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Strand A, Shen ST, Tomchick D, Wang J, Wang CR, Deisenhofer J. Structure and dynamics of major histocompatibility class Ib molecule H2-M3 complexed with mitochondrial-derived peptides. J Biomol Struct Dyn 2022; 40:10300-10312. [PMID: 34176438 PMCID: PMC8722451 DOI: 10.1080/07391102.2021.1942214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Presentation of antigenic peptides to T-cell receptors is an essential step in the adaptive immune response. In the mouse the class Ib major histocompatibility complex molecule, H2-M3, presents bacterial- and mitochondrial-derived peptides to T-cell receptors on cytotoxic T cells. Four mitochondrial heptapeptides, differing only at residue 6, form complexes with H2-M3 which can be distinguished by T cells. No structures of relevant receptors are available. To investigate the structural basis for this distinction, crystal structures were determined and molecular dynamics simulations over one microsecond were done for each complex. In the crystal structures of the heptapeptide complexes with H2-M3, presented here, the side chains of the peptide residues at position 6 all point into the H2-M3 binding groove, and are thus inaccessible, so that the very similar structures do not suggest how recognition and initiation of responses by the T cells may occur. However, conformational differences, which could be crucial to T-cell discrimination, appear within one microsecond during molecular dynamics simulations of the four complexes. Specifically, the three C-terminal residues of peptide ligands with alanine or threonine at position 6 partially exit the binding groove; this does not occur in peptide ligands with isoleucine or valine at position 6. Structural changes associated with partial peptide exit from the binding groove, along with relevant peptide binding energetics and immunological results are discussed. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Arne Strand
- Green Center for Systems Biology, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - San-Tai Shen
- AnTaimmu Biomed Co., Ltd., Zhubei City, Hsinchu County, Taiwan
| | - Diana Tomchick
- Department of Biophysics, UT Southwestern Medical Center, Dallas, Texas, United States of America,Department of Biochemistry, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Junmei Wang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Chyung-Ru Wang
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Johann Deisenhofer
- Green Center for Systems Biology, UT Southwestern Medical Center, Dallas, Texas, United States of America,Department of Biophysics, UT Southwestern Medical Center, Dallas, Texas, United States of America,Corresponding author
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Unconventional Peptide Presentation by Classical MHC Class I and Implications for T and NK Cell Activation. Int J Mol Sci 2020; 21:ijms21207561. [PMID: 33066279 PMCID: PMC7590165 DOI: 10.3390/ijms21207561] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 10/09/2020] [Accepted: 10/10/2020] [Indexed: 12/20/2022] Open
Abstract
T cell-mediated immune recognition of peptides is initiated upon binding of the antigen receptor on T cells (TCR) to the peptide-MHC complex. TCRs are typically restricted by a particular MHC allele, while polymorphism within the MHC molecule can affect the spectrum of peptides that are bound and presented to the TCR. Classical MHC Class I molecules have a confined binding groove that restricts the length of the presented peptides to typically 8-11 amino acids. Both N- and C-termini of the peptide are bound within binding pockets, allowing the TCR to dock in a diagonal orientation above the MHC-peptide complex. Longer peptides have been observed to bind either in a bulged or zig-zag orientation within the binding groove. More recently, unconventional peptide presentation has been reported for different MHC I molecules. Here, either N- or C-terminal amino acid additions to conventionally presented peptides induced a structural change either within the MHC I molecule that opened the confined binding groove or within the peptide itself, allowing the peptide ends to protrude into the solvent. Since both TCRs on T cells and killer immunoglobulin receptors on Natural Killer (NK) cells contact the MHC I molecule above or at the periphery of the peptide binding groove, unconventionally presented peptides could modulate both T cell and NK cell responses. We will highlight recent advances in our understanding of the functional consequences of unconventional peptide presentation in cellular immunity.
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Goodall KJ, Nguyen A, McKenzie C, Eckle SBG, Sullivan LC, Andrews DM. The murine CD94/NKG2 ligand, Qa-1 b, is a high-affinity, functional ligand for the CD8αα homodimer. J Biol Chem 2020; 295:3239-3246. [PMID: 31992596 PMCID: PMC7062157 DOI: 10.1074/jbc.ra119.010509] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 01/22/2020] [Indexed: 11/06/2022] Open
Abstract
The immune co-receptor CD8 molecule (CD8) has two subunits, CD8α and CD8β, which can assemble into homo or heterodimers. Nonclassical (class-Ib) major histocompatibility complex (MHC) molecules (MHC-Ibs) have recently been identified as ligands for the CD8αα homodimer. This was demonstrated by the observation that histocompatibility 2, Q region locus 10 (H2-Q10) is a high-affinity ligand for CD8αα which also binds the MHC-Ib molecule H2-TL. This suggests that MHC-Ib proteins may be an extended source of CD8αα ligands. Expression of H2-T3/TL and H2-Q10 is restricted to the small intestine and liver, respectively, yet CD8αα-containing lymphocytes are present more broadly. Therefore, here we sought to determine whether murine CD8αα binds only to tissue-specific MHC-Ib molecules or also to ubiquitously expressed MHC-Ib molecules. Using recombinant proteins and surface plasmon resonance-based binding assays, we show that the MHC-Ib family furnishes multiple binding partners for murine CD8αα, including H2-T22 and the CD94/NKG2-A/B-activating NK receptor (NKG2) ligand Qa-1b We also demonstrate a hierarchy among MHC-Ib proteins with respect to CD8αα binding, in which Qa-1b > H2-Q10 > TL. Finally, we provide evidence that Qa-1b is a functional ligand for CD8αα, distinguishing it from its human homologue MHC class I antigen E (HLA-E). These findings provide additional clues as to how CD8αα-expressing cells are controlled in different tissues. They also highlight an unexpected immunological divergence of Qa-1b/HLA-E function, indicating the need for more robust studies of murine MHC-Ib proteins as models for human disease.
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Affiliation(s)
- Katharine Jennifer Goodall
- Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia.
| | - Angela Nguyen
- Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
| | - Craig McKenzie
- Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
| | - Sidonia Barbara Guiomar Eckle
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, 3000, Australia
| | - Lucy Catherine Sullivan
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, 3000, Australia
| | - Daniel Mark Andrews
- Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia
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Mir SA, Sharma S. Adjunctive Immunotherapeutic Efficacy of N-Formylated Internal Peptide of Mycobacterial Glutamine Synthetase in Mouse Model of Tuberculosis. Protein Pept Lett 2019; 27:236-242. [PMID: 31746288 DOI: 10.2174/0929866526666191028151615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 08/17/2019] [Accepted: 08/19/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Host-directed therapies are a comparatively new and promising method for the treatment of tuberculosis. A variety of host pathways, vaccines and drugs have the potential to provide novel adjunctive therapies for the treatment of tuberculosis. In this connection, we have earlier reported the immunotherapeutic potential of N-formylated N-terminal peptide of glutamine synthetase of Mycobacterim tuberculosis H37Rv (Mir SA and Sharma S, 2014). Now in the present study, we investigated the immunotherapeutic effect of N-terminally formylated internal-peptide 'f- MLLLPD' of mycobacterial glutamine synthetase (Rv2220) in mouse model of tuberculosis. METHODS The N-terminally formylated peptide, f-MLLLPD was tested for its potential to generate Reactive Oxygen Species (ROS) in murine neutrophils. Further, its therapeutic effect alone or in combination with anti-tubercular drugs was evaluated in mouse model of tuberculosis. RESULTS The f-MLLLPD peptide treatment alone and in combination with ATDs reduced the bacterial load (indicated as colony forming units) in lungs of infected mice by 0.58 (p<0.01) and 2.92 (p<0.001) log10 units respectively and in their spleens by 0.46 (p<0.05) and 2.46 (p<0.001) log10 units respectively. In addition, the observed histopathological results correlated well with the CFU data. CONCLUSION The results of the current study show that f-MLLLPD peptide confers an additional therapeutic efficacy to the anti-tuberculosis drugs.
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Affiliation(s)
- Shabir Ahmad Mir
- Department of Biochemistry, Postgraduate Institute of Medical Education & Research (PGIMER), Chandigarh - 160012, India.,Department of Medical Laboratory Sciences, College of Applied Medical Science, Majmaah University, Al Majmaah-11952, Saudi Arabia
| | - Sadhna Sharma
- Department of Biochemistry, Postgraduate Institute of Medical Education & Research (PGIMER), Chandigarh - 160012, India
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Mir SA, Sharma S. Immunotherapeutic potential of an N-formylated peptide of Listeria monocytogenes in experimental tuberculosis. Immunopharmacol Immunotoxicol 2019; 41:292-298. [PMID: 31046503 DOI: 10.1080/08923973.2019.1593446] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Objective: The current therapeutic regimens for tuberculosis (TB) are complex and involve the prolonged use of multiple antibiotics with diverse side effects that lead to therapeutic failure and bacterial resistance. The standard appliance of immunotherapy may aid as a powerful tool to combat the ensuing threat of TB. We have earlier reported the immunotherapeutic potential of N-formylated peptides of two secretory proteins of Mycobacterium tuberculosis H37Rv. Here, we investigated the immunotherapeutic effect of an N-formylated peptide from Listeria monocytogenes in experimental TB. Methods: The N-terminally formylated listerial peptide with amino acid sequence 'f-MIGWII' was tested for its adjunctive therapeutic efficacy in combination with anti-tuberculosis drugs (ATDs) in the mouse model of TB. In addition, its potential to generate reactive oxygen species (ROS) in murine neutrophils was also evaluated. Results: The LemA peptide (f-MIGWII) induced a significant increase in the intracellular ROS levels of mouse neutrophils (p ≤ .05). The ATD treatment reduced the colony forming units (CFU) in lungs and spleen of infected mice by 2.39 and 1.67 log10 units, respectively (p < .001). Treatment of the infected mice with combination of ATDs and LemA peptide elicited higher therapeutic efficacy over ATDs alone. The histopathological changes in the lungs of infected mice also correlated well with the CFU data. Conclusions: Our results clearly indicate that LemA peptide conferred an additional therapeutic effect when given in combination with the ATDss (p < .01) and hence can be used as adjunct to the conventional chemotherapy against TB.
