A new unconventional HLA-A2-restricted epitope from HBV core protein elicits antiviral cytotoxic T lymphocytes

Abstract

Cytotoxic T cells (CTLs) play a key role in the control of Hepatitis B virus (HBV) infection and viral clearance. However, most of identified CTL epitopes are derived from HBV of genotypes A and D, and few have been defined in virus of genotypes B and C which are more prevalent in Asia. As HBV core protein (HBc) is the most conservative and immunogenic component, in this study we used an overlapping 9-mer peptide pool covering HBc to screen and identify specific CTL epitopes. An unconventional HLA-A2-restricted epitope HBc141–149 was discovered and structurally characterized by crystallization analysis. The immunogenicity and anti-HBV activity were further determined in HBV and HLAA2 transgenic mice. Finally, we show that mutations in HBc141–149 epitope are associated with viral parameters and disease progression in HBV infected patients. Our data therefore provide insights into the structure characteristics of this unconventional epitope binding to MHC-I molecules, as well as epitope specific CTL activity that orchestrate T cell response and immune evasion in HBV infected patients.

Keywords

chronic hepatitis B / HLA-A2 / HBc peptide / CTL response / antiviral cytotoxity

References

[1] Bertoletti A, Gehring AJ (2006) The immune response during hepatitis B virus infection. J Gen Virol87: 1439-1449

[2] Bertoni R, Sidney J, Fowler P, Chesnut RW, Chisari FV, Sette A (1997) Human histocompatibility leukocyte antigen-binding supermotifs predict broadly cross-reactive cytotoxic T lymphocyte responses in patients with acute hepatitis. J Clin Invest100: 503-513

[3] Chen X, Wang W, Wang S, Meng G, Zhang M, Ni B, Wu Y, Wang L (2013) An immunodominant HLA-A*1101-restricted CD8⁺ T cell response targeting hepatitis B surface antigen in chronic hepatitis B patients. J Gen Virol94: 2717-2723

[4] Desmond CP, Bartholomeusz A, Gaudieri S, Revill PA, Lewin SR (2008) A systematic review of T-cell epitopes in hepatitis B virus: identification, genotypic variation and relevance to antiviral therapeutics. Antivir Ther13: 161-175

[5] Fan H, Yan X, Zhang Y, Zhang X, Gao Y, Xu Y, Wang F, Meng S (2013) Increased expression of Gp96 by HBx-induced NF-κB activation feedback enhances hepatitis B virus production. PloS ONE8:e65588

[6] Frelin L, Wahlstrom T, Tucker AE, Jones J, Hughes J, Lee BO, Billaud JN, Peters C, Whitacre D, Peterson D, Milich DR (2009) Amechanismto explain the selection of the hepatitis e antigen-negativemutant during chronic hepatitis B virus infection. J Virol83: 1379-1392

[7] Garboczi DN, Hung DT, Wiley DC (1992) HLA-A2-peptide complexes: refolding and crystallization of molecules expressed in Escherichia coli and complexed with single antigenic peptides. Proc Natl Acad Sci USA89: 3429-3433

[8] Gordon SC (2013) Antiviral Therapy for Chronic HBV Infection and Development of Hepatocellular Carcinoma in a U.S. Population. Clin Gastroenterol HepatolS1542-3565-01511-01515

[9] Guo YJ, Zhu Y, Sun SH (2011) Identification and functional studies of HLA-A0201 restricted CTL epitopes in the X protein of hepatitis B virus. Acta Virol55: 107-115

[10] Harari A, Dutoit V, Cellerai C, Bart PA, Du Pasquier RA, Pantaleo G (2006) Functional signatures of protective antiviral T-cell immunity in human virus infections. Immunol Rev211: 236-254

[11] Hwang YK, Kim NK, Park JM, Lee Ky, Han WK, Kim HI, Cheong HS (2002) HLA-A2 1 restricted peptides from the HBx antigen induce specific CTL responses in vitro and in vivo. Vaccine20: 3770-3777

[12] Inchauspe G, Michel ML (2007) Vaccines and immunotherapies against hepatitis B and hepatitis C viruses. J Viral Hepat14 (Suppl. 1): 97-103

[13] Kim D, Lyoo KS, Smith D, Hur W, Hong SW, Sung PS, Yoon SK, Mehta S (2011) Number of mutations within CTL-defined epitopes of the hepatitis B virus (HBV) core region is associated with HBV disease progression. J Med Virol83: 2082-2087

[14] Lavanchy D (2005) Worldwide epidemiology of HBV infection, disease burden, and vaccine prevention. J Clin Virol Suppl1: S1-S3

[15] Lee HG, Lim JS, Lee KY, Choi YK, Choe IS, Chung TW, Kim K (1997) Peptide-specific CTL induction in HBV-seropositive PBMC by stimulation with peptides in vitro: novel epitopes identified from chronic carriers. Virus Res50: 185-194

[16] Li Y, Song H, Li J, Wang Y, Yan X, Zhao B, Zhang X, Wang S, Chen L, Qiu B, Meng S (2011) Hansenula polymorpha expressed heat shock protein gp96 exerts potent T cell activation activity as an adjuvant. J Biotechnol151: 343-349

