期刊论文详细信息
BMC Research Notes
Epitope reactions can be gauged by relative antibody discriminating specificity (RADS) values supported by deletion, substitution and cysteine bridge formation analyses: potential uses in pathogenesis studies
Andrew K I Falconar1 
[1] Laboratorio de Investigaciones en Enfermedades Tropicales, Departamento de Medicina, Universidad del Norte, Km5 Antigua via Puerto Colombia, Barranquilla, Colombia
关键词: Relative antibody discriminating specificity value;    Monoclonal antibody;    Synthetic peptide;    Mapping;    Epitope;   
Others  :  1166472
DOI  :  10.1186/1756-0500-5-208
 received in 2011-10-28, accepted in 2012-04-30,  发布年份 2012
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【 摘 要 】

Background

Epitope-mapping of infectious agents is essential for pathogenesis studies. Since polyclonal antibodies (PAbs) and monoclonal antibodies (MAbs) are always polyspecific and can react with multiple epitopes, it is important to distinguish between specific and non-specific reactions. Relative antibody discriminating specificity (RADS) values, obtained from their relative ELISA reactions with L-amino acid peptides prepared in the natural versus reverse orientations (x-fold absorbance natural/absorbance reverse = RADS value) may be valuable for this purpose.

PAbs generated against the dengue type-2 virus (DENV-2) nonstructural-1 (NS1) glycoprotein candidate vaccine also reacted with both DENV envelope (E) glycoproteins and blood-clotting proteins. New xKGSx/xSGKx amino acid motifs were identified on DENV-2 glycoproteins, HIV-1 gp41 and factor IXa. Their potential roles in DENV and HIV-1 antibody-enhanced replication (AER) and auto-immunity were assessed.

In this study, a) RADS values were determined for MAbs and PAbs, generated in congeneic (H2: class II) mice against DENV NS1 glycoprotein epitopes, to account for their cross-reaction patterns, and b) MAb 1G5.3 reactions with xKGSx/xSGKx motifs present in the DENV-4 NS1, E and HIV-1 glycoproteins and factor IXa were assessed after the introduction of amino acid substitutions, deletions, or intra-/inter-cysteine (C-C) bridges.

Results

MAbs 1H7.4, 5H4.3, 3D1.4 and 1G5.3 had high (4.23- to 16.83-fold) RADS values against single epitopes on the DENV-2 NS1 glycoprotein, and MAb 3D1.4 defined the DENV complex-conserved LX1 epitope. In contrast, MAbs 1G5.4-A1-C3 and 1C6.3 had low (0.47- to 1.67-fold) RADS values against multiple epitopes. PAb DENV complex-reactions occurred through moderately-high (2.77- and 3.11-fold) RADS values against the LX1 epitope. MAb 1G5.3 reacted with xSGKx motifs present in DENV-4 NS1 and E glycoproteins, HIV-1 gp41 and factor IXa, while natural C-C bridge formations or certain amino acid substitutions increased its binding activity.

Conclusions

These results: i) were readily obtained using a standard 96-well ELISA format, ii) showed the LX1 epitope to be the immuno-dominant DENV complex determinant in the NS1 glycoprotein, iii) supported an antigenic co-evolution of the DENV NS1 and E glycoproteins, and iv) identified methods that made it possible to determine the role of anti-DENV PAb reactions in viral pathogenesis.

