title: Improved immunogenicity of tetanus toxoid by Brucella abortus S19 LPS adjuvant.
abstract: BACKGROUND
  Adjuvants are used to increase the immunogenicity of new generation vaccines, especially those based on recombinant proteins. Despite immunostimulatory properties, the use of bacterial lipopolysaccharide (LPS) as an adjuvant has been hampered due to its toxicity and pyrogenicity. Brucella abortus LPS is less toxic and has no pyrogenic properties compared to LPS from other gram negative bacteria.
  
  
  OBJECTIVE
  To evaluate the adjuvant effect of B. abortus (vaccine strain, S19) LPS for tetanus toxoid antigen (TT) and to investigate the protective effect of different tetanus vaccine preparations.
  
  
  METHODS
  LPS was extracted and purified from B. abortus S19 and KDO, glycan, phosphate content, and protein contamination were measured. Adipic acid dihydrazide (ADH) was used as a linker for conjugation of TT to LPS. Different amounts of B. abortus LPS, TT, TT conjugated with LPS, and TT mixed with LPS or complete Freund's adjuvant (CFA) were injected into mice and antibody production against TT was measured. The protective effect of induced antibodies was determined by LD50.
  
  
  RESULTS
  Immunization of mice with TT+LPS produced the highest anti-TT antibody titer in comparison to the group immunized with TT without any adjuvant or the groups immunized with TT-LPS or TT+CFA. Tetanus toxid-S19 LPS also produced a 100% protective effect against TT in immunized mice.
  
  
  CONCLUSIONS
  These data indicate that B. abortus LPS enhances the immune responses to TT and suggest the possible use of B. abortus LPS as an adjuvant in vaccine preparations.
authors.affiliation: Immunology Lab, Institute of Biochemistry and Biophysics, University of Tehran, Iran, e-mail:mohammadi@ibb.ut.ac.ir.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Mohammadi
authors.forename: Zahra
authors.initials: Z
authors.lastname: Kianmehr
authors.forename: Sussan
authors.initials: S
authors.lastname: Kaboudanian Ardestani
authors.forename: Behnaz
authors.initials: B
authors.lastname: Gharegozlou
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D000917:Antibody Formation; D002003:Brucella abortus / Q000276:immunology*; D004195:Disease Models, Animal; D005260:Female; D007114:Immunization; D007928:Lethal Dose 50; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000276:immunology*; D051379:Mice; D013742:Tetanus / Q000517:prevention & control; D013745:Tetanus Toxoid / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000907:Antibodies, Bacterial; D008070:Lipopolysaccharides; D013745:Tetanus Toxoid