1
|
Ettinger RA, Buitinga M, Vandamme C, Afonso G, Gomez R, Arribas-Layton D, Bissenova S, Speake C, Reijonen H, Kinnunen T, Overbergh L, Mallone R, Kwok WW, James EA. Technical Validation and Utility of an HLA Class II Tetramer Assay for Type 1 Diabetes: A Multicenter Study. J Clin Endocrinol Metab 2023; 109:183-196. [PMID: 37474341 DOI: 10.1210/clinem/dgad434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 06/28/2023] [Accepted: 06/17/2023] [Indexed: 07/22/2023]
Abstract
CONTEXT Validated assays to measure autoantigen-specific T-cell frequency and phenotypes are needed for assessing the risk of developing diabetes, monitoring disease progression, evaluating responses to treatment, and personalizing antigen-based therapies. OBJECTIVE Toward this end, we performed a technical validation of a tetramer assay for HLA-DRA-DRB1*04:01, a class II allele that is strongly associated with susceptibility to type 1 diabetes (T1D). METHODS HLA-DRA-DRB1*04:01-restricted T cells specific for immunodominant epitopes from islet cell antigens GAD65, IGRP, preproinsulin, and ZnT8, and a reference influenza epitope, were enumerated and phenotyped in a single staining tube with a tetramer assay. Single and multicenter testing was performed, using a clone-spiked specimen and replicate samples from T1D patients, with a target coefficient of variation (CV) less than 30%. The same assay was applied to an exploratory cross-sectional sample set with 24 T1D patients to evaluate the utility of the assay. RESULTS Influenza-specific T-cell measurements had mean CVs of 6% for the clone-spiked specimen and 11% for T1D samples in single-center testing, and 20% and 31%, respectively, for multicenter testing. Islet-specific T-cell measurements in these same samples had mean CVs of 14% and 23% for single-center and 23% and 41% for multicenter testing. The cross-sectional study identified relationships between T-cell frequencies and phenotype and disease duration, sex, and autoantibodies. A large fraction of the islet-specific T cells exhibited a naive phenotype. CONCLUSION Our results demonstrate that the assay is reproducible and useful to characterize islet-specific T cells and identify correlations between T-cell measures and clinical traits.
Collapse
Affiliation(s)
- Ruth A Ettinger
- Center for Translational Immunology, Benaroya Research Institute, Seattle, WA 98101, USA
| | - Mijke Buitinga
- Laboratory for Clinical and Experimental Endocrinology, KU Leuven, 3000 Leuven, Belgium
| | - Céline Vandamme
- Department of Clinical Microbiology, Institute of Clinical Medicine, University of Eastern Finland, 70210 Kuopio, Finland
| | - Georgia Afonso
- Diabetes and Autoimmunity Research Laboratory, Université Paris Cité, Institut Cochin, CNRS, INSERM, 75014 Paris, France
| | - Rebecca Gomez
- Center for Translational Immunology, Benaroya Research Institute, Seattle, WA 98101, USA
| | - David Arribas-Layton
- Department of Immunology and Theranostics, City of Hope Medical Center, Beckman Research Institute, Duarte, CA 91010, USA
| | - Samal Bissenova
- Laboratory for Clinical and Experimental Endocrinology, KU Leuven, 3000 Leuven, Belgium
| | - Cate Speake
- Center for Interventional Immunology, Benaroya Research Institute, Seattle, WA 98101, USA
| | - Helena Reijonen
- Department of Immunology and Theranostics, City of Hope Medical Center, Beckman Research Institute, Duarte, CA 91010, USA
| | - Tuure Kinnunen
- Department of Clinical Microbiology, Institute of Clinical Medicine, University of Eastern Finland, 70210 Kuopio, Finland
- Eastern Finland Laboratory Centre (ISLAB), 70210 Kuopio, Finland
| | - Lut Overbergh
- Laboratory for Clinical and Experimental Endocrinology, KU Leuven, 3000 Leuven, Belgium
| | - Roberto Mallone
- Diabetes and Autoimmunity Research Laboratory, Université Paris Cité, Institut Cochin, CNRS, INSERM, 75014 Paris, France
- Department of Internal Medicine, Assistance Publique Hôpitaux de Paris, Service de Diabétologie et Immunologie Clinique, Cochin Hospital, 75014 Paris, France
| | - William W Kwok
- Center for Translational Immunology, Benaroya Research Institute, Seattle, WA 98101, USA
| | - Eddie A James
- Center for Translational Immunology, Benaroya Research Institute, Seattle, WA 98101, USA
| |
Collapse
|
2
|
Ettinger RA, Liberman JA, Gunasekera D, Puranik K, James EA, Thompson AR, Pratt KP. FVIII proteins with a modified immunodominant T-cell epitope exhibit reduced immunogenicity and normal FVIII activity. Blood Adv 2018; 2:309-322. [PMID: 29444872 PMCID: PMC5858479 DOI: 10.1182/bloodadvances.2017013482] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 01/16/2018] [Indexed: 02/08/2023] Open
Abstract
Factor VIII (FVIII)-neutralizing antibodies (inhibitors) are a serious complication in hemophilia A (HA). The peptide FVIII2194-2213 contains an immunodominant HLA-DRA*01-DRB1*01:01 (DRB1*01:01)-restricted epitope recognized by CD4+ T-effector cells from HA subjects. The aim of this study was to identify amino acid substitutions to deimmunize this epitope while retaining procoagulant function and expression levels comparable to those of wild-type (WT) FVIII proteins. The shortest DRB1*01:01-binding peptide was FVIII2194-2205, and residues important for affinity were identified as F2196, M2199, A2201, and S2204. T-cell proliferation experiments with Ala-substituted FVIII2194-2205 peptides identified F2196A as a substitution that abrogated proliferation of clones specific for the WT sequence. T-cell clones that were stimulated by recombinant WT-FVIII-C2 (rWT-FVIII-C2) protein did not proliferate when cultured with rFVIII-C2-F2196A, indicating the immunogenic peptide includes a naturally processed T-cell epitope. Additional amino acid substitutions at F2196 and M2199 were evaluated by peptide-MHC class II (MHCII)-binding assays, T-cell proliferation assays, epitope prediction algorithms, and sequence homologies. Six B-domain-deleted (BDD)-FVIII proteins with substitutions F2196A, F2196L, F2196K, M2199A, M2199W, or M2199R were produced. Proliferation of T-cell clones and polyclonal lines in response to rBDD-FVIII-F2196K and rBDD-FVIII-M2199A was reduced compared with responses to WT-BDD-FVIII. The BDD-FVIII-F2196K sequence modification appears to be the most promising sequence variant tested here, due to its effectiveness at eliminating DRB1*01:01-restricted immunogenicity, low potential immunogenicity in the context of other MHCII alleles, expression level comparable to WT-BDD-FVIII, and retained procoagulant activity. These results provide proof of principle for the design of less immunogenic FVIII proteins targeted to specific subsets of HA patients.
