Engineering Escherichia Coli For Novel Vesicle Vaccine Methods

Abstract

Vaccines are one of the most economically effective courses of preventative medicine and their efficacy has been proven in the eradication of many deadly, infectious diseases [3]. Despite their success in developed nations, the World Health Organization estimates that 2.5 million children worldwide still die of vaccinepreventable diseases and of these children 70% are in the world's poorest nations. Among the many vaccine strategies, glycoconjugate vaccines are an effective method, however their high cost of development and manufacture makes them inaccessible to developing nations. Thus, the main goal of this research is to employ bacteria for the development of low-cost glycoconjugate vesicle vaccines. A vesicle vaccine takes advantage of the inherent immunostimulatory properties of the components naturally found in the outer membrane which are included when parts of the outer membrane bleb off as outer membrane vesicles, or OMVs. We hypothesize that glycoconjugate vesicle vaccines will address many of the current challenges surrounding glycoconjugate vaccines and make them attainable worldwide. This research has shown that we can produce two types of glycoconjugate vaccines. One variation is the conjugation of heterologous bacterial polysaccharides to lipid A, an adjuvant yet toxic component of lipopolysaccharide, or LPS, which is a major component of OMVs. The second variation is to utilize a conjugating enzyme, an oligosaccharyltransferase (OST), from the bacterium Camphylobacter jejuni to attach the bacterial polysaccharide to an outer membrane protein, which will bleb off with the outer membrane vesicles. Both techniques utilize the stability and delivery benefits of bacterial outer membrane vesicles. This research has the potential to offer a stable, immunogenic, non-toxic, all-in-one vaccine and delivery system that may offer protection against diverse infectious diseases that is inexpensive and accessible to developing nations. ii