1
|
Li Y, Jiang W, Mellins ED. TCR-like antibodies targeting autoantigen-mhc complexes: a mini-review. Front Immunol 2022; 13:968432. [PMID: 35967436 PMCID: PMC9363607 DOI: 10.3389/fimmu.2022.968432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 07/06/2022] [Indexed: 11/13/2022] Open
Abstract
T cell receptors (TCRs) recognize peptide antigens bound to major histocompatibility complex (MHC) molecules (p/MHC) that are expressed on cell surfaces; while B cell-derived antibodies (Abs) recognize soluble or cell surface native antigens of various types (proteins, carbohydrates, etc.). Immune surveillance by T and B cells thus inspects almost all formats of antigens to mount adaptive immune responses against cancer cells, infectious organisms and other foreign insults, while maintaining tolerance to self-tissues. With contributions from environmental triggers, the development of autoimmune disease is thought to be due to the expression of MHC risk alleles by antigen-presenting cells (APCs) presenting self-antigen (autoantigen), breaking through self-tolerance and activating autoreactive T cells, which orchestrate downstream pathologic events. Investigating and treating autoimmune diseases have been challenging, both because of the intrinsic complexity of these diseases and the need for tools targeting T cell epitopes (autoantigen-MHC). Naturally occurring TCRs with relatively low (micromolar) affinities to p/MHC are suboptimal for autoantigen-MHC targeting, whereas the use of engineered TCRs and their derivatives (e.g., TCR multimers and TCR-engineered T cells) are limited by unpredictable cross-reactivity. As Abs generally have nanomolar affinity, recent advances in engineering TCR-like (TCRL) Abs promise advantages over their TCR counterparts for autoantigen-MHC targeting. Here, we compare the p/MHC binding by TCRs and TCRL Abs, review the strategies for generation of TCRL Abs, highlight their application for identification of autoantigen-presenting APCs, and discuss future directions and limitations of TCRL Abs as immunotherapy for autoimmune diseases.
Collapse
Affiliation(s)
- Ying Li
- Department of Pediatrics, Divisions of Human Gene Therapy and Allergy, Immunology & Rheumatology, Stanford University School of Medicine, Stanford, CA, United States
- Stanford Program in Immunology, Stanford University School of Medicine, Stanford, CA, United States
| | - Wei Jiang
- Department of Pediatrics, Divisions of Human Gene Therapy and Allergy, Immunology & Rheumatology, Stanford University School of Medicine, Stanford, CA, United States
- Stanford Program in Immunology, Stanford University School of Medicine, Stanford, CA, United States
- *Correspondence: Wei Jiang, ; Elizabeth D. Mellins,
| | - Elizabeth D. Mellins
- Department of Pediatrics, Divisions of Human Gene Therapy and Allergy, Immunology & Rheumatology, Stanford University School of Medicine, Stanford, CA, United States
- Stanford Program in Immunology, Stanford University School of Medicine, Stanford, CA, United States
- *Correspondence: Wei Jiang, ; Elizabeth D. Mellins,
| |
Collapse
|
2
|
DeLeo JA, Tanga FY, Tawfik VL. Neuroimmune Activation and Neuroinflammation in Chronic Pain and Opioid Tolerance/Hyperalgesia. Neuroscientist 2016; 10:40-52. [PMID: 14987447 DOI: 10.1177/1073858403259950] [Citation(s) in RCA: 301] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
One area that has emerged as a promising therapeutic target for the treatment and prevention of chronic pain and opioid tolerance/hyperalgesia is the modulation of the central nervous system (CNS) immunological response that ensues following injury or opioid administration. Broadly defined, central neuroimmune activation involves the activation of cells that interface with the peripheral nervous system and blood. Activation of these cells, as well as parenchymal microglia and astrocytes by injury, opioids, and other stressors, leads to subsequent production of cytokines, cellular adhesion molecules, chemokines, and the expression of surface antigens that enhance a CNS immune cascade. This response can lead to the production of numerous pain mediators that can sensitize and lower the threshold of neuronal firing: the pathologic correlate to central sensitization and chronic pain states. CNS innate immunity and Toll-like receptors, in particular, may be vital players in this orchestrated immune response and may hold the answers to what initiates this complex cascade. The challenge remains in the careful perturbation of injury/opioid-induced neuroimmune activation to down-regulate this process without inhibiting beneficial CNS autoimmunity that subserves neuronal protection following injury.
Collapse
Affiliation(s)
- Joyce A DeLeo
- Department of Anesthesiology, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756, USA.
| | | | | |
Collapse
|
3
|
Spanier JA, Frederick DR, Taylor JJ, Heffernan JR, Kotov DI, Martinov T, Osum KC, Ruggiero JL, Rust BJ, Landry SJ, Jenkins MK, McLachlan JB, Fife BT. Efficient generation of monoclonal antibodies against peptide in the context of MHCII using magnetic enrichment. Nat Commun 2016; 7:11804. [PMID: 27292946 PMCID: PMC4909947 DOI: 10.1038/ncomms11804] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 05/02/2016] [Indexed: 11/09/2022] Open
Abstract
Monoclonal antibodies specific for foreign antigens, auto-antigens, allogeneic antigens and tumour neo-antigens in the context of major histocompatibility complex II (MHCII) are highly desirable as novel immunotherapeutics. However, there is no standard protocol for the efficient generation of monoclonal antibodies that recognize peptide in the context of MHCII, and only a limited number of such reagents exist. In this report, we describe an approach for the generation and screening of monoclonal antibodies specific for peptide bound to MHCII. This approach exploits the use of recombinant peptide:MHC monomers as immunogens, and subsequently relies on multimers to pre-screen and magnetically enrich the responding antigen-specific B cells before fusion and validation, thus saving significant time and reagents. Using this method, we have generated two antibodies enabling us to interrogate antigen presentation and T-cell activation. This methodology sets the standard to generate monoclonal antibodies against the peptide–MHCII complexes. Generating antibodies specific for the peptide–MHCII complexes has been challenging, with only a handful made to date. Here, the authors develop a more efficient approach to generate these antibodies, and demonstrate their potential in research and therapeutic applications.
