Multidisciplinary Approaches to Study O-Antigen: Antibody Recognition in Support of the Development of Synthetic Carbohydrate-Based Enteric Vaccines

Abstract

Enteric infections, including bacterium-induced diarrhoeal diseases, represent a major health burden worldwide. In developed countries, infectious diarrhoea contributes primarily to morbidity. It remains the second leading cause of death in children below 5 years of age living in the developing world (Cheng et al. 2005; You et al. 2010). It is anticipated that improved living conditions will contribute to diminish the transmission of enteric pathogens and lower the incidence of enteric diseases. In the meantime, the introduction of vaccines could play an active part in reducing the vulnerability of the target populations to the predominant enteric pathogens. Along this line, Shigella, ETEC, cholera, and typhoid fever were identified by WHO since the early 1990s as the highest bacterial disease priorities for the development of new or improved enteric vaccines. Substantial progress was made (Levine 2006). In this context, polysaccharide-based parenteral vaccines have been investigated with some success. The licensure of the purified capsular Vi polysaccharide against typhoid fever was an important achievement, especially since recent evidence of herd protection conferred by the vaccine has highlighted the benefit of large-scale use in endemic countries (Khan et al. 2010). Moreover, encouraging investigational studies on a Vi polysaccharide–protein conjugate vaccine, which could be introduced into the infant immunization schedule, were reported (Canh et al. 2004; Cui et al. 2010).