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Abstract
Therapeutic options aimed at tackling the HIV pandemic face many obstacles. The lack of readily accessible and affordable therapies means that most of those affected go untreated. The array of escape mechanisms used by HIV has undermined the efficiency of many antiviral products and continually represents a barrier to the development of an effective vaccine. Recent developments have seen a shift away from a cytopathic viral model of HIV pathogenesis towards the crucial role of immunopathogenic features--notably generalised immune activation--in the development of AIDS. As conventional vaccine strategies have sought to promote viral neutralisation and suppressive cellular responses, novel strategies that aim to address HIV immunopathogenesis should be sought. We review current opinion on HIV-induced pathogenic immune activation and strategies aimed at eliminating HIV, including a potential role for non-neutralising antibodies as part of a therapeutic vaccine option.
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Cadogan M, Austen B, Heeney JL, Dalgleish AG. HLA homology within the C5 domain promotes peptide binding by HIV type 1 gp120. AIDS Res Hum Retroviruses 2008; 24:845-55. [PMID: 18544021 DOI: 10.1089/aid.2007.0194] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The mechanisms by which HIV-1 induces chronic pathogenic immune activation associated with disease progression remain unclear despite many years of AIDS research. One proposal suggests that sequence and structural mimicry between gp120 and HLA may endow HIV with the capacity to arouse alloreactive and autoimmune responses within the susceptible host, fueling disease progression in a manner similar to graft-versus-host disease (GVHD). Both gp120 and HLA share a common functional interaction with CD4 but also demonstrate peptide binding properties. Here we report the conserved nature of this feature across HIV-1 envelopes, the crucial role of the HLA homologous C5 region for peptide interactions, and the elimination of this property through specific antibody targeting. Given that the C5 domain mimics a HLA activation domain and the reported clinical benefits associated with nonneutralizing antibodies against this region, targeting the C5 domain may have use as a therapeutic vaccine to protect against disease progression.
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Affiliation(s)
- Martin Cadogan
- Department of Cellular and Molecular Medicine, St. George's University of London, London SW17 0RE, UK
| | - Brian Austen
- Department of Basic Medical Sciences, St. George's University of London, London SW17 0RE, UK
| | - Jonathan L. Heeney
- Department of Virology, Biomedical Primate Research Centre, Rijswijk 2280-GH, The Netherlands
| | - Angus G. Dalgleish
- Department of Cellular and Molecular Medicine, St. George's University of London, London SW17 0RE, UK
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Huan JY, Meza-Romero R, Mooney JL, Chou YK, Edwards DM, Rich C, Link JM, Vandenbark AA, Bourdette DN, Bächinger HP, Burrows GG. Rationally designed mutations convert complexes of human recombinant T cell receptor ligands into monomers that retain biological activity. JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY (OXFORD, OXFORDSHIRE : 1986) 2005; 80:2-12. [PMID: 22973070 PMCID: PMC3438139 DOI: 10.1002/jctb.1086] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Single-chain human recombinant T cell receptor ligands derived from the peptide binding/TCR recognition domain of human HLA-DR2b (DRA*0101/DRB1*1501) produced in Escherichia coli with and without amino-terminal extensions containing antigenic peptides have been described previously. While molecules with the native sequence retained biological activity, they formed higher order aggregates in solution. In this study, we used site-directed mutagenesis to modify the β-sheet platform of the DR2-derived RTLs, obtaining two variants that were monomeric in solution by replacing hydrophobic residues with polar (serine) or charged (aspartic acid) residues. Size exclusion chromatography and dynamic light scattering demonstrated that the modified RTLs were monomeric in solution, and structural characterization using circular dichroism demonstrated the highly ordered secondary structure of the RTLs. Peptide binding to the `empty' RTLs was quantified using biotinylated peptides, and functional studies showed that the modified RTLs containing covalently tethered peptides were able to inhibit antigen-specific T cell proliferation in vitro, as well as suppress experimental autoimmune encephalomyelitis in vivo. These studies demonstrated that RTLs encoding the Ag-binding/TCR recognition domain of MHC class II molecules are innately very robust structures, capable of retaining potent biological activity separate from the Ig-fold domains of the progenitor class II structure, with prevention of aggregation accomplished by modification of an exposed surface that was buried in the progenitor structure.