[17] Liu HG, Fan ZP, Chen WW, Yang HY, Liu QF, Zhang H, Tien P, Wang FS (2008) A mutant HBs antigen (HBsAg)183-191 epitope elicits specific cytotoxic T lymphocytes in acute hepatitis B patients. Clin Exp Immunol151: 441-447

[18] Liu Z, Li XH, Qiu LP, Zhang XJ, Chen LZ, Cao S, Wang FS, Meng SD (2009) Treg suppress CTL responses upon immunization with HSP gp96. Eur J Immunol39: 3110-3120

[19] Liu J, Zhang SH, Tan SG, Zheng BW, Gao GF (2011) Revival of the identification of cytotoxic T-lymphocyte epitopes for immunological diagnosis. Exp Biol Med (Maywood)236: 253-267

[20] Liu Q, Zheng Y, Yu Y, Tan Q, Huang X (2012) Identification of HLAA* 0201-restricted CD8+ T-cell epitope C64-72 from hepatitis B virus core protein. Int Immunopharmacol13: 141-147

[21] Liu J (2013a) Conserved epitopes dominate cross-CD8+ T-cell responses against influenza A H1N1 virus among Asian populations. Eur J Immunol43: 2055-2069

[22] Liu J (2013b) Cross-allele cytotoxic T lymphocyte responses against 2009 pandemic H1N1 influenza A virus among HLA-A24 and HLA-A3 supertype-positive individuals. J Virol86: 13281-13294

[23] Maman Y, Blancher A, Benichou J, Yablonka A, Efroni S, Louzoun Y (2011) Immune-induced evolutionary selection focused on a single reading frame in overlapping hepatitis B virus proteins. J Virol85: 4558-4566

[24] Neuveut C, Wei Y, Buendia MA (2010) Mechanisms of HBV-related hepatocarcinogenesis. J Hepatol52: 594-604

[25] Ouyang L, Li X, Liang Z, Yang D, Gong F, Shen G, Weng X, Wu X (2013) CD8(low) T-cell subpopulation is increased in patients with chronic hepatitis B virus infection. Mol Immunol56: 698-704

[26] Rehermann B, Fowler P, Sidney J, Person J, Redeker A, Brown M, Moss B, Sette A, Chisari FV (1995) The cytotoxic T lymphocyte response to multiple hepatitis B virus polymerase epitopes during and after acute viral hepatitis. J Exp Med181: 1047-1058

[27] Sendi H, Mehrab-Mohseni M, Shahraz S, Norder H, Alavian SM, Noorinayer B, Zali MR, Pumpens P, Bonkovsky HL, Magnius LO (2009) CTL escape mutations of core protein are more frequent in strains of HBeAg negative patients with low levels of HBV DNA. J Clin Virol46: 259-264

[28] Tan AT (2008) Host ethnicity and virus genotype shape the hepatitis B virus-specific T-cell repertoire. J Virol82: 10986-10997

[29] Tan AT, Sodsai P, Chia A, Moreau E, Chng MH, Tham CY, Ho ZZ, Banu N, Hirankarn N, Bertoletti A (2013) Immunoprevalence and immunodominance of HLA-Cw0801 restricted T cell response targeting the HBV envelope transmembrane region. J Virol88: 1332-1341

[30] Thimme R, Wieland S, Steiger C, Ghrayeb J, Reimann KA, Purcell RH, Chisari FV (2003) CD8(+) Tcells mediate viral clearance and disease pathogenesis during acute hepatitis B virus infection. J Virol77: 68-76

[31] Westover KM, Hughes AL (2007) Evolution of cytotoxic T-lymphocyte epitopes in hepatitis B virus. Infect Genet Evol7: 254-262

[32] Xu Z (2011) Association of hepatitis B virus mutations in basal core promoter and precore regions with severity of liver disease: an investigation of 793 Chinese patients with mild and severe chronic hepatitis B and acute-on-chronic liver failure. J Gastroenterol46: 391-400

[33] Yang PL, Althage A, Chung J, Chisari FV (2002) Hydrodynamic injection of viral DNA: a mouse model of acute hepatitis B virus infection. Proc Natl Acad Sci USA99: 13825-13830

[34] Yukihiro S (2012) T cell immunopathogenesis and immunotherapeutic strategies for chronic hepatitis B virus infection. World J Gastroenterol18: 2443-2451

[35] Zhang Y, Li S, Shan M, Pan X, Zhuang K, He L, Gould K, Tien P (2007) Hepatitis B virus core antigen epitopes presented by HLAA2 single-chain trimers induce functional epitope-specific CD8+T-cell responses in HLA-A2.1/Kb transgenic mice. Immunology121: 105-112

[36] Zhang Y, Ren Y, Wu Y, Zhao B, Qiu L, Li X, Xu D, Liu J, Gao GF, Meng S (2013) The L60V variation in hepatitis B virus core protein elicits new epitope-specific cytotoxic T lymphocytes and enhances viral replication. J Virol87: 8075-8084

[37] Zhou M (2006) Screening and identification of severe acute respiratory syndrome-associated coronavirus-specific CTL epitopes. J Immunol177: 2138-2145

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