【 授权许可】

   
2012 Falconar; licensee BioMed Central Ltd.

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【 参考文献 】
  • [1]Gershoni JM, Roitburd-Berman A, Siman-Tov DD, Tarnovitski Freund N, Weiss Y: Epitope mapping: the first step in developing epitope-based vaccines. BioDrugs 2007, 21:145-156.
  • [2]Ede NJ: Multiple parallel synthesis of peptides on SynPhase grafted supports. J Immunol Meths 2002, 267:3-11.
  • [3]Tribbick G: Multipin peptide libraries for antibody and receptor epitope screening and characterization. J Immunol Meths 2002, 267:27-35.
  • [4]Carter JM, Loomis-Price L: B cell epitope mapping using synthetic peptides. Curr Protoc Immunol 2004., 9Unit 9.4
  • [5]Price MR, Rye PD, Petrakou E, Murray A, Brady K, Imai S, Haga S, Kiyozuka Y, Schol D, Meulenbroek MF, Snijdewint FG, von Mensdorff-Pouilly S, Verstraeten RA, Kenemans P, Blockzjil A, Nilsson K, Nilsson O, Reddish M, Suresh MR, Koganty RR, Fortier S, Baronic L, Berg A, Longenecker MB, Hilgers J, et al.: Summary report on the ISOBM TD-4 Workshop: analysis of 56 monoclonal antibodies against the MUC1 mucin. San Diego, Calif., November 17–23, 1996. Tumour Biol 1998, 19(Suppl 1):1-20.
  • [6]Falconar AKI: Antibody responses are generated to immunodominant ELK/KLE-type motifs on the dengue virus non-structural-1 glycoprotein during live dengue virus infections in mice and humans: implications for diagnosis, pathogenesis, and vaccine design. Clin Vaccine Immunol 2007, 14:493-504.
  • [7]Falconar AKI: Monoclonal antibodies that bind to common epitopes on the dengue virus type 2 nonstructural-1 and envelope glycoproteins display weak neutralising activity and differentiated responses to virulent strains: implications for pathogenesis and vaccines. Clin Vaccine Immunol 2008, 15:549-561.
  • [8]Falconar AKI: Use of synthetic peptides to represent surface-exposed epitopes defined by neutralising dengue complex- and flavivirus group-reactive monoclonal antibodies on the native dengue type-2 virus envelope glycoprotein. J Gen Virol 2008, 89:1616-1621.
  • [9]Talmage DW: Immunological specificity, unique combinations of selected natural globulins provide an alternative to the classical concept. Science 1959, 129:1643-1648.
  • [10]Richards FF, Konigsberg WH, Rosenstein RW, Varga JM: On the specificity of antibodies. Science 1975, 187:130-137.
  • [11]Sperling R, Francus T, Siskind GW: Degeneracy of antibody specificity. J Immunol 1983, 131:882-885.
  • [12]Edelman GM, Gally JA: Degeneracy and complexity in biological systems. Proc Natl Acad Sci USA 2001, 98:13763-13768.
  • [13]Parnes O: From interception to incorporation: degeneracy and promiscuous recognition as precursors of a paradigm shift in immunology. Mol Immunol 2004, 40:985-991.
  • [14]Van Regenmortel MHV: What is a B-cell epitope? Methods Mol Biol 2009, 524:3-20.
  • [15]Wucherpfennig KW, Allen PM, Celada F, Cohen IR, De Boer R, Garcia KC, Goldstein B, Greenspan R, Hafler D, Hodgkin P, Huseby ES, Krakauer DC, Nemazee D, Perelson AS, Pinilla C, Strong RK, Sercarz EE: Polyspecificity of T cell and B cell receptor recognition. Semin Immunol 2007, 19:216-224.
  • [16]Langman RE, Cohn M: If the immune repertoire evolved to be large, random, and somatically generated, then. Cell Immunol 2002, 216:15-22.
  • [17]Efroni S, Cohen IR: The heuristics of biologic theory: the case of self-nonself discrimination. Cell Immunol 2003, 223:87-89.
  • [18]Cohn M: Degeneracy, mimicry and crossreactivity in immune recognition. Mol Immunol 2005, 42:651-655.
  • [19]Blalock JE: Complementarity of peptides specified by ‘sense’ and ‘antisense’ strands of DNA. Trends Biotechol 1990, 8:140-144.
