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Doan TA, Forward T, Tamburini BAJ. Trafficking and retention of protein antigens across systems and immune cell types. Cell Mol Life Sci 2022; 79:275. [PMID: 35505125 PMCID: PMC9063628 DOI: 10.1007/s00018-022-04303-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 04/01/2022] [Accepted: 04/12/2022] [Indexed: 12/05/2022]
Abstract
In response to infection or vaccination, the immune system initially responds non-specifically to the foreign insult (innate) and then develops a specific response to the foreign antigen (adaptive). The programming of the immune response is shaped by the dispersal and delivery of antigens. The antigen size, innate immune activation and location of the insult all determine how antigens are handled. In this review we outline which specific cell types are required for antigen trafficking, which processes require active compared to passive transport, the ability of specific cell types to retain antigens and the viruses (human immunodeficiency virus, influenza and Sendai virus, vesicular stomatitis virus, vaccinia virus) and pattern recognition receptor activation that can initiate antigen retention. Both where the protein antigen is localized and how long it remains are critically important in shaping protective immune responses. Therefore, understanding antigen trafficking and retention is necessary to understand the type and magnitude of the immune response and essential for the development of novel vaccine and therapeutic targets.
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Affiliation(s)
- Thu A Doan
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Colorado School of Medicine, Aurora, USA.,Immunology Graduate Program, University of Colorado School of Medicine, Aurora, USA
| | - Tadg Forward
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Colorado School of Medicine, Aurora, USA
| | - Beth A Jirón Tamburini
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Colorado School of Medicine, Aurora, USA. .,Immunology Graduate Program, University of Colorado School of Medicine, Aurora, USA. .,Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO, USA.
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Córdoba-Castro LA, Salgado-Morales R, Torres M, Martínez-Aguilar L, Lozano L, Vences-Guzmán MÁ, Guan Z, Dantán-González E, Serrano M, Sohlenkamp C. Ornithine Lipids in Burkholderia spp. Pathogenicity. Front Mol Biosci 2021; 7:610932. [PMID: 33469548 PMCID: PMC7814305 DOI: 10.3389/fmolb.2020.610932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Accepted: 12/07/2020] [Indexed: 11/18/2022] Open
Abstract
The genus Burkholderia sensu lato is composed of a diverse and metabolically versatile group of bacterial species. One characteristic thought to be unique for the genus Burkholderia is the presence of two forms each (with and without 2-hydroxylation) of the membrane lipids phosphatidylethanolamine (PE) and ornithine lipids (OLs). Here, we show that only Burkholderia sensu stricto strains constitutively form OLs, whereas all other analyzed strains belonging to the Burkholderia sensu lato group constitutively form the two forms of PE, but no OLs. We selected two model bacteria to study the function of OL in Burkholderia sensu lato: (1) Burkholderia cenocepacia wild-type which constitutively forms OLs and its mutant deficient in the formation of OLs and (2) Robbsia andropogonis (formerly Burkholderia andropogonis) which does not form OL constitutively, and a derived strain constitutively forming OLs. Both were characterized under free-living conditions and during pathogenic interactions with their respective hosts. The absence of OLs in B. cenocepacia slightly affected bacterial growth under specific abiotic stress conditions such as high temperature and low pH. B. cenocepacia lacking OLs caused lower mortality in Galleria mellonella larvae while R. andropogonis constitutively forming OLs triggers an increased formation of reactive oxygen species immediately after infection of maize leaves, suggesting that OLs can have an important role during the activation of the innate immune response of eukaryotes.
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Affiliation(s)
- Luz América Córdoba-Castro
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico.,Programa de Doctorado en Ciencias Biomédicas, Universidad Nacional Autónoma de México, Centro de Ciencias Genómicas, Cuernavaca, Mexico
| | - Rosalba Salgado-Morales
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Martha Torres
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | | | - Luis Lozano
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | | | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center, Durham, NC, United States
| | - Edgar Dantán-González
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Mario Serrano
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Christian Sohlenkamp
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
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Abstract
γδ T cells form an abundant part of the human cellular immune system, where they respond to tissue damage, infection, and cancer. The spectrum of known molecular targets recognized by Vδ1-expressing γδ T cells is becoming increasingly diverse. Here we describe human γδ T cells that recognize CD1b, a lipid antigen-presenting molecule, which is inducibly expressed on monocytes and dendritic cells. Using CD1b tetramers to study multiple donors, we found that many CD1b-specific γδ T cells use Vδ1. Despite their common use of Vδ1, three CD1b-specific γδ T cell receptors (TCRs) showed clear differences in the surface of CD1b recognized, the requirement for lipid antigens, and corecognition of butryophilin-like proteins. Several Vγ segments were present among the CD1b-specific TCRs, but chain swap experiments demonstrated that CD1b specificity was mediated by the Vδ1 chain. One of the CD1b-specific Vδ1+ TCRs paired with Vγ4 and shows dual reactivity to CD1b and butyrophilin-like proteins. αβ TCRs typically recognize the peptide display platform of MHC proteins. In contrast, our results demonstrate the use of rearranged receptors to mediate diverse modes of recognition across the surface of CD1b in ways that do and do not require carried lipids.
