune response.
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Affiliation(s)
- Julia K Archbold
- The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia
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124
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Abstract
Major histocompatibility complex (MHC) class I molecules present short, perfectly cleaved peptides on the cell surface for immune surveillance by CD8(+) T cells. The pathway for generating these peptides begins in the cytoplasm, and the peptide-MHC I (pMHC I) repertoire is finalized in the endoplasmic reticulum. Recent studies show that the peptides for MHC I are customized by the ER aminopeptidase associated with antigen processing and by dynamic interactions within the MHC peptide-loading complex. Failure to customize the pMHC I repertoire has profound immunological consequences.
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Affiliation(s)
- Gianna Elena Hammer
- Division of Immunology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA
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125
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Philip R, Murthy S, Krakover J, Sinnathamby G, Zerfass J, Keller L, Philip M. Shared immunoproteome for ovarian cancer diagnostics and immunotherapy: potential theranostic approach to cancer. J Proteome Res 2007; 6:2509-17. [PMID: 17547437 PMCID: PMC2533805 DOI: 10.1021/pr0606777] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Elimination of cancer through early detection and treatment is the ultimate goal of cancer research and is especially critical for ovarian and other forms of cancer typically diagnosed at very late stages that have very poor response rates. Proteomics has opened new avenues for the discovery of diagnostic and therapeutic targets. Immunoproteomics, which defines the subset of proteins involved in the immune response, holds considerable promise for providing a better understanding of the early-stage immune response to cancer as well as important insights into antigens that may be suitable for immunotherapy. Early administration of immunotherapeutic vaccines can potentially have profound effects on prevention of metastasis and may potentially cure through efficient and complete tumor elimination. We developed a mass-spectrometry-based method to identify novel autoantibody-based serum biomarkers for the early diagnosis of ovarian cancer that uses native tumor-associated proteins immunoprecipitated by autoantibodies from sera obtained from cancer patients and from cancer-free controls to identify autoantibody signatures that occur at high frequency only in cancer patient sera. Interestingly, we identified a subset of more than 50 autoantigens that were also processed and presented by MHC class I molecules on the surfaces of ovarian cancer cells and thus were common to the two immunological processes of humoral and cell-mediated immunity. These shared autoantigens were highly representative of families of proteins with roles in key processes in carcinogenesis and metastasis, such as cell cycle regulation, cell proliferation, apoptosis, tumor suppression, and cell adhesion. Autoantibodies appearing at the early stages of cancer suggest that this detectable immune response to the developing tumor can be exploited as early-stage biomarkers for the development of ovarian cancer diagnostics. Correspondingly, because the T-cell immune response depends on MHC class I processing and presentation of peptides, proteins that go through this pathway are potential candidates for the development of immunotherapeutics designed to activate a T-cell immune response to cancer. To the best of our knowledge, this is the first comprehensive study that identifies and categorizes proteins that are involved in both humoral and cell-mediated immunity against ovarian cancer, and it may have broad implications for the discovery and selection of theranostic molecular targets for cancer therapeutics and diagnostics in general.
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Affiliation(s)
- Ramila Philip
- Immunotope Inc., The Pennsylvania Biotechnology Center, 3805 Old Easton Road, Doylestown, Pennsylvania 18902, USA.
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126
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Crawford F, Jordan KR, Stadinski B, Wang Y, Huseby E, Marrack P, Slansky JE, Kappler JW. Use of baculovirus MHC/peptide display libraries to characterize T-cell receptor ligands. Immunol Rev 2007; 210:156-70. [PMID: 16623770 DOI: 10.1111/j.0105-2896.2006.00365.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peptide/protein display libraries are powerful tools for identifying and manipulating receptor/ligand pairs. While the large size of bacterial phage display libraries has made them the platform of choice in many applications, often considerable engineering has been required to achieve display of properly folded and active eukaryotic proteins, such as antibodies. This problem has been partially solved in several eukaryotic display systems, e.g. using yeast or retroviruses, but these systems have their own limitations. Recently, baculovirus has been developed as a display system using the virus itself or infected insect cells as the display platform. Here, we review the development and use of baculovirus-infected cells as a platform for display libraries of peptides bound to major histocompatibility complex (MHC) class I (MHCI) or class II (MHCII). We have used fluorescent multimeric soluble T-cell receptors (TCRs) to screen these libraries and to identify peptide antigen mimotopes. We also present some improvements to this system that allow very large libraries to be constructed and screened. We have used these libraries to examine the role of MHCII-bound peptides in the presentation of the staphylococcal enterotoxin A (SEA) and to manipulate an MHCI tumor-associated antigen.
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Affiliation(s)
- Frances Crawford
- Integrated Department of Immunology, National Jewish Medical and Research Center, Denver, CO 80206, USA
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127
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Doytchinova IA, Flower DR. Predicting class I major histocompatibility complex (MHC) binders using multivariate statistics: comparison of discriminant analysis and multiple linear regression. J Chem Inf Model 2007; 47:234-8. [PMID: 17238269 DOI: 10.1021/ci600318z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The accurate in silico identification of T-cell epitopes is a critical step in the development of peptide-based vaccines, reagents, and diagnostics. It has a direct impact on the success of subsequent experimental work. Epitopes arise as a consequence of complex proteolytic processing within the cell. Prior to being recognized by T cells, an epitope is presented on the cell surface as a complex with a major histocompatibility complex (MHC) protein. A prerequisite therefore for T-cell recognition is that an epitope is also a good MHC binder. Thus, T-cell epitope prediction overlaps strongly with the prediction of MHC binding. In the present study, we compare discriminant analysis and multiple linear regression as algorithmic engines for the definition of quantitative matrices for binding affinity prediction. We apply these methods to peptides which bind the well-studied human MHC allele HLA-A*0201. A matrix which results from combining results of the two methods proved powerfully predictive under cross-validation. The new matrix was also tested on an external set of 160 binders to HLA-A*0201; it was able to recognize 135 (84%) of them.