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Affiliation(s)
- Shabir Ahmad Mir
- a Department of Biochemistry , Postgraduate Institute of Medical Education & Research (PGIMER) , Chandigarh , India.,b Department of Medical Laboratory Sciences, College of Applied Medical Science , Majmaah University , Al Majmaah , Saudi Arabia
| | - Sadhna Sharma
- a Department of Biochemistry , Postgraduate Institute of Medical Education & Research (PGIMER) , Chandigarh , India
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Jiang J, Natarajan K, Margulies DH. MHC Molecules, T cell Receptors, Natural Killer Cell Receptors, and Viral Immunoevasins-Key Elements of Adaptive and Innate Immunity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1172:21-62. [PMID: 31628650 DOI: 10.1007/978-981-13-9367-9_2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Molecules encoded by the Major Histocompatibility Complex (MHC) bind self or foreign peptides and display these at the cell surface for recognition by receptors on T lymphocytes (designated T cell receptors-TCR) or on natural killer (NK) cells. These ligand/receptor interactions govern T cell and NK cell development as well as activation of T memory and effector cells. Such cells participate in immunological processes that regulate immunity to various pathogens, resistance and susceptibility to cancer, and autoimmunity. The past few decades have witnessed the accumulation of a huge knowledge base of the molecular structures of MHC molecules bound to numerous peptides, of TCRs with specificity for many different peptide/MHC (pMHC) complexes, of NK cell receptors (NKR), of MHC-like viral immunoevasins, and of pMHC/TCR and pMHC/NKR complexes. This chapter reviews the structural principles that govern peptide/MHC (pMHC), pMHC/TCR, and pMHC/NKR interactions, for both MHC class I (MHC-I) and MHC class II (MHC-II) molecules. In addition, we discuss the structures of several representative MHC-like molecules. These include host molecules that have distinct biological functions, as well as virus-encoded molecules that contribute to the evasion of the immune response.
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Affiliation(s)
- Jiansheng Jiang
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11D07, 10 Center Drive, Bethesda, MD, 20892-1892, USA.
| | - Kannan Natarajan
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11D07, 10 Center Drive, Bethesda, MD, 20892-1892, USA
| | - David H Margulies
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11D12, 10 Center Drive, Bethesda, MD, 20892-1892, USA
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7
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Goodall KJ, Nguyen A, Sullivan LC, Andrews DM. The expanding role of murine class Ib MHC in the development and activation of Natural Killer cells. Mol Immunol 2018; 115:31-38. [PMID: 29789149 DOI: 10.1016/j.molimm.2018.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 04/21/2018] [Accepted: 05/02/2018] [Indexed: 12/12/2022]
Abstract
Major Histocompatibility Complex-I (MHC-I) molecules can be divided into class Ia and class Ib, with three distinct class Ib families found in the mouse. These families are designated as Q, T and M and are largely unexplored in terms of their immunological function. Among the class Ib MHC, H2-T23 (Qa-1b) has been a significant target for Natural Killer (NK) cell research, owing to its homology with the human class Ib human leukocyte antigen (HLA)-E. However, recent data has indicated that members of the Q and M family of class Ib MHC also play a critical role in the development and regulation NK cells. Here we discuss the recent advances in the control of NK cells by murine class Ib MHC as a means to stimulate further exploration of these molecules.
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Affiliation(s)
- Katharine J Goodall
- Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, Australia
| | - Angela Nguyen
- Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, Australia
| | - Lucy C Sullivan
- Department of Microbiology and Immunology, University of Melbourne, Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
| | - Daniel M Andrews
- Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, Australia.
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9
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Legoux F, Salou M, Lantz O. Unconventional or Preset αβ T Cells: Evolutionarily Conserved Tissue-Resident T Cells Recognizing Nonpeptidic Ligands. Annu Rev Cell Dev Biol 2017; 33:511-535. [PMID: 28661722 DOI: 10.1146/annurev-cellbio-100616-060725] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A majority of T cells bearing the αβ T cell receptor (TCR) are specific for peptides bound to polymorphic classical major histocompatibility complex (MHC) molecules. Smaller subsets of T cells are reactive toward various nonpeptidic ligands associated with nonpolymorphic MHC class-Ib (MHC-Ib) molecules. These cells have been termed unconventional for decades, even though only the composite antigen is different from the one seen by classical T cells. Herein, we discuss the identity of these particular T cells in light of the coevolution of their TCR and MHC-Ib restricting elements. We examine their original thymic development: selection on hematopoietic cells leading to the acquisition of an original differentiation program. Most of these cells acquire memory cell features during thymic maturation and exhibit unique patterns of migration into peripheral nonlymphoid tissues to become tissue resident. Thus, these cells are termed preset T cells, as they also display a variety of effector functions. They may act as microbial or danger sentinels, fight microbes, or regulate tissue homeostasis.
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Affiliation(s)
- Francois Legoux
- Institut Curie, PSL Research University, INSERM, U 932, 75005 Paris, France; , ,
| | - Marion Salou
- Institut Curie, PSL Research University, INSERM, U 932, 75005 Paris, France; , ,
| | - Olivier Lantz
- Institut Curie, PSL Research University, INSERM, U 932, 75005 Paris, France; , , .,Center of Clinical Investigations, CIC-1428 IGR/Curie, 75005 Paris, France.,Laboratoire d'immunologie clinique, Institut Curie, 75005 Paris, France
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Abstract
Evidence is mounting that the major histocompatibility complex (MHC) molecule HLA-F (human leukocyte antigen F) regulates the immune system in pregnancy, infection, and autoimmunity by signaling through NK cell receptors (NKRs). We present structural, biochemical, and evolutionary analyses demonstrating that HLA-F presents peptides of unconventional length dictated by a newly arisen mutation (R62W) that has produced an open-ended groove accommodating particularly long peptides. Compared to empty HLA-F open conformers (OCs), HLA-F tetramers bound with human-derived peptides differentially stained leukocytes, suggesting peptide-dependent engagement. Our in vitro studies confirm that NKRs differentiate between peptide-bound and peptide-free HLA-F. The complex structure of peptide-loaded β2m-HLA-F bound to the inhibitory LIR1 revealed similarities to high-affinity recognition of the viral MHC-I mimic UL18 and a docking strategy that relies on contacts with HLA-F as well as β2m, thus precluding binding to HLA-F OCs. These findings provide a biochemical framework to understand how HLA-F could regulate immunity via interactions with NKRs.
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11
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MHC-I peptides get out of the groove and enable a novel mechanism of HIV-1 escape. Nat Struct Mol Biol 2017; 24:387-394. [PMID: 28218747 DOI: 10.1038/nsmb.3381] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Accepted: 01/20/2017] [Indexed: 12/18/2022]
Abstract
Major histocompatibility complex class I (MHC-I) molecules play a crucial role in immunity by capturing peptides for presentation to T cells and natural killer (NK) cells. The peptide termini are tethered within the MHC-I antigen-binding groove, but it is unknown whether other presentation modes occur. Here we show that 20% of the HLA-B*57:01 peptide repertoire comprises N-terminally extended sets characterized by a common motif at position 1 (P1) to P2. Structures of HLA-B*57:01 presenting N-terminally extended peptides, including the immunodominant HIV-1 Gag epitope TW10 (TSTLQEQIGW), showed that the N terminus protrudes from the peptide-binding groove. The common escape mutant TSNLQEQIGW bound HLA-B*57:01 canonically, adopting a dramatically different conformation than the TW10 peptide. This affected recognition by killer cell immunoglobulin-like receptor (KIR) 3DL1 expressed on NK cells. We thus define a previously uncharacterized feature of the human leukocyte antigen class I (HLA-I) immunopeptidome that has implications for viral immune escape. We further suggest that recognition of the HLA-B*57:01-TW10 epitope is governed by a 'molecular tension' between the adaptive and innate immune systems.
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12
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Formylated MHC Class Ib Binding Peptides Activate Both Human and Mouse Neutrophils Primarily through Formyl Peptide Receptor 1. PLoS One 2016; 11:e0167529. [PMID: 27907124 PMCID: PMC5132201 DOI: 10.1371/journal.pone.0167529] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 11/15/2016] [Indexed: 12/17/2022] Open
Abstract
Two different immune recognition systems have evolved in parallel to recognize peptides starting with an N-formylated methionine, and recognition similarities/differences between these two systems have been investigated. A number of peptides earlier characterized in relation to the H2-M3 complex that presents N-formylated peptides to cytotoxic T cells, have been characterized in relation to the formyl peptide receptors expressed by phagocytic neutrophils in both men (FPRs) and mice (Fprs). FPR1/Fpr1 was identified as the preferred receptor for all fMet-containing peptides examined, but there was no direct correlation between H2-M3 binding and the neutrophil activation potencies. Similarly, there was no direct correlation between the activities induced by the different peptides in human and mouse neutrophils, respectively. The formyl group was important in both H2-M3 binding and FPR activation, but FPR2 was the preferred receptor for the non-formylated peptide. The structural requirements differed between the H2-M3 and FPR/Fpr recognition systems and these data suggest that the two recognition systems have different evolutionary traits.
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Morita D, Sugita M. Lipopeptides: a novel antigen repertoire presented by major histocompatibility complex class I molecules. Immunology 2016; 149:139-45. [PMID: 27402593 DOI: 10.1111/imm.12646] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 07/04/2016] [Accepted: 07/06/2016] [Indexed: 01/13/2023] Open
Abstract
Post-translationally modified peptides, such as those containing either phosphorylated or O-glycosylated serine/threonine residues, may be presented to cytotoxic T lymphocytes (CTLs) by MHC class I molecules. Most of these modified peptides are captured in the MHC class I groove in a similar manner to that for unmodified peptides. N-Myristoylated 5-mer lipopeptides have recently been identified as a novel chemical class of MHC class I-presented antigens. The rhesus classical MHC class I allele, Mamu-B*098, was found to be capable of binding N-myristoylated lipopeptides and presenting them to CTLs. A high-resolution X-ray crystallographic analysis of the Mamu-B*098:lipopeptide complex revealed that the myristic group as well as conserved C-terminal serine residue of the lipopeptide ligand functioned as anchors, whereas the short stretch of three amino acid residues located in the middle of the lipopeptides was only exposed externally with the potential to interact directly with specific T-cell receptors. Therefore, the modes of lipopeptide-ligand interactions with MHC class I and with T-cell receptors are novel and fundamentally distinct from that for MHC class I-presented peptides. Another lipopeptide-presenting MHC class I allele has now been identified, leading us to the prediction that MHC class I molecules may be separated on a functional basis into two groups: one presenting long peptides and the other presenting short lipopeptides. Since the N-myristoylation of viral proteins is often linked to pathogenesis, CTLs capable of sensing N-myristoylation may serve to control pathogenic viruses, raising the possibility for the development of a new type of lipopeptide vaccine.