Collapse
Affiliation(s)
- Justin A Spanier
- Department of Medicine, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | - Daniel R Frederick
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA
| | - Justin J Taylor
- Department of Microbiology and Immunology, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | - James R Heffernan
- Department of Medicine, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | - Dmitri I Kotov
- Department of Microbiology and Immunology, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | - Tijana Martinov
- Department of Medicine, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | - Kevin C Osum
- Department of Medicine, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | - Jenna L Ruggiero
- Department of Medicine, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | - Blake J Rust
- Department of Biochemistry, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA
| | - Samuel J Landry
- Department of Biochemistry, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA
| | - Marc K Jenkins
- Department of Microbiology and Immunology, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| | - James B McLachlan
- Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, Louisiana 70112, USA
| | - Brian T Fife
- Department of Medicine, Center for Immunology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
| |
Collapse
|
4
|
|
5
|
Juang J, Ebert PJR, Feng D, Garcia KC, Krogsgaard M, Davis MM. Peptide-MHC heterodimers show that thymic positive selection requires a more restricted set of self-peptides than negative selection. ACTA ACUST UNITED AC 2010; 207:1223-34. [PMID: 20457759 PMCID: PMC2882826 DOI: 10.1084/jem.20092170] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
T cell selection and maturation in the thymus depends on the interactions between T cell receptors (TCRs) and different self-peptide-major histocompatibility complex (pMHC) molecules. We show that the affinity of the OT-I TCR for its endogenous positively selecting ligands, Catnb-H-2Kb and Cappa1-H-2Kb, is significantly lower than for previously reported positively selecting altered peptide ligands. To understand how these extremely weak endogenous ligands produce signals in maturing thymocytes, we generated soluble monomeric and dimeric peptide-H-2Kb ligands. Soluble monomeric ovalbumin (OVA)-Kb molecules elicited no detectable signaling in OT-I thymocytes, whereas heterodimers of OVA-Kb paired with positively selecting or nonselecting endogenous peptides, but not an engineered null peptide, induced deletion. In contrast, dimer-induced positive selection was much more sensitive to the identity of the partner peptide. Catnb-Kb-Catnb-Kb homodimers, but not heterodimers of Catnb-Kb paired with a nonselecting peptide-Kb, induced positive selection, even though both ligands bind the OT-I TCR with detectable affinity. Thus, both positive and negative selection can be driven by dimeric but not monomeric ligands. In addition, positive selection has much more stringent requirements for the partner self-pMHC.
Collapse
Affiliation(s)
- Jeremy Juang
- The Department of Microbiology and Immunology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | | | | | | | | |
Collapse
|
6
|
Ebert PJR, Li QJ, Huppa JB, Davis MM. Functional development of the T cell receptor for antigen. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2010; 92:65-100. [PMID: 20800817 PMCID: PMC4887107 DOI: 10.1016/s1877-1173(10)92004-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
For over three decades now, the T cell receptor (TCR) for antigen has not ceased to challenge the imaginations of cellular and molecular immunologists alike. T cell antigen recognition transcends every aspect of adaptive immunity: it shapes the T cell repertoire in the thymus and directs T cell-mediated effector functions in the periphery, where it is also central to the induction of peripheral tolerance. Yet, despite its central position, there remain many questions unresolved: how can one TCR be specific for one particular peptide-major histocompatibility complex (pMHC) ligand while also binding other pMHC ligands with an immunologically relevant affinity? And how can a T cell's extreme specificity (alterations of single methyl groups in their ligand can abrogate a response) and sensitivity (single agonist ligands on a cell surface are sufficient to trigger a measurable response) emerge from TCR-ligand interactions that are so low in affinity? Solving these questions is intimately tied to a fundamental understanding of molecular recognition dynamics within the many different contexts of various T cell-antigen presenting cell (APC) contacts: from the thymic APCs that shape the TCR repertoire and guide functional differentiation of developing T cells to the peripheral APCs that support homeostasis and provoke antigen responses in naïve, effector, memory, and regulatory T cells. Here, we discuss our recent findings relating to T cell antigen recognition and how this leads to the thymic development of foreign-antigen-responsive alphabetaT cells.