Collapse
Affiliation(s)
- Ruth A Ettinger
- Bloodworks Northwest Research Institute, Seattle, WA
- Benaroya Research Institute, Seattle, WA
| | | | - Devi Gunasekera
- Bloodworks Northwest Research Institute, Seattle, WA
- Uniformed Services University of the Health Sciences, Bethesda, MD; and
| | - Komal Puranik
- Bloodworks Northwest Research Institute, Seattle, WA
| | | | - Arthur R Thompson
- Bloodworks Northwest Research Institute, Seattle, WA
- Division of Hematology, Department Medicine, University of Washington, Seattle, WA
| | - Kathleen P Pratt
- Bloodworks Northwest Research Institute, Seattle, WA
- Uniformed Services University of the Health Sciences, Bethesda, MD; and
- Division of Hematology, Department Medicine, University of Washington, Seattle, WA
| |
Collapse
|
3
|
Lewis KB, Hughes RJ, Epstein MS, Josephson NC, Kempton CL, Kessler CM, Key NS, Howard TE, Kruse-Jarres R, Lusher JM, Walsh CE, Watts RG, Ettinger RA, Pratt KP. Phenotypes of allo- and autoimmune antibody responses to FVIII characterized by surface plasmon resonance. PLoS One 2013; 8:e61120. [PMID: 23667433 PMCID: PMC3648518 DOI: 10.1371/journal.pone.0061120] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Accepted: 03/06/2013] [Indexed: 11/19/2022] Open
Abstract
Evidence of antibody isotype/subtype switching may provide prognostic value regarding the state of immune responses to therapeutic proteins, e.g. anti-factor VIII (FVIII) antibodies that develop in many hemophilia A patients, clinically termed “inhibitors”. A sensitive, high- information-content surface plasmon resonance (SPR) assay has been developed to quantify IgG subtype distributions and the domain specificity of anti-drug antibodies. Plasma samples from 22 subjects with an allo- or auto-immune reaction to FVIII were analyzed. Pre-analytical treatment protocols were developed to minimize non-specific binding and specific matrix interference due to von Willebrand factor-FVIII interactions. The dynamic range for IgG quantification was 0.2–5 µg/ml (∼1–33 nM), allowing characterization of inhibitor-positive samples. Subtype-specific monoclonal antibodies were used to quantify the IgG subtype distribution of FVIII-specific antibodies. Most samples obtained from multiply-infused inhibitor subjects contained IgG4 antibodies. Several distinct phenotypes were assigned based on the IgG subtype distribution: IgG1, IgG4, IgG1 & IgG4, and IgG1, IgG2 & IgG4. An IgG1-only response was found in mild/moderate HA subjects during early FVIII infusions, and analysis of serial samples followed antibody class switching as several subjects’ immune responses developed. Competition studies utilizing a recombinant FVIII-C2 domain indicated 40–80% of FVIII-specific antibodies in most samples were directed against this domain.
Collapse
Affiliation(s)
- Kenneth B. Lewis
- Puget Sound Blood Center Research Institute, Seattle, Washington, United States of America
| | - Richard J. Hughes
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
| | - Melinda S. Epstein
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
| | - Neil C. Josephson
- Puget Sound Blood Center Research Institute, Seattle, Washington, United States of America
- Division of Hematology, University of Washington, Seattle, Washington, United States of America
| | | | | | - Nigel S. Key
- University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Tom E. Howard
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California, United States of America
- Division of Hematology and Oncology, Department of Medicine, David Geffen School of Medicine at UCLA and Department of Pathology and Laboratory Medicine, Keck School of Medicine at USC, Los Angeles, California, United States of America
| | | | - Jeanne M. Lusher
- Wayne State University, Detroit, Michigan, United States of America
| | | | - Raymond G. Watts
- University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Ruth A. Ettinger
- Puget Sound Blood Center Research Institute, Seattle, Washington, United States of America
| | - Kathleen P. Pratt
- Puget Sound Blood Center Research Institute, Seattle, Washington, United States of America
- Division of Hematology, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| | | |
Collapse
|
4
|
Moralejo DH, Fuller JM, Rutledge EA, Van Yserloo B, Ettinger RA, Jensen R, Osborne W, Kwitek A, Lernmark A. BB rat Gimap gene expression in sorted lymphoid T and B cells. Life Sci 2011; 89:748-54. [PMID: 21925515 DOI: 10.1016/j.lfs.2011.08.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 08/15/2011] [Accepted: 08/28/2011] [Indexed: 11/15/2022]
Abstract
AIMS The Gimap gene family has been shown to be integral to T cell survival and development. A frameshift mutation in Gimap5, one of seven members of the Gimap family, results in lymphopenia and is a prerequisite for spontaneous type 1 diabetes (T1D) in the BioBreeding (BB) rat. While not contributing to lymphopenia, the Gimap family members proximal to Gimap5, encompassed within the Iddm39 quantitative trait locus (QTL), have been implicated in T1D. We hypothesized that expression of the Gimap family members within the Iddm39 QTL, during thymocyte development as well as in peripheral T and B cells contribute to T1D. MAIN METHODS Cell sorted subpopulations were analyzed by quantitative real time (qRT) PCR. KEY FINDINGS Gimap4 expression was reduced in DR.(lyp/lyp) rat double negative, double positive and CD8 single positive (SP) thymocytes while expression of Gimap8, Gimap6, and Gimap7 was reduced only in CD8 SP thymocytes. Interestingly, expression of the entire Gimap gene family was reduced in DR.(lyp/lyp) rat peripheral T cells compared to non-lymphopenic, non-diabetic DR.(+/+) rats. With the exception of Gimap6, the Gimap family genes were not expressed in B cells from spleen and mesenteric lymph node (MLN). Expression of Gimap9 was only detected in hematopoietic cells of non B cell lineage such as macrophage, dendritic or NK cells. SIGNIFICANCE These results suggest that lack of the Gimap5 protein in the DR.(lyp/lyp) congenic rat was associated with impaired expression of the entire family of Gimap genes and may regulate T cell homeostasis in the peripheral lymphoid organs.