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Affiliation(s)
- Irini A Doytchinova
- Faculty of Pharmacy, Medical University of Sofia, 2 Dunav st., 1000 Sofia, Bulgaria.
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128
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Brickner AG. Mechanisms of minor histocompatibility antigen immunogenicity: the role of infinitesimal versus structurally profound polymorphisms. Immunol Res 2007; 36:33-41. [PMID: 17337764 DOI: 10.1385/ir:36:1:33] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/11/2022]
Abstract
Minor histocompatibility antigens (mHAgs) are a diverse collection of major histocompatibility complex (MHC)-bound peptides that play a critical role in the induction of detrimental graft-versus-host disease (GVHD) or the development of beneficial graft-versustumor (GVT) effects after allogeneic hematopoietic stem cell transplantation. mHAgs are a consequence of allelic polymorphism that translates to disparity in MHC-presented peptide epitopes between transplant donor and recipient. This donor/recipient allelic disparity can range from infinitesimal amino side chain differences between MHC-presented peptides, to profound structural polymorphisms in genes and proteins that can nullify transcription or translation of one allelic variant and result in the complete abrogation of its presentation by MHC.
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Affiliation(s)
- Anthony G Brickner
- Department of Medicine, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213-1863, USA.
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129
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Moss CX, Tree TI, Watts C. Reconstruction of a pathway of antigen processing and class II MHC peptide capture. EMBO J 2007; 26:2137-47. [PMID: 17396153 PMCID: PMC1852786 DOI: 10.1038/sj.emboj.7601660] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Accepted: 02/26/2007] [Indexed: 11/10/2022] Open
Abstract
Endocytosed antigens are proteolytically processed and small amounts of peptides captured by class II MHC molecules. The details of antigen proteolysis, peptide capture and how destruction of T-cell epitopes is avoided are incompletely understood. Using the tetanus toxin antigen, we show that the introduction of 3-6 cleavage sites is sufficient to trigger a partially unfolded conformation able to bind to class II MHC molecules. The known locations of T-cell epitopes and protease cleavage sites predict that large domains of processed antigen (8-35 kDa) are captured under these conditions. Remarkably, when antigen is bound to the B-cell antigen receptor (BCR), processing can trigger a concerted 'hand-over' reaction whereby BCR-associated processed antigen is captured by neighbouring class II MHC molecules. Early capture of minimally processed antigen and confinement of the processing and class II MHC loading reaction to the membrane plane may improve the likelihood of T-cell epitope survival in the class II MHC pathway and may help explain the reciprocal relationships observed between B- and T-cell epitopes in many protein antigens and autoantigens.
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Affiliation(s)
- Catherine X Moss
- Division of Cell Biology & Immunology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Timothy I Tree
- Department of Immunobiology, King's College London, Guy's King's & St Thomas' School of Medicine, London, UK
| | - Colin Watts
- Division of Cell Biology & Immunology, School of Life Sciences, University of Dundee, Dundee, UK
- Division of Cell Biology and Immunology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK. Tel.: +44 1382 384233; Fax: +44 1382 385783; E-mail:
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130
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Mancini-Bourgine M, Bayard F, Soussan P, Deng Q, Lone YC, Kremsdorf D, Michel ML. Hepatitis B virus splice-generated protein induces T-cell responses in HLA-transgenic mice and hepatitis B virus-infected patients. J Virol 2007; 81:4963-72. [PMID: 17360751 PMCID: PMC1900232 DOI: 10.1128/jvi.02619-06] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Hepatitis B virus splice-generated protein (HBSP), encoded by a spliced hepatitis B virus RNA, was recently identified in liver biopsy specimens from patients with chronic active hepatitis B. We investigated the possible generation of immunogenic peptides by the processing of this protein in vivo. We identified a panel of potential epitopes in HBSP by using predictive computational algorithms for peptide binding to HLA molecules. We used transgenic mice devoid of murine major histocompatibility complex (MHC) class I molecules and positive for human MHC class I molecules to characterize immune responses specific for HBSP. Two HLA-A2-restricted peptides and one immunodominant HLA-B7-restricted epitope were identified following the immunization of mice with DNA vectors encoding HBSP. Most importantly, a set of overlapping peptides covering the HBSP sequence induced significant HBSP-specific T-cell responses in peripheral blood mononuclear cells from patients with chronic hepatitis B. The response was multispecific, as several epitopes were recognized by CD8(+) and CD4(+) human T cells. This study provides the first evidence that this protein generated in vivo from an alternative reading frame of the hepatitis B virus genome activates T-cell responses in hepatitis B virus-infected patients. Given that hepatitis B is an immune response-mediated disease, the detection of T-cell responses directed against HBSP in patients with chronic hepatitis B suggests a potential role for this protein in liver disease progression.
