Correlates of protective immunity to HCV and rational vaccine design: Project 3

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Hepatitis C virus (HCV) continues to infect ~71 million people worldwide with an estimated 1.5 to 2 million new infections each year. A complete eradication of HCV infection warrants development of an effective vaccine that can rapidly induce a durable anti-viral immunity and prevent infection. Evidence from spontaneous controllers suggests that a broad and durable HCV-specific CD4 and CD8 T cell responses are critical for effective control of HCV infection. In addition, a protective role for neutralizing antibody against viral glycoproteins E1&E2 has also been implicated. Furthermore, it is critical generate anti-viral immunity in the liver (the primary site of virus replication). Thus, the primary goal of this proposal is to develop a vaccination strategy using DNA, modified vaccinia Ankara (MVA), and protein-based vaccines that will generate a robust and broad HCV specific T and B cell responses in blood and liver against multiple HCV proteins. We hypothesize that induction of a strong, broad, and persistent T cell response against HCV antigens in the blood and liver combined with induction of strong neutralizing antibody response will provide protection against HCV infection and different combinations of DNA/MVA/protein vaccination can be harnessed to achieve the desired protective immunity. We propose to achieve these objectives using 3 specific aims. In Aim 1 we will construct and characterize DNA and MVA vaccines expressing HCV core, NS3-NS5 and E1E2 proteins. In Aim 2 we will optimize the DNA/MVA vaccine modality for inducing strong T cell and antibody responses. The optimizations will include testing the E1E2 in two forms either presented on the virus-like particle (VLP) or secreted. In addition, we will test the influence of CD40L adjuvant on cellular and humoral immunity. In Aim 3 we will optimize E1E2 protein boosts for DNA/MVA vaccine for further enhancing the antibody responses. By completion of these studies we hope generate an optimal vaccine against HCV that induces strong T cell and neutralizing antibody responses.