Collapse
Affiliation(s)
- Daniel H Moralejo
- Department of Comparative Medicine, University of Washington 1959 N.E. Pacific St., Box 357710, Seattle, WA 98195, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
5
|
James EA, van Haren SD, Ettinger RA, Fijnvandraat K, Liberman JA, Kwok WW, Voorberg J, Pratt KP. T-cell responses in two unrelated hemophilia A inhibitor subjects include an epitope at the factor VIII R593C missense site. J Thromb Haemost 2011; 9:689-99. [PMID: 21251204 PMCID: PMC4323178 DOI: 10.1111/j.1538-7836.2011.04202.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Development of neutralizing anti-factor (F)VIII antibodies ('inhibitors') is a serious clinical problem in hemophilia A. Increased inhibitor risk has been associated with certain FVIII missense substitutions, including R593C in the A2 domain. OBJECTIVES The aim of the present study was to identify T-cell epitopes in FVIII and characterize T-cell responses in two unrelated hemophilia A subjects sharing F8-R593C and HLA-DRB1*1101 genotypes. We hypothesized that the hemophilic substitution site coincides with an important T-cell epitope. PATIENTS/METHODS The binding affinities of peptides for recombinant HLA-DR proteins were measured and compared with epitope prediction results. CD4+ T cells were stimulated using peptides and stained with fluorescent, peptide-loaded tetramers. RESULTS The inhibitor subjects, but not HLA-matched controls, had high-avidity HLA-DRB1*1101-restricted T-cell responses against FVIII(589-608), which contains the hemophilic missense site. Antigen-specific T cells secreted Th1 and Th2 cytokines and proliferated in response to FVIII and FVIII(592-603). FVIII(589-608) bound with physiologically relevant (micromolar) IC(50) values to recombinant DR0101, DR1101 and DR1501 proteins. CONCLUSIONS Hemophilia A patients with R593C missense substitutions and these HLA haplotypes had an increased incidence of inhibitors in our cohorts, supporting a paradigm in which presentation of FVIII epitopes containing the wild-type R593 influences inhibitor risk in this hemophilia A sub-population.
Collapse
Affiliation(s)
- E A James
- Benaroya Research Institute, Seattle, WA, USA
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Ettinger RA, James EA, Kwok WW, Thompson AR, Pratt KP. HLA-DR-restricted T-cell responses to factor VIII epitopes in a mild haemophilia A family with missense substitution A2201P. Haemophilia 2011; 16:44-55. [PMID: 20536985 DOI: 10.1111/j.1365-2516.2008.01905.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An HLA-DRA-DRB1*0101-restricted T-cell epitope in the factor VIII (FVIII) C2 domain occurred in a mild haemophilia A patient with missense substitution FVIII-A2201P. His T cells responded to synthetic peptides FVIII(2186-2205) and FVIII(2194-2213) (J Thromb Haemost 2007; 5: 2399). T cells from family members with genotype FVIII-A2201P were analysed to determine if FVIII-specific T cells occur in individuals with a haemophilic mutation but no clinically significant inhibitor response. Fluorescent MHC class II tetramers corresponding to subjects'HLA-DRB1 types were loaded with 20-mer peptides and utilized to label antigen-specific CD4+ T cells. T-cell responses to peptides spanning the FVIII-C2 sequence were evaluated. T cells recognizing specific peptides were cloned, and antigen specificity was verified by proliferation assays. Plasma and/or purified IgG samples were tested for FVIII inhibitory activity. CD4+ T cells and T-cell clones from two brothers who shared the DRB1*0101 allele responded to FVIII(2194-2213). A haemophilic cousin's HLA-DRA-DRB1*1104-restricted response to FVIII(2202-2221) was detected only when CD4+CD25+ cells were depleted. A great uncle and two obligate carriers had no detectable FVIII-C2-specific T cells. Concentrated IgG from the brother without a clinical inhibitor response showed a low-titre FVIII inhibitor. FVIII-specific T cells and inhibitory IgG were found in a previously infused, haemophilic subject who had a sub-clinical FVIII inhibitor. CD4+CD25+ depleted T cells from a non-infused haemophilic cousin recognized an overlapping FVIII epitope, indicating a latent HLA-DRA-DRB1*1104-restricted T-cell response to FVIII. Specific T-cell responses to FVIII can occur without clinically significant inhibitors.
Collapse
Affiliation(s)
- R A Ettinger
- Puget Sound Blood Center, BRI Rm 3016, 921 Terry Avenue, Seattle, WA 98104, USA
| | | | | | | | | |
Collapse
|
7
|
Ettinger RA, James EA, Liberman JA, Kwok WW, Thompson AR, Pratt KP. Distinct lineages of human T-cell clones, including Th17/Th1 cells, isolated at different stages of anti-factor VIII immune responses (48.26). The Journal of Immunology 2009. [DOI: 10.4049/jimmunol.182.supp.48.26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
Approximately 25% of hemophilia A patients, who lack functional factor VIII (FVIII), develop neutralizing antibodies after receiving therapeutic infusions of FVIII. HLA-DRA-DRB1*0101-restricted T-cell clones that respond to FVIII2194-2213 were isolated from a hemophilia A subject (the proband) ~5 and 21 months following his development of a high-titer FVIII neutralizing antibody response, and from his brother who has not developed a clinically significant antibody response. Three clones obtained from the proband at 5 months were TH17/TH1-polarized and two were TH1/TH2-polarized. The 8 proband clones isolated at 21 months were TH2-polarized, indicating T-cell lineage changes over time. The 6 clones from the brother were TH1-polarized, indicating that B-cell tolerance to FVIII can be maintained even with circulating antigen-specific TH1-polarized cells. Several TCRBV-D-J junction sequences were identified suggesting differences in TCR interaction with the MHC class II-peptide complex. Current investigations are examining the response of clones to altered peptide ligands. This is the first evidence that TH17/TH1-polarized cells play a role in hemophilic immune responses to FVIII; it is also the first detailed characterization of antigen-specific TH17/TH1 clones isolated using standard culture conditions.
Research Support: Bayer Hemophilia Award, CSL Behring Hemophilia Research Award, NIH.
Collapse
Affiliation(s)
- Ruth A Ettinger
- 1Puget Sound Blood Center, Seattle, WA
- 2Benaroya Research Institute, Seattle, WA
| | | | | | | | | | | |
Collapse
|
8
|
James EA, Kwok WW, Ettinger RA, Thompson AR, Pratt KP. T-cell responses over time in a mild hemophilia A inhibitor subject: epitope identification and transient immunogenicity of the corresponding self-peptide. J Thromb Haemost 2007; 5:2399-407. [PMID: 18034765 DOI: 10.1111/j.1538-7836.2007.02762.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Antibodies that neutralize factor (F) VIII activity, clinically referred to as 'inhibitors', complicate the treatment of hemophilia A patients; current tolerance and bypass strategies are extremely costly and sometimes ineffective. The development of inhibitors requires T-cell help. OBJECTIVES We characterized T-cell responses of a subject with mild hemophilia A with missense genotype A2201P for one year following his initial inhibitor response, with the goals of defining the primary epitope(s) and its (their) MHC Class II restriction. We investigated the possible involvement of regulatory T cells in modulating immune responses. PATIENTS/METHODS The subject developed high-titer FVIII-neutralizing antibodies (250 BU mL(-1)) that declined over time to 8 BU ml(-1). His clotting activity was initially impaired (3%) but returned to baseline (8-10%) within four weeks. MHC Class II tetramers were used to analyze his CD4 T cells, which were stimulated with peptides spanning the C2 domain. Responses of total and CD25-depleted CD4 cells to sequences containing A2201 (native), P2201 (hemophilic), and other predicted T-cell epitopes were evaluated. RESULTS AND CONCLUSIONS An HLA-DRA-DRB1*0101 restricted T-cell epitope containing the wild-type A2201 sequence was identified. Interestingly, peptides containing A2201 were recognized by CD4 T cells at all time points, whereas a P2201 peptide was recognized only near the initial peak response. The responsiveness of CD25-depleted CD4 cells to an A2201 peptide was enhanced 11 and 19 weeks following inhibitor detection, suggesting the possible involvement of CD4+CD25+ regulatory T cells in modulating immune responses. Patient-derived T-cell clones proliferated in response to C2 protein and to peptides containing A2201 but not P2201.