Collapse
Affiliation(s)
- Peter J R Ebert
- The Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA
| | | | | | | |
Collapse
|
7
|
Ebert PJR, Jiang S, Xie J, Li QJ, Davis MM. An endogenous positively selecting peptide enhances mature T cell responses and becomes an autoantigen in the absence of microRNA miR-181a. Nat Immunol 2009; 10:1162-9. [PMID: 19801983 PMCID: PMC3762483 DOI: 10.1038/ni.1797] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Accepted: 09/01/2009] [Indexed: 11/09/2022]
Abstract
Thymic positive selection is based on the interactions of T cell antigen receptors (TCRs) with self peptide-major histocompatibility complex (MHC) ligands, but the identity of selecting peptides for MHC class II-restricted TCRs and the functional consequences of this peptide specificity are not clear. Here we identify several endogenous self peptides that positively selected the MHC class II-restricted 5C.C7 TCR. The most potent of these also enhanced mature T cell activation, which supports the hypothesis that one function of positive selection is to produce T cells that can use particular self peptide-MHC complexes for activation and/or homeostasis. We also show that inhibiting the microRNA miR-181a resulted in maturation of T cells that overtly reacted toward these erstwhile positively selecting peptides. Therefore, miR-181a helps to guarantee the clonal deletion of particular moderate-affinity clones by modulating the TCR signaling threshold of thymocytes.
Collapse
Affiliation(s)
- Peter J R Ebert
- The Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, California, USA
| | | | | | | | | |
Collapse
|
8
|
Ebert PJR, Ehrlich LIR, Davis MM. Low ligand requirement for deletion and lack of synapses in positive selection enforce the gauntlet of thymic T cell maturation. Immunity 2008; 29:734-45. [PMID: 18993085 DOI: 10.1016/j.immuni.2008.09.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 07/18/2008] [Accepted: 09/09/2008] [Indexed: 11/16/2022]
Abstract
Immature double-positive (CD4(+)CD8(+)) thymocytes respond to negatively selecting peptide-MHC ligands by forming an immune synapse that sustains contact with the antigen-presenting cell (APC). Using fluorescently labeled peptides, we showed that as few as two agonist ligands could promote APC contact and subsequent apoptosis in reactive thymocytes. Furthermore, we showed that productive signaling for positive selection, as gauged by nuclear translocation of a green fluorescent protein (GFP)-labeled NFATc construct, did not involve formation of a synapse between thymocytes and selecting epithelial cells in reaggregate thymus cultures. Antibody blockade of endogenous positively selecting ligands prevented NFAT nuclear accumulation in such cultures and reversed NFAT accumulation in previously stimulated thymocytes. Together, these data suggest a "gauntlet" model in which thymocytes mature by continually acquiring and reacquiring positively selecting signals without sustained contact with epithelial cells, thereby allowing them to sample many cell surfaces for potentially negatively selecting ligands.
Collapse
Affiliation(s)
- Peter J R Ebert
- Howard Hughes Medical Institute and The Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | | |
Collapse
|
9
|
Tseng SY, Liu M, Dustin ML. CD80 cytoplasmic domain controls localization of CD28, CTLA-4, and protein kinase Ctheta in the immunological synapse. THE JOURNAL OF IMMUNOLOGY 2006; 175:7829-36. [PMID: 16339518 PMCID: PMC1626532 DOI: 10.4049/jimmunol.175.12.7829] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The binding of costimulatory ligand CD80 to CD28 or CTLA-4 on T cells plays an important role in the regulation of the T cell response. We have examined the role of the cytoplasmic domain of CD80 in murine T cell costimulation and its organization in the immunological synapse (IS). Removal of CD80 cytoplasmic tail decreased its effectiveness in costimulating T cell proliferative response and early IL-2 production in response to agonist MHC-peptide complexes. Immunofluorescent study showed a decreased tailless CD80 accumulation in the IS of naive T cells. The two forms of CD80 accumulated differently at the IS; the tailless CD80 was colocalized with the TCR whereas the full-length CD80 was segregated from the TCR. In addition, we showed that CD80, CD28, and protein kinase Ctheta colocalized in the presence or absence of the CD80 cytoplasmic tail. Thus, the cytoplasmic tail of CD80 regulates its spatial localization at the IS and that of its receptors and T cell signaling molecules such as protein kinase Ctheta, and thereby facilitates full T cell activation.
Collapse
Affiliation(s)
- Su-Yi Tseng
- NYU School of Medicine, Skirball Institute, 540 First Avenue, SK2-4, New York, NY 10016, USA
| | - Mengling Liu
- Division of Biostatistics, NYU Cancer Institute, 650 First Avenue, 5th floor New York, NY 10016, USA
| | - Michael L. Dustin
- NYU School of Medicine, Skirball Institute, 540 First Avenue, SK2-4, New York, NY 10016, USA
- Address correspondence to Dr. Michael L. Dustin. NYU School of Medicine, Skirball Institute, 540 First Avenue, SK2-4, New York, NY 10016, USA.
| |
Collapse
|
10
|
Malherbe L, Hausl C, Teyton L, McHeyzer-Williams MG. Clonal selection of helper T cells is determined by an affinity threshold with no further skewing of TCR binding properties. Immunity 2004; 21:669-79. [PMID: 15539153 DOI: 10.1016/j.immuni.2004.09.008] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2004] [Revised: 09/09/2004] [Accepted: 09/29/2004] [Indexed: 10/26/2022]
Abstract
Helper T cell responses that focus the TCR repertoire of responding clones provide experimental access to the mechanisms of clonal selection in vivo. Using TCRbeta chain animals, we directly evaluate the extent of TCRalpha CDR3 diversity and the pMHCII binding attributes of individual antigen-specific Th cells. Here, we demonstrate that dominant clonotypes, as defined by TCR junctional sequence similarities, are surprisingly diverse at the level of pMHCII binding properties, before and after antigen exposure. During an immune response, we can detect and quantify the selective loss of antigen-specific clonotypes that express lower-affinity TCR. This affinity threshold selection is followed by the unbiased propagation of preferred clonotypes regardless of TCR-pMHCII half-lives or affinity. Thus, an affinity threshold mechanism discriminates Th clones with TCR of best fit and propagates clonal diversity without promoting autoreactivity.
