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Abstract
T cells respond to threats in an antigen-specific manner using T cell receptors (TCRs) that recognize short peptide antigens presented on major histocompatibility complex (MHC) proteins. The TCR-peptide-MHC interaction mediated between a T cell and its target cell dictates its function and thereby influences its role in disease. A lack of approaches for antigen discovery has limited the fundamental understanding of the antigenic landscape of the overall T cell response. Recent advances in high-throughput sequencing, mass cytometry, microfluidics and computational biology have led to a surge in approaches to address the challenge of T cell antigen discovery. Here, we summarize the scope of this challenge, discuss in depth the recent exciting work and highlight the outstanding questions and remaining technical hurdles in this field.
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Brown LV, Gaffney EA, Wagg J, Coles MC. An in silico model of cytotoxic T-lymphocyte activation in the lymph node following short peptide vaccination. J R Soc Interface 2019. [PMID: 29540543 DOI: 10.1098/rsif.2018.0041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Tumour immunotherapy is dependent upon activation and expansion of tumour-targetting immune cells, known as cytotoxic T-lymphocytes (CTLs). Cancer vaccines developed in the past have had limited success and the mechanisms resulting in failure are not well characterized. To elucidate these mechanisms, we developed a human-parametrized, in silico, agent-based model of vaccination-driven CTL activation within a clinical short-peptide vaccination context. The simulations predict a sharp transition in the probability of CTL activation, which occurs with variation in the separation rate (or off-rate) of tumour-specific immune response-inducing peptides (cognate antigen) from the major histocompatibility class I (MHC-I) receptors of dendritic cells (DCs) originally at the vaccination site. For peptides with MHC-I off-rates beyond this transition, it is predicted that no vaccination strategy will lead to successful expansion of CTLs. For slower off-rates, below the transition, the probability of CTL activation becomes sensitive to the numbers of DCs and T cells that interact subsequent to DC migration to the draining lymph node of the vaccination site. Thus, the off-rate is a key determinant of vaccine design.
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Affiliation(s)
- Liam V Brown
- Wolfson Centre For Mathematical Biology, Mathematical Institute, University of Oxford, Oxford, UK
| | - Eamonn A Gaffney
- Wolfson Centre For Mathematical Biology, Mathematical Institute, University of Oxford, Oxford, UK
| | - Jonathan Wagg
- Clinical Pharmacology, Roche Innovation Center Basel, Basel, Switzerland
| | - Mark C Coles
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
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3
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Nelde A, Kowalewski DJ, Stevanović S. Purification and Identification of Naturally Presented MHC Class I and II Ligands. Methods Mol Biol 2019; 1988:123-136. [PMID: 31147937 DOI: 10.1007/978-1-4939-9450-2_10] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The large-scale and in-depth identification of MHC class I- and II-presented peptides is indispensable for gaining insight into the fundamental rules of immune recognition as well as for developing innovative immunotherapeutic approaches against cancer and other diseases. In this chapter we briefly review the existing strategies for the isolation of MHC-restricted peptides and provide a detailed protocol for the immunoaffinity purification of MHC class I- and II-presented peptides from primary tissues or cells.
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Affiliation(s)
- Annika Nelde
- Department of Immunology, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany
| | - Daniel J Kowalewski
- Department of Immunology, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany
| | - Stefan Stevanović
- Department of Immunology, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany.
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4
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Lowe DB, Bivens CK, Mobley AS, Herrera CE, McCormick AL, Wichner T, Sabnani MK, Wood LM, Weidanz JA. TCR-like antibody drug conjugates mediate killing of tumor cells with low peptide/HLA targets. MAbs 2018; 9:603-614. [PMID: 28273004 DOI: 10.1080/19420862.2017.1302630] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
The currently marketed antibody-drug conjugates (ADC) destabilize microtubule assembly in cancer cells and initiate apoptosis in patients. However, few tumor antigens (TA) are expressed at high densities on cancer lesions, potentially minimizing the therapeutic index of current ADC regimens. The peptide/human leukocyte antigen (HLA) complex can be specifically targeted by therapeutic antibodies (designated T cell receptor [TCR]-like antibodies) and adequately distinguish malignant cells, but has not been the focus of ADC development. We analyzed the killing potential of TCR-like ADCs when cross-linked to the DNA alkylating compound duocarmycin. Our data comprise proof-of-principle results that TCR-like ADCs mediate potent tumor cytotoxicity, particularly under common scenarios of low TA/HLA density, and support their continued development alongside agents that disrupt DNA replication. Additionally, TCR-like antibody ligand binding appears to play an important role in ADC functionality and should be addressed during therapy development to avoid binding patterns that negate ADC killing efficacy.
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Affiliation(s)
- Devin B Lowe
- a Department of Immunotherapeutics and Biotechnology , School of Pharmacy, Texas Tech University Health Sciences Center , Abilene , TX , USA
| | - Camille K Bivens
- a Department of Immunotherapeutics and Biotechnology , School of Pharmacy, Texas Tech University Health Sciences Center , Abilene , TX , USA
| | - Alexis S Mobley
- a Department of Immunotherapeutics and Biotechnology , School of Pharmacy, Texas Tech University Health Sciences Center , Abilene , TX , USA
| | - Christian E Herrera
- a Department of Immunotherapeutics and Biotechnology , School of Pharmacy, Texas Tech University Health Sciences Center , Abilene , TX , USA
| | - Amanda L McCormick
- a Department of Immunotherapeutics and Biotechnology , School of Pharmacy, Texas Tech University Health Sciences Center , Abilene , TX , USA
| | - Timea Wichner
- a Department of Immunotherapeutics and Biotechnology , School of Pharmacy, Texas Tech University Health Sciences Center , Abilene , TX , USA
| | - Manoj K Sabnani
- b Department of Biology , College of Science, University of Texas at Arlington , Arlington , TX , USA
| | - Laurence M Wood
- a Department of Immunotherapeutics and Biotechnology , School of Pharmacy, Texas Tech University Health Sciences Center , Abilene , TX , USA
| | - Jon A Weidanz
- b Department of Biology , College of Science, University of Texas at Arlington , Arlington , TX , USA
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5
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Bentzen AK, Marquard AM, Lyngaa R, Saini SK, Ramskov S, Donia M, Such L, Furness AJS, McGranahan N, Rosenthal R, Straten PT, Szallasi Z, Svane IM, Swanton C, Quezada SA, Jakobsen SN, Eklund AC, Hadrup SR. Large-scale detection of antigen-specific T cells using peptide-MHC-I multimers labeled with DNA barcodes. Nat Biotechnol 2016; 34:1037-1045. [PMID: 27571370 DOI: 10.1038/nbt.3662] [Citation(s) in RCA: 225] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 08/04/2016] [Indexed: 01/17/2023]
Abstract
Identification of the peptides recognized by individual T cells is important for understanding and treating immune-related diseases. Current cytometry-based approaches are limited to the simultaneous screening of 10-100 distinct T-cell specificities in one sample. Here we use peptide-major histocompatibility complex (MHC) multimers labeled with individual DNA barcodes to screen >1,000 peptide specificities in a single sample, and detect low-frequency CD8 T cells specific for virus- or cancer-restricted antigens. When analyzing T-cell recognition of shared melanoma antigens before and after adoptive cell therapy in melanoma patients, we observe a greater number of melanoma-specific T-cell populations compared with cytometry-based approaches. Furthermore, we detect neoepitope-specific T cells in tumor-infiltrating lymphocytes and peripheral blood from patients with non-small cell lung cancer. Barcode-labeled pMHC multimers enable the combination of functional T-cell analysis with large-scale epitope recognition profiling for the characterization of T-cell recognition in various diseases, including in small clinical samples.