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Affiliation(s)
- Jianya Y Huan
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Roberto Meza-Romero
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Jeffery L Mooney
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Yuan K Chou
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
| | - David M Edwards
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Cathleen Rich
- Neuroimmunology Research, Veterans Affairs Medical Center, Portland, OR 97207, USA
| | - Jason M Link
- Neuroimmunology Research, Veterans Affairs Medical Center, Portland, OR 97207, USA
| | - Arthur A Vandenbark
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
- Neuroimmunology Research, Veterans Affairs Medical Center, Portland, OR 97207, USA
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239, USA
| | - Dennis N Bourdette
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
| | | | - Gregory G Burrows
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
- Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, OR 97239, USA
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Wang C, Mooney JL, Meza-Romero R, Chou YK, Huan J, Vandenbark AA, Offner H, Burrows GG. Recombinant TCR ligand induces early TCR signaling and a unique pattern of downstream activation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 171:1934-40. [PMID: 12902496 DOI: 10.4049/jimmunol.171.4.1934] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Recombinant TCR ligands (RTLs) consisting of covalently linked alpha(1) and beta(1) domains of MHC class II molecules tethered to specific antigenic peptides represent minimal TCR ligands. In a previous study we reported that the rat RTL201 construct, containing RT1.B MHC class II domains covalently coupled to the encephalitogenic guinea pig myelin basic protein (Gp-MBP(72-89)) peptide, could prevent and treat actively and passively induced experimental autoimmune encephalomyelitis in vivo by selectively inhibiting Gp-MBP(72-89) peptide-specific CD4(+) T cells. To evaluate the inhibitory signaling pathway, we tested the effects of immobilized RTL201 on T cell activation of the Gp-MBP(72-89)-specific A1 T cell hybridoma. Activation was exquisitely Ag-specific and could not be induced by RTL200 containing the rat MBP(72-89) peptide that differed by a threonine for serine substitution at position 80. Partial activation by RTL201 included a CD3zeta p23/p21 ratio shift, ZAP-70 phosphorylation, calcium mobilization, NFAT activation, and transient IL-2 production. In comparison, anti-CD3epsilon treatment produced stronger activation of these cellular events with additional activation of NF-kappaB and extracellular signal-regulated kinases as well as long term increased IL-2 production. These results demonstrate that RTLs can bind directly to the TCR and modify T cell behavior through a partial activation mechanism, triggering specific downstream signaling events that deplete intracellular calcium stores without fully activating T cells. The resulting Ag-specific activation of the transcription factor NFAT uncoupled from the activation of NF-kappaB or extracellular signal-regulated kinases constitutes a unique downstream activation pattern that accounts for the inhibitory effects of RTL on encephalitogenic CD4(+) T cells.
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MESH Headings
- Amino Acid Sequence
- Animals
- CD3 Complex/metabolism
- Calcium Signaling/genetics
- Calcium Signaling/immunology
- DNA-Binding Proteins/metabolism
- Guinea Pigs
- HLA-DR2 Antigen/metabolism
- HLA-DR2 Antigen/physiology
- Histocompatibility Antigens/metabolism
- Histocompatibility Antigens/physiology
- Humans
- Hybridomas
- Interleukin-2/biosynthesis
- Ligands
- Lymphocyte Activation/genetics
- Mice
- Mitogen-Activated Protein Kinases/metabolism
- Molecular Sequence Data
- Myelin Basic Protein/metabolism
- Myelin Basic Protein/pharmacology
- NF-kappa B/metabolism
- NFATC Transcription Factors
- Nuclear Proteins
- Peptide Fragments/metabolism
- Peptide Fragments/pharmacology
- Phosphorylation
- Protein-Tyrosine Kinases/metabolism
- Rats
- Rats, Inbred Lew
- Receptors, Antigen, T-Cell/physiology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/physiology
- Recombinant Proteins/metabolism
- Recombinant Proteins/pharmacology
- T-Lymphocytes/enzymology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Transcription Factors/metabolism
- Tumor Cells, Cultured
- ZAP-70 Protein-Tyrosine Kinase
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Affiliation(s)
- Chunhe Wang
- Department of Neurology, Oregon Health and Science University, Portland, OR 97239, USA