Collapse
Affiliation(s)
- Laurent Malherbe
- Department of Immunology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | | | | | | |
Collapse
|
11
|
Abstract
Monoclonal antibodies specific for defined peptide-MHC complexes are now being used to physically detect T-cell receptor ligands. These reagents have resulted in the identification of the cells that present antigen in lymphoid and non-lymphoid tissues after various forms of antigen administration. In addition, recent advances in real-time imaging technology have begun to measure the rate and directionality of T-cell movement relative to antigen-presenting cells in lymph nodes, shedding light on the earliest events in T-cell activation in a physiological setting.
Collapse
Affiliation(s)
- Ronald N Germain
- Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 10 Center Drive, MSC-1892, Bethesda, MD 20892-1892, USA.
| | | |
Collapse
|
12
|
Abstract
A functional immune system requires the selection of T lymphocytes expressing receptors that are major histocompatibility complex restricted but tolerant to self-antigens. This selection occurs predominantly in the thymus, where lymphocyte precursors first assemble a surface receptor. In this review we summarize the current state of the field regarding the natural ligands and molecular factors required for positive and negative selection and discuss a model for how these disparate outcomes can be signaled via the same receptor. We also discuss emerging data on the selection of regulatory T cells. Such cells require a high-affinity interaction with self-antigens, yet differentiate into regulatory cells instead of being eliminated.
Collapse
Affiliation(s)
- Timothy K Starr
- Center for Immunology and the Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis 55455, USA.
| | | | | |
Collapse
|
13
|
Viret C, He X, Janeway CA. Altered positive selection due to corecognition of floppy peptide/MHC II conformers supports an integrative model of thymic selection. Proc Natl Acad Sci U S A 2003; 100:5354-9. [PMID: 12700352 PMCID: PMC154349 DOI: 10.1073/pnas.0831129100] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Thymocytes bearing the E alpha 52-68/I-A(b) complex-specific 1H3.1 alpha beta T cell antigen receptor are positively selected in Ab-Ep [Ab-Ep transgenic, invariant chain (Ii)(-/-), I-A beta(b-/-)] mice, where I-A(b) molecules present only E alpha 52-68. Although Ii reintroduction led to deletion, I-A beta(b) reintroduction disrupted positive selection. T cell antigen receptor transgenic Ab-Ep I-A beta(b+) mice had a large thymus with an increased absolute number of CD4(+)CD8(+) cells and no overt signs of deletion. Unlike Ab-Ep Ii(+) antigen-presenting cells, Ab-Ep I-A beta(b+) antigen-presenting cells did not activate 1H3.1 T cells. However, their capacity to present E alpha 52-68 was intact. Thus, positive selection of 1H3.1 thymocytes on the tight compact E alpha 52-68/I-A(b) complex is neutralized by the corecognition of loose compact self-peptide/I-A(b) conformers that do not interfere with the cognate activation of mature 1H3.1 T cells. The data support the notion that the integration of distinct signals generated by the simultaneous recognition of multiple self-peptide/MHC complexes directs intrathymic selection of T cells.
Collapse
Affiliation(s)
- Christophe Viret
- Howard Hughes Medical Institute and Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA
| | | | | |
Collapse
|
14
|
Santori FR, Brown SM, Vukmanović S. Genomics-based identification of self-ligands with T cell receptor-specific biological activity. Immunol Rev 2002; 190:146-60. [PMID: 12493012 DOI: 10.1034/j.1600-065x.2002.19011.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Self-peptide/major histocompatibility complex (MHC) complexes profoundly influence the biology of T lymphocytes. They promote the selection of the T cell receptor (TCR) repertoire in the thymus, maintain the homeostasis of peripheral T cells prior to encounter with antigen, and modify the responsiveness of T cells to foreign antigens. In addition, they can serve as antigens for autoaggressive T cells that induce autoimmune diseases. The complete sequencing of the genomes of human, mouse, and many pathogenic organisms now provides us with a comprehensive list of all possible proteins that may be the source of foreign antigenic and self-peptides. A computational approach using profile-based similarity searches on potential self-MHC-binding peptides can be used to efficiently predict self-peptides with biological activities. The common feature of the identified peptides is similarity to antigen. Thus, self-peptides may form 'hazy' images of the universe of antigens that are used as templates to create and maintain the TCR repertoire.