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Affiliation(s)
- Maryline Mancini-Bourgine
- INSERM U812, Unité de Pathogénèse des Hépatites Virales B et Immunothérapie, Bâtiment Lwoff, Institut Pasteur, 28, rue du Docteur Roux, 75724 Paris Cedex 15, France
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131
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Tellam J, Fogg MH, Rist M, Connolly G, Tscharke D, Webb N, Heslop L, Wang F, Khanna R. Influence of translation efficiency of homologous viral proteins on the endogenous presentation of CD8+ T cell epitopes. ACTA ACUST UNITED AC 2007; 204:525-32. [PMID: 17312009 PMCID: PMC2137904 DOI: 10.1084/jem.20062508] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
A significant proportion of endogenously processed CD8(+) T cell epitopes are derived from newly synthesized proteins and rapidly degrading polypeptides (RDPs). It has been hypothesized that the generation of rapidly degrading polypeptides and CD8(+) T cell epitopes from these RDP precursors may be influenced by the efficiency of protein translation. Here we address this hypothesis by using the Epstein-Barr virus-encoded nuclear antigen 1 protein (EBNA1), with or without its internal glycine-alanine repeat sequence (EBNA1 and EBNA1DeltaGA, respectively), which display distinct differences in translation efficiency. We demonstrate that RDPs constitute a significant proportion of newly synthesized EBNA1 and EBNA1DeltaGA and that the levels of RDPs produced by each of these proteins directly correlate with the translation efficiency of either EBNA1 or EBNA1DeltaGA. As a consequence, a higher number of major histocompatibility complex-peptide complexes can be detected on the surface of cells expressing EBNA1DeltaGA, and these cells are more efficiently recognized by virus-specific cytotoxic T lymphocytes compared to the full-length EBNA1. More importantly, we also demonstrate that the endogenous processing of these CD8(+) T cell epitopes is predominantly determined by the rate at which the RDPs are generated rather than the intracellular turnover of these proteins.
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Affiliation(s)
- Judy Tellam
- Australian Centre for Vaccine Development and Tumour Immunology Laboratory, Division of Infectious Diseases and Immunology, Clive Berghofer Cancer Research Centre, Queensland Institute of Medical Research, Brisbane (Qld) 4006, Australia
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132
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Firat E, Saveanu L, Aichele P, Staeheli P, Huai J, Gaedicke S, Nil A, Besin G, Kanzler B, van Endert P, Niedermann G. The Role of Endoplasmic Reticulum-Associated Aminopeptidase 1 in Immunity to Infection and in Cross-Presentation. THE JOURNAL OF IMMUNOLOGY 2007; 178:2241-8. [PMID: 17277129 DOI: 10.4049/jimmunol.178.4.2241] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Endoplasmic reticulum-associated aminopeptidase 1 (ERAP1) is involved in the final processing of endogenous peptides presented by MHC class I molecules to CTLs. We generated ERAP1-deficient mice and analyzed cytotoxic responses upon infection with three viruses, including lymphocytic choriomeningitis virus, which causes vigorous T cell activation and is controlled by CTLs. Despite pronounced effects on the presentation of selected epitopes, the in vivo cytotoxic response was altered for only one of several epitopes tested. Moreover, control of lymphocytic choriomeningitis virus was not impaired in the knockout mice. Thus, we conclude that lack of ERAP1 has little influence on antiviral immunohierarchies and antiviral immunity in the infections studied. We also focused on the role of ERAP1 in cross-presentation. We demonstrate that ERAP1 is required for efficient cross-presentation of cell-associated Ag and of OVA/anti-OVA immunocomplexes. Surprisingly, however, ERAP1 deficiency has no effect on cross-presentation of soluble OVA, suggesting that for soluble exogenous proteins, final processing may not take place in an environment containing active ERAP1.
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Affiliation(s)
- Elke Firat
- Clinic for Radiotherapy, University Hospital of Freiburg, Freiburg, Germany
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133
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Monu N, Trombetta ES. Cross-talk between the endocytic pathway and the endoplasmic reticulum in cross-presentation by MHC class I molecules. Curr Opin Immunol 2007; 19:66-72. [PMID: 17157489 DOI: 10.1016/j.coi.2006.11.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2006] [Accepted: 11/27/2006] [Indexed: 10/23/2022]
Abstract
Cross-presentation of exogenous proteins on MHC class I complexes contributes to the priming CD8(+) T-cell responses. However, the mechanisms by which antigen-presenting cells transfer internalized proteins to the MHC class I loading pathway are not well understood. Endocytosed proteins often appear to require proteasomal processing and transport into the endoplasmic reticulum, but the intracellular routes involved in cross-presentation remain unclear. Understanding the molecular and cellular basis of cross-presentation will illuminate novel aspects of cell physiology and might lead to improved vaccine design.
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Affiliation(s)
- Ngozi Monu
- Cancer Institute, New York University School of Medicine, 522 First Avenue, New York, NY 10016, USA
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134
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Mishra S, Sinha S. Prediction and molecular modeling of T-cell epitopes derived from placental alkaline phosphatase for use in cancer immunotherapy. J Biomol Struct Dyn 2006; 24:109-21. [PMID: 16928134 DOI: 10.1080/07391102.2006.10507104] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
In our ongoing efforts to combat cancer, peptide-based tumor vaccines are promising as one of the several alternatives used for cancer immunotherapy and immunoprevention. We have attempted to identify T-cell epitopes suitable for the development of a peptide-based cancer vaccine directed towards placental isozyme of alkaline phosphatase (PLAP), an oncofetal antigen. After identifying amino acid residues specific to PLAP and distinct from other close PLAP homologs, we have used sequence-based immunoinformatics tools (BIMAS and SYFPEITHI) and conducted molecular modeling studies using InsightII to investigate the binding affinity of the epitopes containing the unique residues with respective MHC class I molecules. Promiscuous epitopes binding to different alleles of different class I HLA loci were analyzed to get a population coverage that is widespread. Binding affinity deduced from the modeling studies corroborated the status of most of the epitopes scoring high in BIMAS and SYFPEITHI. We have thus identified specific epitopes from PLAP that have a potential for binding to their respective MHC class I alleles with high affinity. These peptides would be analysed in experiments to demonstrate their involvement in the induction of primary cytotoxic T-cell responses in vitro, using respective HLA-restricted T-cells in our way towards the development of an effective anti-cancer vaccine in a background of diverse MHC haplotypes.