Collapse
Affiliation(s)
- E A James
- Benaroya Research Institute, Seattle, WA 98104, USA
| | | | | | | | | |
Collapse
|
9
|
Maruyama T, Oak S, Hall TR, Banga JP, Ortqvist E, Ettinger RA, Endl J, Hampe CS. Autoantibody epitopes to the smaller isoform of glutamate decarboxylase do not differ in Swedish and Japanese type 1 diabetes patients and may be associated with high-risk human leucocyte antigen class II alleles. Clin Exp Immunol 2007; 150:416-21. [PMID: 17956579 DOI: 10.1111/j.1365-2249.2007.03527.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Type 1 diabetes (T1D) is an autoimmune disease with a strong human leucocyte antigen (HLA) class II association. Depending on geographic locations, the disease-associated HLA class II alleles vary. We evaluated the beta cell-specific autoimmunity reflected in autoantibodies directed to the smaller isoform of glutamate decarboxylase (GAD65) in Japanese and Swedish T1D patients. GAD65Ab epitope specificities were assessed using GAD65-specific recombinant Fab. GAD65Ab epitope specificities did not differ between Swedish and Japanese patients. Only recognition of the MICA-4-defined middle epitope was significantly stronger in the Japanese T1D patient group compared to the Swedish T1D patients (P = 0.001). Binding to the b96.11-defined middle epitope was substantial in both groups and showed significant associations with high-risk HLA class II haplotypes. In the Japanese T1D group the association was with haplotype DRB1*0802-DQB1*0302 (P = 0.0008), while in the Swedish T1D patients binding to the b96.11-defined epitope as associated with the presence of high-risk HLA genotypes DR3-DQB1*0201 and/or DR4-DQB1*0302 (P = 0.02). A significant association between reduction in binding in the presence of recombinant Fab (rFab) DPD and high-risk allele DQB1*0201 was found (P = 0.008) in the Swedish T1D patients only. We hypothesize that epitope-specific autoantibodies effect the peptide presentation on HLA class II molecules by modulating antigen uptake and processing. Molecular modelling of the high-risk HLA class II molecules will be necessary to test whether these different molecules present similar peptide-binding specificities.
Collapse
Affiliation(s)
- T Maruyama
- Department of Internal Medicine, Saitama Social Insurance Hospital, Saitama, Japan
| | | | | | | | | | | | | | | |
Collapse
|
10
|
Ettinger RA, Papadopoulos GK, Moustakas AK, Nepom GT, Kwok WW. Allelic variation in key peptide-binding pockets discriminates between closely related diabetes-protective and diabetes-susceptible HLA-DQB1*06 alleles. J Immunol 2006; 176:1988-98. [PMID: 16424231 DOI: 10.4049/jimmunol.176.3.1988] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
HLA-DQA1*0102-DQB1*0602 is associated with protection against type 1 diabetes (T1D). A similar allele, HLA-DQA1*0102-DQB1*0604, contributes to T1D susceptibility in certain populations but differs only at seven amino acids from HLA-DQA1*0102-DQB1*0602. Five of these polymorphisms are found within the peptide-binding groove, suggesting that differences in peptide binding contribute to the mechanism of their association with T1D. In this study, we determine the peptide-binding motif for HLA-DQA1*0102-DQB1*0604 allelic protein (DQ0604) in comparison to the established HLA-DQA1*0102-DQB1*0602 (DQ0602) motif using binding assays with model peptides from T1D autoantigens and homology modeling using the coordinates of the DQ0602-hypocretin 1-13 crystal structure. The peptide binding preferences were deduced with a peptide from insulin that bound both with a 2- to 3-fold difference in avidity using the same amino acids in the peptide as anchors. Peptide binding differences directly influenced by the polymorphisms in or nearby pockets 1, 6, and 9 were observed. In pocket 1, DQ0604 was better able to accommodate aromatic residues due to the beta86 and beta87 polymorphisms. A negatively charged amino acid was preferred by DQ0604 in pocket 6 due to the positively charged beta30His. In pocket 9, DQ0604 preferred aromatic amino acids due to the beta9 and beta30 polymorphisms and had low tolerance of acidic residues. beta57Val in DQ0604 functions differently than beta57Ala, in that it pushes alpha76Arg outside of the pocket, preventing the formation of a salt bridge with an acidic amino acid in the peptide. This study furthers our understanding of the structure-function relationships of MHC class II polymorphisms.
Collapse
Affiliation(s)
- Ruth A Ettinger
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA.
| | | | | | | | | |
Collapse
|
11
|
Ettinger RA, Moustakas AK, Lobaton SD. Open reading frame sequencing and structure-based alignment of polypeptides encoded by RT1-Bb, RT1-Ba, RT1-Db, and RT1-Da alleles. Immunogenetics 2004; 56:585-96. [PMID: 15517241 DOI: 10.1007/s00251-004-0725-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Revised: 09/13/2004] [Indexed: 10/26/2022]
Abstract
MHC class II genes are major genetic components in rats developing autoimmunity. The majority of rat MHC class II sequencing has focused on exon 2, which forms the first external domain. Sequence of the complete open reading frame for rat MHC class II haplotypes and structure-based alignment is lacking. Herein, the complete open reading frame for RT1-Bbeta, RT1-Balpha, RT1-Dbeta, and RT1-Dalpha was sequenced from ten different rat strains, covering eight serological haplotypes, namely a, b, c, d, k, l, n, and u. Each serological haplotype was unique at the nucleotide level of the sequenced RT1-B/D region. Within individual genes, the number of alleles identified was seven, seven, six, and three and the degree of amino-acid polymorphism between allotypes for each gene was 22%, 16%, 19%, and 0.4% for RT1-Bbeta, RT1-Balpha, RT1-Dbeta, and RT1-Dalpha, respectively. The extent and distribution of amino-acid polymorphism was comparable with mouse and human MHC class II. Structure-based alignment identified the beta65-66 deletion, the beta84a insertion, the alpha9a insertion, and the alpha1a-1c insertion in RT1-B previously described for H2-A. Rat allele-specific deletions were found at RT1-Balpha76 and RT1-Dbeta90-92. The mature RT1-Dbeta polypeptide was one amino acid longer than HLA-DRB1 due to the position of the predicted signal peptide cleavage site. These data are important to a comprehensive understanding of MHC class II structure-function and for mechanistic studies of rat models of autoimmunity.
