Rotavirus VLPs in Plants as Vaccine Candidate

Rodolfo E. Bégué, MD, Principal Investigator
Michael Lan, PhD

Abstract
Background: Rotaviruses cause approximately 3 million infections and 50,000 hospitalizations in the US every year. A live vaccine was developed at NIAID and licensed in 1998 but its use was soon discontinued because it would cause intussusception, a form of intestinal obstruction. The mechanism of intussusception is unknown but it may be related to virus replication. Vaccines based on non-replicating particles might not have a similar complication.

Long-term Objective: T produce a safe and effective rotavirus vaccine.

Specific Objectives: a) To construct rotavirus-like particles (RVLPs) in Arabidopsis thaliana plant cells; b) To test the immunogenicity of the plant-made RVLPs in mice.

Design: Recombinant viral proteins VP2, VP4, VP6 and VP7 of serotype G1 rotavirus strain WA will be expressed into E. coli and the product tested for physical, chemical and immunologic properties. Next, using a constitutive Agrobacterium system, Arabidopsis thaliana plants will be transformed to express each one of the 4 VPs and the products tested again for physical, chemical and immunologic properties as compared to bacterial rVPs. Plants will then be cross-pollinated to produce offsprings that simultaneously express all 4 VPs. Location of rVPs within the plant cells and aggregation into RVLPs will be evaluated by electron microscopy. Finally, mice will be orally immunized with plants expressing RVLPs and the production of serum and instestinal antibodies determined.

Health Importance: The project should advance our knowledge of mucosal vaccines and the use of viral-like particles as a mode of antigen presentation to the immune system. In the long run, a vaccine to prevent rotavirus infection should avoid significant morbidity and mortality worldwide.

Collaborations:
James H. Oard, PhD, LSU Agricultural Center, Baton Rouge

Sponsor: NIH
Duration: 01/04 - 12/05