# A stabilized MERS-CoV spike ferritin nanoparticle vaccine elicits robust and protective neutralizing antibody responses

## TL;DR

Researchers developed a MERS-CoV vaccine using a nanoparticle that triggers strong antibody responses and protects animals from infection.

## Contribution

A stabilized MERS-CoV spike nanoparticle vaccine is shown to elicit robust neutralizing antibodies and protective immunity in multiple animal models.

## Key findings

- The vaccine induced high neutralizing antibody titers in mice and non-human primates.
- Immunization fully protected alpacas from MERS-CoV infection in a challenge model.
- Antibodies showed cross-reactivity against multiple MERS-CoV clades and related viruses.

## Abstract

Middle East respiratory syndrome coronavirus (MERS-CoV) was identified as a human pathogen in 2012 and causes ongoing sporadic infections and outbreak clusters. Despite case fatality rates (CFRs) of over 30% and considerable pandemic potential, a safe and efficacious vaccine has not been developed. Here we report the design, characterization, and preclinical evaluation of MERS-CoV antigens. Our lead candidate comprises a stabilized spike displayed on a self-assembling ferritin nanoparticle that can be produced from a high-expressing, stable cell pool. This vaccine elicits robust MERS-CoV pseudovirus and authentic virus neutralizing antibody titers in BALB/c mice. Immunization of male non-human primates (NHPs) with one dose of Alhydrogel-adjuvanted vaccine elicited a > 103 geometric mean titer of pseudovirus neutralizing antibodies that was boosted with a second dose. Sera from these NHPs exhibited cross-reactivity against spike-pseudotyped lentiviruses from MERS-CoV clades A, B, and C as well as a distant pangolin merbecovirus. In human DPP4 transgenic mice, immunization provided dose-dependent protection against MERS-CoV lethal challenge, and in an established alpaca challenge model using female alpacas, immunization fully protected against MERS-CoV infection. This MERS-CoV nanoparticle vaccine is a promising candidate for clinical advancement to protect at-risk individuals and for future use in a potential outbreak setting.

Despite high morbidity and mortality, there are currently no approved vaccines for protection against Middle East respiratory syndrome (MERS) coronavirus. Here the authors develop a ferritin nanoparticle-based MERS-CoV vaccine that elicits high levels of neutralizing antibodies in mice, non-human primates, and alpacas and prevents infection in an alpaca challenge model.