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Affiliation(s)
- Amalie Kai Bentzen
- Section for Immunology and Vaccinology, National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark
| | - Andrea Marion Marquard
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Rikke Lyngaa
- Section for Immunology and Vaccinology, National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark
| | - Sunil Kumar Saini
- Section for Immunology and Vaccinology, National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark
| | - Sofie Ramskov
- Section for Immunology and Vaccinology, National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark
| | - Marco Donia
- Center for Cancer Immune Therapy, Department of Hematology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
- Department of Oncology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Lina Such
- Section for Immunology and Vaccinology, National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark
| | - Andrew J S Furness
- CRUK Lung Cancer Center of Excellence, UCL Cancer Institute, London, UK
- Cancer Immunology Unit, UCL Cancer Institute, University College London, London, UK
| | - Nicholas McGranahan
- CRUK Lung Cancer Center of Excellence, UCL Cancer Institute, London, UK
- Translational Cancer Therapeutics Laboratory, The Francis Crick Institute, London, UK
| | - Rachel Rosenthal
- CRUK Lung Cancer Center of Excellence, UCL Cancer Institute, London, UK
- Translational Cancer Therapeutics Laboratory, The Francis Crick Institute, London, UK
| | - Per Thor Straten
- Center for Cancer Immune Therapy, Department of Hematology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
- Department of Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark
| | - Zoltan Szallasi
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Inge Marie Svane
- Center for Cancer Immune Therapy, Department of Hematology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
- Department of Oncology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Charles Swanton
- CRUK Lung Cancer Center of Excellence, UCL Cancer Institute, London, UK
- Translational Cancer Therapeutics Laboratory, The Francis Crick Institute, London, UK
| | - Sergio A Quezada
- CRUK Lung Cancer Center of Excellence, UCL Cancer Institute, London, UK
- Cancer Immunology Unit, UCL Cancer Institute, University College London, London, UK
| | - Søren Nyboe Jakobsen
- Section for Immunology and Vaccinology, National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark
- Immudex, Copenhagen, Denmark
| | - Aron Charles Eklund
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Sine Reker Hadrup
- Section for Immunology and Vaccinology, National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark
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6
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Immunological challenges for peptide-based immunotherapy in glioblastoma. Cancer Treat Rev 2014; 40:248-58. [DOI: 10.1016/j.ctrv.2013.08.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 08/28/2013] [Accepted: 08/30/2013] [Indexed: 02/04/2023]
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Alloreactive cytotoxic T cells provide means to decipher the immunopeptidome and reveal a plethora of tumor-associated self-epitopes. Proc Natl Acad Sci U S A 2013; 111:403-8. [PMID: 24344295 DOI: 10.1073/pnas.1306549111] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
HLA molecules presenting peptides derived from tumor-associated self-antigens (self-TAA) are attractive targets for T-cell-based immunotherapy of cancer. However, detection of such epitopes is hampered by self-tolerance and limitations in the sensitivity of mass spectrometry. Here, we used T cells from HLA-A2-negative donors as tools to detect HLA-A2-bound peptides from two leukemia-associated differentiation antigens; CD20 and the previously undescribed cancer target myeloperoxidase. A high-throughput platform for epitope discovery was designed using dendritic cells cotransfected with full-length transcripts of self-TAA and HLA-A2 to allow presentation of all naturally processed peptides from a predefined self-protein on foreign HLA. Antigen-reactive T cells were directly detected using panels of color-coded peptide-HLA multimers containing epitopes predicted by a computer algorithm. Strikingly, cytotoxic T cells were generated against 37 out of 50 peptides predicted to bind HLA-A2. Among these, 36 epitopes were previously undescribed. The allorestricted T cells were exquisitely peptide- and HLA-specific and responded strongly to HLA-A2-positive leukemic cells with endogenous expression of CD20 or myeloperoxidase. These results indicate that the repertoire of self-peptides presented on HLA class I has been underestimated and that a wealth of self-TAA can be targeted by T cells when using nontolerized T-cell repertoires.
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Sturm T, Leinders-Zufall T, Maček B, Walzer M, Jung S, Pömmerl B, Stevanović S, Zufall F, Overath P, Rammensee HG. Mouse urinary peptides provide a molecular basis for genotype discrimination by nasal sensory neurons. Nat Commun 2013; 4:1616. [PMID: 23511480 DOI: 10.1038/ncomms2610] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 02/15/2013] [Indexed: 01/07/2023] Open
Abstract
Selected groups of peptides, including those that are presented by major histocompatibility complex (MHC) proteins, have been proposed to transmit information to the olfactory system of vertebrates via their ability to stimulate chemosensory neurons. However, the lack of knowledge about such peptides in natural sources accessible for nasal recognition has been a major barrier for this hypothesis. Here we analyse urinary peptides from selected mouse strains with respect to genotype-related individual differences. We discover many abundant peptides with single amino-acid variations corresponding to genomic differences. The polymorphism of major urinary proteins is reflected by variations in prominent urinary peptides. We also demonstrate an MHC-dependent peptide (SIINFEKL) occurring at very low concentrations in mouse urine. Chemoreceptive neurons in the vomeronasal organ detect and discriminate single amino-acid variation peptides as well as SIINFEKL. Hence, urinary peptides represent a real-time sampling of the expressed genome available for chemosensory assessment by other individuals.
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Affiliation(s)
- Theo Sturm
- Department of Immunology, Institute for Cell Biology, University of Tübingen, Tübingen, Germany
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Rammensee HG, Singh-Jasuja H. HLA ligandome tumor antigen discovery for personalized vaccine approach. Expert Rev Vaccines 2013; 12:1211-7. [PMID: 24090147 PMCID: PMC3821395 DOI: 10.1586/14760584.2013.836911] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Every cancer is different and cancer cells differ from normal cells, in particular, through genetic alterations. HLA molecules on the cell surface enable T lymphocytes to recognize cellular alterations as antigens, including mutations, increase in gene product copy numbers or expression of genes usually not used in the adult organism. The search for cancer-associated antigens shared by many patients with a particular cancer has yielded a number of hits used in clinical vaccination trials with indication of survival benefit. Targeting cancer-specific antigens, which are exclusively expressed on cancer cells and not on normal cells, holds the promise for much better results and perhaps even a cure. Such antigens, however, may specifically appear in very few patients or may be mutated appearing just in one patient. Therefore, to target these in a molecularly defined way, the approach has to be individualized.
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Affiliation(s)
- Hans-Georg Rammensee
- Department of Immunology, Institute of Cell Biology, and German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ) Partner Site Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
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10
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Abstract
The large-scale identification of MHC class I presented peptides is indispensable for gaining insight into the fundamental rules of immune recognition as well as it is an invaluable tool in identifying potential targets for the immunotherapy of disease. In this chapter we briefly review the existing strategies for the analysis of MHC ligandomes and provide an in-depth protocol for the immunoaffinity purification of MHC class I presented peptides from primary tissues or cells.
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11
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Luciani F, Sanders MT, Oveissi S, Pang KC, Chen W. Increasing viral dose causes a reversal in CD8+ T cell immunodominance during primary influenza infection due to differences in antigen presentation, T cell avidity, and precursor numbers. THE JOURNAL OF IMMUNOLOGY 2012; 190:36-47. [PMID: 23233728 DOI: 10.4049/jimmunol.1200089] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
T cell responses are characterized by the phenomenon of immunodominance (ID), whereby peptide-specific T cells are elicited in a reproducible hierarchy of dominant and subdominant responses. However, the mechanisms that give rise to ID are not well understood. We investigated the effect of viral dose on primary CD8(+) T cell (T(CD8+)) ID by injecting mice i.p. with various doses of influenza A virus and assessing the primary T(CD8+) response to five dominant and subdominant peptides. Increasing viral dose enhanced the overall strength of the T(CD8+) response, and it altered the ID hierarchy: specifically, NP(366-374) T(CD8+) were dominant at low viral doses but were supplanted by PA(224-233) T(CD8+) at high doses. To understand the basis for this reversal, we mathematically modeled these T(CD8+) responses and used Bayesian statistics to obtain estimates for Ag presentation, T(CD8+) precursor numbers, and avidity. Interestingly, at low viral doses, Ag presentation most critically shaped ID hierarchy, enabling T(CD8+) specific to the more abundantly presented NP(366-374) to dominate. By comparison, at high viral doses, T(CD8+) avidity and precursor numbers appeared to be the major influences on ID hierarchy, resulting in PA(224-233) T(CD8+) usurping NP(366-374) cells as the result of higher avidity and precursor numbers. These results demonstrate that the nature of primary T(CD8+) responses to influenza A virus is highly influenced by Ag dose, which, in turn, determines the relative importance of Ag presentation, T(CD8+) avidity, and precursor numbers in shaping the ID hierarchy. These findings provide valuable insights for future T(CD8+)-based vaccination strategies.
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Affiliation(s)
- Fabio Luciani
- Infection and Inflammation Research Centre, School of Medical Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia
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12
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Currie J, Castro M, Lythe G, Palmer E, Molina-París C. A stochastic T cell response criterion. J R Soc Interface 2012; 9:2856-70. [PMID: 22745227 PMCID: PMC3479899 DOI: 10.1098/rsif.2012.0205] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The adaptive immune system relies on different cell types to provide fast and coordinated responses, characterized by recognition of pathogenic challenge, extensive cellular proliferation and differentiation, as well as death. T cells are a subset of the adaptive immune cellular pool that recognize immunogenic peptides expressed on the surface of antigen-presenting cells by means of specialized receptors on their membrane. T cell receptor binding to ligand determines T cell responses at different times and locations during the life of a T cell. Current experimental evidence provides support to the following: (i) sufficiently long receptor–ligand engagements are required to initiate the T cell signalling cascade that results in productive signal transduction and (ii) counting devices are at work in T cells to allow signal accumulation, decoding and translation into biological responses. In the light of these results, we explore, with mathematical models, the timescales associated with T cell responses. We consider two different criteria: a stochastic one (the mean time it takes to have had N receptor–ligand complexes bound for at least a dwell time, τ, each) and one based on equilibrium (the time to reach a threshold number N of receptor–ligand complexes). We have applied mathematical models to previous experiments in the context of thymic negative selection and to recent two-dimensional experiments. Our results indicate that the stochastic criterion provides support to the thymic affinity threshold hypothesis, whereas the equilibrium one does not, and agrees with the ligand hierarchy experimentally established for thymic negative selection.