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Camacho F, Sarmiento ME, Reyes F, Kim L, Huggett J, Lepore M, Otero O, Gilleron M, Puzo G, Norazmi MN, Rook G, Mori L, De Libero G, Acosta A. Selection of phage-displayed human antibody fragments specific for CD1b presenting the Mycobacterium tuberculosis glycolipid Ac2SGL. Int J Mycobacteriol 2016; 5:120-7. [DOI: 10.1016/j.ijmyco.2015.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 12/15/2015] [Indexed: 11/28/2022] Open
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Pierce BG, Vreven T, Weng Z. Modeling T cell receptor recognition of CD1-lipid and MR1-metabolite complexes. BMC Bioinformatics 2014; 15:319. [PMID: 25260513 PMCID: PMC4261541 DOI: 10.1186/1471-2105-15-319] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Accepted: 09/22/2014] [Indexed: 11/10/2022] Open
Abstract
Background T cell receptors (TCRs) can recognize diverse lipid and metabolite antigens presented by MHC-like molecules CD1 and MR1, and the molecular basis of many of these interactions has not been determined. Here we applied our protein docking algorithm TCRFlexDock, previously developed to perform docking of TCRs to peptide-MHC (pMHC) molecules, to predict the binding of αβ and γδ TCRs to CD1 and MR1, starting with the structures of the unbound molecules. Results Evaluating against TCR-CD1d complexes with crystal structures, we achieved near-native structures in the top 20 models for two out of four cases, and an acceptable-rated prediction for a third case. We also predicted the structure of an interaction between a MAIT TCR and MR1-antigen that has not been structurally characterized, yielding a top-ranked model that agreed remarkably with a characterized TCR-MR1-antigen structure that has a nearly identical TCR α chain but a different β chain, highlighting the likely dominance of the conserved α chain in MR1-antigen recognition. Docking performance was improved by re-training our scoring function with a set of TCR-pMHC complexes, and for a case with an outlier binding mode, we found that alternative docking start positions improved predictive accuracy. We then performed unbound docking with two mycolyl-lipid specific TCRs that recognize lipid-bound CD1b, which represent a class of interactions that is not structurally characterized. Highly-ranked models of these complexes showed remarkable agreement between their binding topologies, as expected based on their shared germline sequences, while differences in residue-level interactions with their respective antigens point to possible mechanisms underlying their distinct specificities. Conclusions Together these results indicate that flexible docking simulations can provide accurate models and atomic-level insights into TCR recognition of MHC-like molecules presenting lipid and other small molecule antigens. Electronic supplementary material The online version of this article (doi:10.1186/1471-2105-15-319) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Brian G Pierce
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, MA 01605, USA.
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Gonzalez-Juarrero M, Mima N, Trunck LA, Schweizer HP, Bowen RA, Dascher K, Mwangi W, Eckstein TM. Polar lipids of Burkholderia pseudomallei induce different host immune responses. PLoS One 2013; 8:e80368. [PMID: 24260378 PMCID: PMC3832426 DOI: 10.1371/journal.pone.0080368] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 10/08/2013] [Indexed: 12/12/2022] Open
Abstract
Melioidosis is a disease in tropical and subtropical regions of the world that is caused by Burkholderia pseudomallei. In endemic regions the disease occurs primarily in humans and goats. In the present study, we used the goat as a model to dissect the polar lipids of B. pseudomallei to identify lipid molecules that could be used for adjuvants/vaccines or as diagnostic tools. We showed that the lipidome of B. pseudomallei and its fractions contain several polar lipids with the capacity to elicit different immune responses in goats, namely rhamnolipids and ornithine lipids which induced IFN-γ, whereas phospholipids and an undefined polar lipid induced strong IL-10 secretion in CD4+ T cells. Autologous T cells co-cultured with caprine dendritic cells (cDCs) and polar lipids of B. pseudomallei proliferated and up-regulated the expression of CD25 (IL-2 receptor) molecules. Furthermore, we demonstrated that polar lipids were able to up-regulate CD1w2 antigen expression in cDCs derived from peripheral blood monocytes. Interestingly, the same polar lipids had only little effect on the expression of MHC class II DR antigens in the same caprine dendritic cells. Finally, antibody blocking of the CD1w2 molecules on cDCs resulted in decreased expression for IFN-γ by CD4+ T cells. Altogether, these results showed that polar lipids of B. pseudomallei are recognized by the caprine immune system and that their recognition is primarily mediated by the CD1 antigen cluster.
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Affiliation(s)
- Mercedes Gonzalez-Juarrero
- Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United State of America
| | - Naoko Mima
- Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United State of America
| | - Lily A. Trunck
- Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United State of America
| | - Herbert P. Schweizer
- Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United State of America
| | - Richard A. Bowen
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Kyle Dascher
- Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United State of America
| | - Waithaka Mwangi
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas, United States of America
| | - Torsten M. Eckstein
- Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United State of America
- * E-mail:
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8
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Girardi E, Wang J, Mac TT, Versluis C, Bhowruth V, Besra G, Heck AJR, Van Rhijn I, Zajonc DM. Crystal structure of bovine CD1b3 with endogenously bound ligands. THE JOURNAL OF IMMUNOLOGY 2010; 185:376-86. [PMID: 20519644 DOI: 10.4049/jimmunol.1000042] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The CD1 family of Ag-presenting molecules is able to display lipids to T cells by binding them within a hydrophobic groove connected to the protein surface. In particular, the CD1b isotype is capable of binding ligands with greatly varying alkyl chain lengths through a complex network of interconnected hydrophobic pockets. Interestingly, mycobacterial lipids such as glucose monomycolate exclusively bind to CD1b. We determined the crystal structure of one of the three expressed bovine CD1b proteins, CD1b3, in complex with endogenous ligands, identified by mass spectrometry as a mixture of phosphatidylcholine and phosphatidylethanolamine, and analyzed the ability of the protein to bind glycolipids in vitro. The structure reveals a complex binding groove architecture, similar to the human ortholog but with consequential differences. Intriguingly, in bovine CD1b3 only the A', C' and F' pockets are present, whereas the T' pocket previously described in human CD1b is closed. This different pocket conformation could affect the ability of boCD1b3 to recognize lipids with long acyl chains such as glucose monomycolate. However, even in the absence of a T' tunnel, bovine CD1b3 is able to bind mycolates from Rhodococcus ruber in vitro.