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Affiliation(s)
- Daisuke Morita
- Laboratory of Cell Regulation, Institute for Virus Research, Kyoto University, Kyoto, Japan
| | - Masahiko Sugita
- Laboratory of Cell Regulation, Institute for Virus Research, Kyoto University, Kyoto, Japan
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14
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Sullivan LC, Berry R, Sosnin N, Widjaja JML, Deuss FA, Balaji GR, LaGruta NL, Mirams M, Trapani JA, Rossjohn J, Brooks AG, Andrews DM. Recognition of the Major Histocompatibility Complex (MHC) Class Ib Molecule H2-Q10 by the Natural Killer Cell Receptor Ly49C. J Biol Chem 2016; 291:18740-52. [PMID: 27385590 DOI: 10.1074/jbc.m116.737130] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Indexed: 01/15/2023] Open
Abstract
Murine natural killer (NK) cells are regulated by the interaction of Ly49 receptors with major histocompatibility complex class I molecules (MHC-I). Although the ligands for inhibitory Ly49 were considered to be restricted to classical MHC (MHC-Ia), we have shown that the non-classical MHC molecule (MHC-Ib) H2-M3 was a ligand for the inhibitory Ly49A. Here we establish that another MHC-Ib, H2-Q10, is a bona fide ligand for the inhibitory Ly49C receptor. H2-Q10 bound to Ly49C with a marginally lower affinity (∼5 μm) than that observed between Ly49C and MHC-Ia (H-2K(b)/H-2D(d), both ∼1 μm), and this recognition could be prevented by cis interactions with H-2K in situ To understand the molecular details underpinning Ly49·MHC-Ib recognition, we determined the crystal structures of H2-Q10 and Ly49C bound H2-Q10. Unliganded H2-Q10 adopted a classical MHC-I fold and possessed a peptide-binding groove that exhibited features similar to those found in MHC-Ia, explaining the diverse peptide binding repertoire of H2-Q10. Ly49C bound to H2-Q10 underneath the peptide binding platform to a region that encompassed residues from the α1, α2, and α3 domains, as well as the associated β2-microglobulin subunit. This docking mode was conserved with that previously observed for Ly49C·H-2K(b) Indeed, structure-guided mutation of Ly49C indicated that Ly49C·H2-Q10 and Ly49C·H-2K(b) possess similar energetic footprints focused around residues located within the Ly49C β4-stand and L5 loop, which contact the underside of the peptide-binding platform floor. Our data provide a structural basis for Ly49·MHC-Ib recognition and demonstrate that MHC-Ib represent an extended family of ligands for Ly49 molecules.
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Affiliation(s)
- Lucy C Sullivan
- From the Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Richard Berry
- the Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia, the ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Natasha Sosnin
- the Cancer Cell Death Laboratory, Peter MacCallum Cancer Centre, East Melbourne, Victoria 3000, Australia, The Sir Peter MacCallum Department of Oncology, University of Melbourne, Victoria 3010, Parkville, Australia
| | - Jacqueline M L Widjaja
- From the Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Felix A Deuss
- the Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia, the ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Gautham R Balaji
- the Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia, the ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Nicole L LaGruta
- From the Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria 3010, Australia, the Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Michiko Mirams
- From the Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Joseph A Trapani
- the Cancer Cell Death Laboratory, Peter MacCallum Cancer Centre, East Melbourne, Victoria 3000, Australia, The Sir Peter MacCallum Department of Oncology, University of Melbourne, Victoria 3010, Parkville, Australia
| | - Jamie Rossjohn
- the Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia, the ARC Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia, the Institute of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, Wales, United Kingdom, and
| | - Andrew G Brooks
- From the Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria 3010, Australia,
| | - Daniel M Andrews
- the Department of Immunology and Pathology, Central Clinical School, Monash University, Melbourne, Victoria 3004, Australia
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15
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Anderson CK, Brossay L. The role of MHC class Ib-restricted T cells during infection. Immunogenetics 2016; 68:677-91. [PMID: 27368413 DOI: 10.1007/s00251-016-0932-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/22/2016] [Indexed: 01/02/2023]
Abstract
Even though major histocompatibility complex (MHC) class Ia and many Ib molecules have similarities in structure, MHC class Ib molecules tend to have more specialized functions, which include the presentation of non-peptidic antigens to non-classical T cells. Likewise, non-classical T cells also have unique characteristics, including an innate-like phenotype in naïve animals and rapid effector functions. In this review, we discuss the role of MAIT and NKT cells during infection but also the contribution of less studied MHC class Ib-restricted T cells such as Qa-1-, Qa-2-, and M3-restricted T cells. We focus on describing the types of antigens presented to non-classical T cells, their response and cytokine profile following infection, as well as the overall impact of these T cells to the immune system.
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Affiliation(s)
- Courtney K Anderson
- Department of Molecular Microbiology and Immunology, Division of Biology and Medicine, Brown University, Box G-B618, Providence, RI, 02912, USA
| | - Laurent Brossay
- Department of Molecular Microbiology and Immunology, Division of Biology and Medicine, Brown University, Box G-B618, Providence, RI, 02912, USA.
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16
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Nonclassical MHC Ib-restricted CD8+ T Cells Recognize Mycobacterium tuberculosis-Derived Protein Antigens and Contribute to Protection Against Infection. PLoS Pathog 2016; 12:e1005688. [PMID: 27272249 PMCID: PMC4896622 DOI: 10.1371/journal.ppat.1005688] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 05/18/2016] [Indexed: 12/26/2022] Open
Abstract
MHC Ib-restricted CD8+ T cells have been implicated in host defense against Mycobacterium tuberculosis (Mtb) infection. However, the relative contribution of various MHC Ib-restricted T cell populations to anti-mycobacterial immunity remains elusive. In this study, we used mice that lack MHC Ia (Kb-/-Db-/-), MHC Ia/H2-M3 (Kb-/-Db-/-M3-/-), or β2m (β2m-/-) to study the role of M3-restricted and other MHC Ib-restricted T cells in immunity against Mtb. Unlike their dominant role in Listeria infection, we found that M3-restricted CD8+ T cells only represented a small proportion of the CD8+ T cells responding to Mtb infection. Non-M3, MHC Ib-restricted CD8+ T cells expanded preferentially in the lungs of Mtb-infected Kb-/-Db-/-M3-/- mice, exhibited polyfunctional capacities and conferred protection against Mtb. These MHC Ib-restricted CD8+ T cells recognized several Mtb-derived protein antigens at a higher frequency than MHC Ia-restricted CD8+ T cells. The presentation of Mtb antigens to MHC Ib-restricted CD8+ T cells was mostly β2m-dependent but TAP-independent. Interestingly, a large proportion of Mtb-specific MHC Ib-restricted CD8+ T cells in Kb-/-Db-/-M3-/- mice were Qa-2-restricted while no considerable numbers of MR1 or CD1-restricted Mtb-specific CD8+ T cells were detected. Our findings indicate that nonclassical CD8+ T cells other than the known M3, CD1, and MR1-restricted CD8+ T cells contribute to host immune responses against Mtb infection. Targeting these MHC Ib-restricted CD8+ T cells would facilitate the design of better Mtb vaccines with broader coverage across MHC haplotypes due to the limited polymorphism of MHC class Ib molecules.
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17
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Sun M, Liu J, Qi J, Tefsen B, Shi Y, Yan J, Gao GF. Nα-terminal acetylation for T cell recognition: molecular basis of MHC class I-restricted nα-acetylpeptide presentation. THE JOURNAL OF IMMUNOLOGY 2014; 192:5509-19. [PMID: 24829406 DOI: 10.4049/jimmunol.1400199] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
As one of the most common posttranslational modifications (PTMs) of eukaryotic proteins, N(α)-terminal acetylation (Nt-acetylation) generates a class of N(α)-acetylpeptides that are known to be presented by MHC class I at the cell surface. Although such PTM plays a pivotal role in adjusting proteolysis, the molecular basis for the presentation and T cell recognition of N(α)-acetylpeptides remains largely unknown. In this study, we determined a high-resolution crystallographic structure of HLA (HLA)-B*3901 complexed with an N(α)-acetylpeptide derived from natural cellular processing, also in comparison with the unmodified-peptide complex. Unlike the α-amino-free P1 residues of unmodified peptide, of which the α-amino group inserts into pocket A of the Ag-binding groove, the N(α)-linked acetyl of the acetylated P1-Ser protrudes out of the groove for T cell recognition. Moreover, the Nt-acetylation not only alters the conformation of the peptide but also switches the residues in the α1-helix of HLA-B*3901, which may impact the T cell engagement. The thermostability measurements of complexes between N(α)-acetylpeptides and a series of MHC class I molecules derived from different species reveal reduced stability. Our findings provide the insight into the mode of N(α)-acetylpeptide-specific presentation by classical MHC class I molecules and shed light on the potential of acetylepitope-based immune intervene and vaccine development.
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Affiliation(s)
- Mingwei Sun
- School of Life Sciences, University of Science and Technology of China, Hefei 230027, China; CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jun Liu
- National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; and
| | - Jianxun Qi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Boris Tefsen
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yi Shi
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Research Network of Immunity and Health, Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing 100101, China
| | - Jinghua Yan
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - George F Gao
- School of Life Sciences, University of Science and Technology of China, Hefei 230027, China; CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; and Research Network of Immunity and Health, Beijing Institutes of Life Science, Chinese Academy of Sciences, Beijing 100101, China
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18
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Mir SA, Sharma S. Cloning, expression and N-terminal formylation of ESAT-6 of Mycobacterium tuberculosis H37Rv. Protein Expr Purif 2013; 92:223-9. [DOI: 10.1016/j.pep.2013.09.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 09/02/2013] [Accepted: 09/10/2013] [Indexed: 11/16/2022]
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19
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Mir SA, Sharma S. Role of MHC class Ib molecule, H2-M3 in host immunity against tuberculosis. Vaccine 2013; 31:3818-25. [PMID: 23628242 DOI: 10.1016/j.vaccine.2013.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 03/22/2013] [Accepted: 04/01/2013] [Indexed: 01/21/2023]
Abstract
The MHC class I family comprises both classical (class Ia) and non-classical (class Ib) members. While the prime function of classical MHC class I molecules (MHC class Ia) is to present peptide antigens to pathogen-specific cytotoxic T cells, non-classical MHC-I (MHC class Ib) antigens perform diverse array of functions in both innate and adaptive immunity. Vaccines against intracellular pathogens such as Mycobacterium tuberculosis need to induce strong cellular immune responses. Recent studies have shown that MHC class I molecules play an important role in the protective immune response to M. tuberculosis infection. Both MHC Ia-restricted and MHC class Ib-restricted M. tuberculosis -reactive CD8(+) T cells have been identified in humans and mice, but their relative contributions to immunity is still uncertain. Unlike MHC class Ia-restricted CD8(+) T cells, MHC class Ib-restricted CD8(+) T cells are constitutively activated in naive animals and respond rapidly to infection challenge, hence filling the temporal gap between innate and adaptive immunity. The present review article summarizes the general host immunity against M. tuberculosis infection highlighting the possible role of MHC class Ib molecule, H2-M3 and their ligands (N-formylated peptides) in protection against tuberculosis.