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Affiliation(s)
- James Currie
- Department of Applied Mathematics, School of Mathematics, University of Leeds, Leeds LS2 9JT, UK
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13
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de Miranda NFCC, Hes FJ, van Wezel T, Morreau H. Role of the microenvironment in the tumourigenesis of microsatellite unstable and MUTYH-associated polyposis colorectal cancers. Mutagenesis 2012; 27:247-53. [DOI: 10.1093/mutage/ger077] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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de Miranda NFCC, Goudkade D, Jordanova ES, Tops CMJ, Hes FJ, Vasen HFA, van Wezel T, Morreau H. Infiltration of Lynch colorectal cancers by activated immune cells associates with early staging of the primary tumor and absence of lymph node metastases. Clin Cancer Res 2012; 18:1237-45. [PMID: 22261803 DOI: 10.1158/1078-0432.ccr-11-1997] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE Lynch syndrome colorectal cancers often lose human leukocyte antigen (HLA) class I expression. The outgrowth of clones with immune evasive phenotypes is thought to be positively selected by the action of cytotoxic T cells that target HLA class I-positive cancer cells. To investigate this hypothesis, we related the type and density of tumor lymphocytic infiltrate in Lynch colorectal cancers with their HLA class I phenotype and clinicopathologic stage. EXPERIMENTAL DESIGN HLA class I expression was assessed by means of immunohistochemistry. Characterization of tumor-infiltrating lymphocytes was carried out by using a triple immunofluorescence procedure that allowed the simultaneous detection of CD3-, CD8-, and granzyme B (GZMB)-positive cells. Additional markers were also used for further characterization of an elusive CD3(-)/CD8(-)/GZMB(+) cell population. RESULTS We discovered that high tumor infiltration by activated CD8(+) T cells correlated with aberrant HLA class I expression and associated with early tumor stages (P < 0.05). CD8(+) T cells were most abundant in HLA class I heterogeneous tumors (P = 0.02) and frequent in HLA class I-negative cases (P = 0.04) when compared with HLA class I-positive carcinomas. An elusive immune cell population (CD45(+)/CD8(-)/CD56(-)/GZMB(+)) was characteristic for HLA class I-negative tumors lacking lymph node metastases (P < 0.01). CONCLUSIONS The immune system assumes an important role in counteracting the progression of Lynch colorectal cancers and in selecting abnormal HLA class I phenotypes. Our findings support the development of clinical strategies that explore the natural antitumor immune responses occurring in Lynch syndrome carriers.
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Myers CE, Hanavan P, Antwi K, Mahadevan D, Nadeem AJ, Cooke L, Scheck AC, Laughrey Z, Lake DF. CTL recognition of a novel HLA-A*0201-binding peptide derived from glioblastoma multiforme tumor cells. Cancer Immunol Immunother 2011; 60:1319-32. [PMID: 21626031 PMCID: PMC11028898 DOI: 10.1007/s00262-011-1032-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 05/09/2011] [Indexed: 12/22/2022]
Abstract
Genetic instability of tumor cells can result in translation of proteins that are out of frame, resulting in expression of neopeptides. These neopeptides are not self-proteins and therefore should be immunogenic. By eluting peptides from human glioblastoma multiforme (GBM) tumor cell surfaces and subjecting them to tandem mass spectrometry, we identified a novel peptide (KLWGLTPKVTPS) corresponding to a frameshift in the 3' beta-hydroxysteroid dehydrogenase type 7 (HSD3B7) gene. HLA-binding algorithms predicted that a 9-amino acid sequence embedded in this peptide would bind to HLA-A*0201. We confirmed this prediction using an HLA-A*0201 refolding assay followed by live cell relative affinity assays, but also showed that the 12-mer binds to HLA-A*0201. Based on the 9-mer sequence, optimized peptide ligands (OPL) were designed and tested for their affinities to HLA-A*0201 and their abilities to elicit anti-peptide and CTL capable of killing GBM in vitro. Wild-type peptides as well as OPL induced anti-peptide CTL as measured by IFN-γ ELISPOTS. These CTL also killed GBM tumor cells in chromium-51 release assays. This study reports a new CTL target in GBM and further substantiates the concept that rational design and testing of multiple peptides for the same T-cell epitope elicits a broader response among different individuals than single peptide immunization.
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Affiliation(s)
- Cheryl E. Myers
- School of Life Sciences, Arizona State University, Tempe, AZ 85287 USA
| | - Paul Hanavan
- School of Life Sciences, Arizona State University, Tempe, AZ 85287 USA
| | - Kwasi Antwi
- School of Life Sciences, Arizona State University, Tempe, AZ 85287 USA
| | - Daruka Mahadevan
- Department of Medicine, Arizona Cancer Center, University of Arizona, Tucson, AZ 85724 USA
| | - A. Jamal Nadeem
- Department of Medicine, Arizona Cancer Center, University of Arizona, Tucson, AZ 85724 USA
| | - Laurence Cooke
- Department of Medicine, Arizona Cancer Center, University of Arizona, Tucson, AZ 85724 USA
| | | | - Zachary Laughrey
- Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287 USA
| | - Douglas F. Lake
- School of Life Sciences, Arizona State University, Tempe, AZ 85287 USA
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16
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Mester G, Hoffmann V, Stevanović S. Insights into MHC class I antigen processing gained from large-scale analysis of class I ligands. Cell Mol Life Sci 2011; 68:1521-32. [PMID: 21387142 PMCID: PMC11114492 DOI: 10.1007/s00018-011-0659-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 02/17/2011] [Accepted: 02/18/2011] [Indexed: 01/06/2023]
Abstract
Short peptides derived from intracellular proteins and presented on MHC class I molecules on the cell surface serve as a showcase for the immune system to detect pathogenic or malignant alterations inside the cell, and the sequencing and analysis of the presented peptide pool has received considerable attention over the last two decades. In this review, we give a comprehensive presentation of the methods employed for the large-scale qualitative and quantitative analysis of the MHC class I ligandome. Furthermore, we focus on insights gained into the underlying processing pathway, especially involving the roles of the proteasome, the TAP complex, and the peptide specificities and motifs of MHC molecules. The identification of post-translational modifications in MHC ligands and their implications for processing are also considered. Finally, we review the correlations of the ligandome to the proteome and the transcriptome.
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Affiliation(s)
- Gabor Mester
- Institute for Cell Biology, Department of Immunology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Vanessa Hoffmann
- Institute for Cell Biology, Department of Immunology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Stefan Stevanović
- Institute for Cell Biology, Department of Immunology, Eberhard Karls University Tübingen, Tübingen, Germany
- Abteilung für Immunologie, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 15, 72076 Tübingen, Germany
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17
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Abstract
T-cells are a vital type of white blood cell that circulate around our bodies, scanning for cellular abnormalities and infections. They recognise disease-associated antigens via a surface receptor called the T-cell antigen receptor (TCR). If there were a specific TCR for every single antigen, no mammal could possibly contain all the T-cells it needs. This is clearly absurd and suggests that T-cell recognition must, to the contrary, be highly degenerate. Yet highly promiscuous TCRs would appear to be equally impossible: they are bound to recognise self as well as non-self antigens. We review how contributions from mathematical analysis have helped to resolve the paradox of the promiscuous TCR. Combined experimental and theoretical work shows that TCR degeneracy is essentially dynamical in nature, and that the T-cell can differentially adjust its functional sensitivity to the salient epitope, "tuning up" sensitivity to the antigen associated with disease and "tuning down" sensitivity to antigens associated with healthy conditions. This paradigm of continual modulation affords the TCR repertoire, despite its limited numerical diversity, the flexibility to respond to almost any antigenic challenge while avoiding autoimmunity.