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Okawa-Takatsuji M, Aotsuka S, Uwatoko S, Takaono M, Iwasaki K, Kinoshita M, Sumiya M. Endothelial cell-binding activity of anti-U1-ribonucleoprotein antibodies in patients with connective tissue diseases. Clin Exp Immunol 2001; 126:345-54. [PMID: 11703381 PMCID: PMC1906203 DOI: 10.1046/j.1365-2249.2001.01669.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to elucidate the immunological properties of anti-U1-ribonucleoprotein (RNP) antibody, one of the autoantibodies detected in patients with connective tissue diseases (CTDs), we tested the endothelial cell-binding by anti-U1-RNP antibodies and epitopes on human pulmonary artery endothelial cells (HPAECs) to which the autoantibody bound. IgG fractions positive for anti-U1-RNP from patients with CTDs bound to the HPAECs. Furthermore, intact and F(ab')2 IgG anti-U1-RNP purified by affinity chromatography also bound to endothelial cells. The binding activity of IgG fractions positive for anti-U1-RNP to the endothelial cells could be effectively absorbed by U1-RNP-Sepharose. An immunoblotting assay of purified IgG anti-U1-RNP antibodies showed that these antibodies could bind to various membrane proteins of NP40-treated HPAECs such as 68, 48, 43, 38, 33, 29, 28 and 24 kDa. Some bands, 68, 33, 28 and 24 kDa, seemed to correspond to components of U1-RNP, i.e. 68 kDa, A, B' and C peptides, respectively. We confirmed that the anti-U1-RNP antibody from patients with CTDs can directly recognize a variety of antigens on the endothelial surface of the pulmonary artery, including the components of U1-RNP or other unknown polypeptides. These results suggest that binding to pulmonary artery endothelial cells of this autoantibody may be one of the triggers of endothelial cell inflammation in CTDs.
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Affiliation(s)
- M Okawa-Takatsuji
- Division of Clinical Immunology, Research Institute, International Medical Center of Japan, Tokyo, Japan.
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van Rensen AJ, Taams LS, Grosfeld-Stulemeyer MC, van Eden W, Crommelin DJ, Wauben MH. Induction of T cell anergy by liposomes with incorporated major histocompatibility complex (MHC) II/peptide complexes. Pharm Res 2000; 17:720-6. [PMID: 10955847 DOI: 10.1023/a:1007586400631] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The aim of this study was to use small unilamellar liposomes with incorporated MHC II/peptide complexes as a carrier system for multivalent antigen presentation to CD4 + T cells. METHODS Purified peptide pre-loaded MHC II molecules were incorporated into small unilamellar liposomes and tested for their ability to activate A2b T cells. The outcome of T cell activation by such liposomes in the absence of accessory cells was tested via flow cytometry and a T cell anergy assay. RESULTS Provided the presence of external co-stimulation, MHC II/ peptide liposomes were able to induce proliferation of the A2b T cell clone. More importantly incubation of these T cells with MHC II/ peptide liposomes in the absence of co-stimulation did not induce proliferation, however, a MHC/peptide ligand-density dependent down-regulation of the TCR was observed. Interestingly, when T cells after incubation with the MHC II/peptide liposomes were restimulated with their specific antigen in the presence of professional APC, these cells were anergic. CONCLUSIONS We propose MHC II/peptide liposomes as a novel means to induce T cell anergy. The possibility to prepare 'tailor-made' liposomal formulations may provide liposomes with an important advantage for applications in immunotherapy.
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Affiliation(s)
- A J van Rensen
- Department of Pharmaceutics, Faculty of Pharmacy, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, The Netherlands
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Burrows GG, Chang JW, Bächinger HP, Bourdette DN, Offner H, Vandenbark AA. Design, engineering and production of functional single-chain T cell receptor ligands. PROTEIN ENGINEERING 1999; 12:771-8. [PMID: 10506287 DOI: 10.1093/protein/12.9.771] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Major histocompatibility complex (MHC) class II molecules are membrane-anchored heterodimers on the surface of antigen presenting cells (APCs) that bind the T cell receptor, initiating a cascade of interactions that results in antigen-specific activation of clonal populations of T cells. The peptide binding/T cell recognition domains of rat MHC class II (alpha-1 and beta-1 domains) were expressed as a single exon for structural and functional characterization. These recombinant single-chain T cell receptor ligands (termed 'beta1alpha1' molecules) of approximately 200 amino acid residues were designed using the structural backbone of MHC class II molecules as template, and have been produced in Escherichia coli with and without N-terminal extensions containing antigenic peptides. Structural characterization using circular dichroism predicted that these molecules retained the antiparallel beta-sheet platform and antiparallel alpha-helices observed in the native MHC class II heterodimer. The proteins exhibited a cooperative two-state thermal folding-unfolding transition. Beta1alpha1 molecules with a covalently linked MBP-72-89 peptide showed increased stability to thermal unfolding relative to the empty beta1alpha1 molecules. This new class of small soluble polypeptide provides a template for designing and refining human homologues useful in detecting and regulating pathogenic T cells.