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Affiliation(s)
- Shabir Ahmad Mir
- Department of Biochemistry, Postgraduate Institute of Medical Education & Research, Chandigarh 160012, India
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20
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Adams EJ, Luoma AM. The adaptable major histocompatibility complex (MHC) fold: structure and function of nonclassical and MHC class I-like molecules. Annu Rev Immunol 2013; 31:529-61. [PMID: 23298204 DOI: 10.1146/annurev-immunol-032712-095912] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The MHC fold is found in proteins that have a range of functions in the maintenance of an organism's health, from immune regulation to fat metabolism. Well adapted for antigen presentation, as seen for peptides in the classical MHC molecules and for lipids in CD1 molecules, the MHC fold has also been modified to perform Fc-receptor activity (e.g., FcRn) and for roles in host homeostasis (e.g., with HFE and ZAG). The more divergent MHC-like molecules, such as some of those that interact with the NKG2D receptor, represent the minimal MHC fold, doing away with the α3 domain and β2m while maintaining the α1/α2 platform domain for receptor engagement. Viruses have also co-opted the MHC fold for immune-evasive functions. The variations on the theme of a β-sheet topped by two semiparallel α-helices are discussed in this review, highlighting the fantastic adaptability of this fold for good and for bad.
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Affiliation(s)
- Erin J Adams
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637, USA.
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21
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Chamero P, Leinders-Zufall T, Zufall F. From genes to social communication: molecular sensing by the vomeronasal organ. Trends Neurosci 2012; 35:597-606. [PMID: 22658923 DOI: 10.1016/j.tins.2012.04.011] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 04/27/2012] [Accepted: 04/30/2012] [Indexed: 12/22/2022]
Abstract
The ability to distinguish molecular cues emitted by other individuals is a fundamental feature of social interactions such as finding and identifying a mate, establishing social hierarchies, and initiating interspecies defensive behaviors. In rodents, this ability involves the vomeronasal organ (VNO), a distinct chemoreceptive structure that is part of the olfactory system. Recent insights have led to unprecedented progress in identifying ligand and receptor families underlying vomeronasal recognition, characterizing the behavioral consequences caused by VNO activation, and defining higher neural circuits underlying the initiation of instinctive behaviors such as aggression. Here, we review such findings and discuss future areas for investigation, including large-scale mapping studies, immune system-VNO interactions, in vivo recording of neural activity, and optogenetic alteration of sexual and social behaviors.
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Affiliation(s)
- Pablo Chamero
- Department of Physiology, University of Saarland School of Medicine, D-66424 Homburg, Germany
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22
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Zeng L, Sullivan LC, Vivian JP, Walpole NG, Harpur CM, Rossjohn J, Clements CS, Brooks AG. A structural basis for antigen presentation by the MHC class Ib molecule, Qa-1b. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2012; 188:302-10. [PMID: 22131332 DOI: 10.4049/jimmunol.1102379] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The primary function of the monomorphic MHC class Ib molecule Qa-1(b) is to present peptides derived from the leader sequences of other MHC class I molecules for recognition by the CD94-NKG2 receptors expressed by NK and T cells. Whereas the mode of peptide presentation by its ortholog HLA-E, and subsequent recognition by CD94-NKG2A, is known, the molecular basis of Qa-1(b) function is unclear. We have assessed the interaction between Qa-1(b) and CD94-NKG2A and shown that they interact with an affinity of 17 μM. Furthermore, we have determined the structure of Qa-1(b) bound to the leader sequence peptide, Qdm (AMAPRTLLL), to a resolution of 1.9 Å and compared it with that of HLA-E. The crystal structure provided a basis for understanding the restricted peptide repertoire of Qa-1(b). Whereas the Qa-1(b-AMAPRTLLL) complex was similar to that of HLA-E, significant sequence and structural differences were observed between the respective Ag-binding clefts. However, the conformation of the Qdm peptide bound by Qa-1(b) was very similar to that of peptide bound to HLA-E. Although a number of conserved innate receptors can recognize heterologous ligands from other species, the structural differences between Qa-1(b) and HLA-E manifested in CD94-NKG2A ligand recognition being species specific despite similarities in peptide sequence and conformation. Collectively, our data illustrate the structural homology between Qa-1(b) and HLA-E and provide a structural basis for understanding peptide repertoire selection and the specificity of the interaction of Qa-1(b) with CD94-NKG2 receptors.
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Affiliation(s)
- Li Zeng
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
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23
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Chow MT, Teh H. H2‐M3‐restricted CD8
+
T cells augment CD4
+
T‐cell responses by promoting DC maturation. Eur J Immunol 2010; 40:1408-17. [DOI: 10.1002/eji.200939934] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Michael T. Chow
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Hung‐Sia Teh
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
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24
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Kumar P, Vahedi-Faridi A, Saenger W, Merino E, López de Castro JA, Uchanska-Ziegler B, Ziegler A. Structural basis for T cell alloreactivity among three HLA-B14 and HLA-B27 antigens. J Biol Chem 2009; 284:29784-97. [PMID: 19617632 PMCID: PMC2785609 DOI: 10.1074/jbc.m109.038497] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 07/09/2009] [Indexed: 01/07/2023] Open
Abstract
The existence of cytotoxic T cells (CTL) cross-reacting with the human major histocompatibility antigens HLA-B14 and HLA-B27 suggests that their alloreactivity could be due to presentation of shared peptides in similar binding modes by these molecules. We therefore determined the crystal structures of the subtypes HLA-B*1402, HLA-B*2705, and HLA-B*2709 in complex with a proven self-ligand, pCatA (peptide with the sequence IRAAPPPLF derived from cathepsin A (residues 2-10)), and of HLA-B*1402 in complex with a viral peptide, pLMP2 (RRRWRRLTV, derived from latent membrane protein 2 (residues 236-244) of Epstein-Barr virus). Despite the exchange of 18 residues within the binding grooves of HLA-B*1402 and HLA-B*2705 or HLA-B*2709, the pCatA peptide is presented in nearly identical conformations. However, pLMP2 is displayed by HLA-B*1402 in a conformation distinct from those previously found in the two HLA-B27 subtypes. In addition, the complexes of HLA-B*1402 with the two peptides reveal a nonstandard, tetragonal mode of the peptide N terminus anchoring in the binding groove because of the exchange of the common Tyr-171 by His-171 of the HLA-B*1402 heavy chain. This exchange appears also responsible for reduced stability of HLA-B14-peptide complexes in vivo and slow assembly in vitro. The studies with the pCatA peptide uncover that CTL cross-reactive between HLA-B14 and HLA-B27 might primarily recognize the common structural features of the bound peptide, thus neglecting amino acid replacements within the rim of the binding grooves. In contrast, structural alterations between the three complexes with the pLMP2 peptide indicate how heavy chain polymorphisms can influence peptide display and prevent CTL cross-reactivity between HLA-B14 and HLA-B27 antigens.
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Affiliation(s)
- Pravin Kumar
- From the Institut für Immungenetik, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Freie Universität Berlin, Thielallee 73, 14195 Berlin, Germany
| | - Ardeschir Vahedi-Faridi
- the Institut für Chemie und Biochemie/Kristallographie, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany, and
| | - Wolfram Saenger
- the Institut für Chemie und Biochemie/Kristallographie, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany, and
| | - Elena Merino
- the Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Cientificas and Universidad Autónoma de Madrid, Nicolás Cabrera, N.1, Universidad Autónoma, 28049 Madrid, Spain
| | - José A. López de Castro
- the Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Cientificas and Universidad Autónoma de Madrid, Nicolás Cabrera, N.1, Universidad Autónoma, 28049 Madrid, Spain
| | - Barbara Uchanska-Ziegler
- From the Institut für Immungenetik, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Freie Universität Berlin, Thielallee 73, 14195 Berlin, Germany
| | - Andreas Ziegler
- From the Institut für Immungenetik, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Freie Universität Berlin, Thielallee 73, 14195 Berlin, Germany
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25
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Marrack P, Scott-Browne JP, Dai S, Gapin L, Kappler JW. Evolutionarily conserved amino acids that control TCR-MHC interaction. Annu Rev Immunol 2008; 26:171-203. [PMID: 18304006 DOI: 10.1146/annurev.immunol.26.021607.090421] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The rules for the conserved reaction of alphabeta T cell receptors (TCRs) with major histocompatibility complex (MHC) proteins plus peptides are poorly understood, probably because thymocytes bearing TCRs with the strongest MHC reactivity are lost by negative selection. Thus, only TCRs with an attenuated ability to react with MHC appear on mature T cells. Also, the interaction sites between TCRs and MHC may be inherently flexible and hence difficult to spot. We reevaluated contacts between TCRs and MHC in the solved structures of their complexes with these points in mind. Relatively conserved amino acids in the TCR complementarity-determining regions (CDR) 1 and CDR2 are often used to bind exposed areas of the MHC alpha-helices. These areas are exposed because of small amino acids that allow somewhat flexible binding of the TCRs. The TCR amino acids involved are specific to families of variable (V) regions and to some extent different rules may govern the recognition of MHCI versus MHCII.
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Affiliation(s)
- Philippa Marrack
- Howard Hughes Medical Institute, University of Colorado Denver Health Science Center, Denver, Colorado 80206, USA.
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26
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Adams EJ, Juo ZS, Venook RT, Boulanger MJ, Arase H, Lanier LL, Garcia KC. Structural elucidation of the m157 mouse cytomegalovirus ligand for Ly49 natural killer cell receptors. Proc Natl Acad Sci U S A 2007; 104:10128-33. [PMID: 17537914 PMCID: PMC1891256 DOI: 10.1073/pnas.0703735104] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Indexed: 11/18/2022] Open
Abstract
Natural killer (NK) cells express activating and inhibitory receptors that, in concert, survey cells for proper expression of cell surface major histocompatibility complex (MHC) class I molecules. The mouse cytomegalovirus encodes an MHC-like protein, m157, which is the only known viral antigen to date capable of engaging both activating (Ly49H) and inhibitory (Ly49I) NK cell receptors. We have determined the 3D structure of m157 and studied its biochemical and cellular interactions with the Ly49H and Ly49I receptors. m157 has a characteristic MHC-fold, yet possesses several unique structural features not found in other MHC class I-like molecules. m157 does not bind peptides or other small ligands, nor does it associate with beta(2)-microglobulin. Instead, m157 engages in extensive intra- and intermolecular interactions within and between its domains to generate a compact minimal MHC-like molecule. m157's binding affinity for Ly49I (K(d) approximately 0.2 microM) is significantly higher than that of classical inhibitory Ly49-MHC interactions. Analysis of viral escape mutations on m157 that render it resistant to NK killing reveals that it is likely to be recognized by Ly49H in a binding mode that differs from Ly49/MHC-I. In addition, Ly49H+ NK cells can efficiently lyse RMA cells expressing m157, despite the presence of native MHC class I. Collectively, our results show that m157 represents a structurally divergent form of MHC class I-like proteins that directly engage Ly49 receptors with appreciable affinity in a noncanonical fashion.