  • [20]Siemion IZ, Zbozień-Pacamaj R, Stefanowicz P: New hypothesis on amino acid complementarity and its evaluation on TGF-beta(2)-related peptides. J Mol Recognit 2011 , 14:1-12.
  • [21]Trifilieff E, Dubs MC, Van Regenmortel MHV: Antigenic cross-reactivity potential of synthetic peptides immobilized on polyethylene rods. Mol Immunol 1991, 28:889-896.
  • [22]Van Regenmortel MHV: Requirements for empirical immunogenicity trials, rather than structure-based design, for developing an effective HIV vaccine. Arch Virol 2012, 157:1-20.
  • [23]Falconar AKI: The dengue virus non-structural-1 protein (NS1) generates antibodies to common epitopes on human blood clotting, integrin/adhesion proteins and binds to human endothelial cells: potential implications in haemorrhagic fever pathogenesis. Arch Virol 1997, 142:897-916.
  • [24]Falconar AKI, Martinez F: The NS1 glycoprotein can generate dramatic antibody-enhanced dengue viral replication in normal out-bred mice resulting in lethal multi-organ disease. PLoS One 2011, 6:e21024.
  • [25]Gubler DJ: Dengue/dengue haemorrhagic fever: history and current status. Novartis Found Symp 2006, 277:3-16.
  • [26]Halstead SB: Neutralization and antibody-dependent enhancement of dengue viruses. Adv Virus Res 2003, 60:421-467.
  • [27]Halstead SB, Mahalingam S, Marovich MA, Ubol S, Mosser DM: Intrinsic antibody-dependent enhancement of microbial infection in macrophages: disease regulation by immune complexes. Lancet Infect Dis 2010, 10:712-722.
  • [28]Fried JR, Gibbons RV, Kalayanarooj S, Thomas SJ, Srikiatkhachorn A, Yoon IK, Jarman RG, Green S, Rothman AL, Cummings DA: Serotype-specific differences in the risk of dengue hemorrhagic fever: an analysis of data collected in Bangkok, Thailand from 1994 to 2006. PLoS Negl Trop Dis 2010, 4:e617.
  • [29]Shashidharamurthy R, Zhang F, Amano A, Kamat A, Panchanathan R, Ezekwudo D, Zhu C, Selvaraj P: Dynamics of the interaction of human IgG subtype immune complexes with cells expressing R and H allelic forms of a low-affinity Fc gamma receptor CD32A. J Immunol 2009, 183:8216-8224.
  • [30]Loke H, Bethell D, Phuong CX, Day N, White N, Farrar J, Hill A: Susceptibility to dengue hemorrhagic fever in Vietnam: evidence of an association with variation in the vitamin d receptor and Fc gamma receptor IIa genes. Am J Trop Med Hyg 2002, 67:102-106.
  • [31]García G, Sierra B, Pérez AB, Aguirre E, Rosado I, Gonzalez N, Izquierdo A, Pupo M, Danay Díaz DR, Sánchez L, Marcheco B, Hirayama B, Guzmán MG: Asymptomatic dengue infection in a Cuban population confirms the protective role of the RR variant of the FcgammaRIIa polymorphism. Am J Trop Med Hyg 2010, 82:1153-1156.
  • [32]Chareonsirisuthigul T, Kalayanarooj S, Ubol S: Dengue virus (DENV) antibody-dependent enhancement of infection upregulates the production of anti-inflammatory cytokines, but suppresses anti-DENV free radical and pro-inflammatory cytokine production, in THP-1 cells. J Gen Virol 2007, 88:365-375.
  • [33]Ubol S, Phuklia W, Kalayanarooj S, Modhiran N: Mechanisms of immune evasion induced by a complex of dengue virus and preexisting enhancing antibodies. J Infect Dis 2010, 201:923-935.
  • [34]Modhiran N, Kalayanarooj S, Ubol S: Subversion of innate defenses by the interplay between DENV and pre-existing enhancing antibodies: TLRs signaling collapse. PLoS Negl Trop Dis 2010, 4:e924.
  • [35]Simmons CP, Popper S, Dolocek C, Chau TN, Griffiths M, Dung NT, Long TH, Hoang DM, Chau NV, Thao LT, Hien TT, Relman DA, Farrar J: Patterns of host genome-wide gene transcript abundance in the peripheral blood of patients with acute dengue hemorrhagic fever. J Infect Dis 2007, 195:1097-1107.
