Objective To develop an O-specific polysaccharide(O-SP) based conjugate against Pseudomonas aeruginosa.Methods Lipopolysaccharide(LPS) from Pseudomonas aeruginosa(IATS 6) was isolated via hot phenol extraction and then hydrolyzed to obtain O-specific polysaccharide(O-SP).O-SP was activated with CDAP,using adipic acid dihydrazide as a linker.Activated O-SP was conjugated to tetanus toxoid via EDAC mediated condensation reaction.Immunogenicity of the conjugate and its immune protection were evaluated in mice....