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Affiliation(s)
| | | | - Andrew K. Sewell
- Department of Medical Biochemistry and Immunology of the Cardiff University School of Medicine
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18
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Baxevanis CN, Voutsas IF, Gritzapis AD, Perez SA, Papamichail M. HER-2/neu as a target for cancer vaccines. Immunotherapy 2010; 2:213-26. [PMID: 20635929 DOI: 10.2217/imt.09.89] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
A novel modality toward the treatment of HER-2/neu-positive malignancies, mostly including breast and, more recently prostate carcinomas, has been the use of vaccines targeting HER-2/neu extracellular and intracellular domains. HER-2/neu-specific vaccines have been demonstrated to generate durable T-cell anti-HER-2/neu immunity when tested in Phase I and II clinical trials with no significant toxicity or autoimmunity directed against normal tissues. Targeting of HER-2/neu in active immunotherapy may involve peptide and DNA vaccines. Moreover, active anti-HER-2/neu immunization could facilitate the ex vivo expansion of HER-2/neu-specific T cells for use in adoptive immunotherapy for the treatment of established metastatic disease. In addition, early data from trials examining the potential use of HER-2/neu-based vaccines in the adjuvant setting to prevent the relapse of breast cancer in high-risk patients have shown promising results. Future approaches include multiepitope preventive vaccines and combinatorial treatments for generating the most efficient protective anti-tumor immunity.
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Kapoerchan VV, Wiesner M, Hillaert U, Drijfhout JW, Overhand M, Alard P, van der Marel GA, Overkleeft HS, Koning F. Design, synthesis and evaluation of high-affinity binders for the celiac disease associated HLA-DQ2 molecule. Mol Immunol 2009; 47:1091-7. [PMID: 19962195 DOI: 10.1016/j.molimm.2009.10.036] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2009] [Accepted: 10/29/2009] [Indexed: 11/26/2022]
Abstract
Celiac disease is caused by uncontrolled CD4 T-cell responses directed to wheat-derived gluten peptides bound to the disease predisposing HLA-DQ molecules. The only available treatment is a life-long gluten-free diet which is complicated by the widespread use of wheat-derived gluten in the food industry. As the binding of gluten-derived peptides is a prerequisite for the induction of the inflammatory T-cell response, blockers that would prevent gluten peptide binding to the HLA-DQ molecules might be used as an alternative to the gluten-free diet. In the present study we have analyzed the binding properties of a set of previously identified natural ligands for HLA-DQ2, the primary disease predisposing allele. An in silico method, Epibase, ranked these peptides and the top one, a peptide with a nine amino acid core FVAEYEPVL, was measured among these peptides as the peptide with the highest binding affinity for HLA-DQ2. In a stepwise approach we subsequently tested the impact of N-terminal extensions and systematic single amino acid substitutions within the core of this peptide which revealed that an N-terminal extension with the tripeptide sequence ADA increased binding affinity 5- to 6-fold. In addition the substitution analysis indicated which amino acids were most preferred at anchor residues in the lead peptide, generally leading to an increase of binding affinity with a factor of 2. Next we tested which combinations of such preferred amino acids yielded the best results. The combined results indicate that a peptide with sequence ADAYDYESEELFAA (core in bold) had superior binding properties. This peptide was chosen as a lead peptide for further optimization with non-natural amino acids at the p1 position, since molecular modeling indicated that none of the natural amino acids is able to optimally occupy the p1 pocket. A set of 8 non-proteinogenic amino acids was designed, synthesized and incorporated in the lead peptide (and in two control peptides) and tested for binding to HLA-DQ2. The results indicate that the effect of the incorporation of these non-proteinogenic amino acids depended on the peptide in which they were incorporated and that the maximum increase in binding affinity obtained was approximately 2-fold. Altogether lead sequences were obtained that have a binding affinity for HLA-DQ2 that is 100- to 200-fold higher compared to that of the gluten-derived peptide that has the highest affinity for HLA-DQ2. Such peptides are candidate lead peptides for further optimization. Our results, however, also indicate that in order to obtain further significant increases in binding affinity alternative approaches will have to be explored.
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Affiliation(s)
- Varsha V Kapoerchan
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden, The Netherlands
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20
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Immune evasion proteins of murine cytomegalovirus preferentially affect cell surface display of recently generated peptide presentation complexes. J Virol 2009; 84:1221-36. [PMID: 19906905 DOI: 10.1128/jvi.02087-09] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
For recognition of infected cells by CD8 T cells, antigenic peptides are presented at the cell surface, bound to major histocompatibility complex class I (MHC-I) molecules. Downmodulation of cell surface MHC-I molecules is regarded as a hallmark function of cytomegalovirus-encoded immunoevasins. The molecular mechanisms by which immunoevasins interfere with the MHC-I pathway suggest, however, that this downmodulation may be secondary to an interruption of turnover replenishment and that hindrance of the vesicular transport of recently generated peptide-MHC (pMHC) complexes to the cell surface is the actual function of immunoevasins. Here we have used the model of murine cytomegalovirus (mCMV) infection to provide experimental evidence for this hypothesis. To quantitate pMHC complexes at the cell surface after infection in the presence and absence of immunoevasins, we generated the recombinant viruses mCMV-SIINFEKL and mCMV-Deltam06m152-SIINFEKL, respectively, expressing the K(b)-presented peptide SIINFEKL with early-phase kinetics in place of an immunodominant peptide of the viral carrier protein gp36.5/m164. The data revealed approximately 10,000 K(b) molecules presenting SIINFEKL in the absence of immunoevasins, which is an occupancy of approximately 10% of all cell surface K(b) molecules, whereas immunoevasins reduced this number to almost the detection limit. To selectively evaluate their effect on preexisting pMHC complexes, cells were exogenously loaded with SIINFEKL peptide shortly after infection with mCMV-SIINFEKA, in which endogenous presentation is prevented by an L174A mutation of the C-terminal MHC-I anchor residue. The data suggest that pMHC complexes present at the cell surface in advance of immunoevasin gene expression are downmodulated due to constitutive turnover in the absence of resupply.
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de Miranda NFCC, Nielsen M, Pereira D, van Puijenbroek M, Vasen HF, Hes FJ, van Wezel T, Morreau H. MUTYH-associated polyposis carcinomas frequently lose HLA class I expression-a common event amongst DNA-repair-deficient colorectal cancers. J Pathol 2009; 219:69-76. [DOI: 10.1002/path.2569] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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23
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Variation in cytotoxic T-lymphocyte responses to peptides derived from tyrosinase-related protein-2. Hum Immunol 2007; 69:24-31. [PMID: 18295672 DOI: 10.1016/j.humimm.2007.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Revised: 11/21/2007] [Accepted: 11/28/2007] [Indexed: 11/20/2022]
Abstract
In this study, we developed three optimized peptide ligands (OPL) that demonstrate increased affinities for HLA-A*0201 compared with wild-type tyrosinase-related protein-2 (TRP-2) peptide. The OPL contain amino acids from TRP-2((180-188)) and preferred primary and auxiliary HLA-A*0201 anchor residues. Cytotoxic T lymphocyte (CTL) lines were generated against wild-type TRP-2 peptide and OPL by multiple rounds of peptide stimulation of peripheral blood mononuclear cells from HLA-A2*0201(+) healthy individuals. CTL reactivity profiles to three different OPL were donor-dependent. Among donors, at least one OPL was particularly stimulatory and elicited high levels of CTL that cross-reacted with wild-type TRP-2 peptide. Cytotoxicity assays using CTL raised on wild-type TRP-2 peptide or OPL demonstrated lysis of HLA-A2-positive glioblastoma cells. Molecular models of TRP-2 and OPL peptides docked with HLA-A*0201 demonstrated that substitution of F for S at position 1 (P1) oriented the peptides favoring a pi-pi aromatic interaction with W 167 of HLA-A*0201. This in turn positions P5 and P8 aromatic rings to face solvent that may promote binding to the T-cell receptor, leading to a robust T-cell activation. The results of this study further substantiate the concept that rational design and testing of multiple peptides for the same T-cell epitope should elicit a broader response among different individuals than single peptide immunization. Our results may partially explain why some patients have better clinical responses to peptide-based immunotherapy, whereas others respond poorly.
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24
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Voutsas IF, Gritzapis AD, Mahaira LG, Salagianni M, Hofe EV, Kallinteris NL, Baxevanis CN. Induction of potent CD4+ T cell-mediated antitumor responses by a helper HER-2/neu peptide linked to the Ii-Key moiety of the invariant chain. Int J Cancer 2007; 121:2031-2041. [PMID: 17634957 DOI: 10.1002/ijc.22936] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Ii-Key fragment from the MHC class II-associated invariant chain (or Ii protein) has been shown to facilitate direct charging of MHC class II epitopes to the peptide binding groove. The purpose of the present study was to test the potential of a series of Ii-Key/HER-2/neu776-790 hybrid peptides to generate increased frequencies of peptide-specific CD4+ T cells over the native peptide in mice transgenic (Tg) for a chimeric human mouse class II molecule (DR4-IE) (H-2b) as well as their antitumor potency. Following in vivo priming, such hybrid peptides induced increased proliferation and frequencies of IFN-gamma producing CD4+ T cells in response to either syngeneic dendritic cells pulsed with native peptide, or HLA-DR4+ human tumor cell lines expressing HER-2/neu. Hybrid peptides were more stable in an off-rate kinetics assay compared to the native peptide. In addition, antigen-specific CD4+ T cells from hybrid peptide immunized DR4-IE Tg mice synergized with HER-2/neu(435-443)-specific CD8+ T cells from HLA-A2.1 Tg HHD (H-2b) mice in producing antitumor immunity into SCID mice xenografted with the HER-2/neu+, HLA-A2.1+ and HLA-DR4+ FM3 human melanoma cell line. High proportions of these adoptively transferred HER-2/neu peptide-specific CD4+ and CD8+ T cells infiltrated FM3-induced tumors (tumor infiltrating lymphocytes; TIL) in SCID mice. CD8+ TIL exhibited long-lasting antitumor activity when cotransferred with CD4+ TIL, inducing regression of FM3 tumors in a group of untreated, tumor-bearing SCID mice, following adoptive transfer. Our data show that Ii-Key modified HER-2/neu776-790 hybrid peptides are sufficiently potent to provide antigen-specific CD4+ TH cells with therapeutic antitumor activity.
