Conjugation of tetanus toxoid with Salmonella typhimurium PTCC 1735 O-specific polysaccharide and its effects on production of opsonizing antibodies in a mouse model.
Serious enteric and extra-intestinal infections with Salmonella typhimurium are very common in many human populations. Phagocytosis is the main defense mechanism against this bacterium; however, the unique structure of S. typhimurium lipopolysaccharide (LPS) makes it resistant to opsonization by complement components. In the present study, the S. typhimurium LPS O-chain was purified and conjugated with tetanus toxoid and the effects of the conjugated vaccine (O-specific polysaccharide tetanus toxoid (O-SP-TT)) on induction of specific antibodies were investigated in a mouse model. In vitro assays measuring phagocytosis in the presence of opsonizing antibodies were performed. Three subcutaneous injections of the O-SP-TT conjugate conferred protection against the intraperitoneal challenge with S. typhimurium and the LD50 was greater for immunized animals than for controls. The mean number of ingested S. typhimirium / mouse peritoneal cell in the presence of sera obtained from immunized mice with purified O-chain, O-SP-TT conjugate, heat-killed bacteria, and negative control were 6.96, 14.24, 15.96, and 6.67, respectively. In summary, we developed an O-SP-TT conjugate that induced opsonizing antibodies that increased phagocytosis, as determined by in vitro assays. In addition, chemiluminescence results, an indicator of oxidative burst, indicated that peritoneal cells respond better to live S. typhimurium cells in the presence of sera obtained from O-SP-TT conjugate immunized mice.
Department of Microbiology, Faculty of Medicine, Uromieh Medical Sciences University, Uromieh, Iran. n_jazani@umsu.ac.ir
Nima Hosseini
NH
Jazani
Elizabeth
E
Worobec
Shahram
S
Shahabi
Ghorban Behzadian
GB
Nejad
D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology*; D005260:Female; D007106:Immune Sera / Q000276:immunology; D007279:Injections, Subcutaneous; D051379:Mice; D008807:Mice, Inbred BALB C; D019081:O Antigens / Q000276:immunology*; D009895:Opsonin Proteins / Q000276:immunology*; D010587:Phagocytosis / Q000276:immunology; D012480:Salmonella Infections / Q000276:immunology* / Q000517:prevention & control; D012486:Salmonella typhimurium / Q000276:immunology*; D013745:Tetanus Toxoid / Q000008:administration & dosage / Q000276:immunology*; D014611:Vaccination; D018074:Vaccines, Conjugate / Q000008:administration & dosage / Q000276:immunology
D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D007106:Immune Sera; D019081:O Antigens; D009895:Opsonin Proteins; D013745:Tetanus Toxoid; D018074:Vaccines, Conjugate