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MESH Headings
- Animals
- Antigens, Ly/chemistry
- Baculoviridae/genetics
- Binding Sites
- Cell Line, Tumor
- Crystallography, X-Ray
- Disulfides/chemistry
- Histocompatibility Antigens Class I/immunology
- Hydrogen Bonding
- Killer Cells, Natural/immunology
- Lectins, C-Type/chemistry
- Ligands
- Lymphoma, T-Cell/pathology
- Mice
- Models, Molecular
- Muromegalovirus/immunology
- NK Cell Lectin-Like Receptor Subfamily A
- Protein Binding
- Protein Conformation
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Receptors, Immunologic/chemistry
- Receptors, Immunologic/genetics
- Receptors, Immunologic/immunology
- Receptors, NK Cell Lectin-Like
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Affiliation(s)
- Erin J. Adams
- *Departments of Molecular and Cellular Physiology and Structural Biology
| | - Z. Sean Juo
- *Departments of Molecular and Cellular Physiology and Structural Biology
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305; and
| | - Rayna Takaki Venook
- Department of Microbiology and Immunology, the Biomedical Sciences Graduate Program, and the Cancer Research Institute, University of California, San Francisco, CA 94143
| | | | - Hisashi Arase
- Department of Microbiology and Immunology, the Biomedical Sciences Graduate Program, and the Cancer Research Institute, University of California, San Francisco, CA 94143
| | - Lewis L. Lanier
- Department of Microbiology and Immunology, the Biomedical Sciences Graduate Program, and the Cancer Research Institute, University of California, San Francisco, CA 94143
| | - K. Christopher Garcia
- *Departments of Molecular and Cellular Physiology and Structural Biology
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305; and
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27
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Doi T, Yamada H, Yajima T, Wajjwalku W, Hara T, Yoshikai Y. H2-M3-restricted CD8+ T cells induced by peptide-pulsed dendritic cells confer protection against Mycobacterium tuberculosis. THE JOURNAL OF IMMUNOLOGY 2007; 178:3806-13. [PMID: 17339479 DOI: 10.4049/jimmunol.178.6.3806] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
One of the oligopolymorphic MHC class Ib molecules, H2-M3, presents N-formylated peptides derived from bacteria. In this study, we tested the ability of an H2-M3-binding peptide, TB2, to induce protection in C57BL/6 mice against Mycobacterium tuberculosis. Immunization with bone marrow-derived dendritic cell (BMDC) pulsed with TB2 or a MHC class Ia-binding peptide, MPT64(190-198) elicited an expansion of Ag-specific CD8+ T cells in the spleen and the lung. The number of TB2-specific CD8+ T cells reached a peak on day 6, contracted with kinetics similar to MPT64(190-198)-specific CD8+ T cells and was maintained at an appreciable level for at least 60 days. The TB2-specific CD8+ T cells produced less effector cytokines but have stronger cytotoxic activity than MPT64(190-198)-specific CD8+ T cells. Mice immunized with TB2-pulsed BMDC as well as those with MPT64(190-198)-pulsed BMDC showed significant protection against an intratracheal challenge with M. tuberculosis H37Rv. However, histopathology of the lung in mice immunized with TB2-pulsed BMDC was different from mice immunized with MPT64(190-198)-pulsed BMDC. Our results suggest that immunization with BMDC pulsed with MHC class Ib-restricted peptides would be a useful vaccination strategy against M. tuberculosis.
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Affiliation(s)
- Takehiko Doi
- Division of Host Defense, Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582, Japan
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28
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Sullivan LC, Hoare HL, McCluskey J, Rossjohn J, Brooks AG. A structural perspective on MHC class Ib molecules in adaptive immunity. Trends Immunol 2006; 27:413-20. [PMID: 16860610 DOI: 10.1016/j.it.2006.07.006] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Revised: 06/26/2006] [Accepted: 07/12/2006] [Indexed: 10/24/2022]
Abstract
The highly polymorphic MHC class Ia molecules have a central role in adaptive immunity. By contrast, the closely related MHC class Ib molecules, which show limited polymorphism, are best known for regulating innate immune responses. Nevertheless, a recent area of interest is the emerging role of class Ib molecules in adaptive immunity, particularly in response to tumours and pathogens such as Mycobacteria, Listeria and Salmonella. Here, we review recent findings in this area, highlighting the structure of a T-cell receptor complexed with a cytomegalovirus peptide bound to the class Ib molecule, HLA-E. Collectively, these findings have implications for immunity, transplantation and autoimmunity, and our understanding of the evolution and plasticity of the molecular interactions mediating adaptive immunity.
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Affiliation(s)
- Lucy C Sullivan
- Department of Microbiology and Immunology, University of Melbourne, Parkville, Victoria, 3010, Australia
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29
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Colmone A, Wang CR. H2–M3-restricted T cell response to infection. Microbes Infect 2006; 8:2277-83. [PMID: 16824777 DOI: 10.1016/j.micinf.2006.03.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Accepted: 03/01/2006] [Indexed: 12/13/2022]
Abstract
H2-M3 is a major histocompatibility complex class Ib molecule that presents N-formylated peptides to specific CD8+ T cells. Prokaryotic, but not eukaryotic, translation begins with the addition of N-formyl methionine, suggesting a role for these H2-M3-restricted T cells in response to bacterial infection. Indeed, these cells constitute a non-redundant "early" component of anti-microbial response.
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Affiliation(s)
- Angela Colmone
- Department of Pathology, University of Chicago, JFK R422 924 E 57th St., Chicago, IL 60637, USA
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30
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Charrier L, Merlin D. The oligopeptide transporter hPepT1: gateway to the innate immune response. J Transl Med 2006; 86:538-46. [PMID: 16652110 DOI: 10.1038/labinvest.3700423] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Bacterial products that are normally present in the lumen of the colon, such as N-formylated peptides and muramyl-dipeptide, are important for inducing the development of mucosal inflammation. The intestinal dipeptide transporter, hPepT1, which is expressed in inflamed but not in noninflamed colonic epithelial cells, mediates the transport of these bacterial products into the cytosol of colonic epithelial cells. The small bacterial peptides subsequently induce an inflammatory response, including the induction of MHC class I molecules expression and cytokines secretion, via the activation of nucleotide-binding site and leucine-rich repeat (NBS-LRR) proteins, for example NOD2, and activation of NF-kappaB. Subsequent secretion of chemoattractants by colonic epithelial cells induces the movement of neutrophils through the underlying matrix, as well as across the epithelium. These bacterial products can also reach the lamina propria through the paracellular pathway and across the basolateral membrane of epithelial cells. As a consequence, small formylated peptides can interact directly with immune cells through specific membrane receptors. Since immune cells, including macrophages, also express hPepT1, they can transport small bacterial peptides into the cytosol where these may interact with the NBS-LRR family of intracellular receptors. As in intestinal epithelial cells, the presence of these small bacterial peptides in immune cells may trigger immune response activation.
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Affiliation(s)
- Laetitia Charrier
- Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
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31
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Xu H, Chun T, Choi HJ, Wang B, Wang CR. Impaired response to Listeria in H2-M3-deficient mice reveals a nonredundant role of MHC class Ib-specific T cells in host defense. ACTA ACUST UNITED AC 2006; 203:449-59. [PMID: 16476767 PMCID: PMC2118219 DOI: 10.1084/jem.20051866] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The major histocompatibility complex (MHC) class Ib molecule H2-M3 primes the rapid expansion of CD8+ T cells by presenting N-formylated bacterial peptides. However, the significance of H2-M3-restricted T cells in host defense against bacteria is unclear. We generated H2-M3-deficient mice to investigate the role of H2-M3 in immunity against Listeria monocytogenes (LM), a model intracellular bacterial pathogen. H2-M3-deficient mice are impaired in early bacterial clearance during primary infection, with diminished LM-specific CD8+ T cell responses and compromised innate immune functions. Although H2-M3-restricted CD8+ T cells constitute a significant proportion of the anti-listerial CD8+ T cell repertoire, the kinetics and magnitude of MHC class Ia-restricted T cell responses are not altered in H2-M3-deficient mice. The fact that MHC class Ia-restricted responses cannot compensate for the H2-M3-mediated immunity suggests a nonredundant role of H2-M3 in the protective immunity against LM. Thus, the early H2-M3-restricted response temporally bridges the gap between innate and adaptive immune responses, subsequently affecting the function of both branches of the immune system.
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Affiliation(s)
- Honglin Xu
- Department of Pathology, University of Chicago, Chicago, IL 60637, USA
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32
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D'Orazio SEF, Shaw CA, Starnbach MN. H2-M3-restricted CD8+ T cells are not required for MHC class Ib-restricted immunity against Listeria monocytogenes. ACTA ACUST UNITED AC 2006; 203:383-91. [PMID: 16461341 PMCID: PMC2118191 DOI: 10.1084/jem.20052256] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Studies using major histocompatibility complex (MHC)-Ia-deficient mice have shown that MHC-Ib-restricted CD8+ T cells can clear infections caused by intracellular pathogens such as Listeria monocytogenes. M3-restricted CD8+ T cells, which recognize short hydrophobic N-formylated peptides, appear to comprise a substantial portion of the MHC-Ib-restricted T cell response in the mouse model of L. monocytogenes infection. In this study, we isolated formyltransferase (fmt) mutant strains of L. monocytogenes that lacked the ability to add formyl groups to nascent polypeptides. These fmt mutant Listeria strains did not produce antigens that could be recognized by M3-restricted T cells. We showed that immunization of MHC-Ia-deficient mice with fmt mutant Listeria resulted in stimulation of a protective memory response that cleared subsequent challenge with wild-type L. monocytogenes, despite the fact that M3-restricted CD8+ T cells did not proliferate in these mice. These data suggest that M3-restricted T cells are not required for protection against L. monocytogenes and underscore the importance of searching for new antigen-presenting molecules among the large MHC-Ib family of proteins.