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Affiliation(s)
- Seema Mishra
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, 110029 India
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135
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Kanaseki T, Blanchard N, Hammer GE, Gonzalez F, Shastri N. ERAAP synergizes with MHC class I molecules to make the final cut in the antigenic peptide precursors in the endoplasmic reticulum. Immunity 2006; 25:795-806. [PMID: 17088086 PMCID: PMC2746443 DOI: 10.1016/j.immuni.2006.09.012] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 08/31/2006] [Accepted: 09/13/2006] [Indexed: 10/23/2022]
Abstract
The major histocompatibility complex class I molecules display peptides (pMHC I) on the cell surface for immune surveillance by CD8(+) T cells. These peptides are generated by proteolysis of intracellular polypeptides by the proteasome in the cytoplasm and then in the endoplasmic reticulum (ER) by the ER aminopeptidase associated with antigen processing (ERAAP). To define the unknown mechanism of ERAAP function in vivo, we analyzed naturally processed peptides in cells with or without appropriate MHC I and ERAAP. In the absence of MHC I, ERAAP degraded the antigenic precursors in the ER. However, MHC I molecules could bind proteolytic intermediates and were essential for generation of the final peptide by ERAAP. Thus, ERAAP synergizes with MHC I to generate the final pMHC I repertoire.
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Affiliation(s)
- Takayuki Kanaseki
- Division of Immunology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
| | - Nicolas Blanchard
- Division of Immunology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
| | - Gianna Elena Hammer
- Division of Immunology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
| | - Federico Gonzalez
- Division of Immunology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
| | - Nilabh Shastri
- Division of Immunology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720
- Correspondence:
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136
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Hammer GE, Gonzalez F, James E, Nolla H, Shastri N. In the absence of aminopeptidase ERAAP, MHC class I molecules present many unstable and highly immunogenic peptides. Nat Immunol 2006; 8:101-8. [PMID: 17128277 DOI: 10.1038/ni1409] [Citation(s) in RCA: 163] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Accepted: 10/13/2006] [Indexed: 12/11/2022]
Abstract
Immunosurveillance by cytotoxic T cells requires that cells generate a diverse spectrum of peptides for presentation by major histocompatibility complex (MHC) class I molecules. Those peptides are generated by proteolysis, which begins in the cytoplasm and continues in the endoplasmic reticulum by the unique aminopeptidase ERAAP. The overall extent to which trimming by ERAAP modifies the peptide pool and the immunological consequences of ERAAP deficiency are unknown. Here we show that the peptide-MHC repertoire of ERAAP-deficient mice was missing many peptides. Furthermore, ERAAP-deficient cells presented many unstable and structurally unique peptide-MHC complexes, which elicited potent CD8+ T cell and B cell responses. Thus, ERAAP is a 'quintessential editor' of the peptide-MHC repertoire and, paradoxically, its absence enhances immunogenicity.
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Affiliation(s)
- Gianna Elena Hammer
- Division of Immunology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
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137
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Guil S, Rodríguez-Castro M, Aguilar F, Villasevil EM, Antón LC, Del Val M. Need for tripeptidyl-peptidase II in major histocompatibility complex class I viral antigen processing when proteasomes are detrimental. J Biol Chem 2006; 281:39925-34. [PMID: 17088258 DOI: 10.1074/jbc.m608522200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CD8(+) T lymphocytes recognize infected cells that display virus-derived antigenic peptides complexed with major histocompatibility complex class I molecules. Peptides are mainly byproducts of cellular protein turnover by cytosolic proteasomes. Cytosolic tripeptidyl-peptidase II (TPPII) also participates in protein degradation. Several peptidic epitopes unexpectedly do not require proteasomes, but it is unclear which proteases generate them. We studied antigen processing of influenza virus nucleoprotein epitope NP(147-155), an archetype epitope that is even destroyed by a proteasome-mediated mechanism. TPPII, with the assistance of endoplasmic reticulum trimming metallo-aminopeptidases, probably ERAAP (endoplasmic reticulum aminopeptidase associated with antigen processing), was crucial for nucleoprotein epitope generation both in the presence of functional proteasomes and when blocked by lactacystin, as shown with specific chemical inhibitors and gene silencing. Different protein contexts and subcellular targeting all allowed epitope processing by TPPII as well as trimming. The results show the plasticity of the cell's assortment of proteases for providing ligands for recognition by antiviral CD8(+) T cells. Our observations identify for the first time a set of proteases competent for antigen processing of an epitope that is susceptible to destruction by proteasomes.