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Affiliation(s)
- G G Burrows
- Department of Neurology, Department of Biochemistry and Molecular Biology and Department of Molecular Microbiology and Immunology, Oregon Health Sciences University, Portland, OR 97201, USA
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Burrows GG, Bebo BF, Adlard KL, Vandenbark AA, Offner H. Two-Domain MHC Class II Molecules Form Stable Complexes with Myelin Basic Protein 69–89 Peptide That Detect and Inhibit Rat Encephalitogenic T Cells and Treat Experimental Autoimmune Encephalomyelitis. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.161.11.5987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
We designed and expressed in bacteria a single-chain two-domain MHC class II molecule capable of binding and forming stable complexes with antigenic peptide. The prototype “β1α1” molecule included the β1 domain of the rat RT1.B class II molecule covalently linked to the amino terminus of the α1 domain. In association with the encephalitogenic myelin basic protein (MBP) 69–89 peptide recognized by Lewis rat T cells, the β1α1/MBP-69–89 complex specifically labeled and inhibited activation of MBP-69–89 reactive T cells in an IL-2-reversible manner. Moreover, this complex both suppressed and treated clinical signs of experimental autoimmune encephalomyelitis and inhibited delayed-type hypersensitivity reactions and lymphocyte proliferation in an Ag-specific manner. These data indicate that the β1α1/MBP-69–89 complex functions as a simplified natural TCR ligand with potent inhibitory activity that does not require additional signaling from the β2 and α2 domains. This new class of small soluble polypeptide may provide a template for designing human homologues useful in detecting and regulating potentially autopathogenic T cells.
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Affiliation(s)
- Gregory G. Burrows
- *Neuroimmunology Research, Veterans Affairs Medical Center, Portland, OR 97201; and
- †Department of Neurology,
- ‡Department of Biochemistry and Molecular Biology, and
| | - Bruce F. Bebo
- *Neuroimmunology Research, Veterans Affairs Medical Center, Portland, OR 97201; and
- †Department of Neurology,
| | - Kirsten L. Adlard
- *Neuroimmunology Research, Veterans Affairs Medical Center, Portland, OR 97201; and
| | - Arthur A. Vandenbark
- *Neuroimmunology Research, Veterans Affairs Medical Center, Portland, OR 97201; and
- †Department of Neurology,
- §Department of Molecular Microbiology and Immunology, Oregon Health Sciences University, Portland, OR 97201
| | - Halina Offner
- *Neuroimmunology Research, Veterans Affairs Medical Center, Portland, OR 97201; and
- †Department of Neurology,
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Radu CG, Ober BT, Colantonio L, Qadri A, Ward ES. Expression and Characterization of Recombinant Soluble Peptide: I-A Complexes Associated with Murine Experimental Autoimmune Diseases. THE JOURNAL OF IMMUNOLOGY 1998. [DOI: 10.4049/jimmunol.160.12.5915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Structural and functional studies of murine MHC class II I-A molecules have been limited by the low yield and instability of soluble, recombinant heterodimers. In the murine autoimmune diseases experimental autoimmune encephalomyelitis and collagen-induced arthritis, MHC class II molecules I-Au and I-Aq present peptides derived from myelin basic protein and type II collagen, respectively, to autoreactive T cells. To date, systems for the expression of these two I-A molecules in soluble form for use in structure-function relationship studies have not been reported. In the present study, we have expressed functional I-Au and I-Aq molecules using a baculovirus insect cell system. The chain pairing and stability of the molecules were increased by covalently linking the antigenic peptides to β-chains and adding carboxyl-terminal leucine zippers. Peptide:I-Aq complex quantitatively formed an SDS-stable dimer, whereas peptide:I-Au formed undetectable amounts. However, the two complexes did not show any significant difference in their response to thermal denaturation as assessed by circular dichroism analyses. The autoantigen peptide:I-A complexes were highly active in stimulating cognate T cells to secrete IL-2 and inducing Ag-specific apoptosis of the T cells. Interestingly, the T cells were stimulated by these soluble molecules in the apparent absence of experimentally induced cross-linking of TCRs, indicating that they may have therapeutic potential in autoimmune disease models.
