PreS1-decorated recombinant adenovirus encoding HBV antigens generates neutralizing humoral and cellular immunity

Background & Aims Achieving functional cure for chronic hepatitis B (CHB) will likely require a combinatorial approach targeting multiple aspects of the complex hepatitis B virus (HBV) life cycle and host adaptive immune responses. Here, we developed a therapeutic vaccination strategy targeting the PreS1 region of L-HBsAg, required for cellular entry of both hepatitis B and D viruses. An established potent T-cell inducing platform, recombinant adenovirus (Ad), was used as a nanoparticle scaffold for PreS1 attachment, to generate antibodies that neutralize virus entry and to establish T-cell mediated immune control. Approach & Results Screening a cohort of 61 patients diagnosed with CHB revealed minimal evidence of natural anti-PreS1 responses. Thus, Ad particles encoding multiple HBV antigens were decorated with PreS1 peptide using DogTag/DogCatcher protein superglue. Mice vaccinated with PreS1-decorated Ad induced robust anti-PreS1 antibody responses that neutralized HBV and HDV infection. In contrast, an undecorated Ad encoding L-HBsAg failed to neutralize HBV, demonstrating that PreS1 decoration was required for potent HBV neutralization. Strong CD8+ and CD4+ T-cell responses were induced against HBV antigens encoded in the Ad genome. Conclusions PreS1-decorated Ad combines immunological HBV and HDV entry inhibition with potent anti-HBV T-cell induction in a single platform, providing a promising addition to current therapeutic strategies against CHB, with particular utility in HBV/HDV co-infection.