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MESH Headings
- Animals
- Antigens, Differentiation, B-Lymphocyte/chemistry
- Antigens, Differentiation, B-Lymphocyte/genetics
- Antigens, Differentiation, B-Lymphocyte/immunology
- Antigens, Differentiation, B-Lymphocyte/metabolism
- CD4-Positive T-Lymphocytes/cytology
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- Cell Proliferation
- Cells, Cultured
- Dendritic Cells/immunology
- Dendritic Cells/metabolism
- Histocompatibility Antigens Class II/chemistry
- Histocompatibility Antigens Class II/genetics
- Histocompatibility Antigens Class II/immunology
- Histocompatibility Antigens Class II/metabolism
- Humans
- Kinetics
- Mice
- Mice, SCID
- Mice, Transgenic
- Neoplasms/immunology
- Neoplasms/metabolism
- Neoplasms/pathology
- Peptide Fragments/genetics
- Peptide Fragments/immunology
- Peptide Fragments/metabolism
- Protein Binding
- Receptor, ErbB-2/genetics
- Receptor, ErbB-2/immunology
- Receptor, ErbB-2/metabolism
- T-Lymphocytes, Cytotoxic/cytology
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
- Xenograft Model Antitumor Assays
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Affiliation(s)
- Ioannis F Voutsas
- Cancer Immunology and Immunotherapy Center, Saint Savas Cancer Hospital, Athens, Greece
| | - Angelos D Gritzapis
- Cancer Immunology and Immunotherapy Center, Saint Savas Cancer Hospital, Athens, Greece
| | - Louisa G Mahaira
- Cancer Immunology and Immunotherapy Center, Saint Savas Cancer Hospital, Athens, Greece
| | - Maria Salagianni
- Cancer Immunology and Immunotherapy Center, Saint Savas Cancer Hospital, Athens, Greece
| | - Eric von Hofe
- Antigen Express Inc., Biotech III, One Innovation Drive, Worcester, MA
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Abstract
We review recent advances toward a comprehensive mathematical theory of T-cell immunity. A key insight is that the efficacy of the T-cell response is best analyzed in terms of T-cell receptor (TCR) avidity and the distribution of this avidity across the TCR repertoire (the 'avidity spectrum'). Modification of this avidity spectrum by a wide range of tuning and tolerance mechanisms allows the system to adapt cross-reactivity and specificity to the challenge at hand while avoiding inappropriate responses against non-pathogenic cells and tissues. Theoretical models relate molecular kinetic parameters and cellular properties to systemic level statistics such as avidity spectra. Such bridge equations are crucial for rational clinical manipulation of T cells at the molecular level.
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Affiliation(s)
- Hugo A van den Berg
- Warwick Systems Biology Centre, Mathematics Institute, University of Warwick, Coventry, UK.
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HNPCC versus sporadic microsatellite-unstable colon cancers follow different routes toward loss of HLA class I expression. BMC Cancer 2007; 7:33. [PMID: 17316446 PMCID: PMC1808468 DOI: 10.1186/1471-2407-7-33] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Accepted: 02/22/2007] [Indexed: 11/23/2022] Open
Abstract
Background Abnormalities in Human Leukocyte Antigen (HLA) class I expression are common in colorectal cancer. Since HLA expression is required to activate tumor antigen-specific cytotoxic T-lymphocytes (CTL), HLA class I abnormalities represent a mechanism by which tumors circumvent immune surveillance. Tumors with high microsatellite instability (MSI-H) are believed to face strong selective pressure to evade CTL activity since they produce large amounts of immunogenic peptides. Previous studies identified the prevalence of HLA class I alterations in MSI-H tumors. However, those reports did not compare the frequency of alterations between hereditary and sporadic MSI-H tumors neither the mechanisms that led to HLA class I alterations in each subgroup. Methods To characterize the HLA class I expression among sporadic MSI-H and microsatellite-stable (MSS) tumors, and HNPCC tumors we compared immunohistochemically the expression of HLA class I, β2-microglobulin (β2m), and Antigen Processing Machinery (APM) components in 81 right-sided sporadic and 75 HNPCC tumors. Moreover, we investigated the genetic basis for these changes. Results HLA class I loss was seen more frequently in MSI-H tumors than in MSS tumors (p < 0.0001). Distinct mechanisms were responsible for HLA class I loss in HNPCC and sporadic MSI-H tumors. Loss of HLA class I expression was associated with β2m loss in HNPCC tumors, but was correlated with APM component defects in sporadic MSI-H tumors (p < 0.0001). In about half of the cases, loss of expression of HLA class I was concordant with the detection of one or more mutations in the β2m and APM components genes. Conclusion HLA class I aberrations are found at varying frequencies in different colorectal tumor types and are caused by distinct genetic mechanisms. Chiefly, sporadic and hereditary MSI-H tumors follow different routes toward HLA class I loss of expression supporting the idea that these tumors follow different evolutionary pathways in tumorigenesis. The resulting variation in immune escape mechanisms may have repercussions in tumor progression and behavior.
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27
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Hillen N, Stevanovic S. Contribution of mass spectrometry-based proteomics to immunology. Expert Rev Proteomics 2007; 3:653-64. [PMID: 17181480 DOI: 10.1586/14789450.3.6.653] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Antigen processing forwards various information about the cellular status and the proteome to the cell surface for scrutiny by the cellular immune system. Thus the repertoire of major histocompatibility complex (MHC)-bound peptides and the MHC ligandome, indirectly mirrors the proteome in order to make alterations instantly detectable and, if necessary, to oppose them. Mass spectrometry is the core technology for analysis of both proteome and MHC ligandome and has evoked several strategies to gain qualitative and quantitative insight into the MHC-presented peptide repertoire. After immunoaffinity purification of detergent-solubilized peptide-MHC complexes followed by acid elution of peptides, liquid chromatography-mass spectrometry is applied to determine individual peptide sequences and, thus, allow qualitative characterization of the MHC-bound repertoire. Differential quantification based on stable isotope labeling enables the relative comparison of two samples, such as diseased and healthy tissue. Targeted searches for certain natural ligands, such as the 'predict-calibrate-detect' strategy, include motif-based epitope prediction and calibration with reference peptides. Thus, various approaches are now available for exposing and understanding the intricacies of the MHC ligand repertoire. Analysis of differences in the MHC ligandome under distinct conditions contributes to our understanding of basic cellular processes, but also enables the formulation of immunodiagnostic or immunotherapeutic strategies.
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Affiliation(s)
- Nina Hillen
- University of Tübingen, Department of Immunology, Institute for Cell Biology, 72076 Tübingen, Germany.
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28
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Scherer A, Salathé M, Bonhoeffer S. High epitope expression levels increase competition between T cells. PLoS Comput Biol 2006; 2:e109. [PMID: 16933984 PMCID: PMC1550274 DOI: 10.1371/journal.pcbi.0020109] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Accepted: 07/11/2006] [Indexed: 01/07/2023] Open
Abstract
Both theoretical predictions and experimental findings suggest that T cell populations can compete with each other. There is some debate on whether T cells compete for aspecific stimuli, such as access to the surface on antigen-presenting cells (APCs) or for specific stimuli, such as their cognate epitope ligand. We have developed an individual-based computer simulation model to study T cell competition. Our model shows that the expression level of foreign epitopes per APC determines whether T cell competition is mainly for specific or aspecific stimuli. Under low epitope expression, competition is mainly for the specific epitope stimuli, and, hence, different epitope-specific T cell populations coexist readily. However, if epitope expression levels are high, aspecific competition becomes more important. Such between-specificity competition can lead to competitive exclusion between different epitope-specific T cell populations. Our model allows us to delineate the circumstances that facilitate coexistence of T cells of different epitope specificity. Understanding mechanisms of T cell coexistence has important practical implications for immune therapies that require a broad immune response. Pathogens are masters of disguise, and frequently escape recognition by the immune response. Therefore, broad immune responses, directed at many epitopes of the pathogen, are thought to improve control of infection. There is evidence that competition between immune cells of different epitope specificity reduces the breadth of the immune response. It has been suggested that the resource that T cells compete for is access to antigen-presenting cells (APCs). However, the experimental data regarding competition for access to APCs is controversial. In this study, Scherer, Salathé, and Bonhoeffer have used an individual-based model to investigate the mechanisms of T cell competition. They find that T cells only compete for access to APCs when epitopes are expressed abundantly on APCs. In contrast, when epitope expression is limiting, competition is for the specific epitope rather than for access to APCs. The distinction between competition for epitope and for access to APCs is relevant because the model predicts qualitatively different outcomes for either case. When competition is for the specific epitope, different epitope-specific T cell responses coexist readily and hence the immune response is broad. However, when T cells compete for access to APCs, immunodominant T cell responses can outcompete subdominant ones, which leads to narrow immune responses.
