Development and characterization of a plant-derived norovirus-like particle vaccine.

Background: Norovirus (NoV) is the most common cause of diarrheal episodes globally. Issues with in vitro cultivation systems, genetic variation, and animal models have hindered vaccine development. Plant-derived virus-like particles (VLPs) may address some of these concerns because they are highly immunogenic, can be administered by different routes, and can be rapidly produced to accommodate emerging viral strains.

Elimination of receptor binding by influenza hemagglutinin improves vaccine-induced immunity.

The binding of influenza hemagglutinin (HA) to sialic acid (SA) receptors plays a well-defined role in shaping infection but the impact of such binding on vaccine responses has not yet been explored. We generated a virus-like particle (VLP) vaccine bearing the HA of H1N1 A/California/07/09 that is unable to bind to its α(2,6)-linked SA receptor (H1-VLP) and compared its immunogenicity and efficacy to a wild-type H1-VLP (H1-VLP) in mice. The H1-VLP elicited significantly stronger and more durable antibody responses (hemagglutination inhibition and microneutralization titers) and greater avidity maturation, likely attributable to improved germinal center formation.

Plant-made virus-like particle vaccines bearing the hemagglutinin of either seasonal (H1) or avian (H5) influenza have distinct patterns of interaction with human immune cells in vitro.

Introduction: The recent emergence of avian influenza strains has fuelled concern about pandemic preparedness since vaccines targeting these viruses are often poorly immunogenic. Weak antibody responses to vaccines have been seen across multiple platforms including plant-made VLPs. To better understand these differences, we compared the in vitro responses of human immune cells exposed to plant-made virus-like particle (VLP) vaccines targeting H1N1 (H1-VLP) and H5N1 (H5-VLP).