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Affiliation(s)
- Enrico Girardi
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, La Jolla, CA, USA
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9
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De Libero G, Mori L. How the immune system detects lipid antigens. Prog Lipid Res 2010; 49:120-7. [DOI: 10.1016/j.plipres.2009.10.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Revised: 10/19/2009] [Accepted: 10/20/2009] [Indexed: 10/20/2022]
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10
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Odyniec AN, Barral DC, Garg S, Tatituri RV, Besra GS, Brenner MB. Regulation of CD1 antigen-presenting complex stability. J Biol Chem 2010; 285:11937-47. [PMID: 20133943 PMCID: PMC2852931 DOI: 10.1074/jbc.m109.077933] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
For major histocompatibility complex class I and II molecules, the binding of specific peptide antigens is essential for assembly and trafficking and is at the center of their quality control mechanism. However, the role of lipid antigen binding in stabilization and quality control of CD1 heavy chain (HC)·β2-microglobulin (β2m) complexes is unclear. Furthermore, the distinct trafficking and loading routes of CD1 proteins take them from mildly acidic pH in early endososmal compartments (pH 6.0) to markedly acidic pH in lysosomes (pH 5.0) and back to neutral pH of the cell surface (pH 7.4). Here, we present evidence that the stability of each CD1 HC·β2m complex is determined by the distinct pH optima identical to that of the intracellular compartments in which each CD1 isoform resides. Although stable at acidic endosomal pH, complexes are only stable at cell surface pH 7.4 when bound to specific lipid antigens. The proposed model outlines a quality control program that allows lipid exchange at low endosomal pH without dissociation of the CD1 HC·β2m complex and then stabilizes the antigen-loaded complex at neutral pH at the cell surface.
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Affiliation(s)
- Artur N Odyniec
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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12
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Silk JD, Salio M, Brown J, Jones EY, Cerundolo V. Structural and functional aspects of lipid binding by CD1 molecules. Annu Rev Cell Dev Biol 2008; 24:369-95. [PMID: 18593354 DOI: 10.1146/annurev.cellbio.24.110707.175359] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Over the past ten years, investigators have shown that T lymphocytes can recognize not only peptides in the context of MHC class I and class II molecules but also foreign and self-lipids in association with the nonclassical MHC class I molecules the CD1 proteins. We describe the events that have led to the discovery of the role of CD1 molecules, their pattern of intracellular trafficking, and their ability to sample different intracellular compartments for self- and foreign lipids. Structural and functional aspects of lipid presentation by CD1 molecules are presented in the context of the function of CD1-restricted T cells in antimicrobial responses, antitumor immunity, and the regulation of the tolerance and autoimmunity immunoregulatory axis. Particular emphasis is on invariant NKT (iNKT) cells and their ability to modulate innate and adaptive immune responses.
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Affiliation(s)
- Jonathan D Silk
- Tumour Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
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13
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Trans-species activation of human T cells by rhesus macaque CD1b molecules. Biochem Biophys Res Commun 2008; 377:889-93. [DOI: 10.1016/j.bbrc.2008.10.075] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2008] [Accepted: 10/16/2008] [Indexed: 11/22/2022]
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pH-dependent interdomain tethers of CD1b regulate its antigen capture. Immunity 2008; 28:774-86. [PMID: 18538591 DOI: 10.1016/j.immuni.2008.04.017] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 03/10/2008] [Accepted: 04/15/2008] [Indexed: 11/20/2022]
Abstract
As CD1 proteins recycle between the cell surface and endosomes, they show altered receptiveness to lipid antigen loading. We hypothesized that changes in proton concentration encountered within distinct endosomal compartments influence the charge state of residues near the entrance to the CD1 groove and thereby control antigen loading. Molecular dynamic models identified flexible areas of the CD1b heavy chain in the superior and lateral walls of the A' pocket. In these same areas, residues that carry charge in a pH-dependent manner (D60, E62) were found to tether the rigid alpha1 helix to flexible areas of the alpha2 helix and the 50-60 loop. After disruption of these tethers with acid pH or mutation, we observed increased association and dissociation of lipids with CD1b and preferential presentation of antigens with bulky lipid tails. We propose that ionic tethers act as molecular switches that respond to pH fluxes during endosomal recycling and regulate the conformation of the CD1 heavy chain to control the size and rate of antigens captured.
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15
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CD1d-restricted glycolipid antigens: presentation principles, recognition logic and functional consequences. Expert Rev Mol Med 2008; 10:e20. [PMID: 18601810 DOI: 10.1017/s1462399408000732] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Invariant natural killer T (iNKT) cells are innate lymphocytes whose functions are regulated by self and foreign glycolipid antigens presented by the antigen-presenting molecule CD1d. Activation of iNKT cells in vivo results in rapid release of copious amounts of effector cytokines and chemokines with which they regulate innate and adaptive immune responses to pathogens, certain types of cancers and self-antigens. The nature of CD1d-restricted antigens, the manner in which they are recognised and the unique effector functions of iNKT cells suggest an innate immunoregulatory role for this subset of T cells. Their ability to respond fast and our ability to steer iNKT cell cytokine response to altered lipid antigens make them an important target for vaccine design and immunotherapies against autoimmune diseases. This review summarises our current understanding of CD1d-restricted antigen presentation, the recognition of such antigens by an invariant T-cell receptor on iNKT cells, and the functional consequences of these interactions.
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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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Willcox BE, Willcox CR, Dover LG, Besra G. Structures and Functions of Microbial Lipid Antigens Presented by CD1. Curr Top Microbiol Immunol 2007; 314:73-110. [PMID: 17593658 DOI: 10.1007/978-3-540-69511-0_4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The CD1 family of proteins has evolved to bind a range of endogenous and foreign lipids and present these at the cell surface for antigen-specific recognition by T cells. The distinct intracellular trafficking pathways of CD 1 molecules indicate that collectively, they have the potential to survey the endocytic system widely for antigen, consistent with a role in the presentation of lipids derived from intracellular microbial pathogens. In keeping with this idea, CDla, CDlb, CDlc and CDld have now been shown to present foreign lipid antigens derived from mycobacteria, Gram-negative bacteria and also protozoan species to T cells. These antigens are extremely diverse chemically, and include naturally occurring lipopeptide, glycolipid and phospholipid structures that are distinct from mammalian lipids. CD1-restricted mycobacterial lipids defined to date derive from the highly complex microbial cell envelope. They play a variety of physiological roles for the microbe, including formation of the plasma membrane and protective cell wall and as metabolic intermediates in iron-scavenging pathways. In each case, alkyl chains of CD 1-restricted lipid antigens are accommodated within a deep hydrophobic groove in the membrane-distal alphal-alpha2 domains of the CD1 molecule, with hydrophilic elements solvent-exposed and accessible for recognition by the T cell receptor. Variation in the number, length and saturation of alkyl chains, and the precise chemistry and chirality of the lipid headgroup, clearly exert dominant influences on antigenicity, mediated by effects on CD1 binding and T cell receptor recognition. In the context of structural studies of CD1-lipid complexes, these data suggest that the CD1 isoforms have evolved binding specificities for different classes of foreign lipids, and strongly support a model for antigen recognition involving fine discrimination of lipid headgroup components by the alpha beta T cell receptor. In this review, we summarise our current knowledge of foreign lipid antigens bound by CD 1, focusing on the roles their distinct structural features play in presentation and T cell antigen recognition, and their likely function in antimicrobial T cell responses.