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Affiliation(s)
- Almut Scherer
- Theoretical Biology, Institute of Integrative Biology, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Marcel Salathé
- Theoretical Biology, Institute of Integrative Biology, Swiss Federal Institute of Technology, Zurich, Switzerland
| | - Sebastian Bonhoeffer
- Theoretical Biology, Institute of Integrative Biology, Swiss Federal Institute of Technology, Zurich, Switzerland
- * To whom correspondence should be addressed. E-mail:
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29
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Gritzapis AD, Mahaira LG, Perez SA, Cacoullos NT, Papamichail M, Baxevanis CN. Vaccination with Human HER-2/neu (435-443) CTL Peptide Induces Effective Antitumor Immunity against HER-2/neu-Expressing Tumor Cells In vivo. Cancer Res 2006; 66:5452-60. [PMID: 16707474 DOI: 10.1158/0008-5472.can-05-4018] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
HER-2/neu is a self-antigen expressed by tumors and nonmalignant epithelial tissues. The possibility of self-tolerance to HER-2/neu-derived epitopes has raised questions concerning their utility in antitumor immunotherapy. Altered HER-2/neu peptide ligands capable of eliciting enhanced immunity to tumor-associated HER-2/neu epitopes may circumvent this problem. The human CTL peptide HER-2/neu (435-443) [hHER-2(9(435))] represents a xenogeneic altered peptide ligand of its mouse homologue, differing by one amino acid residue at position 4. In contrast to mHER-2(9(435)), vaccination of HLA-A*0201 transgenic (HHD) mice with hHER-2(9(435)) significantly increased the frequency of mHER-2(9(435))-specific CTL and also induced strong protective and therapeutic immunity against the transplantable ALC tumor cell line transfected to coexpress HLA-A*0201 and hHER-2/neu or rHER-2/neu. Similar results were also obtained with wild-type C57BL/6 mice inoculated with HER-2/neu transfectants of ALC. Adoptive transfer of CD8(+) CTL from mice immunized with hHER-2(9(435)) efficiently protected naive syngeneic mice inoculated with ALC tumors. In conclusion, our results show that HER-2(9(435)) serves as a tumor rejection molecule. They also propose a novel approach for generating enhanced immunity against a self-HER-2/neu CTL epitope by vaccinating with xenogeneic altered peptide ligands and provide useful insights for the design of improved peptide-based vaccines for the treatment of patients with HER-2/neu-overexpressing tumors.
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Affiliation(s)
- Angelos D Gritzapis
- Cancer Immunology and Immunotherapy Center, St. Savas Cancer Hospital, Athens, Greece.
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30
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Olinger GG, Bailey MA, Dye JM, Bakken R, Kuehne A, Kondig J, Wilson J, Hogan RJ, Hart MK. Protective cytotoxic T-cell responses induced by venezuelan equine encephalitis virus replicons expressing Ebola virus proteins. J Virol 2006; 79:14189-96. [PMID: 16254354 PMCID: PMC1280180 DOI: 10.1128/jvi.79.22.14189-14196.2005] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infection with Ebola virus causes a severe disease accompanied by high mortality rates, and there are no licensed vaccines or therapies available for human use. Filovirus vaccine research efforts still need to determine the roles of humoral and cell-mediated immune responses in protection from Ebola virus infection. Previous studies indicated that exposure to Ebola virus proteins expressed from packaged Venezuelan equine encephalitis virus replicons elicited protective immunity in mice and that antibody-mediated protection could only be demonstrated after vaccination against the glycoprotein. In this study, the murine CD8(+) T-cell responses to six Ebola virus proteins were examined. CD8(+) T cells specific for Ebola virus glycoprotein, nucleoprotein, and viral proteins (VP24, VP30, VP35, and VP40) were identified by intracellular cytokine assays using splenocytes from vaccinated mice. The cells were expanded by restimulation with peptides and demonstrated cytolytic activity. Adoptive transfer of the CD8(+) cytotoxic T cells protected filovirus naïve mice from challenge with Ebola virus. These data support a role for CD8(+) cytotoxic T cells as part of a protective mechanism induced by vaccination against six Ebola virus proteins and provide additional evidence that cytotoxic T-cell responses can contribute to protection from filovirus infections.
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Affiliation(s)
- Gene G Olinger
- United States Army Medical Research Institute of Infectious Diseases, Division of Virology, 1425 Porter Street, Frederick, MD 21702-5011, USA
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31
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van den Berg HA, Rand DA. Foreignness as a matter of degree: the relative immunogenicity of peptide/MHC ligands. J Theor Biol 2005; 231:535-48. [PMID: 15488530 DOI: 10.1016/j.jtbi.2004.07.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2004] [Revised: 07/07/2004] [Accepted: 07/12/2004] [Indexed: 12/31/2022]
Abstract
The ability of T lymphocytes (T cells) to recognize and attack foreign invaders while leaving healthy cells unharmed is often analysed as a discrete self/non-self dichotomy, with each peptide/MHC ligand classified as either self or non-self. We argue that the ligand immunogenicity is more naturally treated as a continuous quantity, and show how to define and quantitate relative ligand immunogenicity. In our theory, self-tolerance is acquired through reduction of the relative immunogenicity of autoantigens, whereas xenoantigens, typically not presented during induction of deletional tolerance, retain a high degree of relative immunogenicity. Autoantigens that are not prominently presented in deletional tolerance likewise retain a high relative immunogenicity and remain essentially foreign. According to our analysis, any given autoantigen can attain a high level of relative immunogenicity, provided it is presented at sufficiently high levels. Our theory provides a quantitative tool to analyse the immunogenicity of tumour-associated neoantigens and the aetiology of autoimmune disease.
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Affiliation(s)
- Hugo A van den Berg
- Interdisciplinary Programme for Cellular Regulation, Mathematics Institute, University of Warwick, Coventry CV4 7AL, UK.
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32
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Gritzapis AD, Sotiriadou NN, Papamichail M, Baxevanis CN. Generation of human tumor-specific CTLs in HLA-A2.1-transgenic mice using unfractionated peptides from eluates of human primary breast and ovarian tumors. Cancer Immunol Immunother 2004; 53:1027-40. [PMID: 15164233 PMCID: PMC11033028 DOI: 10.1007/s00262-004-0541-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2003] [Accepted: 03/16/2004] [Indexed: 11/27/2022]
Abstract
HER-2/neu oncoprotein is overexpressed in a variety of human tumors and is associated with malignant transformation and aggressive disease. Due to its overexpression in tumor cells and because it has been shown to be immunogenic, this protein represents an excellent target for T-cell immunotherapy. Peptide extracts derived from primary HLA-A*0201-positive (+) HER-2/neu+ human tumors by acid elution (acid cell extracts (ACEs)) were tested for their capacity to elicit in HLA-A*0201 transgenic mice, cytotoxic T lymphocytes (CTLs) lysing HLA-A*0201+ HER-2/neu+ tumor cells. Injections of ACE in transgenic mice induced CTLs capable of specifically lysing HER-2/neu+ tumor cell lines (also including the original HER-2/neu+ primary tumor cells from which the ACEs were derived) in an HLA-A*0201-restricted fashion. Adoptive transfer of ACE-induced CTLs was sufficient to significantly prolong survival of SCID mice inoculated with HLA-A*0201+ HER-2/ neu+ human tumor cell lines. Cytotoxicity of such ACE-induced CTL lines was directed, at least as detected herein, also against the HER-2/ neu peptides HER-2 (9(369)) and HER-2 (9(435)) demonstrating the immunodominance of these epitopes. HER-2 peptide-specific CTLs generated in the HLA-A*0201-transgenic mice, upon peptide immunization, lysed in vitro HER-2/neu+ human tumor cell lines in an HLA-A*0201-restricted manner and, when adoptively transferred, conferred sufficient protection in SCID mice inoculated with the same human tumor cell lines as above. However, CTLs induced by ACEs displayed enhanced efficacy in the therapy of xenografted SCID mice compared with the HER-2 peptide-specific CTLs (i.e., HER-2 [9(369)] or HER-2 [9(435)]). Even by administering mixtures of CTLs specific for each of these peptides, the prolongation of survival achieved was still inferior compared with that obtained with ACE-induced CTLs. This suggested that additional epitopes may contribute to the immunogenicity of such tumor-derived ACEs. Thus, immunization with ACEs from HER-2/neu+ primary tumor cells appears to be an effective approach to generate multiple and potent CTL-mediated immune responses against HER-2/neu+ tumors expressing the appropriate HLA allele(s). By screening ACE-induced CTL lines with synthetic peptides encompassing the HER-2/neu sequence, it is feasible to identify immunodominant epitopes which may be used in mixtures as vaccines with enhanced efficacy in both the prevention and therapy of HER-2/neu+ malignancies.
