Outer membrane vesicles for vaccine antigen display

Outer membrane vesicles (OMVs) are secreted by many bacteria, and can act as nonliving proxies stimulating the immune system. Genetic engineering of OMV-producing bacteria such as Salmonella and Neisseria can be used to expand the range of protection and improve the safety of OMVs. They therefore have great potential as vaccines. Emerging infectious diseases and increasing antibiotic resistance call for innovative new vaccination approaches which can be rapidly developed against new threats. Methods to express a wide range of heterologous antigens at the surface of OMVs in established production strains can provide such a solution.

InTraVacc and Abera have collaborated towards this application of the OMV platform for novel vaccines against Mycobacterium tuberculosis and Acinetobacter baumannii, bacteria which are problematic because of causing antibiotic resistant infections. Using an autotransporter display platform, multiple antigens from both pathogens were successfully expressed in Salmonella OMVs. Mice were immunized with these OMVs in order to investigate the antibody response generated. The project has laid the foundation for this novel concept for vaccines against the two pathogenic bacteria.