Preparation and Evaluation of a New Lipopolysaccharide-based Conjugate as a Vaccine Candidate for Brucellosis

다국어 초록 (Multilingual Abstract)

Objectives: Development of an efficacious vaccine against brucellosis has been a challenge for scientists for many years. At present, there is no licensed vaccine against human brucellosis. To overcome this problem, currently, antigenic determinants of Brucella cell wall such as Lipopolysaccharide (LPS) are considered as potential candidates to develop subunit vaccines. Methods: In this study, Brucella abortus LPS was used for conjugation to Neisseria meningitidis serogroup B outer membrane vesicle (OMV) as carrier protein using carbodiimide and adipic acid-mediated coupling and linking, respectively. Groups of eight BALB/c mice were injected subcutaneously with 10 ㎍LPS alone, combined LPS + OMV and conjugated LPS-OMV on 0 days, 14 days, 28 days and 42 days. Anti-LPS IgG was measured in serum. Results: The yield of LPS to OMV in LPS-OMV conjugate was 46.55%, on the basis of carbohydrate content. The ratio for LPS to OMV was 4.07. The LPS-OMV conjugate was the most immunogenic compound that stimulated following the first injection with increased IgG titer of ~ 5-fold and ~1.3-fold higher than that produced against LPS and LPS in noncovalent complex to OMV (LPS + OMV), respectively. The highest anti-LPS IgG titer was detected 2 weeks after the third injection (Day 42) of LPS-OMV conjugate. The conjugated compound elicited higher titers of IgG than LPS + OMV, that showed a 100-120-fold rise of anti-LPS IgG in mice. Conclusion: These results indicate that our conjugated LPS-OMV can be used as a brucellosis vaccine, but further investigation is required.

참고문헌 (Reference)

1 Cabrera O, "and evaluation of Vibrio cholerae O1 EL Tor Ogawa lipopolysaccharide-tetanus toxoid conjugates" 24 (24): S74-S75, 2006

2 Sh Yu, "Synthesis and characterization of lipooligosaccharide-based conjugate vaccines for serotype B Moraxella catarrhalis" 73 : 2790-2796, 2005

3 Sharifat Salmani A, "Serological evaluation of Brucella abortus S99 lipopolysaccharide extracted by an optimized method" 5 : 11-16, 2009

4 Jin Z, "Preparation and characterization of group A meningococcal capsular polysaccharide conjugates and evaluation of their immunogenicity in mice" 71 : 5115-5120, 2003

5 Siadat SD, "Past, present and future perspective of meningococcal vaccine" 1 : 129-146, 2007

6 Sardinas G, "Outer membrane vesicles of Neisseria lactamica as a potential mucosal adjuvant" 24 : 206-214, 2006

7 Sharifat Salmani A, "Outer membrane vesicle of Neisseria meningitidis serogroup B as an adjuvant to induce specific antibody response against the lipopolysaccharide of Brucella abortus S99" 59 : 145-149, 2009

8 Shapuri R, "Optimization of Brucella abortus fermenter cultural conditions and LPS extraction methods for antigen production" 3 : 1-8, 2008

9 Sharifat Salmani A, "Optimization of Brucella abortus S99 lipopolysaccharide extraction by phenol and butanol methods" 3 : 576-580, 2008

10 Cabrera O, "New method for obtaining conjugated vaccines" 24 (24): S76-S78, 2006

11 Kheirandish M, "Measurement of opsonophagocytic activity of antibodies specific to Neisseria meningitidis serogroup A capsular polysaccharide-serogroup B outer membrane vesicle conjugate in animal model" 59 : 801-806, 2009

12 Jacques I, "Induction of antibody and protective responses in mice by Brucella O-poly-saccharide-BSA conjugate" 9 : 896-900, 1991

13 Oliveira SC, "Immunization of mice with recombinant L7/L12 ribosomal protein confers protection against Brucella abortus infection" 14 : 959-962, 1996

14 Siadat SD, "Evaluation of serum bactericidal activity specific for Neisseria meningitidis Serogroup A and B: effect of immunization with Neisseria meningitidis serogroup A polysaccharide and serogroup B outer membrane vesicle conjugate as a bivalent meningococcus vaccine candidate" 2 : 436-444, 2007

15 Winter AJ, "Effectiveness of natural and synthetic complexes of porin and O-polysaccharide as vaccines against Brucella abortus in mice" 56 : 2808-2817, 1988

16 Bhattacharjee AK, "Comparison of protective efficacy of subcutaneous versus intranasal immunization of mice with a Brucella melitensis lipopolysaccharide subunit vaccine" 74 : 5820-5825, 2006

17 Siadat SD, "Comparative studies of conjugated capsular polysaccharide of Neisseria meningitidis serogroup A with outer membrane vesicle of Neisseria meningitidis serogroup B" 2 : 337-345, 2007

18 Cloeckaert A, "Characterization of O-polysaccharide-specific monoclonal antibodies derived from mice infected with the rough Brucella melitensis strain B115" 139 : 1551-1556, 1993

19 Ada G, "Carbohydrate-protein conjugate vaccines" 9 : 79-85, 2003

20 Sh Yu, "Biological and immunological characteristics of lipooligosaccharide-based conjugate vaccines for serotype C Moraxella catarrhalis" 75 : 2974-2980, 2007

21 Siadat SD, "Biological and immunological characteristics of Brucella abortus S99 major outer membrane proteins" 4 : 29-36, 2011

22 Siadat SD, "A flow cytometric opsonophagocytic assay for measurement of functional antibodies elicited after immunization with outer membrane vesicle of Neisseria meningitidis serogroup B" 10 : 3578-3584, 2007