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Affiliation(s)
- B E Willcox
- CRUK Institute for Cancer Studies, Edgbaston, B 15 2TT Birmingham, United Kingdom.
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18
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Abstract
Self lipid antigens induce selection and expansion of autoreactive T cells which have a role in immunoregulation and disease pathogenesis. Here we review the important biological rules which determine lipid immunogenicity. The impact of lipid structure, synthesis, traffic, membrane distribution and CD1 loading are discussed.
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Affiliation(s)
- G De Libero
- Department of Research, University Hospital, Basel, Switzerland.
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19
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Abstract
CD1-restricted T cells can be activated by diverse lipids derived from mammals, bacteria and protozoa. Certain lipids function as antigens, which bind to CD1 proteins and contact T cell antigen receptors. Other lipids activate CD1-restricted T cells by functioning as adjuvants. By stimulating Toll-like receptors on antigen-presenting cells, these adjuvants alter cytokine secretion, lipid antigen synthesis and CD1 protein translation. Delineation of the separate mechanisms by which adjuvants and antigens activate CD1-restricted T cells is leading to new hypotheses about the functions of individual CD1 proteins during the transition from innate to acquired immune responses.
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Affiliation(s)
- D Branch Moody
- Division of Rheumatology, Immunology & Allergy, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA.
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20
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De Libero G, Mori L. How T lymphocytes recognize lipid antigens. FEBS Lett 2006; 580:5580-7. [PMID: 16949584 DOI: 10.1016/j.febslet.2006.08.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2006] [Revised: 08/15/2006] [Accepted: 08/15/2006] [Indexed: 11/18/2022]
Abstract
Recognition of lipid antigens by T lymphocytes is well established. Lipids are recognized by T cells when presented in association with CD1 antigen-presenting molecules. Both microbial and self lipids stimulate specific T lymphocytes, thus participating in immune reactions during infections and autoimmune diseases. The immune system uses a variety of strategies to solubilise lipid antigens, to facilitate their internalization, processing, and loading on CD1 molecules. Recent studies in the field of lipid antigen presentation have revealed new mechanisms which allow the immune system to sense lipids as stimulatory antigens.
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Affiliation(s)
- Gennaro De Libero
- Experimental Immunology, Department of Research, University Hospital, University of Basel, Hebelstrasse 20, CH-4031 Basel, Switzerland.
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de la Salle H, Mariotti S, Angenieux C, Gilleron M, Garcia-Alles LF, Malm D, Berg T, Paoletti S, Maître B, Mourey L, Salamero J, Cazenave JP, Hanau D, Mori L, Puzo G, De Libero G. Assistance of microbial glycolipid antigen processing by CD1e. Science 2005; 310:1321-4. [PMID: 16311334 DOI: 10.1126/science.1115301] [Citation(s) in RCA: 206] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Complexes between CD1 molecules and self or microbial glycolipids represent important immunogenic ligands for specific subsets of T cells. However, the function of one of the CD1 family members, CD1e, has yet to be determined. Here, we show that the mycobacterial antigens hexamannosylated phosphatidyl-myo-inositols (PIM6) stimulate CD1b-restricted T cells only after partial digestion of the oligomannose moiety by lysosomal alpha-mannosidase and that soluble CD1e is required for this processing. Furthermore, recombinant CD1e was able to bind glycolipids and assist in the digestion of PIM6. We propose that, through this form of glycolipid editing, CD1e helps expand the repertoire of glycolipidic T cell antigens to optimize antimicrobial immune responses.
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Affiliation(s)
- Henri de la Salle
- INSERM, U725, Etablissement Francais du Sang-Alsace, F-67065 Strasbourg, France
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Abstract
Recent studies have shown that the recognition of lipid antigens by the immune system is important for defence against infection and other diseases, and that lipid-specific responses occur at higher frequencies than previously suspected. Thanks to several recent advances in this field, we now have a better appreciation of the molecular and cellular requirements of T-cell stimulation by lipids. These findings have raised new questions about the mechanisms of lipid presentation, the priming and clonal expansion of lipid-specific T cells, and their differentiation into memory cells. A greater understanding of lipid-specific T cells and the molecular mechanisms of lipid immunogenicity should facilitate the development of lipid-based vaccines.
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Affiliation(s)
- Gennaro De Libero
- Experimental Immunology, Department of Research, University Hospital, Basel 4031, Switzerland.
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23
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Abstract
CD1 proteins bind lipids to form antigen complexes that contact T-cell receptors and activate T cells. Recent crystal structures of CD1 proteins show that their antigen-binding grooves are composed of up to four pockets (A', C', F' and T') and two antigen portals (C' and F'). Although certain structural features are conserved among CD1 proteins, the grooves of CD1a, CD1b and CD1d differ in the number, shape and connectivity of their antigen-binding pockets. Here, we outline how the portals and pockets of CD1 antigen-binding grooves influence ligand specificity and facilitate the presentation of a surprisingly diverse set of antigenic lipids, glycolipids, lipopeptides and even small, non-lipidic molecules.
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Affiliation(s)
- D Branch Moody
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Harvard Medical School, Smith Building, Room 514, 1 Jimmy Fund Way, Boston, Massachusetts 02115, USA.
