Cross-protectivity of henipavirus soluble glycoprotein in an in vivo model of Nipah virus disease.

INTRODUCTION: Nipah virus (NiV) is one of a group of highly pathogenic viruses classified within the Henipavirus genus. Since 2012 at least 11 new henipa-like viruses have been identified, including from new locations and reservoir hosts; the pathogenicity of these new viruses has yet to be determined, but two of them have been associated with morbidity, including fatalities. METHODS: The efficacy and cross-reactivity of two vaccine candidates derived from the soluble glycoproteins of both NiV and Hendra virus (HeV) was evaluated in our recently established hamster model. RESULTS: Both vaccine preparations resulted in strong humoral responses against NiV antigenic targets, demonstrating cross-reactive immunity. Efficacy was determined through challenge of hamsters with NiV Malaysian (NiV-M) strain. 100% of the hamsters survived a lethal challenge dose after prime/boost immunisation with glycoproteins derived from both NiV and HeV in the presence of adjuvant, with clinical signs and pathology being significantly reduced in immunised animals. DISCUSSION: This is first time the NiV and HeV soluble glycoproteins have been compared in the NiV-M hamster challenge model in the presence of Alhydrogel and AddaVax, providing evidence that glycoproteins from closely related henipavirus species can provide cross-protectivity against infection from alternate henipaviruses, supporting the potential of an effective pan-henipavirus vaccine for use in a frontline outbreak response.