Collapse
Affiliation(s)
- Ruth A Ettinger
- Robert H. Williams Lab, Department of Immunology, University of Washington, Box 357710, 1959 NE Pacific St, HSB K-165, Seattle, WA 98195-7710, USA.
| | | | | |
Collapse
|
12
|
Michalkiewicz M, Michalkiewicz T, Ettinger RA, Rutledge EA, Fuller JM, Moralejo DH, Van Yserloo B, MacMurray AJ, Kwitek AE, Jacob HJ, Lander ES, Lernmark A. Transgenic rescue demonstrates involvement of the Ian5 gene in T cell development in the rat. Physiol Genomics 2004; 19:228-32. [PMID: 15328390 DOI: 10.1152/physiolgenomics.00126.2004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A single point mutation in a novel immune-associated nucleotide gene 5 ( Ian5) coincides with severe T cell lymphopenia in BB rats. We used a transgenic rescue approach in lymphopenic BB-derived congenic F344. lyp/ lyp rats to determine whether this mutation is responsible for lymphopenia and to establish the functional importance of this novel gene. A 150-kb P1 artificial chromosome (PAC) transgene harboring a wild-type allele of the rat Ian5 gene restored Ian5 transcript and protein levels, completely rescuing the T cell lymphopenia in the F344. lyp/ lyp rats. This successful complementation provides direct functional evidence that the Ian5 gene product is essential for maintaining normal T cell levels. It also demonstrates that transgenic rescue in the rat is a practical and definitive method for revealing the function of a novel gene.
Collapse
Affiliation(s)
- Mieczyslaw Michalkiewicz
- Department of Physiology, Human Molecular and Genetics Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226-0509, USA.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
MacMurray AJ, Moralejo DH, Kwitek AE, Rutledge EA, Van Yserloo B, Gohlke P, Speros SJ, Snyder B, Schaefer J, Bieg S, Jiang J, Ettinger RA, Fuller J, Daniels TL, Pettersson A, Orlebeke K, Birren B, Jacob HJ, Lander ES, Lernmark A. Lymphopenia in the BB rat model of type 1 diabetes is due to a mutation in a novel immune-associated nucleotide (Ian)-related gene. Genome Res 2002; 12:1029-39. [PMID: 12097339 PMCID: PMC186618 DOI: 10.1101/gr.412702] [Citation(s) in RCA: 176] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The BB (BioBreeding) rat is one of the best models of spontaneous autoimmune diabetes and is used to study non-MHC loci contributing to Type 1 diabetes. Type 1 diabetes in the diabetes-prone BB (BBDP) rat is polygenic, dependent upon mutations at several loci. Iddm1, on chromosome 4, is responsible for a lymphopenia (lyp) phenotype and is essential to diabetes. In this study, we report the positional cloning of the Iddm1/lyp locus. We show that lymphopenia is due to a frameshift deletion in a novel member (Ian5) of the Immune-Associated Nucleotide (IAN)-related gene family, resulting in truncation of a significant portion of the protein. This mutation was absent in 37 other inbred rat strains that are nonlymphopenic and nondiabetic. The IAN gene family, lying within a tight cluster on rat chromosome 4, mouse chromosome 6, and human chromosome 7, is poorly characterized. Some members of the family have been shown to be expressed in mature T cells and switched on during thymic T-cell development, suggesting that Ian5 may be a key factor in T-cell development. The lymphopenia mutation may thus be useful not only to elucidate Type 1 diabetes, but also in the function of the Ian gene family as a whole.
Collapse
MESH Headings
- Amino Acid Sequence
- Animals
- Animals, Congenic/genetics
- Apoptosis Regulatory Proteins
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/genetics
- Disease Models, Animal
- GTP-Binding Proteins/biosynthesis
- GTP-Binding Proteins/genetics
- Hematopoietic Stem Cells/chemistry
- Hematopoietic Stem Cells/metabolism
- Humans
- Lymphopenia/etiology
- Lymphopenia/genetics
- Mice
- Molecular Sequence Data
- Protein Tyrosine Phosphatase, Non-Receptor Type 1
- Protein Tyrosine Phosphatase, Non-Receptor Type 22
- Protein Tyrosine Phosphatases/genetics
- Rats
- Rats, Inbred BB
- Rats, Inbred F344
- Rats, Inbred LEC
- Rats, Inbred OLETF
- Sequence Deletion/genetics
Collapse
Affiliation(s)
- Armand J MacMurray
- Robert H. Williams Laboratory, Department of Medicine, University of Washington, Seattle, Washington 98195, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Reichstetter S, Papadopoulos GK, Moustakas AK, Swanson E, Liu AW, Beheray S, Ettinger RA, Nepom GT, Kwok WW. Mutational analysis of critical residues determining antigen presentation and activation of HLA-DQ0602 restricted T-cell clones. Hum Immunol 2002; 63:185-93. [PMID: 11872236 DOI: 10.1016/s0198-8859(01)00377-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Three different HLA-DQ0602 restricted T-lymphocyte clones (clones 5, 44, and 48) specific for two different Herpes simplex virus type 2 (HSV-2) VP16 peptides were used in a series of proliferation assays with BLS-1 cell lines expressing mutated HLA-DQ0604 molecules as APC. Up to four residues in the peptide-binding region of DQ0604 were replaced by the respective DQ0602 residue. For all three clones, residue beta70 played a crucial role in TCR recognition; beta30 and beta57 were important, although beta86 was less significant. Clone 5 and 48, specific to the HSV-2 VP16 369--379 peptide, responded to the same mutated DQ0604 molecules. Both clones could be stimulated only when the antigen presenting DQ molecule contained the DQ0602-like Gly at position beta70. Stimulation of clone 44, which recognized a different HSV-2 VP16 epitope (VP16 40-50), was less restricted. Molecular homology modeling showed that the beta70Arg of DQ0604 partially covered the peptide around P5/P6. Interactions of beta70 with residues from the antigen-peptide and polymorphic residues at positions beta30 and beta57 can modulate this effect. Supported by molecular modeling data, we conclude that the distinct molecular topography of DQ0602 is not contributed by a single residue, but rather the interactions of various polymorphic DQ residues with particular antigenic peptides.
Collapse
|
15
|
Ettinger RA, Nepom GT. Molecular aspects of HLA class II alphabeta heterodimers associated with IDDM susceptibility and protection. Rev Immunogenet 2001; 2:88-94. [PMID: 11324697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
HLA-DQ alleles are strongly associated with IDDM susceptibility and protection. Studies assessing the molecular properties of HLA-DR, a HLA class II locus in linkage disequilibrium with HLA-DQ, have made substantial contributions toward elucidating the structure and function of HLA class II molecules. Reports on the molecular properties of HLA-DQ are now following and have revealed interesting observations regarding the stability of HLA-DQ alphabeta heterodimers. Future work is expected to provide an understanding of the mechanism by which HLA-DQ is associated with IDDM susceptibility and protection.