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Affiliation(s)
- Sara Guil
- Unidad de Inmunología Viral, Centro Nacional de Microbiología, Instituto de Salud Carlos III, E-28220 Majadahonda (Madrid), Spain
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138
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Xiong Z, Liu E, Yan Y, Silver RT, Yang F, Chen IH, Chen Y, Verstovsek S, Wang H, Prchal J, Yang XF. An unconventional antigen translated by a novel internal ribosome entry site elicits antitumor humoral immune reactions. THE JOURNAL OF IMMUNOLOGY 2006; 177:4907-16. [PMID: 16982933 PMCID: PMC3902139 DOI: 10.4049/jimmunol.177.7.4907] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Self-tumor Ags that elicit antitumor immune responses in responses to IFN-alpha stimulation remain poorly defined. We screened a human testis cDNA library with sera from three polycythemia vera patients who responded to IFN-alpha and identified a novel Ag, MPD6. MPD6 belongs to the group of cryptic Ags without conventional genomic structure and is encoded by a cryptic open reading frame located in the 3'-untranslated region of myotrophin mRNA. MPD6 elicits IgG Ab responses in a subset of polycythemia vera patients, as well as patients with chronic myelogenous leukemia and prostate cancer, suggesting that it is broadly immunogenic. The expression of myotrophin-MPD6 transcripts was up-regulated in some tumor cells, but only slightly increased in K562 cells in response to IFN-alpha treatment. By using bicistronic reporter constructs, we showed that the translation of MPD6 was mediated by a novel internal ribosome entry site (IRES) upstream of the MPD6 reading frame. Furthermore, the MPD6-IRES-mediated translation, but not myotrophin-MPD6 transcription, was significantly up-regulated in response to IFN-alpha stimulation. These findings demonstrate that a novel IRES-mediated mechanism may be responsible for the translation of unconventional self-Ag MPD6 in responsive to IFN-alpha stimulation. The eliciting antitumor immune response against unconventional Ag MPD6 in patients with myeloproliferative diseases suggests MPD6 as a potential target of novel immunotherapy.
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MESH Headings
- Amino Acid Sequence
- Antigens, Neoplasm/chemistry
- Antigens, Neoplasm/physiology
- Antigens, Neoplasm/ultrastructure
- Blotting, Northern
- Blotting, Western
- Enzyme-Linked Immunosorbent Assay
- Gene Library
- Humans
- Intercellular Signaling Peptides and Proteins/genetics
- Intercellular Signaling Peptides and Proteins/immunology
- Interferon-gamma/immunology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/immunology
- Male
- Molecular Sequence Data
- Polycythemia Vera/immunology
- Prostatic Neoplasms/immunology
- Protein Biosynthesis
- Protein Structure, Secondary
- RNA, Messenger/analysis
- Reverse Transcriptase Polymerase Chain Reaction
- Ribosomes/chemistry
- Ribosomes/genetics
- Ribosomes/ultrastructure
- Testis/physiology
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Affiliation(s)
- Zeyu Xiong
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
| | - Enli Liu
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030
| | - Yan Yan
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
| | - Richard T. Silver
- Department of Medicine, New York Presbyterian-Weill Cornell Medical Center, New York, NY 10021
| | - Fan Yang
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
| | - Irene H. Chen
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
| | - Yangyang Chen
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
| | - Srdan Verstovsek
- Department of Leukemia, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030
| | - Hong Wang
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
| | - Josef Prchal
- Department of Medicine, University of Utah School of Medicine, Salt Lake City, UT 84112
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030
| | - Xiao-Feng Yang
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
- Address correspondence and reprint requests to Dr. Xiao-Feng Yang, Department of Pharmacology, Temple University School of Medicine, 3420 North Broad Street, Philadelphia, PA 19140.
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139
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Zaikin A, Kurths J. Optimal length transportation hypothesis to model proteasome product size distribution. J Biol Phys 2006; 32:231-43. [PMID: 19669465 DOI: 10.1007/s10867-006-9014-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2006] [Accepted: 02/10/2006] [Indexed: 11/30/2022] Open
Abstract
This paper discusses translocation features of the 20S proteasome in order to explain typical proteasome length distributions. We assume that the protein transport depends significantly on the fragment length with some optimal length which is transported most efficiently. By means of a simple one-channel model, we show that this hypothesis can explain both the one- and the three-peak length distributions found in experiments. A possible mechanism of such translocation is provided by so-called fluctuation-driven transport.
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Affiliation(s)
- Alexey Zaikin
- Institute of Physics, University of Potsdam, D-14415 Potsdam, Germany.
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140
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Wang J, Michalak TI. Inhibition by woodchuck hepatitis virus of class I major histocompatibility complex presentation on hepatocytes is mediated by virus envelope pre-S2 protein and can be reversed by treatment with gamma interferon. J Virol 2006; 80:8541-53. [PMID: 16912304 PMCID: PMC1563886 DOI: 10.1128/jvi.00830-06] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Presentation of class I major histocompatibility complex (MHC) is severely down-regulated on hepatocytes in chronic hepatitis caused by woodchuck hepatitis virus (WHV). To determine which of the viral proteins mediates class I MHC antigen suppression, cultured normal woodchuck hepatocytes were transfected with the complete WHV genome, sequences encoding individual virus proteins, or whole virus genomes in which transcription of selected proteins was disabled by site-specific mutagenesis. It was found that hepatocyte presentation of class I MHC antigen was significantly inhibited following transfection with complete WHV genome or with viral subgenomic fragments encoding envelope pre-S2 protein or pre-S1 protein, which naturally encompasses pre-S2 amino acid sequence. In contrast, hepatocytes transfected with WHV X gene alone demonstrated a profound enhancement in the class I antigen display, whereas those expressing virus major S protein or nucleocapsid (core) protein were not different from control hepatocytes. Analysis of the mutated WHV sequences confirmed that the envelope pre-S2 protein was responsible for inhibition of the class I MHC antigen display. Interestingly, treatment with recombinant woodchuck gamma interferon (rwIFN-gamma) restored the inhibited presentation of the class I antigen. Moreover, the class I antigen suppression was not associated with down-regulation of hepatocyte genes for class I MHC heavy chain, beta(2)-microglobulin, transporters associated with antigen processing, and proteasome subunits. These findings indicate that the defective presentation of class I MHC antigen on hepatocytes transcribing WHV is a consequence of posttranscriptional suppression exerted by virus pre-S2 protein and that this hindrance can be fully reversed by IFN-gamma.