  • [36]Ubol S, Masrinoul P, Chaijaruwanich J, Kalayanarooj S, Charoensirisuthikul T, Kasisith J: Differences in global gene expression in peripheral blood mononuclear cells indicate a significant role of the innate responses in progression of dengue fever but not dengue hemorrhagic fever. J Infect Dis 2008, 197:1459-1467.
  • [37]Murphy BR, Whitehead SS: Immune response to dengue virus and prospects for a vaccine. Annu Rev Immunol 2011, 29:587-619.
  • [38]Rothman AL: Immunity to dengue virus: a tale of original antigenic sin and tropical cytokine storms. Nat Rev Immunol 2011, 11:532-543.
  • [39]Schlesinger JJ, Brandriss MW, Walsh EE: Protection of mice against dengue 2 virus encephalitis by immunization with the dengue 2 virus non-structural glycoprotein NS1. J Gen Virol 1987, 68:853-857.
  • [40]Stephenson JR: Understanding dengue pathogenesis: implications for vaccine design. Bull World Health Organ 2005, 83:308-314.
  • [41]Shu PY, Chen LK, Chang SF, Yueh YY, Chow L, Chien LJ, Chin C, Lin TH, Huang JH: Comparison of capture immunoglobulin M (IgM) and IgG enzyme-linked immunosorbent assay (ELISA) and nonstructural protein NS1 serotype-specific IgG ELISA for differentiation of primary and secondary dengue virus infections. Clin Diagn Lab Immunol 2003, 10:622-630.
  • [42]Sittisombut N, Sistayanarain A, Cardosa MJ, Salminen M, Damrongdachakul S, Kalayanarooj S, Rojanasuphot S, Supawadee J, Maneekarn N: Possible occurrence of a genetic bottleneck in dengue serotype 2 viruses between the 1980 and 1987 epidemic seasons in Bangkok, Thailand. Am J Trop Med Hyg 1997, 57:100-108.
  • [43]Klungthong C, Putnak R, Mammen MP, Li T, Zhang C: Molecular genotyping of dengue viruses by phylogenetic analysis of the sequences of individual genes. J Virol Methods 2008, 154:175-181.
  • [44]Falconar AKI, Young PR, Miles MA: Precise location of sequential dengue virus subcomplex and complex B cell epitopes on the nonstructural-1 glycoprotein. Arch Virol 1994, 137:315-326.
  • [45]Falconar AKI: The potential role of antigenic themes in dengue viral pathogenesis. In Recent Research Developments in Virology. Vol.1. IIth edition. Edited by Pandalai SG. Transworld Research Network, Kerala; 1999:437-447.
  • [46]Nimmo GR, Lew AM, Stanley CM, Steward MW: Influence of antibody affinity on the performance of different antibody assays. J Immunol Methods 1984, 72:177-187.
  • [47]Holland GP, Steward MW: The influence of epitope density on the estimation of the affinity of antibody for complex antigens. J Immunol Methods 1991, 138:245-255.
  • [48]Liu W, Peng Z, Liu Z, Lu Y, Ding J, Chen YH: High epitope density in a single recombinant protein molecule of the extracellular domain of influenza A virus M2 protein significantly enhances protective immunity. Vaccine 2004, 23:366-371.
  • [49]Liu W, Chen YH: High epitope density in a single protein molecule significantly enhances antigenicity as well as immunogenicity: a novel strategy for modern vaccine development and a preliminary investigation about B cell discrimination of monomeric proteins. Eur J Immunol 2005, 35:505-514.
  • [50]Ray P, Sharma YD: Molecular cloning and serological characterization of a new Plasmodium vivax recombinant antigen which contains apolipoprotein B-100 like sequences. Biochem Biophys Res Commun 1992, 184:668-672.
  • [51]Tetteh KK, Cavanagh DR, Corran P, Musonda R, McBride JS, Conway DJ: Extensive antigenic polymorphism within the repeat sequence of the Plasmodium falciparum merozoite surface protein 1 block 2 is incorporated in a minimal polyvalent immunogen. Infect Immun 2005, 73:5928-5935.
  • [52]Goto Y, Carter D, Reed SG: Immunological dominance of Trypanosoma cruzi tandem repeat proteins. Infect Immun 2008, 76:3967-3974.
  • [53]Goto Y, Carter D, Guderian J, Inoue N, Kawazu S, Reed SG: Upregulated expression of B-cell antigen family tandem repeat proteins by Leishmania amastigotes. Infect Immun 2010, 78:2138-2145.