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Affiliation(s)
- Caius G. Radu
- Department of Microbiology and Cancer Immunobiology Center, University of Texas Southwestern Medical Center, Dallas, TX 75235
| | - Bertram T. Ober
- Department of Microbiology and Cancer Immunobiology Center, University of Texas Southwestern Medical Center, Dallas, TX 75235
| | - Lucia Colantonio
- Department of Microbiology and Cancer Immunobiology Center, University of Texas Southwestern Medical Center, Dallas, TX 75235
| | - Ayub Qadri
- Department of Microbiology and Cancer Immunobiology Center, University of Texas Southwestern Medical Center, Dallas, TX 75235
| | - E. Sally Ward
- Department of Microbiology and Cancer Immunobiology Center, University of Texas Southwestern Medical Center, Dallas, TX 75235
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Bond AP, Corlett L, Curnow SJ, Spack E, Willcox N, Newsom-Davis J. Diverse patterns of unresponsiveness in an acetylcholine receptor-specific T-cell clone from a myasthenia gravis patient after engaging the T-cell receptor with three different ligands. J Neuroimmunol 1998; 82:182-90. [PMID: 9585815 DOI: 10.1016/s0165-5728(97)00202-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Using an acetylcholine receptor-specific T-cell clone (TCC) from a myasthenia gravis patient, we have compared the induction of unresponsiveness by three agents: an anti-V beta monoclonal antibody (mAb), complexes of MHC class II with specific peptide (DR4:peptide) and free peptide. Pretreatment with each agent without antigen-presenting cells specifically rendered the TCC unresponsive to a subsequent optimal stimulus. A substantial proportion of the DR4:peptide pretreated cells underwent apoptosis and the remainder were profoundly unresponsive. Apoptosis was less prominent after pretreatment with free peptide and was not significant with anti-V beta mab; with both, the unresponsiveness was transient in the survivors. These diverse effects of engaging the T-cell receptor in the absence of costimulation suggest that these agents act via different mechanisms, and give insights to the potential for specific immunotherapy.
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Affiliation(s)
- A P Bond
- Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, UK
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Stöckel J, Döring K, Malotka J, Jähnig F, Dornmair K. Pathway of detergent-mediated and peptide ligand-mediated refolding of heterodimeric class II major histocompatibility complex (MHC) molecules. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 248:684-91. [PMID: 9342218 DOI: 10.1111/j.1432-1033.1997.t01-2-00684.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We investigated the mechanism of refolding and reassembly of recombinant alpha and beta chains of the class II major histocompatibility molecules (MHC-II) HLA-DRB5*0101. Both chains were expressed in the cytosol of Escherichia coli, purified in urea and SDS, and reassembled to functional heterodimers by replacement of SDS by mild detergents, incubation in a redox-shuffling buffer and finally by oxidation and removal of detergent. Refolding was mediated by mild detergents and by peptide ligands. Early stages of structure formation were characterized by circular dichroism, fluorescence, and time-resolved fluorescence anisotropy decay (FAD) spectroscopies. We found that formation of secondary structure was detectable after replacement of SDS by mild detergents. At that stage the alpha and beta chains were still monomeric, the buffer was strongly reducing, and the folding intermediates did not yet interact with peptide ligands. Formation of folding intermediates capable of interacting with peptide ligands was detected after adjusting the redox potential with oxidized glutathione and incubation in mild detergents. We conclude that at that stage a tertiary structure close to the native structure is formed at least locally. The nature and concentration of detergent critically determined the refolding efficiency. We compared detergents with different carbohydrate headgroups, and with aliphatic chains ranging from C6 to C14 in length. For each of the detergents we observed a narrow concentration range for mediating refolding. Surprisingly, detergents with long aliphatic chains had to be used at higher concentrations than short-chain detergents, indicating that increasing the solubility of folding intermediates is not the only function of detergents during a refolding reaction. We discuss structure formation and interactions of detergents with stable folding intermediates. Understanding such interactions will help to develop rational strategies for refolding hydrophobic or oligomeric proteins.