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Affiliation(s)
- Jinguo Wang
- Molecular Virology and Hepatology Research, Division of Basic Medical Science, St. John's, Newfoundland, Canada
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141
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Affiliation(s)
- Nilabh Shastri
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
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142
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Abstract
The immune defences of our organism against pathogens and malignant transformation rely to a large extent on surveillance by cytotoxic T lymphocytes. This surveillance in turn depends on the antigen processing system, which provides peptide samples of the cellular protein composition to MHC (major histocompatibility complex) class I molecules displayed on the cell surface. To continuously and almost in real time provide a representative sample of the array of proteins synthesized by the cell, this system exploits some fundamental pathways of the cellular metabolism, with the help of several dedicated players acting exclusively in antigen processing. Thus, a key element in the turnover of cellular proteins, protein degradation by cytosolic proteasome complexes, is exploited as source of peptides, by recruiting a minor fraction of the produced peptides as ligands for MHC class I molecules. These peptides can be further processed and adapted to the precise binding requirements of allelic MHC class I molecules by enzymes in the cytosol and endoplasmic reticulum. The latter compartment is equipped with several dedicated players helping peptide assembly with class I molecules. These include the TAP (transporter associated with antigen processing) membrane transporter pumping peptides into the ER, and tapasin, a chaperone with a structure similar to MHC molecules that tethers class I molecules awaiting peptide loading to the TAP transporter, and mediates optimization of MHC class I ligand by a still somewhat mysterious mechanism. Additional "house-keeping" chaperones that are known to act in concert in ER quality control, assist and control correct folding, oxidation and assembly of MHC class I molecules. While this processing system handles exclusively endogenous cellular proteins in most cells, dendritic cells employ one or several special pathways to shuttle exogenous, internalized proteins into the system, in a process referred to as cross-presentation. Deciphering the cell biological mechanism creating the link between the endosomal and secretory pathways that enables cross-presentation is one of the challenges faced by contemporary research in the field of MHC class I antigen processing.
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Affiliation(s)
- Peter van Endert
- Inserm U580 et Faculté de Médecine, Université Paris5 René Descartes, 161, rue de Sèvres, 75015 Paris, France.
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143
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Yang F, Chen IH, Xiong Z, Yan Y, Wang H, Yang XF. Model of stimulation-responsive splicing and strategies in identification of immunogenic isoforms of tumor antigens and autoantigens. Clin Immunol 2006; 121:121-33. [PMID: 16890493 DOI: 10.1016/j.clim.2006.06.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 06/13/2006] [Accepted: 06/15/2006] [Indexed: 01/03/2023]
Abstract
We recently proposed a novel model of stimulation-responsive splicing for the selection of autoantigens and self-tumor antigens. Our model theorizes that the significantly higher rates of alternative splicing of autoantigen and self-tumor antigen transcripts that occur in response to stimuli could induce extra-thymic expression of untolerized antigen epitopes for elicitation of autoimmune and anti-tumor responses. To facilitate the identification of immunogenic isoforms of antigens, we have developed strategies using improved SEREX in conjunction with database-mining and immunogenic isoform mapping. Identification of immunogenic isoforms of autoantigens and self-tumor antigens is very important for the development of novel therapeutics and diagnostic tools for autoimmune diseases and tumors, such as: (1) autoantigen isoform microarrays for disease diagnosis and prognosis; (2) autoantigen isoform-specific tolerizing vaccines and splicing-redirection therapies, as well as (3) immunogenic antigen isoform-specific immunotherapy for tumors.
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Affiliation(s)
- Fan Yang
- Department of Pharmacology, Temple University School of Medicine, 3420 North Broad Street, Medical Research Building, Suite 300, Philadelphia, PA 19140, USA.
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144
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Yewdell JW, Nicchitta CV. The DRiP hypothesis decennial: support, controversy, refinement and extension. Trends Immunol 2006; 27:368-73. [PMID: 16815756 DOI: 10.1016/j.it.2006.06.008] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2006] [Revised: 05/19/2006] [Accepted: 06/14/2006] [Indexed: 10/24/2022]
Abstract
In 1996, to explain the rapid presentation of viral proteins to CD8+ T cells, it was proposed that peptides presented by MHC class I molecules derive from defective ribosomal products (DRiPs), presumed to be polypeptides arising from in-frame translation that fail to achieve native structure owing to inevitable imperfections in transcription, translation, post-translational modifications or protein folding. Here, we consider findings that address the DRiP hypothesis, and extend the hypothesis by proposing that cells possess specialized machinery, possibly in the form of "immunoribosomes", to couple protein synthesis to antigen presentation.
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Affiliation(s)
- Jonathan W Yewdell
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892-0440, USA.