Collapse
Affiliation(s)
- Fabio R Santori
- Michael Heidelberger Division of Immunology, Department of Pathology and NYU Cancer Center, New York, NY 10016, USA
| | | | | |
Collapse
|
15
|
Santori FR, Kieper WC, Brown SM, Lu Y, Neubert TA, Johnson KL, Naylor S, Vukmanović S, Hogquist KA, Jameson SC. Rare, structurally homologous self-peptides promote thymocyte positive selection. Immunity 2002; 17:131-42. [PMID: 12196285 DOI: 10.1016/s1074-7613(02)00361-8] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although it is clear that positive selection of T cells involves recognition of specific self-peptide/MHC complexes, the nature of these self-ligands and their relationship to the cognate antigen are controversial. Here we used two complementary strategies to identify naturally occurring self-peptides able to induce positive selection of T cells bearing a specific T cell receptor, OT-I. Both the bioassay- and bioinformatics-based strategies identified the same self-peptides, derived from F-actin capping protein and beta-catenin. These peptides displayed charge conservation at two key TCR contact residues. The biological activity of 43 other self-peptides and of complex peptide libraries directly correlated to the extent of conservation at TCR contact residues. These results demonstrate that selecting self-peptides are rare and can be identified by homology-based search strategies.
Collapse
Affiliation(s)
- Fabio R Santori
- Michael Heidelberger Division of Immunology, Department of Pathology and Kaplan Cancer Center, New York University School of Medicine, 550 First Avenue, NY 10016, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Wülfing C, Sumen C, Sjaastad MD, Wu LC, Dustin ML, Davis MM. Costimulation and endogenous MHC ligands contribute to T cell recognition. Nat Immunol 2002; 3:42-7. [PMID: 11731799 DOI: 10.1038/ni741] [Citation(s) in RCA: 258] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To initiate an immune response, key receptor-ligand pairs must cluster in "immune synapses" at the T cell-antigen-presenting cell (APC) interface. We visualized the accumulation of a major histocompatibility complex (MHC) class II molecule, I-E(k), at a T cell-B cell interface and found it was dependent on both antigen recognition and costimulation. This suggests that costimulation-driven active transport of T cell surface molecules helps to drive immunological synapse formation. Although only agonist peptide-MHC class II (agonist pMHC class II) complexes can initiate T cell activation, endogenous pMHC class II complexes also appeared to accumulate. To test this directly, we labeled a "null" pMHC class II complex and found that, although it lacked major TCR contact residues, it could be driven into the synapse in a TCR-dependent manner. Thus, low-affinity ligands can contribute to synapse formation and T cell signaling.
Collapse
MESH Headings
- Animals
- Autoantigens/immunology
- B-Lymphocytes/immunology
- CD28 Antigens/immunology
- Calcium Signaling
- Cell Communication/immunology
- Cell Polarity
- Cells, Cultured
- Genes, MHC Class II
- Genes, Reporter
- Green Fluorescent Proteins
- Histocompatibility Antigens Class II/immunology
- Histocompatibility Antigens Class II/metabolism
- Imaging, Three-Dimensional
- Immunologic Capping
- Isoantigens/immunology
- Ligands
- Luminescent Proteins/analysis
- Luminescent Proteins/genetics
- Lymphocyte Activation/immunology
- Lymphocyte Function-Associated Antigen-1/immunology
- Macromolecular Substances
- Membrane Proteins/metabolism
- Mice
- Microscopy, Fluorescence
- Microscopy, Video
- Models, Immunological
- Peptide Fragments/immunology
- Peptide Fragments/metabolism
- Protein Transport
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/metabolism
- Recombinant Fusion Proteins/analysis
- Recombinant Fusion Proteins/genetics
- Self Tolerance/immunology
- Transfection
Collapse
Affiliation(s)
- Christoph Wülfing
- The Howard Hughes Medical Institute and The Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | | | | | | | | |
Collapse
|
17
|
Viret C, He X, Janeway CA. Paradoxical intrathymic positive selection in mice with only a covalently presented agonist peptide. Proc Natl Acad Sci U S A 2001; 98:9243-8. [PMID: 11470911 PMCID: PMC55405 DOI: 10.1073/pnas.161274698] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Y-Ae mAb and the 1H3.1 alphabeta T cell antigen receptor (TCR) are both specific for the I-Ealpha52-68 peptide bound to the I-A(b) major histocompatibility complex (MHC) class II molecule. Antigen-presenting cells (APCs) from I-A(b+) mice with a natural or transgenic (Tg) I-Ealpha chain activate mature 1H3.1 T cells and cause the deletion of 1H3.1 TCR Tg thymocytes. However, 1H3.1 T cells were neither activated nor inactivated by confrontation with APCs from I-Ab-Ep mice in which I-A(b) molecules are occupied only by the covalently associated Ealpha52-68 peptide. Instead, immature 1H3.1 TCR Tg thymocytes were efficiently positively selected into the CD4 lineage in the I-Ab-Ep thymus. This selection relied on specific recognition of the Ealpha52-68/I-A(b) complex because it was blocked by Y-Ae. 1H3.1 TCR Tg T cells maturing in the I-Ab-Ep thymus efficiently populated the periphery, displayed a naive phenotype, and were specifically reactive to the Ealpha52-68 peptide or to I-A(b+)I-Ealpha(+) APCs, indicating that 1H3.1 T cells were not antagonized in I-Ab-Ep mice. The data identify major histocompatibility complex class II molecules with only a covalently attached self-peptide as a ligand for in vivo positive selection of T cells specific for the same peptide.
