IMMUNOGENETHERAPY OF CHRONIC HCV CARRIER CHIMPANZEES

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Vigorous HCV-specific T cell responses are typically observed in patients who recover spontaneously from acute, self-limited hepatitis C. In contrast, T cell responses are weak and narrowly focused in persistently infected patients. It has been proposed that enhancement and/or de novo induction of HCV-specific cellular immune responses in chronically infected individuals will induce HCV clearance and recovery. This hypothesis can only be tested in chimpanzees, the only animals susceptible to HCV infection. We propose to vaccinate 2 HCV carrier chimpanzees with recombinant vectors expressing HCV NS3, NS4 and NS5B to induce HCV-specific T cell responses and to evaluate whether these HCV-specific T cells can impact on HCV carrier state, by reducing or eliminating viremia and/or by controlling HCV antigen expression. The vaccine has 2 components, a recombinant HCV pox-virus (MVA-HCV) and a recombinant HCV adenovirus (Ad-HCV), and will be applied in a prime-boost regimen. The vaccine expresses 3 HCV antigens, namely HCV NS3, NS4 and NS5B. Both adenoviruses and MVA are known to be strong inducers of T-cell immunity. One HCV carrier chimpanzee will be mock vaccinated with vectors that do not express the HCV antigens.