Collapse
Affiliation(s)
- R A Ettinger
- Virginia Mason Research Center and Department of Immunology, University of Washington School of Medicine, Seattle 98195-7710, USA.
| | | |
Collapse
|
16
|
Reichstetter S, Ettinger RA, Liu AW, Gebe JA, Nepom GT, Kwok WW. Distinct T cell interactions with HLA class II tetramers characterize a spectrum of TCR affinities in the human antigen-specific T cell response. J Immunol 2000; 165:6994-8. [PMID: 11120826 DOI: 10.4049/jimmunol.165.12.6994] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The polyclonal nature of T cells expanding in an ongoing immune response results in a range of disparate affinities and activation potential. Recently developed human class II tetramers provide a means to analyze this diversity by direct characterization of the trimolecular TCR-peptide-MHC interaction in live cells. Two HSV-2 VP16(369-379)-specific, DQA1*0102/DQB1*0602 (DQ0602)-restricted T cell clones were compared by means of T cell proliferation assay and HLA-DQ0602 tetramer staining. These two clones were obtained from the same subject, but show different TCR gene usage. Clone 48 was 10-fold more sensitive to VP16(369-379) peptide stimulation than clone 5 as assayed by proliferation assays, correlating with differences in MHC tetramer binding. Clone 48 gave positive staining with the DQ0602/VP16(369-379) tetramer at either 23 or 37 degrees C. Weak staining was also observed at 4 degrees C. Clone 5 showed weaker staining compared with clone 48 at 37 degrees C, and no staining was observed at 23 degrees C or on ice. Receptor internalization was not required for positive staining. Competitive binding indicates that the cell surface TCR of clone 48 has higher affinity for the DQ0602/VP16(369-379) complex than clone 5. The higher binding affinity of clone 48 for the peptide-MHC complex also correlates with a slower dissociation rate compared with clone 5.
Collapse
Affiliation(s)
- S Reichstetter
- Virginia Mason Research Center and University of Washington School of Medicine, Seattle, WA 98101, USA
| | | | | | | | | | | |
Collapse
|
17
|
Ettinger RA, Liu AW, Nepom GT, Kwok WW. Beta 57-Asp plays an essential role in the unique SDS stability of HLA-DQA1*0102/DQB1*0602 alpha beta protein dimer, the class II MHC allele associated with protection from insulin-dependent diabetes mellitus. J Immunol 2000; 165:3232-8. [PMID: 10975839 DOI: 10.4049/jimmunol.165.6.3232] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Studies of the stability of HLA-DQ have revealed a correlation between SDS stability of MHC class II alphabeta dimers and insulin-dependent diabetes mellitus (IDDM) susceptibility. The MHC class II alphabeta dimer encoded by HLA-DQA1*0102/DQB1*0602 (DQ0602), which is a dominant protective allele in IDDM, exhibits the greatest SDS stability among HLA-DQ molecules in EBV-transformed B-lymphoblastoid cells and PBLs. DQ0602 is also uniquely SDS stable in the HLA-DM-deficient cell line, BLS-1. We addressed the molecular mechanism of the stability of DQ0602 in BLS-1. A panel of mutants based on the polymorphic differences between HLA-DQA1*0102/DQB1*0602 and HLA-DQA1*0102/DQB1*0604 were generated and expressed in BLS-1. An Asp at beta57 was found to be critical for SDS stability, whereas Tyr at beta30, Gly at beta70, and Ala at beta86 played secondary roles. Furthermore, the level of class II-associated invariant chain peptide bound to HLA-DQ did not correlate with SDS stability, suggesting that class II-associated invariant chain peptide does not play a direct role in the unique SDS stability of DQ0602. These results support a role for DQB1 codon 57 in HLA-DQ alphabeta dimer stability and IDDM susceptibility.
Collapse
Affiliation(s)
- R A Ettinger
- Virginia Mason Research Center and Department of Immunology, University of Washington School of Medicine, Seattle, WA 98101, USA.
| | | | | | | |
Collapse
|
18
|
Kwok WW, Liu AW, Novak EJ, Gebe JA, Ettinger RA, Nepom GT, Reymond SN, Koelle DM. HLA-DQ tetramers identify epitope-specific T cells in peripheral blood of herpes simplex virus type 2-infected individuals: direct detection of immunodominant antigen-responsive cells. J Immunol 2000; 164:4244-9. [PMID: 10754321 DOI: 10.4049/jimmunol.164.8.4244] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ag-specific CD4+ T cells are present in peripheral blood in low frequency, where they undergo recruitment and expansion during immune responses and in the pathogenesis of numerous autoimmune diseases. MHC tetramers, which constitute a labeled MHC-peptide ligand suitable for binding to the Ag-specific receptor on T cells, provide a novel approach for the detection and characterization of such rare cells. In this study, we utilized this technology to identify HLA DQ-restricted Ag-specific T cells in the peripheral blood of human subjects and to identify immunodominant epitopes associated with viral infection. Peptides representing potential epitope regions of the VP16 protein from HSV-2 were loaded onto recombinant DQ0602 molecules to generate a panel of Ag-specific DQ0602 tetramers. VP16 Ag-specific DQ-restricted T cells were identified and expanded from the peripheral blood of HSV-2-infected individuals, representing two predominant epitope specificities. Although the VP16 369-380 peptide has a lower binding affinity for DQ0602 molecules than the VP16 33-52 peptide, T cells that recognized the VP16 369-380 peptide occurred at a much higher frequency than those that were specific for the VP16 33-52 peptide.
Collapse
Affiliation(s)
- W W Kwok
- Virginia Mason Research Center, Seattle, WA 98101, USA.
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Ettinger RA, Liu AW, Nepom GT, Kwok WW. Exceptional stability of the HLA-DQA1*0102/DQB1*0602 alpha beta protein dimer, the class II MHC molecule associated with protection from insulin-dependent diabetes mellitus. J Immunol 1998; 161:6439-45. [PMID: 9834137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
HLA-DQ alleles are closely associated with susceptibility and resistance to insulin-dependent diabetes mellitus (IDDM) but the immunologic mechanisms involved are not understood. Structural studies of the IDDM-susceptible allele, HLA-DQA1*0301/DQB1*0302, have classified it as a relatively unstable dimer, particularly at neutral pH. This is reminiscent of studies in the nonobese diabetic mouse, in which I-A(g7) is relatively unstable, in contrast to other murine I-A alleles, suggesting a correlation between unstable MHC class II molecules and IDDM susceptibility. We have addressed this question by analysis of dimer stability patterns among various HLA-DQ molecules. In EBV-transformed B-lymphoblastoid cell lines and PBL, the protein encoded by the IDDM-protective allele HLA-DQA1*0102/DQB1*0602 was the most SDS stable when compared with other HLA-DQ molecules, including HLA-DQA1*0102/DQB1*0604, a closely related allele that is not associated with protection from IDDM. Expression of six different HLA-DQ allelic proteins and three different HLA-DR allelic proteins in the bare lymphocyte syndrome cell line, BLS-1, revealed that HLA-DQA1*0102/DQB1*0602 is SDS stable even in the absence of HLA-DM, while other HLA class II molecules are not. These results suggest that the molecular property of HLA-DQ measured by resistance to denaturation of the alphabeta dimer in SDS may play a role in IDDM protection.