Collapse
Affiliation(s)
- C Viret
- Section of Immunobiology, Yale University School of Medicine, and Howard Hughes Medical Institute, New Haven, CT 06520-8011, USA
| | | | | |
Collapse
|
18
|
Chung DH, Belyakov IM, Derby MA, Wang J, Boyd LF, Berzofsky JA, Margulies DH. Competitive inhibition in vivo and skewing of the T cell repertoire of antigen-specific CTL priming by an anti-peptide-MHC monoclonal antibody. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:699-707. [PMID: 11441073 DOI: 10.4049/jimmunol.167.2.699] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have recently described a mAb, KP15, directed against the MHC-I/peptide molecular complex consisting of H-2D(d) and a decamer peptide corresponding to residues 311-320 of the HIV IIIB envelope glycoprotein gp160. When administered at the time of primary immunization with a vaccinia virus vector encoding gp160, the mAb blocks the subsequent appearance of CD8(+) CTL with specificity for the immunodominant Ag, P18-I10, presented by H-2D(d). This inhibition is specific for this particular peptide Ag; another H-2D(d)-restricted gp160 encoded epitope from a different HIV strain is not affected, and an H-2L(d)-restricted epitope encoded by the viral vector is also not affected. Using functional assays and specific immunofluorescent staining with multivalent, labeled H-2D(d)/P18-I10 complexes (tetramers), we have enumerated the effects of blocking of priming on the subsequent appearance, avidity, and TCR Vbeta usage of Ag-specific CTL. Ab blocking skews the proportion of high avidity cells emerging from immunization. Surprisingly, Vbeta7-bearing Ag-specific TCR are predominantly inhibited, while TCR of several other families studied are not affected. The ability of a specific MHC/peptide mAb to inhibit and divert the CD8(+) T cell response holds implications for vaccine design and approaches to modulate the immune response in autoimmunity.
Collapse
MESH Headings
- Animals
- Antibodies, Blocking/administration & dosage
- Antibodies, Blocking/metabolism
- Antibodies, Monoclonal/administration & dosage
- Antibodies, Monoclonal/metabolism
- Binding, Competitive/immunology
- Cytotoxicity, Immunologic/immunology
- Epitopes, T-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/metabolism
- H-2 Antigens/immunology
- H-2 Antigens/metabolism
- HIV Antigens/immunology
- HIV Antigens/metabolism
- HIV Envelope Protein gp160/immunology
- HIV Envelope Protein gp160/metabolism
- Histocompatibility Antigen H-2D
- Humans
- Injections, Intraperitoneal
- Injections, Intravenous
- Lymphocyte Activation/immunology
- Lymphocyte Count
- Mice
- Mice, Inbred BALB C
- Oligopeptides/antagonists & inhibitors
- Oligopeptides/immunology
- Oligopeptides/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/antagonists & inhibitors
- Receptors, Antigen, T-Cell, alpha-beta/biosynthesis
- Stem Cells/immunology
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
Collapse
Affiliation(s)
- D H Chung
- Laboratory of Immunology, National Institute of Allergy and Infectious Disease, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892, USA
| | | | | | | | | | | | | |
Collapse
|
19
|
Abstract
To characterize the ligand binding properties of a naive T cell repertoire capable of responding to a foreign antigen, we analyzed T cell populations from T cell receptor (TCR) beta transgenic mice using a novel, single cell peptide/major histocompatibility complex (MHC) tetramer dissociation assay. The largely CD4+CD8(-/low) antigen-specific thymocyte repertoire exhibited a broad, bimodal distribution of tetramer binding half-lives (t(1/2)s), with a significant underrepresentation in the intermediate half-life range in which the majority of the peripheral repertoire lies. Thus, cells with the potential to bind foreign antigen with the lowest and highest stability are likely to be selectively removed from the repertoire prior to their establishment in the periphery. These studies provide direct evidence that thymic selection biases the naive peripheral T cell repertoire toward TCR-ligand interactions that fall within a moderate half-life "window."
Collapse
Affiliation(s)
- P A Savage
- Program in Cancer Biology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | |
Collapse
|
20
|
Fukui Y, Oono T, Cabaniols JP, Nakao K, Hirokawa K, Inayoshi A, Sanui T, Kanellopoulos J, Iwata E, Noda M, Katsuki M, Kourilsky P, Sasazuki T. Diversity of T cell repertoire shaped by a single peptide ligand is critically affected by its amino acid residue at a T cell receptor contact. Proc Natl Acad Sci U S A 2000; 97:13760-5. [PMID: 11087837 PMCID: PMC17649 DOI: 10.1073/pnas.250470797] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
T cell differentiation in the thymus is driven by positive selection through the interaction of alphabeta T cell receptors (TCRs) with self-peptides bound to self-major histocompatibility complex molecules, yet the influence of the peptide sequence on this process remains unknown. To address this issue, we have compared CD4(+) T cell differentiation between two sets of mouse lines in which MHC class II I-A(b) molecules are occupied with either Ealpha chain-derived peptide ((p)Ealpha) or its variant, (p)60K, with one amino acid substitution from leucine to lysine at P5 residue of TCR contacts. Here, we show that despite the comparable expression of I-A(b)-peptide complex in the thymus, this substitution from leucine to lysine affects efficiency of positive selection, resulting in extremely small numbers of CD4(+) T cells to be selected to mature on I-A(b)-(p)60K complex. Furthermore, we show that, although I-A(b)-(p)Ealpha complex selects diverse T cells, T cell repertoire shaped by I-A(b)-(p)60K complex is markedly constrained. Our findings thus suggest that positive selection is both specific and degenerate, depending on the amino acid residues at TCR contacts of the selecting self-peptides.