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24
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Abstract
This review summarizes the major features of CD1 genes and proteins, the patterns of intracellular trafficking of CD1 molecules, and how they sample different intracellular compartments for self- and foreign lipids. We describe how lipid antigens bind to CD1 molecules with their alkyl chains buried in hydrophobic pockets and expose their polar lipid headgroup whose fine structure is recognized by the TCR of CD1-restricted T cells. CD1-restricted T cells carry out effector, helper, and adjuvant-like functions and interact with other cell types including macrophages, dendritic cells, NK cells, T cells, and B cells, thereby contributing to both innate and adaptive immune responses. Insights gained from mice and humans now delineate the extensive range of diseases in which CD1-restricted T cells play important roles and reveal differences in the role of CD1a, CD1b, and CD1c in contrast to CD1d. Invariant TCR alpha chains, self-lipid reactivity, and rapid effector responses empower a subset of CD1d-restricted T cells (NKT cells) to have unique effector functions without counterpart among MHC-restricted T cells. This review describes the function of CD1-restricted T cells in antimicrobial responses, antitumor immunity, and in regulating the balance between tolerance and autoimmunity.
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Affiliation(s)
- Manfred Brigl
- Division of Rheumatology, Immunology, and Allergy, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
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25
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Batuwangala T, Shepherd D, Gadola SD, Gibson KJC, Zaccai NR, Fersht AR, Besra GS, Cerundolo V, Jones EY. The crystal structure of human CD1b with a bound bacterial glycolipid. THE JOURNAL OF IMMUNOLOGY 2004; 172:2382-8. [PMID: 14764708 DOI: 10.4049/jimmunol.172.4.2382] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The human MHC class I-like molecule CD1b is distinctive among CD1 alleles in that it is capable of presenting a set of glycolipid species that show a very broad range of variation in the lengths of their acyl chains. A structure of CD1b complexed with relatively short acyl chain glycolipids plus detergent suggested how an interlinked network of channels within the Ag-binding groove could accommodate acyl chain lengths of up to 80 carbons. The structure of CD1b complexed with glucose monomycolate, reported in this study, confirms this hypothesis and illustrates how the distinctive substituents of intracellular bacterial glycolipids can be accommodated. The Ag-binding groove of CD1b is, uniquely among CD1 alleles, partitioned into channels suitable for the compact accommodation of lengthy acyl chains. The current crystal structure illustrates for the first time the binding of a natural bacterial lipid Ag to CD1b and shows how its novel structural features fit this molecule for its role in the immune response to intracellular bacteria.
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Affiliation(s)
- Thil Batuwangala
- Cancer Research UK Receptor Structure Group, The Division of Structural Biology, and Cancer Research UK
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26
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Gumperz JE. Antigen specificity of semi‐invariant CD1d‐restricted T cell receptors: The best of both worlds? Immunol Cell Biol 2004; 82:285-94. [PMID: 15186260 DOI: 10.1111/j.0818-9641.2004.01257.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
T lymphocytes are characterized by the use of structurally diverse TCR. The discovery of subsets of canonical T cells that have structurally homogeneous TCR presents an enigma: What antigens do these T cells recognize, and how does their antigen specificity relate to their functions? One subset of canonical T cells is restricted by CD1d, a non-classical antigen presenting molecule that presents lipids and glycolipids. Canonical CD1d-restricted T cells have semi-invariant TCR consisting of an invariantly rearranged TCR alpha chain, paired with diversely rearranged TCR beta chains. Most respond strongly to the unusual glycolipid alpha-galactosylceramide (alpha-GalCer), and can also respond to cellular antigens presented by CD1d. Mounting evidence indicates that alpha-GalCer responsive T cells are heterogeneous in their reactivities to cellular antigens, suggesting that an individual semi-invariant TCR may be capable of recognizing more than one ligand. Recent crystal structures of CD1b molecules with three different bound lipids indicate that the antigenic features of lipids may be localized over a smaller area than those of peptides, and that the positioning of the polar head group can vary substantially. A model that explains how CD1d-restricted T cells could possess both conserved and heterogeneous antigen specificities, is that different lipid antigens may interact with distinct areas of a TCR due to differences in the positioning of the polar head group. Hence, canonical CD1d-restricted TCR could recognize conserved antigens via the invariant TCR alpha chain, and have diverse antigen specificities that are conferred by their individual TCR beta chains.
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Affiliation(s)
- Jenny E Gumperz
- Department of Medical Microbiology and Immunology, University of Wisconsin Medical School, 1300 University Avenue, Madison, WI 53706, USA.
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27
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Karakousis PC, Bishai WR, Dorman SE. Mycobacterium tuberculosiscell envelope lipids and the host immune response. Cell Microbiol 2004; 6:105-16. [PMID: 14706097 DOI: 10.1046/j.1462-5822.2003.00351.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Petros C Karakousis
- Center for Tuberculosis Research, Division of Infectious Diseases, Johns Hopkins University School of Medicine, 1503 E. Jefferson St., Room 105, Baltimore, MD 21231, USA
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28
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Im JS, Yu KOA, Illarionov PA, LeClair KP, Storey JR, Kennedy MW, Besra GS, Porcelli SA. Direct Measurement of Antigen Binding Properties of CD1 Proteins Using Fluorescent Lipid Probes. J Biol Chem 2004; 279:299-310. [PMID: 14551186 DOI: 10.1074/jbc.m308803200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
CD1 proteins are antigen-presenting molecules that bind foreign and self-lipids and stimulate specific T cell responses. In the current study, we investigated ligand binding by CD1 proteins by developing a fluorescent probe binding approach using soluble recombinant human CD1 proteins. To increase stability and yield, soluble group 1 CD1 (CD1b and CD1c) and group 2 CD1 (CD1d) proteins were produced as single chain secreted CD1 proteins in which beta2-microglobulin was fused to the N termini of the CD1 heavy chains by a flexible peptide linker sequence. Analysis of ligand binding properties of single chain secreted CD1 proteins by using fluorescent lipid probes indicated significant differences in ligand preference and in pH dependence of binding by group 1 versus group 2 CD1 proteins. Whereas group 1 CD1 isoforms (CD1b and CD1c) show stronger binding of nitrobenzoxadiazole (NBD)-labeled dialkyl-based ligands (phosphatidylcholine, sphingomyelin, and ceramide), group 2 CD1 (CD1d) proteins were stronger binders of small hydrophobic probes such as 1-anilinonaphthalene-8-sulfonic acid and 4,4'-dianilino-1,1'-naphthyl-5,5'-disulfonic acid. Competition studies indicated that binding of fluorescent lipid probes involved association of the probe with the hydrophobic ligand binding groove of CD1 proteins. Analysis of selected alanine substitution mutants of human CD1b known to inhibit antigen presentation showed that NBD-labeled lipid probe binding could be used to distinguish mutations that interfere with ligand binding from those that affect T cell receptor docking. Our findings provide further evidence for the functional specialization of different CD1 isoforms and demonstrate the value of the fluorescent lipid probe binding method for assisting structure-based studies of CD1 function.