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Affiliation(s)
- Angelos D. Gritzapis
- Cancer Immunology and Immunotherapy Center, Saint Savas Hospital, 171 Alexandras Avenue, 11522 Athens, Greece
| | - Nectaria N. Sotiriadou
- Cancer Immunology and Immunotherapy Center, Saint Savas Hospital, 171 Alexandras Avenue, 11522 Athens, Greece
| | - Michael Papamichail
- Cancer Immunology and Immunotherapy Center, Saint Savas Hospital, 171 Alexandras Avenue, 11522 Athens, Greece
| | - Constantin N. Baxevanis
- Cancer Immunology and Immunotherapy Center, Saint Savas Hospital, 171 Alexandras Avenue, 11522 Athens, Greece
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33
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van den Berg HA, Rand DA. Dynamics of T cell activation threshold tuning. J Theor Biol 2004; 228:397-416. [PMID: 15135038 DOI: 10.1016/j.jtbi.2004.02.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2003] [Revised: 01/23/2004] [Accepted: 02/04/2004] [Indexed: 11/27/2022]
Abstract
T lymphocytes are believed to alter their sensitivity to TCR stimulation by means of a tunable cellular activation threshold. We present two modelling examples which show that the concept of a tunable threshold can be made mechanistically plausible. The tunable threshold is treated as an emergent property of the dynamics of the T cell's signalling machinery. In addition, we discuss how the dynamic properties of activation threshold tuning can be determined experimentally with the aid of these two models. We propose a novel 'avidity selection' mechanism for the initial stages of the immune response, based on the properties of the T cell activation threshold tuning mechanism we propose for the commitment to differentiation. Our main finding is that activation threshold tuning allows T cells to respond to relevant ligands with a detection threshold that is (i) uniform across both the T cell repertoire and the secondary lymphoid tissues, while (ii) retaining tolerance to autostimulation. Our analysis indicates that central tolerance enhances the efficiency of peripheral tolerance, casting new light on the role of negative selection in the thymus.
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Affiliation(s)
- Hugo A van den Berg
- Interdisciplinary Programme for Cellular Regulation Mathematics Institute, University of Warwick, Coventry CV4 7AL, UK.
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34
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van den Berg HA, Rand DA. Antigen presentation on MHC molecules as a diversity filter that enhances immune efficacy. J Theor Biol 2003; 224:249-67. [PMID: 12927531 DOI: 10.1016/s0022-5193(03)00162-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We consider the way in which antigen is presented to T cells on MHC molecules and ask how MHC peptide presentation could be optimized so as to obtain an effective and safe immune response. By analysing this problem with a mathematical model of T-cell activation, we deduce the need for both MHC restriction and high presentation selectivity. We find that the optimal selectivity is such that about one pathogen-derived peptide is presented per MHC isoform, on the average. We also indicate upper and lower bounds to the number of MHC isoforms per individual based on detectability requirements. Thus we deduce that an important role of MHC presentation is to act as a filter that limits the diversity of antigen presentation.
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35
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Schirle M. Identification of tumor-associated HLA-ligands in the post-genomic era. JOURNAL OF HEMATOTHERAPY & STEM CELL RESEARCH 2002; 11:873-81. [PMID: 12590702 DOI: 10.1089/152581602321080538] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Over 10 years ago, the identification of the first tumor-specific T cell epitope shed light on the molecular principles underlying the phenomenon of tumor eradication by the immune system. Since then, a considerable number of different approaches for this task have been introduced and employed successfully, reflecting the growing knowledge about the cellular processes preceding antigen presentation as well as significant technical developments. This review tries to give an overview over available conventional strategies as well as current developments that utilize the potent large-scale screening tools of the post-genomic era.
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Affiliation(s)
- Markus Schirle
- Department of Immunology, Institute for Cell Biology, University of Tübingen, Germany.
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36
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Kessler BM, Glas R, Ploegh HL. MHC class I antigen processing regulated by cytosolic proteolysis-short cuts that alter peptide generation. Mol Immunol 2002; 39:171-9. [PMID: 12200049 DOI: 10.1016/s0161-5890(02)00100-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cytotoxic T lymphocyte (CTL)-mediated immune responses rely on the efficiency of MHC class I ligand generation and presentation by antigen presenting cells (APCs). Whereas the abnormal expression of MHC molecules and transporters associated with antigen processing (TAPs) are commonly discussed as factors that modulate antigen presentation, much less is known about possible regulatory mechanisms at the level of proteolysis responsible for the generation of antigenic peptides. The ubiquitin-proteasome system is recognized as the major component responsible for this process in the cytosol and its activity can be regulated by cytokines, such as IFN-gamma. However, new evidence suggests the involvement of other proteases that can contribute to cytosolic proteolysis and therefore, to the quality and quantity of antigen production. Here, we review recent findings on an increasing number of proteolytic enzymes linked to antigen presentation, and we discuss how regulation of cytosolic protease activities might have implications for immune escape mechanisms that could be used by tumor cells and pathogens.
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Affiliation(s)
- Benedikt M Kessler
- Department of Pathology, Harvard Medical School, Room 137, Building D2, 200 Longwood Avenue, Boston, MA 02115, USA
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37
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Rammensee HG, Weinschenk T, Gouttefangeas C, Stevanović S. Towards patient-specific tumor antigen selection for vaccination. Immunol Rev 2002; 188:164-76. [PMID: 12445290 DOI: 10.1034/j.1600-065x.2002.18815.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In this review, we discuss the possibilities for combining the power of molecular analysis of the antigens expressed in a given individual tumor with the design of a tailored vaccine containing defined antigens. Step 1 is a differential gene expression analysis of tumor and corresponding normal tissue. Step 2 is the analysis of human leukocyte antigen (HLA) ligands on tumor cells. Step 3 is data mining with the aim to select those antigens that might be suitable for tumor attack by the adaptive immune system. Step 4 is the on-the-spot clinical grade production of the constituents of the patient tailored vaccine, e.g. peptides. Step 5 is then vaccination and monitoring. Although it will not be possible to cover all relevant antigens expressed in a tumor, the antigens that can be identified with our present technical possibilities might be enough for improved immunotherapy. The scope of the present review is to explore the possibilities and the formidable technical and logistical challenge for such individual patient-oriented antigen definition to be used for therapeutic immunization.
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MESH Headings
- Algorithms
- Amino Acid Motifs
- Antigen Presentation
- Antigens, Neoplasm/administration & dosage
- Antigens, Neoplasm/immunology
- B-Lymphocytes/immunology
- Cancer Vaccines/immunology
- Cancer Vaccines/therapeutic use
- Clinical Trials as Topic
- Cytotoxicity, Immunologic
- Databases, Factual
- Epitopes, B-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/immunology
- HLA Antigens/immunology
- Humans
- Immunotherapy, Active
- Neoplasms/immunology
- Neoplasms/therapy
- Receptors, Antigen, T-Cell/immunology
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Helper-Inducer/immunology
- Vaccines, Subunit/immunology
- Vaccines, Subunit/therapeutic use
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Affiliation(s)
- Hans-Georg Rammensee
- Department of Immunology, Institute for Cell Biology, University of Tübingen, Tübingen, Germany.
