Comparison of the adjuvanticity of two adjuvant formulations containing de-O-acylated lipooligosaccharide on Japanese encephalitis vaccine in mice
Adjuvants are essential vaccine components used to enhance, accelerate, and/or prolong adaptive immunity against specific vaccine antigens. In this study, we compared the adjuvanticity of two adjuvant formulations containing de-O-acylated lipooligosaccharide (dLOS), a toll-like receptor 4 agonist, on the Japanese encephalitis (JE) vaccine in mice. Mice were immunized once or twice at a two-week interval with inactivated JE vaccine in the absence or presence of adjuvant. We found that both the alum- and the liposome-based formulation induced significantly faster and higher serum IgG antibody responses as compared with the non-adjuvanted vaccine after either one or two immunizations. The antibody titers of the mouse immune sera correlated with 50% plaque reduction neutralization test (PRNT50) antibody titers. In addition, the dLOS/liposome formulation was more effective in inducing a Th1-type immune response than the dLOS/alum formulation, as suggested by a strong antigen-specific interferon (IFN)-γ response. Based on these results, we suggest that both alum- and liposome-based adjuvant formulations containing dLOS may be used for the development of JE vaccines with improved immunogenicity.
KeywordsAdjuvant formulation De-O-acylated lipooligosaccharide Japanese encephalitis vaccine
We thank Prof. J.H. Nam of Catholic University and Prof. B.L. Seong of Yonsei University (Republic of Korea) for providing the JEV Nakayama strain and recombinant JEV E protein, respectively. This study was supported by grants from the Korean Health Technology R&D Project, Ministry of Health & Welfare, Republic of Korea (No. HI14C2664 and No. HI13C0826).
Compliance with ethical standards
Conflict of interest
NG. Lee is an inventor of EyeGene-owned patents on dLOS-based adjuvants and a scientific advisor for EyeGene. The other authors have no conflicts of interests.
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