Collapse
Affiliation(s)
- R A Ettinger
- Virginia Mason Research Center, Department of Immunology, University of Washington School of Medicine, Seattle 98101, USA
| | | | | | | |
Collapse
|
20
|
Ettinger RA, Liu AW, Nepom GT, Kwok WW. Exceptional Stability of the HLA-DQA1*0102/DQB1*0602 αβ Protein Dimer, the Class II MHC Molecule Associated with Protection from Insulin-Dependent Diabetes Mellitus. The Journal of Immunology 1998. [DOI: 10.4049/jimmunol.161.11.6439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
HLA-DQ alleles are closely associated with susceptibility and resistance to insulin-dependent diabetes mellitus (IDDM) but the immunologic mechanisms involved are not understood. Structural studies of the IDDM-susceptible allele, HLA-DQA1*0301/DQB1*0302, have classified it as a relatively unstable dimer, particularly at neutral pH. This is reminiscent of studies in the nonobese diabetic mouse, in which I-Ag7 is relatively unstable, in contrast to other murine I-A alleles, suggesting a correlation between unstable MHC class II molecules and IDDM susceptibility. We have addressed this question by analysis of dimer stability patterns among various HLA-DQ molecules. In EBV-transformed B-lymphoblastoid cell lines and PBL, the protein encoded by the IDDM-protective allele HLA-DQA1*0102/DQB1*0602 was the most SDS stable when compared with other HLA-DQ molecules, including HLA-DQA1*0102/DQB1*0604, a closely related allele that is not associated with protection from IDDM. Expression of six different HLA-DQ allelic proteins and three different HLA-DR allelic proteins in the bare lymphocyte syndrome cell line, BLS-1, revealed that HLA-DQA1*0102/DQB1*0602 is SDS stable even in the absence of HLA-DM, while other HLA class II molecules are not. These results suggest that the molecular property of HLA-DQ measured by resistance to denaturation of the αβ dimer in SDS may play a role in IDDM protection.
Collapse
Affiliation(s)
- Ruth A. Ettinger
- *Virginia Mason Research Center and
- †Department of Immunology, University of Washington School of Medicine, Seattle, WA 98101
| | - Andrew W. Liu
- *Virginia Mason Research Center and
- †Department of Immunology, University of Washington School of Medicine, Seattle, WA 98101
| | - Gerald T. Nepom
- *Virginia Mason Research Center and
- †Department of Immunology, University of Washington School of Medicine, Seattle, WA 98101
| | | |
Collapse
|
21
|
Ettinger RA, Kwok WW. A peptide binding motif for HLA-DQA1*0102/DQB1*0602, the class II MHC molecule associated with dominant protection in insulin-dependent diabetes mellitus. J Immunol 1998; 160:2365-73. [PMID: 9498778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
HLA-DQA1*0102/DQB1*0602 (DQ0602) is observed at a decreased frequency in insulin-dependent diabetes mellitus in different ethnic groups, suggesting a protective role for DQ0602. Analysis of overlapping peptides from human insulin found that insulin B(1-15) bound well to DQ0602 and exhibited a high degree of allelic specificity. Truncation analysis of insulin B(1-15) identified insulin B(5-15) as the minimal peptide for DQ0602 binding. Insulin B(5-15) bound to DQ0602 with an apparent KD of 0.7 to 1.0 microM and peptide binding reached equilibrium at 96 h. Single arginine substitutions at each position of the insulin B(5-15) peptide identified amino acids 6, 8, 9, 11, and 14 (relative positions P1, P3, P4, P6, and P9) as important for binding. Extensive substitutions for each of these amino acids revealed that amino acids 11 and 14 (P6 and P9) exhibited the highest specificity. Amino acid 11 (P6) preferred large aliphatic amino acids, while amino acid 14 (P9) preferred smaller aliphatic and hydroxyl amino acids. Binding of an overlapping series of peptides from a randomly chosen protein, the herpes simplex virus-2 tegument protein UL49, correlated completely with the presence or absence of the DQ0602 peptide binding motif. Peptides 11 amino acids long were selected from GAD65, IA-2, and proinsulin, that contained the DQ0602 peptide binding motif. Of these, 79% (19 of 24) were able to bind DQ0602. This study identifies a peptide binding motif for DQ0602 and peptides from insulin-dependent diabetes mellitus autoantigens that bind DQ0602 in vitro.
Collapse
Affiliation(s)
- R A Ettinger
- Virginia Mason Research Center, Seattle, WA 98101, USA
| | | |
Collapse
|
22
|
Ettinger RA, Kwok WW. A Peptide Binding Motif for HLA-DQA1*0102/DQB1*0602, the Class II MHC Molecule Associated with Dominant Protection in Insulin-Dependent Diabetes Mellitus. The Journal of Immunology 1998. [DOI: 10.4049/jimmunol.160.5.2365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Abstract
HLA-DQA1*0102/DQB1*0602 (DQ0602) is observed at a decreased frequency in insulin-dependent diabetes mellitus in different ethnic groups, suggesting a protective role for DQ0602. Analysis of overlapping peptides from human insulin found that insulin B(1–15) bound well to DQ0602 and exhibited a high degree of allelic specificity. Truncation analysis of insulin B(1–15) identified insulin B(5–15) as the minimal peptide for DQ0602 binding. Insulin B(5–15) bound to DQ0602 with an apparent KD of 0.7 to 1.0 μM and peptide binding reached equilibrium at 96 h. Single arginine substitutions at each position of the insulin B(5–15) peptide identified amino acids 6, 8, 9, 11, and 14 (relative positions P1, P3, P4, P6, and P9) as important for binding. Extensive substitutions for each of these amino acids revealed that amino acids 11 and 14 (P6 and P9) exhibited the highest specificity. Amino acid 11 (P6) preferred large aliphatic amino acids, while amino acid 14 (P9) preferred smaller aliphatic and hydroxyl amino acids. Binding of an overlapping series of peptides from a randomly chosen protein, the herpes simplex virus-2 tegument protein UL49, correlated completely with the presence or absence of the DQ0602 peptide binding motif. Peptides 11 amino acids long were selected from GAD65, IA-2, and proinsulin, that contained the DQ0602 peptide binding motif. Of these, 79% (19 of 24) were able to bind DQ0602. This study identifies a peptide binding motif for DQ0602 and peptides from insulin-dependent diabetes mellitus autoantigens that bind DQ0602 in vitro.
