Characterization of Humoral Responses to Nipah Virus Infection in the Syrian Hamster Model of Disease

Hamsters infected with NiV develop antibodies against the nucleoprotein and glycoprotein. While neutralizing antibodies do not develop until late in infection, early nonneutralizing antibodies possess Fc-mediated effector functions such as antibody-dependent complement deposition and antibody-dependent phagocytosis. Nipah virus (NiV) is a highly pathogenic paramyxovirus. The Syrian hamster model recapitulates key features of human NiV disease and is a critical tool for evaluating antivirals and vaccines. Here we describe longitudinal humoral immune responses in NiV-infected Syrian hamsters. Samples were obtained 1-28 days after infection and analyzed by ELISA, neutralization, and Fc-mediated effector function assays. NiV infection elicited robust antibody responses against the nucleoprotein and attachment glycoprotein. Levels of neutralizing antibodies were modest and only detectable in surviving animals. Fc-mediated effector functions were mostly observed in nucleoprotein-targeting antibodies. Antibody levels and activities positively correlated with challenge dose.