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Affiliation(s)
- J Stöckel
- Max-Planck-Institut für Psychiatrie, Abteilung Neuroimmunologie, Martinsried, Germany
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Arimilli S, Mumm JB, Nag B. Antigen-specific apoptosis in immortalized T cells by soluble MHC class II-peptide complexes. Immunol Cell Biol 1996; 74:96-104. [PMID: 8934660 DOI: 10.1038/icb.1996.13] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The recognition of T cell receptors (TCR) by purified major histocompatibility complex (MHC) class II-peptide complexes in the absence of costimulatory signals leads to the induction of T cell non-responsiveness or anergy. In a recent study using human T cell clones, it was observed that prolonged incubation of resting T cells with soluble MHC II-peptide complexes appears to result in T cell apoptosis. The present study shows that the engagement of TCR by soluble MHC II-peptide complexes also results in antigen-specific apoptosis in immortalized T cells. Apoptosis was demonstrated in a herpes saimiri virus (HSV) transformed human T cell clone (SS8T) restricted for HLA-DR2 in association with an epitope from the myelin basic protein [MBP(84-102)]. A dose- and time-dependent T cell death was observed upon incubation of SS8T cloned T cells with purified complexes of native human HLA-DR2 and MBP(83-102)Y83 peptide. The specificity of T cell apoptosis was demonstrated by exposing SS8T cells with DR2 alone and DR2 bound to another high affinity epitope [MBP(124-143)] from the same MBP. Recently, we have shown that the complexes of HLA-DR2 and [MBP(83-102)Y83] can be reconstituted by refolding Escherichia coli expressed individual DR2 alpha and beta (B5*0101) polypeptide chains lacking the transmembrane region. When SS8T cloned T cells were exposed to purified reconstituted rDR2.MBP(83-102)Y83 complexes, similar apoptosis of T cells was observed. Agarose gel analysis of T cells incubated with complexes showed a degradation of celluar deoxyribonucleic acid (DNA) to oligonucleosomal bands, a characteristic of apoptosis. The quantitative detection of DNA strand breaks was performed by pulsing T cells with 5-bromo-2'-deoxyuridine (BrdU) followed by the detection of BrdU-labelled DNA fragments using an antibody sandwich enzyme-linked immuno assay (ELISA). The fragmentation of DNA was also measured by double fluorescence flow cytometry by 3' end labelling of fragmented DNA with biotinylated-deoxyuridine triphosphate (dUTP) in the presence of terminal deoxynucleotide transferase (TdT) enzyme. The expression of the bcl-2 protein in SS8T cells following TCR engagement by soluble MHC II-peptide complexes was monitored by chemiluminescence blot analysis using anti-bcl-2 monoclonal antibody. Finally, the nucleosomal condensation of T cells following complex treatment, characteristics of typical apoptosis, was demonstrated by transmission electron microscopy. These results suggest that the binding of soluble MHC class II-peptide complexes to TCR induces antigen-specific apoptosis in transformed CD4 positive T cells in vitro. Such induction of apoptosis by soluble MHC II-peptide complexes may provide a novel therapeutic strategy to delete autoreactive T cells in various autoimmune diseases.
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Affiliation(s)
- S Arimilli
- Anergen Inc., Redwood City, California, USA
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Abstract
Synthetic peptides play an important role in many areas of biological research. Advances in synthetic chemistry and automation over the past few years have resulted in increasingly reliable and rapid syntheses. As a result, peptides are now frequently employed in immunological studies, structural studies, as enzyme substrates, in ligand/receptor studies, and as probes for a range of molecular interactions. This review describes solid-phase peptide synthesis and the applications of synthetic peptides in molecular biology and biochemistry.