Collapse
|
23
|
Abstract
Previously we isolated a novel protein that coimmunoprecipitates with the 1,25-dihydroxyvitamin D3-24R-hydroxylase and 25-hydroxyvitamin D3-1 alpha-hydroxylase. This kidney-specific protein found in the inner membrane of mitochondria is named the vitamin D3 hydroxylase-associated protein (VDHAP). To determine a putative function for this protein, an extensive computer search of the deduced amino acid sequence of VDHAP was performed. A BLAST homology search identified amino acid residues 133 through 321 in acetamidase from Aspergillus nidulans that exhibit 38% amino acid identify and 65% amino acid similarity to VDHAP. A protein consensus sequence dictionary, MOTIFS, identified an amidase consensus sequence in VDHAP. This sequence, G-G-S-S-G-G-E-G-A-L-I-A-G-G-G-S-L-L-G-I-G-S-D-V-A-G-S-I-R-L-P-S, in VDHAP is located between amino acids 223 and 254. Propionamide, acetamide, and acrylamide were identified as substrates for an amidase activity in soluble chicken kidney mitochondria. Propionamide is the best substrate with a Vmax of 16.7 nmol NH4+/min/mg protein and an apparent Km of 7.9 mM in soluble chicken kidney mitochondria. A VDHAP monoclonal antibody, IVC2G8, immunoprecipitates 78% of the total propionamidase activity in soluble chicken kidney mitochondria. These results suggest that VDHAP is a propionamidase enzyme in soluble chicken kidney mitochondria and a member of the amidase signature gene family.
Collapse
Affiliation(s)
- R A Ettinger
- Department of Biochemistry, University of Wisconsin-Madison, College of Agricultural and Life Sciences 53706
| | | |
Collapse
|
24
|
Ettinger RA, Ismail R, DeLuca HF. cDNA cloning and characterization of a vitamin D3 hydroxylase-associated protein. J Biol Chem 1994; 269:176-82. [PMID: 8276793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We previously reported the generation of monoclonal antibodies which immunoprecipitate a fraction of the total chick kidney 1,25-dihydroxyvitamin D3-24R-hydroxylase activity. These antibodies were used to screen a chick kidney lambda gt11 cDNA library resulting in the isolation of a full-length cDNA encoding a protein that is not the 1,25-dihydroxyvitamin D3-24R-hydroxylase but another protein we term the vitamin D3 hydroxylase-associated protein (VDHAP). The deduced amino acid sequence agreed with an NH2-terminal amino acid sequence from the isolated VDHAP. Gene and protein bank search did not identify homology to known sequences or functional domains in the VDHAP cDNA. VDHAP mRNA levels are not altered by conditions which either induce 1,25-dihydroxyvitamin D3-24R-hydroxylase activity (78-fold) or 25-hydroxyvitamin D3-1 alpha-hydroxylase activity (30-fold). Northern analysis of poly(A)+ RNA from chick tissues revealed VDHAP only in kidney. Cellular fractionation experiments demonstrated that VDHAP and the 25-hydroxyvitamin D3-1 alpha-hydroxylase are colocalized in the inner membrane of mitochondria. The VDHAP antibody immunoprecipitates 14% of the total 1,25-dihydroxyvitamin D3-24R-hydroxylase activity (7-fold over background) and immunoprecipitates 21% of the total 25-hydroxyvitamin D3-1 alpha-hydroxylase activity (2-fold over background). VDHAP is a novel chick kidney-specific inner membrane protein of mitochondria, which associates with a fraction of the 1,25-dihydroxyvitamin D3-24R-hydroxylase and 25-hydroxyvitamin D3-1 alpha-hydroxylase.
Collapse
Affiliation(s)
- R A Ettinger
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison 53706
| | | | | |
Collapse
|
25
|
Burgos-Trinidad M, Ismail R, Ettinger RA, Prahl JM, DeLuca HF. Immunopurified 25-hydroxyvitamin D 1 alpha-hydroxylase and 1,25-dihydroxyvitamin D 24-hydroxylase are closely related but distinct enzymes. J Biol Chem 1992; 267:3498-505. [PMID: 1310688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The chick kidney mitochondrial cytochrome P-450 1,25-dihydroxyvitamin D3 24-hydroxylase was partially purified by sequential polyethylene glycol precipitation, aminohexyl-Sepharose 4B, and hydroxylapatite chromatography. The specific activity of the final preparation, when reconstituted with NADPH, adrenodoxin, and adrenodoxin reductase, was 245 pmol/min/mg of protein or 0.56 pmol/min/pmol of P-450. The specific cytochrome P-450 content was 0.45-0.73 nmol/mg of protein. BALB/c mice immunized with this preparation developed serum polyclonal antibodies to the 24-hydroxylase, as demonstrated by immunoprecipitation. Splenic lymphocytes from an immunized mouse were fused with myeloma NSI/1-Ag-4-1 cells, and hybridomas secreting monoclonal antibodies to the 24-hydroxylase were detected by immunoprecipitation. The hybridoma lines were cloned by limiting dilution and further characterized as IgG1, IgG3, and IgM subclasses. In one-dimensional immunoblots of soluble 24-hydroxylase preparations, the monoclonal antibodies revealed a single band with an apparent molecular weight of 59,000. The monoclonal antibodies did not cross-react with cytochrome P-450s from other species but immunoprecipitated and immunoblotted a soluble chick renal mitochondrial 25-hydroxyvitamin D3 1 alpha-hydroxylase preparation, demonstrating the close similarity of these two hydroxylases. These antibodies were coupled to Sepharose CL-4B and used to isolate to homogeneity the two enzymes from chick kidney mitochondria. Amino-terminal sequences and amino acid composition data demonstrate that these enzymes are different but homologous.
Collapse
Affiliation(s)
- M Burgos-Trinidad
- Department of Biochemistry, University of Wisconsin-Madison, College of Agricultural and Life Sciences 53706
| | | | | | | | | |
Collapse
|
26
|
Boyer RF, Generous SM, Nieuwenhuis TJ, Ettinger RA. Selective adsorption of apoferritin on immobilized Fe(III): demonstration of Fe(III) binding sites. Biotechnol Appl Biochem 1990; 12:79-84. [PMID: 2310509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Immobilized metal ion affinity chromatography has been used to demonstrate and partially characterize Fe(III) binding sites on apoferritin. Binding of Fe(III) to these sites is influenced by pH, but not affected by high ionic strength. These results suggest that both ionic and coordinate covalent interactions are important in the formation of the Fe(III): apoferritin complex. This is, to our knowledge, the first demonstration of direct Fe(III) binding to apoferritin. Other immobilized metal ions, including Zn(II), Ni(II), Cu(II), Cr(III), Co(II), and Tb(III), displayed little or no adsorption of apoferritin. The analytical technique of immobilized metal ion affinity chromatography also shows great promise in the purification of apoferritin, ferritin, and other iron-binding proteins.
Collapse
Affiliation(s)
- R F Boyer
- Department of Chemistry, Hope College, Holland, Michigan 49423
| | | | | | | |
Collapse
|