  • [54]Valiente-Gabioud AA, Veaute C, Perrig M, Galan-Romano FS, Sferco SJ, Marcipar IS: Effect of repetitiveness on the immunogenicity and antigenicity of Trypanosoma cruzi FRA protein. Exp Parasitol 2011, 127:672-679.
  • [55]McBride JW, Zhang X, Wakeel A, Kuriakose JA: Tyrosine-phosphorylated Ehrlichia chaffeensis and Ehrlichia canis tandem repeat orthologs contain a major continuous cross-reactive antibody epitope in lysine-rich repeats. Infect Immun 2011, 79:3178-3187.
  • [56]Thomas MC, Fernández-Villegas A, Carrilero B, Marañón C, Saura D, Noya O, Segovia M, De Alarcón Noya B, Alonso C, López MC: Characterization of an immunodominant antigenic epitope from Trypanosoma cruzi as a biomarker of chronic Chagas' disease pathology. Clin Vaccine Immunol 2012, 19:167-173.
  • [57]Gnann JW, Nelson JA, Oldstone MB: Fine mapping of an immunodominant domain in the transmembrane glycoprotein of human immunodeficiency virus. J Virol 1987, 61:2639-2641.
  • [58]Oldstone MB, Tishon A, Lewicki H, Dyson HJ, Feher VA, Assa-Munt N, Wright PE: Mapping the anatomy of the immunodominant domain of the human immunodeficiency virus gp41 transmembrane protein: peptide conformation analysis using monoclonal antibodies and proton nuclear magnetic resonance spectroscopy. J Virol 1991, 65:1727-1734.
  • [59]Füst G: Enhancing antibodies in HIV infection. Parasitology 1997, 115(Suppl 1):127-140.
  • [60]Eaton AM, Ugen KE, Weiner DB, Wildes T, Levy JA: An anti-gp41 human monoclonal antibody that enhances HIV-1 infection in the absence of complement. AIDS Res Hum Retroviruses 1994, 10:13-18.
  • [61]Gopinath SC, Shikamoto Y, Mizuno H, Kumar PK: Snake-venom-derived Factor IX-binding protein specifically blocks the gamma-carboxyglutamic acid-rich-domain-mediated membrane binding of human Factors IX and X. Biochem J 2007, 405:351-357.
  • [62]Falconar AKI: Identification of an epitope on the dengue virus membrane (M) protein defined by cross-reactive monoclonal antibodies: design of an improved epitope sequence based on common determinants present in both envelope (E and M) proteins. Arch Virol 1999, 144:2313-233.
  • [63]Modis Y, Ogata S, Clements D, Harrison SC: A ligand-binding pocket in the dengue virus envelope glycoprotein. Proc Natl Acad Sci USA 2003, 100:6986-6991.
  • [64]Modis Y, Ogata S, Clements D, Harrison SC: Variable surface epitopes in the crystal structure of dengue virus type 3 envelope glycoprotein. J Virol 2005, 79:1223-1231.
  • [65]Du AP, Limal D, Semetey V, Dali H, Jolivet M, Desgranges C, Cung MT, Briand JP, Petit MC, Muller S: Structural and immunological characterisation of heteroclitic peptide analogues corresponding to the 600–612 region of the HIV envelope gp41 glycoprotein. J Mol Biol 2002, 323:503-521.
  • [66]Shikamoto Y, Morita T, Fujimoto Z, Mizuno H: Crystal structure of Mg2+- and Ca2+-bound Gla domain of factor IX complexed with binding protein. J Biol Chem 2003, 278:24090-24094.
  • [67]Huang M, Furie BC, Furie B: Crystal structure of the calcium-stabilized human factor IX Gla domain bound to a conformation-specific anti-factor IX antibody. J Biol Chem 2004, 279:14388-14345.
  • [68]Van Regenmortel MHV, Muller S: D-peptides as immunogens and diagnostic reagents. Curr Opin Biotechnol 1998, 9:377-382.
  • [69]Koraka P, Burghoorn CP, Falconar A, Setiati TE, Djamiatun K, Groen J, Osterhaus AD: Detection of immune-complex-dissociated nonstructural-1 antigen in patients with acute dengue virus infections. J Clin Microbiol 2003, 41:4154-4159.
  • [70]Bessoff K, Delorey M, Sun W, Hunsperger E: Comparison of two commercially available dengue virus (DENV) NS1 capture enzyme-linked immunosorbent assays using a single clinical sample for diagnosis of acute DENV infection. Clin Vaccine Immunol 2008, 15:1513-1518.
