Fig. 1From: Constructing conjugate vaccine against Salmonella Typhimurium using lipid-A free lipopolysaccharideDesign of polysaccharide–protein vaccine. a Diagram for connecting the terminal Kdo of LFPS and the lysine residues of carrier protein. The drawings of PS, linker and protein are not proportional to their relative sizes. b Transformation of Kdo-terminated polysaccharide into quinoxalinone (PS–QXO/FG) and amide (PS–amide/FG) linked products via the condensation reaction with o-phenylenediamine and the decarboxylative amidation with amine, respectivelyBack to article page