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145
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York IA, Bhutani N, Zendzian S, Goldberg AL, Rock KL. Tripeptidyl Peptidase II Is the Major Peptidase Needed to Trim Long Antigenic Precursors, but Is Not Required for Most MHC Class I Antigen Presentation. THE JOURNAL OF IMMUNOLOGY 2006; 177:1434-43. [PMID: 16849449 DOI: 10.4049/jimmunol.177.3.1434] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recent reports concluded that tripeptidyl peptidase (TPPII) is essential for MHC class I Ag presentation and that the proteasome in vivo mainly releases peptides 16 residues or longer that require processing by TPPII. However, we find that eliminating TPPII from human cells using small interfering RNA did not decrease the overall supply of peptides to MHC class I molecules and reduced only modestly the presentation of SIINFEKL from OVA, while treatment with proteasome inhibitors reduced these processes dramatically. Purified TPPII digests peptides from 6 to 30 residues long at similar rates, but eliminating TPPII in cells reduced the processing of long antigenic precursors (14-17 residues) more than short ones (9-12 residues). Therefore, TPPII appears to be the major peptidase capable of processing proteasome products longer than 14 residues. However, proteasomes in vivo (like purified proteasomes) release relatively few such peptides, and these peptides processed by TPPII require further trimming in the endoplasmic reticulum (ER) by ER aminopeptidase 1 for presentation. Taken together, these observations demonstrate that TPPII plays a specialized role in Ag processing and one that is not essential for the generation of most presented peptides. Moreover, these findings reveal that three sequential proteolytic steps (by proteasomes, TPPII, and then ER aminopepsidase 1) are required for the generation of a subset of epitopes.
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Affiliation(s)
- Ian A York
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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146
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Schirmbeck R, Riedl P, Kupferschmitt M, Wegenka U, Hauser H, Rice J, Kröger A, Reimann J. Priming Protective CD8 T Cell Immunity by DNA Vaccines Encoding Chimeric, Stress Protein-Capturing Tumor-Associated Antigen. THE JOURNAL OF IMMUNOLOGY 2006; 177:1534-42. [PMID: 16849460 DOI: 10.4049/jimmunol.177.3.1534] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
DNA vaccines encoding heat shock protein (hsp)-capturing, chimeric peptides containing antigenic determinants of the tumor-associated Ag (TAA) gp70 (an envelope protein of endogenous retrovirus) primed stable, specific, and tumor-protective CD8 T cell immunity. Expression of gp70 transcripts was detectable in most normal tissues but was particularly striking in some (but not all) tumor cell lines tested (including the adenocarcinoma cell line CT26). An approximately 200 residue gp70 fragment or its L(d)-binding antigenic AH1 peptide cloned in-frame behind an hsp-capturing (cT(272)) or noncapturing (T(60)) N-terminal large SV40 tumor Ag sequence was expressed as either hsp-binding or -nonbinding chimeric Ags. Only hsp-capturing, chimeric fusion proteins were expressed efficiently in transfected cell lines and primed TAA-specific CD8 T cell immunity. This immunity mediated protection in the CT26 and mKSA models. A vaccination strategy based on delivering antigenic, hsp-associated TAA fragments can thus prime protective CD8 T cell immunity even if these TAA are of low intrinsic immunogenicity.
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MESH Headings
- Adenocarcinoma/immunology
- Adenocarcinoma/prevention & control
- Animals
- Antigens, Neoplasm/administration & dosage
- Antigens, Neoplasm/biosynthesis
- Antigens, Neoplasm/genetics
- Antigens, Neoplasm/immunology
- CD8-Positive T-Lymphocytes/immunology
- Cancer Vaccines/administration & dosage
- Cancer Vaccines/genetics
- Cancer Vaccines/immunology
- Cell Line
- Cell Line, Tumor
- Coculture Techniques
- Colonic Neoplasms/immunology
- Colonic Neoplasms/prevention & control
- Female
- Glycoproteins/administration & dosage
- Glycoproteins/biosynthesis
- Glycoproteins/genetics
- Glycoproteins/immunology
- Heat-Shock Proteins/administration & dosage
- Heat-Shock Proteins/genetics
- Heat-Shock Proteins/immunology
- Lymphoma, T-Cell/immunology
- Lymphoma, T-Cell/prevention & control
- Mammary Neoplasms, Experimental/immunology
- Mammary Neoplasms, Experimental/prevention & control
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mutant Chimeric Proteins/administration & dosage
- Mutant Chimeric Proteins/genetics
- Mutant Chimeric Proteins/immunology
- Peptide Fragments/administration & dosage
- Peptide Fragments/genetics
- Peptide Fragments/immunology
- Vaccines, DNA/administration & dosage
- Vaccines, DNA/immunology
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147
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Kunisawa J, Shastri N. Hsp90alpha chaperones large C-terminally extended proteolytic intermediates in the MHC class I antigen processing pathway. Immunity 2006; 24:523-34. [PMID: 16713971 DOI: 10.1016/j.immuni.2006.03.015] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2005] [Revised: 01/30/2006] [Accepted: 03/14/2006] [Indexed: 01/29/2023]
Abstract
Intracellular proteins are degraded in the antigen processing pathway to generate peptide-loaded MHC I complexes (pMHC I) for immune surveillance. The characteristics of the final pMHC I are clear but those of their precursors and their potential binding partners remain poorly defined. By using a unique method to biochemically detect preprocessed ovalbumin-derived antigenic peptides, we find that cells generate large, C-terminally extended proteolytic intermediates that are associated with the alpha isotype of hsp90 chaperone. Knockdown of hsp90alpha expression by siRNA resulted in the loss of these intermediates and decreased presentation of the final pMHC I on the cell surface. Generation of pMHC I was also inhibited by knockdown of the cochaperone CHIP that interacts with heat shock proteins, ubiquitinates their clients, and delivers them to the proteasome. Thus, hsp90alpha can serve as a chaperone for precursors of pMHC I at an early stage in the antigen processing pathway.