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38
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Abstract
The most important 'on-off' switch within the immune system are the T cells: these decide whether an immune response has to be induced and maintained or not. Since T cells glean their information from the interaction between their specific T cell receptor and a MHC-peptide complex, MHC molecules are invaluable information carriers. Each T cell is usually restricted to only one of the set of autologous MHC molecules, but it is nevertheless able to react upon contact with allogeneic MHC. For a given T cell, both the MHC molecule and presented peptide thus play a crucial role in antigen recognition. MHC molecules govern the allele-specific restriction of T cells or, most important in transplantation immunology, allo-specific recognition, which is often peptide-independent. Peptides serving as MHC ligands are able either to tolerise T cells if presented under certain circumstances, or to activate T cells if presented by professional antigen-presenting cells in an inflammatory environment. The vast polymorphism of human MHC molecules combined with the complexity of thousands of different peptides presented by each allelic product provide the utmost heterogeneity. During the past few years, a huge amount of information about MHC-bound peptides has been compiled that helps us to understand the structural basis of immunogenicity. This contribution describes the characteristics of antigen processing within the MHC class I pathway, from proteasomal processing to the rules of MHC binding. Our current knowledge enables the exact description of many processes within the class I processing pathway and paves the way for the prediction of potential T cell epitopes by employing the rules of peptide presentation.
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Affiliation(s)
- Stefan Stevanović
- Department of Immunology, Institute for Cell Biology, University of Tübingen, Germany.
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39
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Abstract
Proteasomes are highly abundant cytosolic and nuclear protease complexes that degrade most intracellular proteins in higher eukaryotes and appear to play a major role in the cytosolic steps of MHC class I antigen processing. This review summarizes the knowledge of the role of proteasomes in antigen processing and the impact of proteasomal proteolysis on T cell-mediated immunity.
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Affiliation(s)
- G Niedermann
- Max Planck Institute of Immunobiology, Stübeweg 51, 79108 Freiburg, Germany
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40
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Planz O, Dumrese T, Hulpusch S, Schirle M, Stevanovic S, Stitz L. A naturally processed rat major histocompatibility complex class I-associated viral peptide as target structure of borna disease virus-specific CD8+ T cells. J Biol Chem 2001; 276:13689-94. [PMID: 11278578 DOI: 10.1074/jbc.m009889200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The first naturally processed peptide synthesized by a virus and recognized by classical CD8(+) T cells in association with the RT1.A(l) major histocompatibility complex class I molecule of the Lewis rat is reported. Borna disease virus-specific CD8(+) T cells recognize syngeneic target cells pulsed with peptides extracted from Borna disease virus-infected cells. The predicted peptide sequence ASYAQMTTY from the viral p40 protein coeluted with the cytotoxic T-lymphocyte-reactive fraction was identified among natural ligands by tandem mass spectrometry. Numerous naturally processed peptides derived from intracellular bacteria, viruses, or tumors and recognized by CD8(+) T cells of man and mice are known, leading to a better understanding of cellular immune mechanisms against pathogens in these two species. In contrast, for the rat little information exists with regard to the function and role of CD8(+) T cells as part of their cellular immune defense system. This first naturally processed viral epitope in the rat contributes to the understanding of the rat cellular immune response and might trigger the identification of more cytotoxic T-lymphocyte epitopes in this animal.
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Affiliation(s)
- O Planz
- Institut für Immunologie, Bundesforschungsanstalt für Viruskrankheiten der Tiere and Interfakultäres Institut für Zellbiologie, Abteilung Immunologie, 72076 Tübingen, Germany.
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41
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Van Den Berg HA, Rand DA, Burroughs NJ. A reliable and safe T cell repertoire based on low-affinity T cell receptors. J Theor Biol 2001; 209:465-86. [PMID: 11319895 DOI: 10.1006/jtbi.2001.2281] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Antigens are presented to T cells as short peptides bound to MHC molecules on the surface of body cells. The binding between MHC/peptides and T cell receptors (TCRs) has a low affinity and is highly degenerate. Nevertheless, TCR-MHC/peptide recognition results in T cell activation of high specificity. Moreover, the immune system is able to mount a cellular response when only a small fraction of the MHC molecules on an antigen-presenting cell is occupied by foreign peptides, while autoimmunity remains relatively rare. We consider how to reconcile these seemingly contradictory facts using a quantitative model of TCR signalling and T cell activation. Taking into account the statistics of TCR recognition and antigen presentation, we show that thymic selection can produce a working T cell repertoire which will produce safe and effective responses, that is, recognizes foreign antigen presented at physiological levels while tolerating self. We introduce "activation curves" as a useful tool to study the repertoire's statistical activation properties.
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Affiliation(s)
- H A Van Den Berg
- Mathematics Institute, University of Warwick, Coventry CV4 7AL, UK
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42
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Wilson JA, Hart MK. Protection from Ebola virus mediated by cytotoxic T lymphocytes specific for the viral nucleoprotein. J Virol 2001; 75:2660-4. [PMID: 11222689 PMCID: PMC115890 DOI: 10.1128/jvi.75.6.2660-2664.2001] [Citation(s) in RCA: 133] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2000] [Accepted: 12/14/2000] [Indexed: 11/20/2022] Open
Abstract
Cytotoxic T lymphocytes (CTLs) are proposed to be critical for protection from intracellular pathogens such as Ebola virus. However, there have been no demonstrations that protection against Ebola virus is mediated by Ebola virus-specific CTLs. Here, we report that C57BL/6 mice vaccinated with Venezuelan equine encephalitis virus replicons encoding the Ebola virus nucleoprotein (NP) survived lethal challenge with Ebola virus. Vaccination induced both antibodies to the NP and a major histocompatibility complex class I-restricted CTL response to an 11-amino-acid sequence in the amino-terminal portion of the Ebola virus NP. Passive transfer of polyclonal NP-specific antiserum did not protect recipient mice. In contrast, adoptive transfer of CTLs specific for the Ebola virus NP protected unvaccinated mice from lethal Ebola virus challenge. The protective CTLs were CD8(+), restricted to the D(b) class I molecule, and recognized an epitope within amino acids 43 to 53 (VYQVNNLEEIC) in the Ebola virus NP. The demonstration that CTLs can prevent lethal Ebola virus infection affects vaccine development in that protective cellular immune responses may be required for optimal protection from Ebola virus.
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Affiliation(s)
- J A Wilson
- Virology Division, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702-5011, USA
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43
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Kienzle N, Buck M, Silins SL, Burrows SR, Moss DJ, Winterhalter A, Brooks A, Khanna R. Differential splicing of antigen-encoding RNA reduces endogenous epitope presentation that regulates the expansion and cytotoxicity of T cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:1840-6. [PMID: 10925262 DOI: 10.4049/jimmunol.165.4.1840] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The activation of CTLs is dependent on the recognition of MHC-bound peptide present on the surface of APCs. We give evidence in this study that differential splicing of Ag-encoding RNA can decrease the antigenic dose in APCs and regulate the recall of human memory CTLs. Differential splicing of RNA that encoded an immunodominant HLA-B8-restricted CTL epitope of EBV reduced the functional presentation of this epitope, and consequently the in vitro expansion and activity of CTLs, as measured by MHC/peptide-tetramer staining and cytotoxicity assays. The reduced activity of the stimulated CTLs was not only due to lower numbers of Ag-specific CTLs but, surprisingly, was also characterized by decreased cytotoxicity of the CTLs to target cells presenting limiting amounts of the peptide epitope. As indicated by TCR repertoire analysis, the reduction in CTL activity was not caused by stimulation of distinct populations of TCR clonotypes. This study demonstrates how a common eukaryotic posttranscriptional mechanism of gene regulation can modulate the endogenous presentation of Ag and ultimately contribute to the fine tuning of immunological memory cells, which are important in the fight against pathogens and tumors and in autoimmunity.
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MESH Headings
- Alternative Splicing/immunology
- Antigen Presentation/genetics
- Antigen-Presenting Cells/metabolism
- Cell Line, Transformed
- Cytotoxicity Tests, Immunologic
- Cytotoxicity, Immunologic/genetics
- Dose-Response Relationship, Immunologic
- Epitopes, T-Lymphocyte/genetics
- Epitopes, T-Lymphocyte/metabolism
- Epstein-Barr Virus Nuclear Antigens/biosynthesis
- Epstein-Barr Virus Nuclear Antigens/genetics
- Epstein-Barr Virus Nuclear Antigens/immunology
- Epstein-Barr Virus Nuclear Antigens/metabolism
- Genetic Vectors/biosynthesis
- Genetic Vectors/chemical synthesis
- Humans
- Immunodominant Epitopes/genetics
- Immunodominant Epitopes/metabolism
- Immunologic Memory/genetics
- Lymphocyte Activation/genetics
- Oligopeptides/antagonists & inhibitors
- Oligopeptides/biosynthesis
- Oligopeptides/genetics
- Oligopeptides/immunology
- RNA, Viral/genetics
- RNA, Viral/immunology
- Receptors, Antigen, T-Cell, alpha-beta/biosynthesis
- T-Lymphocytes, Cytotoxic/immunology
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Affiliation(s)
- N Kienzle
- EBV Unit, The Queensland Institute of Medical Research and University of Queensland Joint Oncology Program, Brisbane, Queensland, Australia.
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