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Affiliation(s)
- Sarah E F D'Orazio
- Department of Microbiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA
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Rabiet MJ, Huet E, Boulay F. Human mitochondria-derived N-formylated peptides are novel agonists equally active on FPR and FPRL1, while Listeria monocytogenes-derived peptides preferentially activate FPR. Eur J Immunol 2005; 35:2486-95. [PMID: 16025565 DOI: 10.1002/eji.200526338] [Citation(s) in RCA: 155] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
N-formyl peptides are cleavage products of bacterial and mitochondrial proteins, and can attract leukocytes to sites of infection or tissue damage. In this study, HL-60 cell lines expressing the human N-formyl peptide receptor FPR or its two homologues (FPRL1, FPRL2) were used to determine the receptor selectivity of N-formylated peptides derived from Listeria monocytogenes or from human mitochondrial proteins. Bacterial peptides were 100-fold more potent on FPR than on FPRL1, whereas none of them could trigger intracellular signaling through FPRL2. In contrast, N-formylated hexapeptides corresponding to the N terminus of mitochondrial NADH dehydrogenase subunits 4 (fMLKLIV) and 6 (fMMYALF), and cytochrome c oxidase subunit I (fMFADRW) were equally potent on FPR and FPRL1. They triggered cellular responses with the following order of potency: fMMYALF > fMLKLIV > fMFADRW, with an EC50, in a Fura-2 calcium mobilization assay, of 10 nM, 44 nM, and 160 nM on FPR-expressing cells, and 15 nM, 55 nM and 120 nM on FPRL1-expressing cells. fMMYALF was also a low-affinity agonist of FPRL2 (EC50 of 1 microM) and was chemotactic for both FPRL1- and FPRL2-expressing cells. We identified novel mitochondrial host-derived agonists for human N-formyl-peptide receptors that might play a role in inflammatory or degenerative processes linked to their stimulation.
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Affiliation(s)
- Marie-Josèphe Rabiet
- CEA Grenoble, Département de Dynamique et Réponse Cellulaires, Laboratoire de Biochimie et de Biophysique des Systèmes Intégrés, UMR 5092 CEA/CNRS/Université Joseph Fourier, Grenoble, France.
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34
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Olson R, Huey-Tubman KE, Dulac C, Bjorkman PJ. Structure of a pheromone receptor-associated MHC molecule with an open and empty groove. PLoS Biol 2005; 3:e257. [PMID: 16089503 PMCID: PMC1174912 DOI: 10.1371/journal.pbio.0030257] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Accepted: 05/18/2005] [Indexed: 11/24/2022] Open
Abstract
Neurons in the murine vomeronasal organ (VNO) express a family of class Ib major histocompatibility complex (MHC) proteins (M10s) that interact with the V2R class of VNO receptors. This interaction may play a direct role in the detection of pheromonal cues that initiate reproductive and territorial behaviors. The crystal structure of M10.5, an M10 family member, is similar to that of classical MHC molecules. However, the M10.5 counterpart of the MHC peptide-binding groove is open and unoccupied, revealing the first structure of an empty class I MHC molecule. Similar to empty MHC molecules, but unlike peptide-filled MHC proteins and non-peptide–binding MHC homologs, M10.5 is thermally unstable, suggesting that its groove is normally occupied. However, M10.5 does not bind endogenous peptides when expressed in mammalian cells or when offered a mixture of class I–binding peptides. The F pocket side of the M10.5 groove is open, suggesting that ligands larger than 8–10-mer class I–binding peptides could fit by extending out of the groove. Moreover, variable residues point up from the groove helices, rather than toward the groove as in classical MHC structures. These data suggest that M10s are unlikely to provide specific recognition of class I MHC–binding peptides, but are consistent with binding to other ligands, including proteins such as the V2Rs. MHC-like protein M10.5 is expressed in the vomeronasal organ. The structure does not bind endogenous class I-binding peptides, but is thought to interact with a larger V2R pheromone receptor.
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Affiliation(s)
- Rich Olson
- 1 Division of Biology, California Institute of Technology, Pasadena, California, United States of America
| | - Kathryn E Huey-Tubman
- 1 Division of Biology, California Institute of Technology, Pasadena, California, United States of America
- 2 Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, United States of America
| | - Catherine Dulac
- 3 Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, Massachusetts, United States of America
| | - Pamela J Bjorkman
- 1 Division of Biology, California Institute of Technology, Pasadena, California, United States of America
- 2 Howard Hughes Medical Institute, California Institute of Technology, Pasadena, California, United States of America
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35
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Abstract
Our understanding of the classical MHC class I molecules (MHC class Ia molecules) has long focused on their extreme polymorphism. These molecules present peptides to T cells and are central to discrimination between self and non-self. By contrast, the functions of the non-polymorphic MHC class I molecules (MHC class Ib molecules) have been elusive, but emerging evidence reveals that, in addition to antigen presentation, MHC class Ib molecules are involved in immunoregulation. As we discuss here, the subset of MHC class Ib molecules that presents peptides to T cells bridges innate and acquired immunity, and this provides insights into the origins of acquired immunity.
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Affiliation(s)
- John R Rodgers
- Department of Immunology, Baylor College of Medicine, Houston, Texas 77030, USA.
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36
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Moore YF, Lambracht-Washington D, Tabaczewski P, Fischer Lindahl K. Murine MHC class Ib gene, H2-M2, encodes a conserved surface-expressed glycoprotein. Immunogenetics 2004; 56:1-11. [PMID: 15045471 DOI: 10.1007/s00251-004-0661-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2003] [Revised: 02/21/2004] [Indexed: 11/30/2022]
Abstract
We have determined the genomic sequence of H2-M2 in seven haplotypes from nine inbred strains of mice and in five wild-derived haplotypes. Except for the spretus haplotype sp1 with a premature stop codon, we found only limited polymorphism. Four of the five amino acid substitutions in the alpha-helices are at positions that would point out from the antigen-binding groove, indicating that the polymorphism might influence receptor recognition rather than antigen binding. The rat homologue, RT1.M2(lv1), has 89% identity to H2-M2 at the nucleotide level and 91% at the amino acid level, and it also encodes an intact MHC class I glycoprotein. Chimeric proteins with alpha(1)alpha(2) or alpha(3)-transmembrane domains encoded by H2-Q9 were detectable on the surface of transfectants with monoclonal antibodies against Qa2, and the full-length M2 protein, labeled by fusion with green fluorescent protein, was detectable with S19.8 monoclonal antibodies. The H2-M2 protein was thus expressed on the cell surface, even in TAP-deficient RMA-S cells at 37 degrees C, suggesting that it is TAP-independent. We conclude that H2-M2 is a conserved mouse class Ib gene that is translated to a surface-expressed MHC class I molecule with a function still to be elucidated.
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Affiliation(s)
- Yuki F Moore
- Howard Hughes Medical Institute and Center for Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9050, USA
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37
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Ploss A, Lauvau G, Contos B, Kerksiek KM, Guirnalda PD, Leiner I, Lenz LL, Bevan MJ, Pamer EG. Promiscuity of MHC class Ib-restricted T cell responses. THE JOURNAL OF IMMUNOLOGY 2004; 171:5948-55. [PMID: 14634106 PMCID: PMC2791464 DOI: 10.4049/jimmunol.171.11.5948] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Murine infection with the Gram-positive intracellular bacterium Listeria monocytogenes activates CD8(+) T cells that recognize bacterially derived N-formyl methionine peptides in the context of H2-M3 MHC class Ib molecules. Three peptides, fMIGWII, fMIVIL, and fMIVTLF, are targets of L. monocytogenes-specific CD8(+) T cells. To investigate epitope cross-recognition by H2-M3-restricted CD8(+) T cells, we deleted the sequence encoding fMIGWII from a virulent strain of L. monocytogenes. Infection with fMIGWII-deficient L. monocytogenes unexpectedly primed CD8(+) T cells that stain with fMIGWII/H2-M3 tetramers and lyse fMIGWII-coated target cells in vivo. Because the fMIGWII sequence is nonredundant, we speculated that other bacterially derived Ags are priming these responses. HPLC peptide fractionation of bacterial culture supernatants revealed several distinct L. monocytogenes-derived peptides that are recognized by fMIGWII-specific T cells. Our results demonstrate that the dominant H2-M3-restricted CD8(+) T cell population, although reactive with fMIGWII, is primed by other, non-fMIGWII peptides derived from L. monocytogenes. Although this degree of Ag receptor promiscuity is unusual for the adaptive immune system, it may be a more common feature of T cell responses restricted by nonpolymorphic MHC class Ib molecules.
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MESH Headings
- Animals
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/metabolism
- CD8-Positive T-Lymphocytes/microbiology
- Cell Line
- Cell Line, Tumor
- Clone Cells
- Cytotoxicity, Immunologic
- Epitopes, T-Lymphocyte/genetics
- Epitopes, T-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/metabolism
- Female
- Histocompatibility Antigens Class I/genetics
- Histocompatibility Antigens Class I/immunology
- Histocompatibility Antigens Class I/metabolism
- Immunodominant Epitopes/genetics
- Immunodominant Epitopes/immunology
- Immunodominant Epitopes/metabolism
- Injections, Intravenous
- Ligands
- Listeria monocytogenes/genetics
- Listeria monocytogenes/immunology
- Mast-Cell Sarcoma/immunology
- Mice
- Mice, Inbred C57BL
- Sequence Deletion
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- T-Lymphocyte Subsets/microbiology
- T-Lymphocytes, Cytotoxic/immunology
- T-Lymphocytes, Cytotoxic/metabolism
- T-Lymphocytes, Cytotoxic/microbiology
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Affiliation(s)
- Alexander Ploss
- Infectious Diseases Service, Department of Medicine and Laboratory of Antimicrobial Immunity, Immunology Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021
- Weill Graduate School of Medical Sciences of Cornell University, Immunology Program, New York, NY 10021
| | - Gregoire Lauvau
- Institute National de la Santé et de la Recherche Médicale-E0344, Université de Nice-Sophia Antipolis, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne Sophia-Antipolis, France
| | - Brian Contos
- Section of Immunobiology, Yale University School of Medicine, New Haven, CT 06520
| | | | | | - Ingrid Leiner
- Infectious Diseases Service, Department of Medicine and Laboratory of Antimicrobial Immunity, Immunology Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021
| | - Laurel L. Lenz
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - Michael J. Bevan
- Department of Immunology and Howard Hughes Medical Institute, University of Washington, Seattle, WA 98195
| | - Eric G. Pamer
- Infectious Diseases Service, Department of Medicine and Laboratory of Antimicrobial Immunity, Immunology Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10021
- Address correspondence and reprint requests to Dr. Eric G. Pamer, Infectious Diseases Service, Department of Medicine and Laboratory of Antimicrobial Immunity, Immunology Program, Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021.