  • [71]Lima Mda R, Nogueira RM, Schatzmayr HG, dos Santos FB: Comparison of three commercially available dengue NS1 antigen capture assays for acute diagnosis of dengue in Brazil. PLoS Negl Trop Dis 2010, 6:e738.
  • [72]World Health Organization: Dengue haemorrhagic fever: diagnosis, treatment, prevention and control. World Health Organization, Geneva; 1997.
  • [73]World Health Organization: Dengue haemorrhagic fever: diagnosis, treatment, and control. World Health Organization/Tropical Disease Research, Geneva; 2009.
  • [74]Falconar AKI, Romero-Vivas CME: Simple prognostic criteria can definitively identify patients who develop severe versus non-severe dengue disease, or have other febrile illnesses. J Clin Med Res 2012, 4:33-44.
  • [75]Giannelli F, Green PM, High KA, Sommer S, Poon MC, Ludwig M, Schwaab R, Reitsma PH, Goossens M, Yoshioka A: Haemophilia B: database of point mutations and short additions and deletions–fourth edition, 1993. Nucleic Acids Res 1993, 21:3075-3087.
  • [76]Wagenvoord R, Hendrix H, Tran T, Hemker HC: Development of a sensitive and rapid chromogenic factor IX assay for clinical use. Haemostasis 1990, 20:276-288.
  • [77]Mitrakul C, Poshyachinda M, Futrakul P, Sangkawibha N, Ahandrik S: Hemostatic and platelet kinetic studies in dengue hemorrhagic fever. Am J Trop Med Hyg 1977, 26:975-984.
  • [78]Wang J, Tan W, Chen Y, Lu X, Lu Y, Qin S, Li S, Bu H, Li Y, Cheng J: Full-length cDNA cloning and protein three-dimensional structure modelling of factor VII of rhesus monkey, Macaca mulatta. Blood Cells Mol Dis 2008, 40:237-243.
  • [79]Bhamarapravati N: Pathology of dengue infections. In Dengue and dengue hemorrhagic fever. Edited by Gubler DJ, Kuno G. CAB International, New York; 1997:115-132.
  • [80]Lin YS, Yeh TM, Lin CF, Wan SW, Chuang YC, Hsu TK, Liu HS, Liu CC, Anderson R, Lei HY: Molecular mimicry between virus and host and its implications for dengue disease pathogenesis. Exp Biol Med (Maywood) 2011, 236:515-523.
  • [81]Wills BA, Oragui EE, Stephens AC, Daramola OA, Dung NM, Loan HT, Chau NV, Chambers M, Stepniewska K, Farrar JJ, Levin M: Coagulation abnormalities in dengue hemorrhagic fever: serial investigations in 167 Vietnamese children with dengue shock syndrome. Clin Infect Dis 2002, 35:277-285.
  • [82]Brown SE, Howard CR, Zuckerman AJ, Steward MW: Affinity of antibody responses in man to hepatitis B vaccine determined with synthetic peptides. Lancet 1984, 2:184-187.
  • [83]Crill WD, Chang GJ: Localization and characterization of flavivirus envelope glycoprotein cross-reactive epitopes. J Virol 2004, 78:13975-13986.
  • [84]Goncalvez AP, Purcell RH, Lai CJ: Epitope determinants of a chimpanzee Fab antibody that efficiently cross-neutralizes dengue type 1 and type 2 viruses map to inside and in close proximity to fusion loop of the dengue type 2 virus envelope glycoprotein. J Virol 2004, 78:12919-12928.
  • [85]Halstead SB: Dengue. Lancet 2007, 307:1644-1652.
  • [86]Chau TN, Anders KL, le Lien B, Hung NT, Hieu LT, Tuan NM, Thuy TT, le Phuong T, Tham NT, Lanh MN, Farrar JJ, Whitehead SS, Simmons CP: Clinical and virological features of dengue in Vietnamese infants. PLoS Negl Trop Dis 2010, 4:e657.
  • [87]Chau TN, Quyen NT, Thuy TT, Tuan NM, Hoang DM, Dung NT, le Lien B, Quy NT, Hieu NT, Hieu LT, Hien TT, Hung NT, Farrar J, Simmons CP: Dengue in Vietnamese infants–results of infection-enhancement assays correlate with age-related disease epidemiology, and cellular immune responses correlate with disease severity. J Infect Dis 2008, 198:516-524.
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