AIM:To analyze the amino acid sequences of hypervariableregion 1 (HVR1) of HCV isolates in China and to construct acombinatorial chimeric HVR1 protein having a very broadhigh cross-reactivity.METHODS:All of the published HVR1 sequences from Chinawere collected and processed with a computer program.Several representative HVRI’s sequences were formulatedbased on a consensus profile and homology within certainsubdivision.A few reported HVR1 mimotope sequences werealso included for a broader representation.All of them werecloned and expressed in E.coli.The cross-reactivity of thepurified recombinant HVR1 antigens was tested by ELISAwith a panel of sera from HCV infected patients in China.Some of them were further ligated together to form acombinatorial HVR1 chimera.RESULTS:Altogether 12 HVR1_s were selected andexpressed in E.coliand purified to homogeneity.All ofthese purified antigens showed some cross-reactivity withsera in a 27 HCV positive panel.Recombinant HVRls ofNo.1,2,4,and 8# showing broad cross-reactivities andcomplementarity with each other,were selected for theligation elements.The chimera containing these 4 HVRlswas highly expressed in E.coli.The purified chimericantigen could react not only with all the HCV antibodypositive sera in the panel but also with 90/91 sera of HCV-infected patients.CONCLUSION:The chimeric antigen was shown to have abroad cross-reactivity.It may be helpful for solving theproblem caused by high variability of HCV,and in the effortsfor a novel vaccine against the virus. AIM: To analyze the amino acid sequences of hypervariable region 1 (HVR1) of HCV isolates in China and to construct acombinatorial chimeric HVR1 protein having a very broad cross-reactivity. METHODS: All of the published HVR1 sequences from China web collected and processed with a computer program. Seralralistic HVRI’s of the sequences were formulated were based on a consensus profile and homology within certain subdivision. A few reported HVR1 mimotope sequences were found included for a broader representation. All of them were cloned and expressed in E. coli. The cross-reactivity of thepurified recombinant HVR1 antigens was tested by ELISA with a panel of sera from HCV infected patients in China. Some of them were further ligated together to form acombinatorial HVR1 chimera .RESULTS: Altogether 12 HVR1_s were selected andexpressed in E. coli and purified to homogeneity. All of the purified antigens showed some cross-reactivity with sera in a 27 HCV positive panel. Recombinant HVRls of No. 1, 2, 4, and 8 # show ing broad cross-reactivities and complexarity with each other, were selected for the ligation elements. The chimera containing these 4 HVRlswas highly expressed in E. coli. purified chimeric antigen could react not only with all the HCV antibody positive sera in the panel but also with 90 / 91 sera of HCV-infected patients. CONCLUSION: The chimeric antigen was shown to have abroad cross activity. It may be helpful for solving the problem caused by high variability of HCV, and in the efforts for a novel vaccine against the virus.