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Affiliation(s)
- Jin S Im
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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29
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Abstract
CD1 proteins mediate T cell activation in response to self and foreign lipids, including lipid antigens from the intracellular pathogen Mycobacterium tuberculosis. During natural infections, myeloid cells migrate to sites of infection and use microbial pattern recognition receptors to internalize live bacteria and lipid antigens into the endosomal network. New studies show that certain CD1 proteins are particularly receptive to binding lipid antigens in the low pH environment of endosomes. Therefore, the endosomal network may represent a depot for concentrating and then selectively presenting exogenous foreign lipid antigens to T cells.
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Affiliation(s)
- Carme Roura-Mir
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital and Harvard Medical School, Smith Building Room 514, 1 Jimmy Fund Way, Boston, MA 02115, USA
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30
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Stanic AK, Park JJ, Joyce S. Innate self recognition by an invariant, rearranged T-cell receptor and its immune consequences. Immunology 2003; 109:171-84. [PMID: 12757612 PMCID: PMC1782955 DOI: 10.1046/j.1365-2567.2003.01657.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
This review attempts to illuminate the glycolipid antigen presentation properties of CD1d, how CD1d controls the function of natural T (iNKT) cells and how CD1d and iNKT cells interact to jump-start the immune system. It is postulated that the CD1d-iNKT cell system functions as a sensor, sensing alterations in cellular lipid content by virtue of its affinity for such ligands. The presentation of a neo-self glycolipid, presumably by infectious assault of antigen-presenting cells, activates iNKT cells, which promptly release pro-inflammatory and anti-inflammatory cytokines and jump-start the immune system.
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Affiliation(s)
- Aleksandar K Stanic
- Department of Microbiology and Immunology, Vanderbilt University School of Medical School, Nashville, TN 37232, USA
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31
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Ulrichs T, Moody DB, Grant E, Kaufmann SHE, Porcelli SA. T-cell responses to CD1-presented lipid antigens in humans with Mycobacterium tuberculosis infection. Infect Immun 2003; 71:3076-87. [PMID: 12761085 PMCID: PMC155760 DOI: 10.1128/iai.71.6.3076-3087.2003] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CD1-restricted presentation of lipid or glycolipid antigens derived from Mycobacterium tuberculosis has been demonstrated by in vitro experiments using cultured T-cell lines. In the present work, the frequency of T-cell responses to natural mycobacterial lipids was analyzed in ex vivo studies of peripheral blood lymphocytes from human patients with pulmonary tuberculosis, from asymptomatic individuals with known contact with M. tuberculosis documented by conversion of their tuberculin skin tests, and from healthy tuberculin skin test-negative individuals or individuals vaccinated with Mycobacterium bovis BCG. Proliferation and gamma interferon enzyme-linked immunospot assays using peripheral blood lymphocytes and autologous CD1(+) immature dendritic cells revealed that T cells from asymptomatic M. tuberculosis-infected donors responded with significantly greater magnitude and frequency to mycobacterial lipid antigen preparations than lymphocytes from uninfected healthy donors. By use of these methods, lipid-antigen-specific proliferative responses were minimally detectable or absent in blood samples from patients with active tuberculosis prior to chemotherapy but became detectable in blood samples drawn 2 weeks after the start of treatment. Lipid antigen-reactive T cells were detected predominantly in the CD4-enriched T-cell fractions of circulating lymphocytes, and anti-CD1 antibody blocking experiments confirmed the CD1 restriction of these T-cell responses. Our results provide further support for the hypothesis that lipid antigens serve as targets of the recall response to M. tuberculosis, and they indicate that CD1-restricted T cells responding to these antigens comprise a significant portion of the circulating pool of M. tuberculosis-reactive T cells in healthy individuals with previous exposure to M. tuberculosis.
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Affiliation(s)
- Timo Ulrichs
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Yeshiva University, Bronx, New York 10461, USA
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32
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Cantu C, Benlagha K, Savage PB, Bendelac A, Teyton L. The paradox of immune molecular recognition of alpha-galactosylceramide: low affinity, low specificity for CD1d, high affinity for alpha beta TCRs. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:4673-82. [PMID: 12707346 DOI: 10.4049/jimmunol.170.9.4673] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CD1 resembles both class I and class II MHC but differs by the important aspect of presenting lipid/glycolipids, instead of peptides, to T cells. Biophysical studies of lipid/CD1 interactions have been limited, and kinetics of binding are in contradiction with functional studies. We have revisited this issue by designing new assays to examine the loading of CD1 with lipids. As expected for hydrophobic interactions, binding affinity was not high and had limited specificity. Lipid critical micelle concentration set the limitation to these studies. Once loaded onto CD1d, the recognition of glycolipids by alphabeta T cell receptor was studied by surface plasmon resonance using soluble Valpha14-Vbeta8.2 T cell receptors. The Valpha14 Jalpha18 chain could be paired with NK1.1 cell-derived Vbeta chain, or any Vbeta8 chain, to achieve high affinity recognition of alpha-galactosylceramide. Biophysical analysis indicated little effect of temperature or ionic strength on the binding interaction, in contrast to what has been seen in peptide/MHC-TCR studies. This suggests that there is less accommodation made by this TCR in recognizing alpha-galactosylceramide, and it can be assumed that the most rigid part of the Ag, the sugar moiety, is critical in the interaction.
