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

Abstract

ObjectivesDevelopment 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.MethodsIn 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 μg 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.ResultsThe 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.ConclusionThese results indicate that our conjugated LPS–OMV can be used as a brucellosis vaccine, but further investigation is required.

Designing an immunosensor for detection of Brucella abortus based on coloured silica nanoparticles

“…Other bacteria were cultured in nutrient-agar. After 24 h incubation at 37 C, colonies were confirmed by a biochemical test, and stored at À70 C before use [21].…”

Comparative Study of Lipopolysaccharide and Killed Vaccines of Brucella suis Field Isolate in Mice

“…This implies that the role of IL-10 in immune response is limited to offset the Th1 cytokines production rather an exaggerated proinflammatory response (Pasquali et al, 2001). Further, IL12, a cytokine which plays crucial role in activating interferon producing NK and T helper cells leads to antibacterial response mechanism (Zhan and Cheers, 1995;Siadat et al, 2015).…”

Evaluation of Biochemical Differences and Immunostimulatory Properties of LPS and Lipid a Extracted From Brucella Strains

“…These properties make B. abortus LPS a safe adjuvant to be used in vaccine production with different antigens for eliciting immunostimulatory activities. For these reasons, several studies evaluated effectiveness of B. abortus LPS as a safe adjuvant in combination with different antigens for designing new vaccine formulation [35][36][37][38][39] or developing an efficacious subunit vaccine against brucellosis using B. abortus LPS conjugated to carrier protein [40,41].…”