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38
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D'Orazio SEF, Velasquez M, Roan NR, Naveiras-Torres O, Starnbach MN. The Listeria monocytogenes lemA gene product is not required for intracellular infection or to activate fMIGWII-specific T cells. Infect Immun 2004; 71:6721-7. [PMID: 14638756 PMCID: PMC308916 DOI: 10.1128/iai.71.12.6721-6727.2003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clearance of the intracellular bacterial pathogen Listeria monocytogenes requires antigen-specific CD8(+) T cells. Recently it was shown that activation of class Ib major histocompatibility complex (MHC)-restricted CD8(+) T cells alone is sufficient for immune protection against listeriae. A major component of the class Ib MHC-restricted T-cell response is T cells that recognize formylated peptide antigens presented by M3 molecules. Although three N-formylated peptides derived from L. monocytogenes are known to bind to M3 molecules, fMIGWII is the immunodominant epitope presented by M3 during infection of mice. The source of fMIGWII peptide is the L. monocytogenes lemA gene, which encodes a 30-kDa protein of unknown function. In this report, we describe the generation of two L. monocytogenes lemA deletion mutants. We show that lemA is not required for growth of listeriae in tissue culture cells or for virulence during infection of mice. Surprisingly, we found that fMIGWII-specific T cells were still primed following infection with lemA mutant listeriae, suggesting that L. monocytogenes contains at least one additional antigen that is cross-reactive with the fMIGWII epitope. This cross-reactive antigen appears to be a small protease-resistant molecule that is secreted by L. monocytogenes.
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Affiliation(s)
- Sarah E F D'Orazio
- Department of Microbiology & Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
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39
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Doyle CK, Cook RG, Rich RR, Rodgers JR. Cotton rat Sihi-M3 is a minimally oligomorphic Mhc I-b molecule that binds the chemotactic peptide fMLF under stringent conditions. Evidence that positive selection drives inter-species diversity of residues interacting with the termini of short peptides. Immunogenetics 2003; 55:389-94. [PMID: 12942207 DOI: 10.1007/s00251-003-0593-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2003] [Revised: 06/18/2003] [Indexed: 11/27/2022]
Abstract
The leading model for class I-b evolution suggests non-polymorphic I-b genes evolve by gene duplication from polymorphic I-a genes. We recently found N-formyl peptide-specific orthologs of the class I-b gene H2-M3 in the rodent subfamily Sigmodontinae. To test if sigmodont M3 is a I-b gene, we sequenced M3 from wild cotton rats ( Sigmodon hispidus) diverse at the class II locus, Sihi-DQA. These haplotypes carry a single allele of M3 that closely resembles H2-M3. However, peptide-binding assays showed that cotton rat M3 bound the chemotactic N-formylpeptide fMLF better than did rat or mouse M3. The Ala116-->Lys substitution in cotton rat M3 might enhance binding of fMLF and is one of eight residues of M3 that interact with ligand residues P3 and P4 and that are positively selected, with a d(N) /d(S) ratio of 1.8. Thus, M3 is a class I-b gene in both sigmodontine and murine murids, but positive selection operates on a small subset of residues in the traditionally defined antigen recognition site.
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Affiliation(s)
- C Kuyler Doyle
- Department of Immunology, Baylor College of Medicine, TX 77030, Houston, USA
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40
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Doyle CK, Davis BK, Cook RG, Rich RR, Rodgers JR. Hyperconservation of the N-formyl peptide binding site of M3: evidence that M3 is an old eutherian molecule with conserved recognition of a pathogen-associated molecular pattern. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:836-44. [PMID: 12847252 DOI: 10.4049/jimmunol.171.2.836] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The mouse MHC class I-b molecule H2-M3 has unique specificity for N-formyl peptides, derived from bacteria (and mitochondria), and is thus a pathogen-associated molecular pattern recognition receptor (PRR). To test whether M3 was selected for this PRR function, we studied M3 sequences from diverse murid species of murine genera Mus, Rattus, Apodemus, Diplothrix, Hybomys, Mastomys, and Tokudaia and of sigmodontine genera Sigmodon and PEROMYSCUS: We found that M3 is highly conserved, and the 10 residues coordinating the N-formyl group are almost invariant. The ratio of nonsynonymous and synonymous substitution rates suggests the Ag recognition site of M3, unlike the Ag recognition site of class I-a molecules, is under strong negative (purifying) selection and has been for at least 50-65 million years. Consistent with this, M3 alpha1alpha2 domains from Rattus norvegicus and Sigmodon hispidus and from the "null" allele H2-M3(b) specifically bound N-formyl peptides. The pattern of nucleotide substitution in M3 suggests M3 arose rapidly from murid I-a precursors by an evolutionary leap ("saltation"), perhaps involving intense selective pressure from bacterial pathogens. Alternatively, M3 arose more slowly but prior to the radiation of eutherian (placental) mammals. Older dates for the emergence of M3, and the accepted antiquity of CD1, suggest that primordial class I MHC molecules could have evolved originally as monomorphic PRR, presenting pathogen-associated molecular patterns. Such MHC PRR molecules could have been preadaptations for the evolution of acquired immunity during the early vertebrate radiation.
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Affiliation(s)
- C Kuyler Doyle
- Baylor College of Medicine, Department of Immunology, Houston, TX 77030, USA
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41
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Crew MD, Bates LM. Sequence, expression, and polymorphism of the Peromyscus leucopus Mhc class Ib gene, M4. Immunogenetics 2003; 55:95-9. [PMID: 12700875 DOI: 10.1007/s00251-003-0569-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2003] [Revised: 03/18/2003] [Indexed: 10/25/2022]
Abstract
The H2 M region harbors about 20 class I genes or gene fragments the function of which are largely obscure. The rat Mhc ( RT1) appears to contain several orthologs of H2 M region genes although orthologs in more distantly related species have yet to be clearly identified. In this report, the sequence of a genomic clone containing a Peromyscus leucopus Mhc ( Pele) class I gene is presented and based on sequence similarity was found to be the Pele ortholog of H2-M4. Unlike H2-M4, which is a pseudogene, PeleM4 appeared to be an intact Mhc class Ib gene. Appropriately splice PeleM4 mRNA transcripts were detected in the liver, lung, and thymus. Polymorphism of PeleM4 was examined by sequencing exon 2 and 3 of the PeleM4 gene from seven different Pele haplotypes and six PeleM4 alleles were identified. These results suggest that the existence of some H2 M region class Ib genes predates the divergence of Peromyscus and Mus genera which occurred 40-60 million years ago and provide an example of unique pathways in the evolution of Mhc class Ib genes.
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Affiliation(s)
- Mark D Crew
- Central Arkansas Veterans Healthcare System and Departments of Microbiology and Immunology and Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
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42
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Takada T, Kumánovics A, Amadou C, Yoshino M, Jones EP, Athanasiou M, Evans GA, Fischer Lindahl K. Species-specific class I gene expansions formed the telomeric 1 mb of the mouse major histocompatibility complex. Genome Res 2003; 13:589-600. [PMID: 12671000 PMCID: PMC430170 DOI: 10.1101/gr.975303] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We have determined the complete sequence of 951,695 bp from the class I region of H2, the mouse major histocompatibility complex (Mhc) from strain 129/Sv (haplotype bc). The sequence contains 26 genes. The sequence spans from the last 50 kb of the H2-T region, including 2 class I genes and 3 class I pseudogenes, and includes the H2-M region up to Gabbr1. A 500-kb stretch of the H2-M region contains 9 class I genes and 4 pseudogenes, which fall into two subfamilies, M1 and M10, distinct from other mouse class I genes. This M1/M10 class I gene-cluster is separated from the centromeric H2-T and the telomeric H2-M4, -5 and -6 class I genes by "nonclass I genes". Comparison with the corresponding 853-kb region of the human Mhc, which includes the HLA-A region, shows a mosaic of conserved regions of orthologous nonclass I genes separated by regions of species-specific expansion of paralogous Mhc class I genes. The analysis of this mosaic structure illuminates the dynamic evolution of the Mhc class I region among mammals and provides evidence for the framework hypothesis.
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Affiliation(s)
- Toyoyuki Takada
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
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43
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Treiner E, Duban L, Bahram S, Radosavljevic M, Wanner V, Tilloy F, Affaticati P, Gilfillan S, Lantz O. Selection of evolutionarily conserved mucosal-associated invariant T cells by MR1. Nature 2003; 422:164-9. [PMID: 12634786 DOI: 10.1038/nature01433] [Citation(s) in RCA: 839] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2002] [Accepted: 01/10/2003] [Indexed: 12/17/2022]
Abstract
The evolutionary conservation of T lymphocyte subsets bearing T-cell receptors (TCRs) using invariant alpha-chains is indicative of unique functions. CD1d-restricted natural killer T (NK-T) cells that express an invariant Valpha14 TCRalpha chain have been implicated in microbial and tumour responses, as well as in auto-immunity. Here we show that T cells that express the canonical hValpha7.2-Jalpha33 or mValpha19-Jalpha33 TCR rearrangement are preferentially located in the gut lamina propria of humans and mice, respectively, and are therefore genuine mucosal-associated invariant T (MAIT) cells. Selection and/or expansion of this population requires B lymphocytes, as MAIT cells are absent in B-cell-deficient patients and mice. In addition, we show that MAIT cells are selected and/or restricted by MR1, a monomorphic major histocompatibility complex class I-related molecule that is markedly conserved in diverse mammalian species. MAIT cells are not present in germ-free mice, indicating that commensal flora is required for their expansion in the gut lamina propria. This indicates that MAIT cells are probably involved in the host response at the site of pathogen entry, and may regulate intestinal B-cell activity.