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MESH Headings
- Animals
- Antigen Presentation/immunology
- Antigens, CD1/immunology
- Antigens, CD1/metabolism
- Antigens, CD1d
- Binding Sites/immunology
- Calorimetry/methods
- Cell Line
- Dimerization
- Epitopes, T-Lymphocyte/immunology
- Epitopes, T-Lymphocyte/metabolism
- Galactosylceramides/immunology
- Galactosylceramides/metabolism
- Genes, T-Cell Receptor alpha
- Genes, T-Cell Receptor beta
- Isoelectric Focusing/methods
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Kinetics
- Lymphocyte Activation
- Mice
- Protein Binding/immunology
- Receptors, Antigen, T-Cell, alpha-beta/biosynthesis
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Recombinant Proteins/biosynthesis
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- Thermodynamics
- Transfection
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Affiliation(s)
- Carlos Cantu
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA
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33
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De Libero G, Mori L. Self glycosphingolipids: new antigens recognized by autoreactive T lymphocytes. Physiology (Bethesda) 2003; 18:71-6. [PMID: 12644623 DOI: 10.1152/nips.01418.2002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
T cells may recognize glycolipids and lipids of bacterial and self origin associated with the CD1 antigen-presenting molecules. Understanding the mechanisms governing CD1-self glycolipid interaction will provide information on the molecular rules of glycolipid presentation and suggest new approaches to immunotherapy.
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Affiliation(s)
- Gennaro De Libero
- Experimental Immunology, Department of Research, University Hospital, Basel, CH-4031 Basel, Switzerland
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34
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Affiliation(s)
- Sebastian Joyce
- Department of Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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35
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Abstract
Each of the human CD1 proteins takes a different route through secretory and endocytic compartments before finally arriving at the cell surface, where these proteins present glycolipid antigens to T cells. Recent studies have shown that adaptor-protein complexes and CD1-associated chaperones control not only CD1 trafficking, but also the development and activation of CD1-restricted T cells. This indicates that CD1 proteins, similar to MHC class I and II molecules, selectively acquire certain antigens in distinct cellular subcompartments. Here, we summarize evidence supporting the hypothesis that CD1 proteins use separate, but parallel, pathways to survey endosomal compartments differentially for lipid antigens.
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Affiliation(s)
- D Branch Moody
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Harvard Medical School, 1 Jimmy Fund Way, Boston, Massachusetts 02114, USA.
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36
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Abstract
For many years it was thought that T lymphocytes recognized only peptide antigens presented by MHC class I or class II molecules. Recently, it has become clear that a wide variety of lipids and glycolipids are also targets of the T cell response. This novel form of cell-mediated immune recognition is mediated by a family of lipid binding and presenting molecules known as CD1. The CD1 proteins represent a small to moderate sized family of beta2-microglobulin-associated transmembrane proteins that are distantly related to MHC class I and class II molecules. They are conserved in most or all mammals, and control the development and function of T cell populations that participate in innate and adaptive immune responses through the recognition of self and foreign lipid antigens. Here we review the current state of our understanding of the structure and function of CD1 proteins, and the role of CD1-restricted T cell responses in the immune system.
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Affiliation(s)
- Y Dutronc
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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37
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Compostella F, Franchini L, De Libero G, Palmisano G, Ronchetti F, Panza L. CD1a-binding glycosphingolipids stimulating human autoreactive T-cells: synthesis of a family of sulfatides differing in the acyl chain moiety. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(02)01092-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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38
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Gadola SD, Zaccai NR, Harlos K, Shepherd D, Castro-Palomino JC, Ritter G, Schmidt RR, Jones EY, Cerundolo V. Structure of human CD1b with bound ligands at 2.3 A, a maze for alkyl chains. Nat Immunol 2002; 3:721-6. [PMID: 12118248 DOI: 10.1038/ni821] [Citation(s) in RCA: 193] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The human genome encodes five nonpolymorphic major histocompatibility complex class I-like glycoproteins, CD1a to CD1e, that present lipid antigens for specific recognition by T lymphocytes. Using single alkyl chain detergents, we developed a protocol to generate recombinant human CD1b-lipid complexes. We present here the crystal structures of CD1b in complex with either phosphatidylinositol or ganglioside GM2 at 2.3 A and 2.8 A resolutions, respectively. The antigen-binding groove houses four interlinked hydrophobic channels that are occupied by the alkyl chains of the glycolipid plus two detergent molecules. A distinct exit beneath the alpha 2 helix further contributes to the plasticity of the binding groove. These structures reveal the mechanism by which two alkyl chain lipids bind to CD1b, and how CD1b can adapt to ligands of different alkyl chain length. They also suggest how very long alkyl chains, such as those of mycolic acid, could be fully contained within the binding groove. These results extend the spectrum of potential CD1b ligands by revealing that, in addition to two alkyl chain lipids, mono-alkyl and triple-alkyl chain lipids can be accommodated in the binding groove.
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Affiliation(s)
- Stephan D Gadola
- Cancer Research UK Tumour Immunology Group, The Weatherall Institute of Molecular Medicine, Nuffield Department of Medicine, University of Oxford, Oxford OX3 9DS, UK. stephan.gadola@inselch
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39
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De Libero G, Donda A, Gober HJ, Manolova V, Mazorra Z, Shamshiev A, Mori L. A new aspect in glycolipid biology: glycosphingolipids as antigens recognized by T lymphocytes. Neurochem Res 2002; 27:675-85. [PMID: 12374202 DOI: 10.1023/a:1020280201809] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
T cells may recognize a large variety of ligands with different chemical structures. Recently, glycosphingolipids have also been shown to stimulate human T lymphocytes. Recognition of glycosphingolipids is restricted by the nonpolymorphic CD1 molecules, expressed by professional antigen-presenting cells and by macrophages infiltrating inflammatory sites. CD1 molecules have a structure resembling that of classical MHC class I molecules, with the terminal extracellular domains characterized by two antiparallel alpha helices placed on two hydrophobic pockets. The glycosphingolipids bound to CD1 insert the lipid tails in the two pockets and position the hydrophilic head on the external part of CD1. The TCR interacts with aminoacids present in the two alpha helices and with residues provided by the carbohydrate moiety of glycosphingolipids and discriminates their structural variations. T cells recognizing self-glycosphingolipids release proinflammatory cytokines and may have a pathogenetic role in autoimmune diseases such as multiple sclerosis.
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Affiliation(s)
- G De Libero
- Experimental Immunology, University Hospital, Basel, Switzerland.