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Affiliation(s)
- Jun Kunisawa
- Division of Immunology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, USA
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148
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Peters B, Bui HH, Frankild S, Nielson M, Lundegaard C, Kostem E, Basch D, Lamberth K, Harndahl M, Fleri W, Wilson SS, Sidney J, Lund O, Buus S, Sette A. A community resource benchmarking predictions of peptide binding to MHC-I molecules. PLoS Comput Biol 2006; 2:e65. [PMID: 16789818 PMCID: PMC1475712 DOI: 10.1371/journal.pcbi.0020065] [Citation(s) in RCA: 227] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2006] [Accepted: 04/25/2006] [Indexed: 11/18/2022] Open
Abstract
Recognition of peptides bound to major histocompatibility complex (MHC) class I molecules by T lymphocytes is an essential part of immune surveillance. Each MHC allele has a characteristic peptide binding preference, which can be captured in prediction algorithms, allowing for the rapid scan of entire pathogen proteomes for peptide likely to bind MHC. Here we make public a large set of 48,828 quantitative peptide-binding affinity measurements relating to 48 different mouse, human, macaque, and chimpanzee MHC class I alleles. We use this data to establish a set of benchmark predictions with one neural network method and two matrix-based prediction methods extensively utilized in our groups. In general, the neural network outperforms the matrix-based predictions mainly due to its ability to generalize even on a small amount of data. We also retrieved predictions from tools publicly available on the internet. While differences in the data used to generate these predictions hamper direct comparisons, we do conclude that tools based on combinatorial peptide libraries perform remarkably well. The transparent prediction evaluation on this dataset provides tool developers with a benchmark for comparison of newly developed prediction methods. In addition, to generate and evaluate our own prediction methods, we have established an easily extensible web-based prediction framework that allows automated side-by-side comparisons of prediction methods implemented by experts. This is an advance over the current practice of tool developers having to generate reference predictions themselves, which can lead to underestimating the performance of prediction methods they are not as familiar with as their own. The overall goal of this effort is to provide a transparent prediction evaluation allowing bioinformaticians to identify promising features of prediction methods and providing guidance to immunologists regarding the reliability of prediction tools. In higher organisms, major histocompatibility complex (MHC) class I molecules are present on nearly all cell surfaces, where they present peptides to T lymphocytes of the immune system. The peptides are derived from proteins expressed inside the cell, and thereby allow the immune system to “peek inside” cells to detect infections or cancerous cells. Different MHC molecules exist, each with a distinct peptide binding specificity. Many algorithms have been developed that can predict which peptides bind to a given MHC molecule. These algorithms are used by immunologists to, for example, scan the proteome of a given virus for peptides likely to be presented on infected cells. In this paper, the authors provide a large-scale experimental dataset of quantitative MHC–peptide binding data. Using this dataset, they compare how well different approaches are able to identify binding peptides. This comparison identifies an artificial neural network as the most successful approach to peptide binding prediction currently available. This comparison serves as a benchmark for future tool development, allowing bioinformaticians to document advances in tool development as well as guiding immunologists to choose good prediction algorithm.
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Affiliation(s)
- Bjoern Peters
- La Jolla Institute for Allergy and Immunology, San Diego, California, USA.
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149
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Dishaw LJ, Herrera ML, Bigger CH. Characterization and phylogenetic analysis of a cnidarian LMP X-like cDNA. Immunogenetics 2006; 58:454-64. [PMID: 16552514 DOI: 10.1007/s00251-006-0105-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2005] [Accepted: 02/15/2006] [Indexed: 12/01/2022]
Abstract
Proteasomes are multisubunit protease complexes which are partly responsible for metabolism of intracellular, ubiquitinylated proteins. Vertebrates have adapted a second and specialized structure responsible for the generation of peptides presented to the adaptive immune system and is thus, commonly referred to as the immunoproteasome. This complex is assembled from paralogous copies of subunits belonging to the constitutive, housekeeping proteasome. The immunoproteasome is more efficient in the generation of peptides for display on major histocompatibility complex (MHC) molecules. Important components of this complex are the paralogous members, LMP X and 7; where the latter replaces the former in the assembly of the immunoproteasome of vertebrates. In this report, we describe an LMP X-like cDNA from an endosymbiont-free gorgonian coral, Swiftia exserta. Cnidarians predate the phylogenetic divergence of protostomes and deuterostomes (P-D split), and are becoming an essential model for our comprehension of immune system evolution. Phylogenetic analyses of available sequences indicates that invertebrate LMP X-like sequences are outgroups to vertebrate LMP X and LMP 7, and is in agreement with previous observations that the duplication event giving rise to the two rapidly diverging lineages of proteasomal subunits occurred before jawed fished divergence.
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Affiliation(s)
- Larry J Dishaw
- Department of Biological Sciences, Florida International University, Miami, FL, 33199, USA
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150
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Lecker SH, Goldberg AL, Mitch WE. Protein degradation by the ubiquitin-proteasome pathway in normal and disease states. J Am Soc Nephrol 2006; 17:1807-19. [PMID: 16738015 DOI: 10.1681/asn.2006010083] [Citation(s) in RCA: 870] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- Stewart H Lecker
- Nephrology Division, Beth Isreal Deaconess, Harvard Medical School, Boston, Massachusetts, USA
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