Construction and characterization of an HCV-derived multi-epitope peptide antigen containing B-cell HVR1 mimotopes and T-cell conserved epitopes.
Hepatitis C (HCV) genome is highly variable, particularly in the hypervariable region 1 (HVR1) of its E2 envelope gene. The variability of HCV genome has been a major obstacle for developing HCV vaccines. Due to B-cell HVR1 mimotopes mimicking the antigenicity of natural HVR1 epitopes and some T-cell epitopes from the consensus sequence of HCV genes conserving among the different HCV genotypes, we synthesized an minigene of HCV-derived multi-epitope peptide antigen (CMEP), which contains 9 B-cell HVR1 mimotopes in E2, 2 conserved CTL epitopes in C, 1 conserved CTL epitope in NS3 and 1 conserved Th epitope in NS3. This minigene was cloned into a GST expression vector to generate a fusion protein GST-CMEP. The immunogenic properties of CEMP were characterized by HCV infected patients' sera, and found that the reactivity frequency reached 75%. The cross reactivity of anti-CEMP antibody with different natural HVR1 variants was up to 90%. Meanwhile, we constructed an HCV DNA vaccine candidate, plasmid pVAX1.0-st-CMEP carrying the recombinant gene (st) of a secretion signal peptide and PADRE universal Th cell epitope sequence in front of the CMEP minigene. Immunization of rabbits with pVAX1.0-st-CMEP resulted in the production of antibody, which was of the same cross reactivity as the fusion protein GST-CMEP. Our findings indicate that the HCV-derived multi-epitope peptide antigen in some degree possessed the characteristics of neutralizing HCV epitopes, and would be of the value as a candidate for the development of HCV vaccines.
Gao
Jun
J
Department of Microbiology, Stake Key Laboratory of Medical Immunology, Second Military Medical University, Shanghai 200433, China.
Gong
Yuping
Y
Zhao
Ping
P
Zhu
Qing
Q
Yang
Xiaoping
X
Qi
Zhongtian
Z
D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000737:chemistry / Q000276:immunology*; D001483:Base Sequence; D003429:Cross Reactions / Q000276:immunology; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D016174:Hepacivirus / Q000276:immunology*; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry / Q000276:immunology*; D011817:Rabbits; D019444:Vaccines, DNA / Q000276:immunology; D014761:Viral Hepatitis Vaccines / Q000276:immunology; D014764:Viral Proteins / Q000737:chemistry / Q000276:immunology*
D000956:Antigens, Viral; D018985:Epitopes, B-Lymphocyte; D018984:Epitopes, T-Lymphocyte; C400562:HVR1 protein, Hepatitis C virus; D010455:Peptides; D019444:Vaccines, DNA; D014761:Viral Hepatitis Vaccines; D014764:Viral Proteins