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Affiliation(s)
- D C Hancock
- Biochemistry of the Cell Nucleus and Peptide Synthesis Laboratories, Imperial Cancer Research Fund, London, UK
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Arimilli S, Cardoso C, Mukku P, Baichwal V, Nag B. Refolding and reconstitution of functionally active complexes of human leukocyte antigen DR2 and myelin basic protein peptide from recombinant alpha and beta polypeptide chains. J Biol Chem 1995; 270:971-7. [PMID: 7529765 DOI: 10.1074/jbc.270.2.971] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Major histocompatibility complex (MHC) class II molecules are cell surface heterodimeric glycoproteins consisting of one alpha and one beta polypeptide chain of similar size. These molecules play a critical role in immune recognition by displaying processed antigens to CD4-positive T helper cells. Several attempts to express the MHC class II molecules by recombinant methods in various systems resulted in either failure or poor recovery of the intact heterodimer. The present study describes our successful effort to refold and reconstitute HLA DR2 heterodimer from individually expressed alpha and beta polypeptide chains lacking the transmembrane hydrophobic regions in Escherichia coli, in the presence of an immunodominant epitope analog from human myelin basic protein (b-MBP(83-102)Y83). The reconstituted DR2 heterodimer complex was selectively purified from unfolded alpha and beta chains using heterodimer-specific monoclonal antibody (L243) coupled to a solid support. The detection of two polypeptide chains in the purified refolded DR2-peptide complex preparations was accomplished by Western blot analysis and enzyme-linked immunosorbent assay using heterodimer- and chain-specific polyclonal antibodies, and the presence of equimolar amounts of both alpha chain and beta chain in the reconstituted complex preparation was confirmed by a double label experiment. The quantitation of the bound peptide in complex preparation was measured by incubating two chains in the presence of 125I-labeled peptide. An increase in the yield of refolded and reconstituted DR2-peptide complexes was observed with increasing peptide concentration in the reaction mixture. Finally, the functional activity of the reconstituted DR2 complexes was measured by their ability to stimulate gamma-interferon production by SS8T cloned T cells in an antigen-specific and dose-dependent manner. These results demonstrate that biologically active complexes of human DR2.b-MBP (83-102)Y83 can be prepared by proper folding of human leukocyte antigen DR2 alpha and beta chains in the presence of antigenic peptide. The yield of such DR2 heterodimers with bound peptide is several thousand-fold higher over native DR2 purified from transformed B cells. Since purified MHC class II-peptide complexes have been shown to prevent autoimmune diseases in various animal models, reconstituted heterodimer complexes may have significant clinical relevance in antigen-specific treatment of various autoimmune diseases. In addition, such complexes with increased yield will provide better understanding of the trimolecular interactions between MHC-peptide and T cell receptor.
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Affiliation(s)
- S Arimilli
- Anergen, Inc., Redwood City, California 94063
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Chapter 29. Applications of Biosensor Technology in Drug Discovery. ANNUAL REPORTS IN MEDICINAL CHEMISTRY 1995. [DOI: 10.1016/s0065-7743(08)60942-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Nicolle MW, Nag B, Sharma SD, Willcox N, Vincent A, Ferguson DJ, Newsom-Davis J. Specific tolerance to an acetylcholine receptor epitope induced in vitro in myasthenia gravis CD4+ lymphocytes by soluble major histocompatibility complex class II-peptide complexes. J Clin Invest 1994; 93:1361-9. [PMID: 7512979 PMCID: PMC294148 DOI: 10.1172/jci117112] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
In autoimmune disorders, inactivation of pathogenic antigen-specific T cells, rather than global immunosuppression, would be highly desirable. One way to achieve this would be to deliver the first antigen-specific signal to the T cell in the absence of the second costimulatory signal. Myasthenia gravis (MG) is a well-characterized autoimmune disease in which T cell-dependent autoantibodies are directed against the acetylcholine receptor (A ChR) at the neuromuscular junction. AChR-specific T cells have been cloned from MG patients, and in this study, we have induced long-lasting tolerance in vitro in one particular clone (PM-A1) with a known peptide epitope (alpha 144-163) and MHC class II restriction (DR4 Dw14.2 or 4.2) by using soluble MHC-class II peptide complexes. Preincubation of PM-A1 T cells with such complexes induced death by apoptosis in < or = 40-50% of the AChR-specific cells. Surviving cells remained refractory to stimulation with AChR-derived synthetic peptides or recombinant polypeptides for < or = 38 d after complex treatment. These effects were highly specific, dose-dependent and required > 2 h preincubation. The T cells could be protected from the tolerizing effects of complex by coincubation with DR-matched or -mismatched antigen-presenting cells. This work shows that antigen-specific T cells can be selectively killed or anergized using soluble MHC class II: peptide complexes. Such an antigen-specific therapy offers a rational approach to the immunotherapy of autoimmune or allergic disease in vivo.
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Affiliation(s)
- M W Nicolle
- Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, United Kingdom
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Intramolecular charge heterogeneity in purified major histocompatibility class II alpha and beta polypeptide chains. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36990-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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