An epitope-specific chemically defined nanoparticle vaccine for respiratory syncytial virus.

Respiratory syncytial virus (RSV) can cause severe respiratory disease in humans, particularly in infants and the elderly. However, attempts to develop a safe and effective vaccine have so far been unsuccessful. Atomic-level structures of epitopes targeted by RSV-neutralizing antibodies are now known, including that bound by Motavizumab and its clinically used progenitor Palivizumab. We developed a chemically defined approach to RSV vaccine design, that allows control of both immunogenicity and safety features of the vaccine. Structure-guided antigen design and a synthetic nanoparticle delivery platform led to a vaccine candidate that elicits high titers of palivizumab-like, epitope-specific neutralizing antibodies. The vaccine protects preclinical animal models from RSV infection and lung pathology typical of vaccine-derived disease enhancement. The results suggest that the development of a safe and effective synthetic epitope-specific RSV vaccine may be feasible by combining this conformationally stabilized peptide and synthetic nanoparticle delivery system.