Collapse
Affiliation(s)
- Y Fukui
- Department of Genetics, CREST (Core Research for Evolutional Science and Technology), Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Viret C, He X, Janeway CA. On the self-referential nature of naive MHC class II-restricted T cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 165:6183-92. [PMID: 11086052 DOI: 10.4049/jimmunol.165.11.6183] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The use of mutant mice expressing a normal MHC class II molecule surface level but a severely restricted self-peptide diversity (H-2Malpha(-/-)) previously revealed that T cells carrying the Ealpha(52-68)-I-A(b) complex-specific 1H3.1 TCR rely on self-peptide(s) recognition for both their peripheral persistence in irradiated hosts and their intrathymic positive selection. Here, we identify Ealpha(52-68) structurally related self-peptide(s) as a major contributor to in vivo positive selection of 1H3.1 TCR-transgenic thymocytes in I-A(b+)/I-Ealpha(-) mice. This is demonstrated by the drastic and specific reduction of the TCR high thymocyte population in 1H3.1 TCR-transgenic (Tg) mice treated with the Ealpha(52-68)-I-A(b) complex-specific Y-Ae mAb. Self-peptide(s) recognition is also driving the maturation of T cells carrying a distinct MHC class II-restricted specificity (the Ealpha(6) alphass TCR), since positive selection was also deficient in Ealpha(6) TCR Tg H-2Malpha(-/-) thymi. Such a requirement for recognition of self-determinants was mirrored in the periphery; Ealpha(6) TCR Tg naive T cells showed an impaired persistence in both H-2Malpha(-/-) and I-A(b)ss(-/-) irradiated hosts, whereas they persisted and slowly cycled in wild-type recipients. This moderate self-peptide(s)-dependent proliferation was associated with a surface phenotype intermediate between those of naive and activated/memory T cells; CD44 expression was up-regulated, but surface expression of other markers such as CD62L remained unaltered. Collectively, these observations indicate that maturation and maintenance of naive MHC class II-restricted T cells are self-oriented processes.
Collapse
Affiliation(s)
- C Viret
- Section of Immunobiology, Yale University School of Medicine, and Howard Hughes Medical Institute, New Haven, CT 06520, USA
| | | | | |
Collapse
|
22
|
Reay PA, Matsui K, Haase K, Wulfing C, Chien YH, Davis MM. Determination of the relationship between T cell responsiveness and the number of MHC-peptide complexes using specific monoclonal antibodies. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2000; 164:5626-34. [PMID: 10820237 DOI: 10.4049/jimmunol.164.11.5626] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We describe the generation of three mAbs that recognize the complex of the class II MHC molecule IEk bound to a peptide derived from the carboxyl terminus of moth cytochrome c (residues 95-103). Reactivities of these mAbs are sensitive to single alterations in the sequence of both helices of the MHC molecule and to the bound peptide. The epitopes of these reagents are distinct but overlap substantially. One of these mAbs specifically blocks lymphokine release by T cells responsive to this complex but not others. We have used another to examine how the number of complexes on an APC is related to its ability to stimulate T cells. We find that 200-400 complexes per cell are necessary and sufficient to induce a degree of stimulation, whereas maximum stimulation is achieved only if more than 5000 complexes are present. The analysis indicates that T cell activation is a stochastic process.
Collapse
Affiliation(s)
- P A Reay
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305, USA.
| | | | | | | | | | | |
Collapse
|
23
|
Krogsgaard M, Wucherpfennig KW, Canella B, Hansen BE, Svejgaard A, Pyrdol J, Ditzel H, Raine C, Engberg J, Fugger L. Visualization of myelin basic protein (MBP) T cell epitopes in multiple sclerosis lesions using a monoclonal antibody specific for the human histocompatibility leukocyte antigen (HLA)-DR2-MBP 85-99 complex. J Exp Med 2000; 191:1395-412. [PMID: 10770805 PMCID: PMC2193136 DOI: 10.1084/jem.191.8.1395] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Susceptibility to multiple sclerosis (MS) is associated with the human histocompatibility leukocyte antigen (HLA)-DR2 haplotype, suggesting that major histocompatibility complex class II-restricted presentation of central nervous system-derived antigens is important in the disease process. Antibodies specific for defined HLA-DR2-peptide complexes may therefore be valuable tools for studying antigen presentation in MS. We have used phage display technology to select HLA-DR2-peptide-specific antibodies from HLA-DR2-transgenic mice immunized with HLA-DR2 molecules complexed with an immunodominant myelin basic protein (MBP) peptide (residues 85-99). Detailed characterization of one clone (MK16) demonstrated that both DR2 and the MBP peptide were required for recognition. Furthermore, MK16 labeled intra- and extracellular HLA-DR2-MBP peptide complexes when antigen-presenting cells (APCs) were pulsed with recombinant MBP. In addition, MK16 inhibited interleukin 2 secretion by two transfectants that expressed human MBP-specific T cell receptors. Analysis of the structural requirement for MK16 binding demonstrated that the two major HLA-DR2 anchor residues of MBP 85-99 and the COOH-terminal part of the peptide, in particular residues Val-96, Pro-98, and Arg-99, were important for binding. Based on these results, the antibody was used to determine if the HLA-DR2-MBP peptide complex is presented in MS lesions. The antibody stained APCs in MS lesions, in particular microglia/macrophages but also in some cases hypertrophic astrocytes. Staining of APCs was only observed in MS cases with the HLA-DR2 haplotype but not in cases that carried other haplotypes. These results demonstrate that HLA-DR2 molecules in MS lesions present a myelin-derived self-peptide and suggest that microglia/macrophages rather than astrocytes are the predominant APCs in these lesions.