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MESH Headings
- Amino Acid Sequence
- Animals
- Antigens, Differentiation, B-Lymphocyte/immunology
- B-Lymphocytes/immunology
- B-Lymphocytes/metabolism
- Base Sequence
- Biological Evolution
- Chimera/genetics
- Chimera/immunology
- Gene Deletion
- Gene Rearrangement, T-Lymphocyte/genetics
- Gene Rearrangement, T-Lymphocyte/immunology
- Histocompatibility Antigens Class I/genetics
- Histocompatibility Antigens Class I/immunology
- Histocompatibility Antigens Class I/metabolism
- Histocompatibility Antigens Class II/immunology
- Humans
- Immunity, Mucosal
- Interleukin-2/biosynthesis
- Intestines/immunology
- Lymphocyte Activation
- Mice
- Mice, Knockout
- Minor Histocompatibility Antigens
- Molecular Sequence Data
- Receptors, Antigen, T-Cell/chemistry
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/immunology
- Selection, Genetic
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
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Affiliation(s)
- Emmanuel Treiner
- Laboratoire d'Immunologie and INSERM U520, Institut Curie, Paris 75005, France
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44
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Loconto J, Papes F, Chang E, Stowers L, Jones EP, Takada T, Kumánovics A, Fischer Lindahl K, Dulac C. Functional expression of murine V2R pheromone receptors involves selective association with the M10 and M1 families of MHC class Ib molecules. Cell 2003; 112:607-18. [PMID: 12628182 DOI: 10.1016/s0092-8674(03)00153-3] [Citation(s) in RCA: 235] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The vomeronasal organ (VNO) of the mouse has two neuronal compartments expressing distinct families of pheromone receptors, the V1Rs and the V2Rs. We report here that two families of major histocompatibility complex (MHC) class Ib molecules, the M10 and the M1 families, show restricted expression in V2R-expressing neurons. Our data suggest that neurons expressing a given V2R specifically co-express one or a few members of the M10 family. Biochemical and immunocytochemical analysis demonstrates that in VNO sensory dendrites M10s belong to large multi-molecular complexes that include pheromone receptors and beta2-microglobulin (beta2m). In cultured cells, M10s appear to function as escort molecules in transport of V2Rs to the cell surface. Accordingly, beta2m-deficient mice exhibit mislocalization of V2Rs in the VNO and a specific defect in male-male aggressive behavior. The functional characterization of M10 highlights an unexpected role for MHC molecules in pheromone detection by mammalian VNO neurons.
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Affiliation(s)
- Jennifer Loconto
- Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
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45
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Liu Y, Xiong Y, Naidenko OV, Liu JH, Zhang R, Joachimiak A, Kronenberg M, Cheroutre H, Reinherz EL, Wang JH. The crystal structure of a TL/CD8alphaalpha complex at 2.1 A resolution: implications for modulation of T cell activation and memory. Immunity 2003; 18:205-15. [PMID: 12594948 DOI: 10.1016/s1074-7613(03)00027-x] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
TL is a nonclassical MHC class I molecule that modulates T cell activation through relatively high-affinity interaction with CD8alphaalpha. To investigate how the TL/CD8alphaalpha interaction influences TCR signaling, we characterized the structure of the TL/CD8alphaalpha complex using X-ray crystallography. Unlike antigen-presenting molecules, the TL antigen-binding groove is occluded by specific conformational changes. This feature eliminates antigen presentation, severely hampers direct TCR recognition, and prevents TL from participating in the TCR activation complex. At the same time, the TL/CD8alphaalpha interaction is strengthened through subtle structure changes in the TL alpha3 domain. Thus, TL functions to sequester and redirect CD8alphaalpha away from the TCR, modifying lck-dependent signaling.
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Affiliation(s)
- Yiwei Liu
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA
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46
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Rudolph MG, Stevens J, Speir JA, Trowsdale J, Butcher GW, Joly E, Wilson IA. Crystal structures of two rat MHC class Ia (RT1-A) molecules that are associated differentially with peptide transporter alleles TAP-A and TAP-B. J Mol Biol 2002; 324:975-90. [PMID: 12470953 DOI: 10.1016/s0022-2836(02)01095-1] [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: 11/20/2022]
Abstract
Antigenic peptides are loaded onto class I MHC molecules in the endoplasmic reticulum (ER) by a complex consisting of the MHC class I heavy chain, beta(2)-microglobulin, calreticulin, tapasin, Erp57 (ER60) and the transporter associated with antigen processing (TAP). While most mammalian species transport these peptides into the ER via a single allele of TAP, rats have evolved different TAPs, TAP-A and TAP-B, that are present in different inbred strains. Each TAP delivers a different spectrum of peptides and is associated genetically with distinct subsets of MHC class Ia alleles, but the molecular basis for the conservation (or co-evolution) of the two transporter alleles is unknown. We have determined the crystal structures of a representative of each MHC subset, viz RT1-A(a) and RT1-A1(c), in association with high-affinity nonamer peptides. The structures reveal how the chemical properties of the two different rat MHC F-pockets match those of the corresponding C termini of the peptides, corroborating biochemical data on the rates of peptide-MHC complex assembly. An unusual sequence in RT1-A1(c) leads to a major deviation from the highly conserved beta(3)/alpha(1) loop (residues 40-59) conformation in mouse and human MHC class I structures. This loop change contributes to profound changes in the shape of the A-pocket in the peptide-binding groove and may explain the function of RT1-A1(c) as an inhibitory natural killer cell ligand.
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Affiliation(s)
- Markus G Rudolph
- Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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47
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Achour A, Michaëlsson J, Harris RA, Odeberg J, Grufman P, Sandberg JK, Levitsky V, Kärre K, Sandalova T, Schneider G. A structural basis for LCMV immune evasion: subversion of H-2D(b) and H-2K(b) presentation of gp33 revealed by comparative crystal structure.Analyses. Immunity 2002; 17:757-68. [PMID: 12479822 DOI: 10.1016/s1074-7613(02)00478-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
LCMV infection of H-2(b) mice generates a CD8(+) CTL response mainly directed toward three immunodominant epitopes. One of these, gp33, is presented by both H-2D(b) and H-2K(b) MHC class I molecules. The virus can escape immune recognition in the context of both these MHC class I molecules through single mutations of the peptide. In order to understand the underlying structural mechanism, we determined the crystal structures of both complexes. The structures reveal that the peptide is presented in two diametrically opposed manners by H-2D(b) and H-2K(b), with residues used as anchor positions in one MHC class I molecule interacting with the TCR in the other. Importantly, the peptide's N-terminal residue p1K protrudes from the binding cleft in H-2K(b). We present structural evidence that explains the functional consequences of single mutations found in escape variants.
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Affiliation(s)
- Adnane Achour
- Microbiology and Tumor Biology Center, Karolinska Institutet, Royal School of Technology, S-106 91 Stockholm, Sweden.
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48
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Weber DA, Attinger A, Kemball CC, Wigal JL, Pohl J, Xiong Y, Reinherz EL, Cheroutre H, Kronenberg M, Jensen PE. Peptide-independent folding and CD8 alpha alpha binding by the nonclassical class I molecule, thymic leukemia antigen. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 169:5708-14. [PMID: 12421950 DOI: 10.4049/jimmunol.169.10.5708] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The nonclassical class I molecule, thymic leukemia (TL), has been shown to be expressed on intestinal epithelial cells and to interact with CD8(+) intraepithelial T lymphocytes. We generated recombinant soluble TL (T18(d)) H chains in bacteria as inclusion bodies and refolded them with beta(2)-microglobulin in the presence or absence of a random peptide library. Using a mAb, HD168, that recognizes a conformational epitope on native TL molecules, we observed that protein folds efficiently in the absence of peptide. Circular dichroism analysis demonstrated that TL molecules have structural features similar to classical class I molecules. Moreover, thermal denaturation experiments indicated that the melting temperature for peptide-free TL is similar to values reported previously for conventional class I-peptide complexes. Our results also show that CD8alphaalpha binding is not dependent on either TL-associated peptide or TL glycosylation.
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Affiliation(s)
- Dominique A Weber
- Department of Pathology, School of Medicine, Emory University, 1639 Pierce Drive, Atlanta, GA 30322, USA
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49
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Ogata K, Wodak SJ. Conserved water molecules in MHC class-I molecules and their putative structural and functional roles. Protein Eng Des Sel 2002; 15:697-705. [PMID: 12364585 DOI: 10.1093/protein/15.8.697] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A set of conserved water positions making direct contacts with the alpha1 and alpha2 domains of the MHC class-I protein was identified by a cluster analysis in 12 high-resolution crystal structures of proteins from different allele types and different species, comprising human, mouse and rat. The analysis revealed a total of 63 clusters, corresponding to water molecules, whose positions are conserved in half or more of the analyzed structures. Analysis of these clusters shows that the most conserved water positions-those appearing in the largest fraction of the structures-were also the most accurately defined, as measured by their normalized crystallographic B-factor. Not too surprisingly, these positions displayed better overlap and formed more H-bonds with the protein. In a second part of this work, a detailed analysis is presented of three of the most conserved water positions and their putative structural and functional roles are discussed. The most highly conserved of the three appears to play an important role in stabilizing the conformation of a twisted beta-turn between residues 118 and 122 (numbering of HLA-B3501, PDB code 1A1N). An equivalent water molecule was found to be associated with a similar beta-turn in 43 unrelated structures surveyed in the PDB, leading to the suggestion that this water molecule plays an important structural role in this type of turn. The second water molecule makes hydrogen bonds with residues lining pocket B in the peptide-binding groove and is suggested to play a role in modulating peptide recognition. The third highly conserved water molecule is located at the first kink of the alpha2 helix, possibly playing a role in determining the position of the N-terminal segment of that helix, which also carries side chains in contact with the bound peptide. This information on conserved water positions in MHC class-I molecules should be helpful in modeling interactions with bound peptide antigens and in designing new peptides with tailor-made affinities.
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Affiliation(s)
- Koji Ogata
- Service de Conformation de Macromolécules Biologiques, Centre de Biologie Structurale et Bioinformatique, Université Libre de Bruxelles,av. F.D. Roosevelt 50, CP160/16, B-1050 Brussels, Belgium
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50
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He XL, Radu C, Sidney J, Sette A, Ward ES, Garcia KC. Structural snapshot of aberrant antigen presentation linked to autoimmunity: the immunodominant epitope of MBP complexed with I-Au. Immunity 2002; 17:83-94. [PMID: 12150894 DOI: 10.1016/s1074-7613(02)00340-0] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Murine experimental allergic encephalomyelitis (EAE) is a useful model for the demyelinating, autoimmune disease multiple sclerosis. In the EAE system, the immunodominant N-terminal epitope of myelin basic protein (MBP) is an unusually short, weakly binding peptide antigen which elicits highly biased TCR chain usage. In the 2.2 A crystal structure of I-A(u)/MBP1-11 complex, only MBP residues 1-7 are bound toward one end of the peptide binding cleft. The fourth residue of MBP1-11 is located in an incompatible p6 pocket of I-A(u), thus explaining the short half-life of I-A(u) complexed with Ac1-11. MBP peptides extended at the C terminus of Ac1-11 result in dramatic affinity increases, likely attributed to register shifting to a higher affinity cryptic epitope, which could potentially mask the presentation of the immunodominant MBP1-11 peptide during thymic education.
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Affiliation(s)
- Xiao-lin He
- Department of Microbiology and Immunology, Stanford University School of Medicine, CA 94305, USA
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