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40
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Ryll R, Kumazawa Y, Yano I. Immunological properties of trehalose dimycolate (cord factor) and other mycolic acid-containing glycolipids--a review. Microbiol Immunol 2002; 45:801-11. [PMID: 11838897 DOI: 10.1111/j.1348-0421.2001.tb01319.x] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mycolic acids are characteristic fatty acids of Mycobacteria and are responsible for the wax-like consistence of these microorganisms. Decades of research revealed that mycolic acid-containing glycolipids, in particular trehalose-6,6'-dimycolate (TDM, cord factor) as their best-studied representative, exert a number of immunomodifying effects. They are able to stimulate innate, early adaptive and both humoral and cellular adaptive immunity. Most functions can be associated with their ability to induce a wide range of chemokines (MCP-1, MIP-1alpha, IL-8) and cytokines (e.g., IL-12, IFN-gamma, TNF-alpha, IL-4, IL-6, IL-10). This review tries to link well-known properties of mycolic acid-containing glycolipids, e.g., stimulation of cellular and humoral immunity, granuloma formation and anti-tumor activity, with recent findings in molecular immunology and to give an outlook on potential practical applications.
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Affiliation(s)
- R Ryll
- Japan BCG Laboratory, Kiyose, Tokyo.
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41
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Grant EP, Beckman EM, Behar SM, Degano M, Frederique D, Besra GS, Wilson IA, Porcelli SA, Furlong ST, Brenner MB. Fine specificity of TCR complementarity-determining region residues and lipid antigen hydrophilic moieties in the recognition of a CD1-lipid complex. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2002; 168:3933-40. [PMID: 11937549 DOI: 10.4049/jimmunol.168.8.3933] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
alphabeta TCR can recognize peptides presented by MHC molecules or lipids and glycolipids presented by CD1 proteins. Whereas the structural basis for peptide/MHC recognition is now clearly understood, it is not known how the TCR can interact with such disparate molecules as lipids. Recently, we demonstrated that the alphabeta TCR confers specificity for both the lipid Ag and CD1 isoform restriction, indicating that the TCR is likely to recognize a lipid/CD1 complex. We hypothesized that lipids may bind to CD1 via their hydrophobic alkyl and acyl chains, exposing the hydrophilic sugar, phosphate, and other polar functions for interaction with the TCR complementarity-determining regions (CDRs). To test this model, we mutated the residues in the CDR3 region of the DN1 TCR beta-chain that were predicted to project between the CD1b alpha helices in a model of the TCR/CD1 complex. In addition, we tested the requirement for the negatively charged and polar functions of mycolic acid for Ag recognition. Our findings indicate that the CDR loops of the TCR form the Ag recognition domain of CD1-restricted TCRs and suggest that the hydrophilic domains of a lipid Ag can form a combinatorial epitope recognized by the TCR.
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MESH Headings
- Amino Acid Sequence
- Antigen Presentation/genetics
- Antigen-Presenting Cells/immunology
- Antigen-Presenting Cells/metabolism
- Antigens, Bacterial/chemistry
- Antigens, Bacterial/immunology
- Antigens, Bacterial/metabolism
- Antigens, CD1/chemistry
- Antigens, CD1/metabolism
- Arginine/genetics
- Cell Line
- Complementarity Determining Regions/chemistry
- Complementarity Determining Regions/genetics
- Complementarity Determining Regions/metabolism
- Epitopes, T-Lymphocyte/chemistry
- Epitopes, T-Lymphocyte/genetics
- Epitopes, T-Lymphocyte/metabolism
- Genes, T-Cell Receptor beta/genetics
- Humans
- Jurkat Cells
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Mycobacterium tuberculosis/chemistry
- Mycobacterium tuberculosis/immunology
- Mycobacterium tuberculosis/metabolism
- Mycolic Acids/chemistry
- Mycolic Acids/immunology
- Mycolic Acids/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Transfection
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Affiliation(s)
- Ethan P Grant
- Lymphocyte Biology Section, Division of Rheumatology, Immunology, and Allergy, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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42
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Park SH, Weiss A, Benlagha K, Kyin T, Teyton L, Bendelac A. The mouse CD1d-restricted repertoire is dominated by a few autoreactive T cell receptor families. J Exp Med 2001; 193:893-904. [PMID: 11304550 PMCID: PMC2193401 DOI: 10.1084/jem.193.8.893] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
To define the phenotype and T cell receptor (TCR) repertoire of CD1d-dependent T cells, we compared the populations of T cells that persisted in major histocompatibility complex (MHC)-deficient mice, which lack mainstream T cells, with those from MHC/CD1d doubly deficient mice, which lack both mainstream and CD1d-dependent T cells. Surprisingly, up to 80% of the CD1d-dependent T cells were stained by tetramers of CD1d/alpha-galactosylceramide, which specifically identify the previously described CD1d autoreactive Valpha14-Jalpha18/Vbeta8 natural killer (NK) T cells. Furthermore, zooming in on the CD1d-dependent non-Valpha14 T cells, we found that, like Valpha14 NK T cells, they mainly expressed recurrent, CD1d autoreactive TCR families and had a natural memory phenotype. Thus, CD1d-restricted T cells differ profoundly from MHC-peptide-specific T cells by their predominant use of autoreactive and semiinvariant, rather than naive and diverse, TCRs. They more closely resemble other lineages of innate lymphocytes such as B-1 B cells, gammadelta T cells, and NK cells, which express invariant or semiinvariant autoreactive receptors. Finally, we demonstrate that the MHC-restricted TCR repertoire is essentially non-cross-reactive to CD1d. Altogether, these findings imply that lipid recognition by CD1d-restricted T cells may have largely evolved as an innate rather than an adaptive arm of the mouse immune system.
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MESH Headings
- Animals
- Antibodies, Monoclonal
- Antigens, CD1/genetics
- Antigens, CD1/immunology
- Antigens, CD1d
- B-Lymphocytes/immunology
- Cell Line
- Cells, Cultured
- Cytotoxicity, Immunologic
- Female
- Hybridomas/immunology
- Lymphocyte Activation
- Major Histocompatibility Complex
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Rats
- Receptors, Antigen, T-Cell/analysis
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Spleen/immunology
- T-Lymphocytes/immunology
- Transfection
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Affiliation(s)
- S H Park
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA.
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