Collapse
Affiliation(s)
- Michelle Krogsgaard
- Department of Pharmacology, Royal Danish School of Pharmacy, DK-2100 Copenhagen, Denmark
- Department of Clinical Immunology, Aarhus University Hospital, Skejby Sygehus, DK-8200 N, Aarhus, Denmark
| | - Kai W. Wucherpfennig
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Barbara Canella
- Department of Pathology/Neuropathology, Albert Einstein College of Medicine, New York, New York 10461
| | - Bjarke E. Hansen
- Department of Clinical Immunology, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark
| | - Arne Svejgaard
- Department of Clinical Immunology, Copenhagen University Hospital, DK-2100 Copenhagen, Denmark
| | - Jason Pyrdol
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115
| | - Henrik Ditzel
- Department of Immunology, The Scripps Research Institute, La Jolla, California 92037
| | - Cedric Raine
- Department of Pathology/Neuropathology, Albert Einstein College of Medicine, New York, New York 10461
| | - Jan Engberg
- Department of Pharmacology, Royal Danish School of Pharmacy, DK-2100 Copenhagen, Denmark
| | - Lars Fugger
- Department of Clinical Immunology, Aarhus University Hospital, Skejby Sygehus, DK-8200 N, Aarhus, Denmark
| |
Collapse
|
24
|
|
25
|
Abstract
To provide a T-cell population that will respond promptly to foreign antigen, the immune system looks inward, using the variety of self-antigens to select and maintain a diverse repertoire of receptors. A protective immune system must include a T-lymphocyte population that is poised to respond to foreign antigenic peptides presented by self-major histocompatibility complex molecules. As the organism cannot predict the precise pathogen-derived antigens that will be encountered, the system uses the diverse array of self-peptides bound to self-major histocompatibility complex molecules, not only to select a receptor repertoire in the thymus, but also to keep naïve T cells alive and 'ready for action' in the periphery.
Collapse
Affiliation(s)
- A W Goldrath
- Department of Immunology and Howard Hughes Medical Institute, University of Washington, Seattle 98195, USA
| | | |
Collapse
|
26
|
Baldwin KK, Trenchak BP, Altman JD, Davis3 MM. Negative Selection of T Cells Occurs Throughout Thymic Development. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.2.689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Thymic positive and negative selections govern the development of a self-MHC-reactive, yet self-tolerant, T cell repertoire. Whether these processes occur independently or sequentially remains controversial. To investigate these issues, we have employed tetrameric peptide-MHC complexes to fluorescently label and monitor polyclonal populations of thymocytes that are specific for moth cytochrome c (MCC)/I-Ek. In TCR β mice tetramer-positive thymocytes are detectable even in the most immature TCR-expressing cells. In the presence of MCC peptide, thymocytes that bind strongly to MCC/I-Ek tetramers are deleted earlier in development and more extensively than cells that bind weakly. This negative selection of the MCC/I-Ek-specific cells occurs continuously throughout development and before any evidence of positive selection. Thus, positive and negative selections are independent processes that need not occur sequentially.
Collapse
Affiliation(s)
| | - Brian P. Trenchak
- †Department of Microbiology and Immunology, and
- ‡Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305; and
| | - John D. Altman
- §Department of Microbiology and Immunology, Emory University, Atlanta, GA 30322
| | - Mark M. Davis3
- †Department of Microbiology and Immunology, and
- ‡Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305; and
| |
Collapse
|
27
|
Grakoui A, Bromley SK, Sumen C, Davis MM, Shaw AS, Allen PM, Dustin ML. The immunological synapse: a molecular machine controlling T cell activation. Science 1999; 285:221-7. [PMID: 10398592 DOI: 10.1126/science.285.5425.221] [Citation(s) in RCA: 2308] [Impact Index Per Article: 92.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The specialized junction between a T lymphocyte and an antigen-presenting cell, the immunological synapse, consists of a central cluster of T cell receptors surrounded by a ring of adhesion molecules. Immunological synapse formation is now shown to be an active and dynamic mechanism that allows T cells to distinguish potential antigenic ligands. Initially, T cell receptor ligands were engaged in an outermost ring of the nascent synapse. Transport of these complexes into the central cluster was dependent on T cell receptor-ligand interaction kinetics. Finally, formation of a stable central cluster at the heart of the synapse was a determinative event for T cell proliferation.
Collapse
Affiliation(s)
- A Grakoui
- Center for Immunology and the Department of Pathology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
| | | | | | | | | | | | | |
Collapse
|
28
|
Abstract
An important issue for immunologists is the difference between the two main processes that determine the mature repertoire of T-cell receptors, termed positive and negative selection. Recent papers have addressed the role of self-peptides in the process of positive selection.
Collapse
Affiliation(s)
- C A Janeway
- Section of Immunobiology, Yale University School of Medicine, The Howard Hughes Medical Institute, New Haven, Connecticut, 06520-8011, USA
| |
Collapse
|