Physico-chemical properties of Salmonella typhi Vi polysaccharide-diphtheria toxoid conjugate vaccines affect immunogenicity

► Vi capsular polysaccharide from Salmonella typhi was conjugated to diphtheria toxoid. ► We produced a series of Vi-DT conjugates with varying amounts of bound DT. ► With more DT bound the size and amount of crosslinking within the conjugate increased. ► The anti-Vi response in mice increased with increasing amounts of DT bound.