Characterization of the structure and immunostimulatory activity of a vaccine adjuvant, de-O-acylated lipooligosaccharide.
Lipopolysaccharide (LPS) is a major component of the outer membrane of Gram-negative bacteria. LPS elicits strong immunopathological responses during bacterial infection, and the lipid A moiety of LPS is responsible for this immunostimulatory activity. Lipid A exerts its biological activity by sending signals via TLR4 present on immune cells, and TLR4 agonists have been a target for vaccine adjuvant. Previously, we demonstrated an adjuvant activity of deacylated lipooligosaccharide (dLOS) to viral and bacterial antigens. In this study, we characterized the chemical structure of dLOS and evaluated its immunostimulatory activity on mouse and human immune cells in comparison with monophosphoryl lipid A (MPL). dLOS consists of the R3-type core, a glucosamine disaccharide with two phosphate groups, and two N-linked acyl groups [corrected], and two N-linked acyl groups. dLOS was similar to MPL in induction of cytokine production in mouse peritoneal macrophages, but was a more potent activator in human monocytes and dendritic cells (DCs). Results of an analysis of allogeneic T cell responses revealed that dLOS induces Th1, Th2, and Th17-type immune responses in a dose-dependent manner. The immunostimulatory activities of dLOS were completely abrogated in TLR4(-/-) mice, which confirms its TLR4-dependency. These results suggest that in the presence of the core oligosaccharide, O-linked acyl groups of LPS are dispensable for activating the TLR4 signaling pathway. dLOS did not cause any pathological effects or death at 0.25, 0.5, or 1 mg per kg body weight in mice in the acute toxicity tests. This result suggests that dLOS has a low toxicity. dLOS should be considered for further development as a safe and effective adjuvant for human vaccines.
Department of Bioscience & Biotechnology, College of Bioscience, Sejong University, Seoul, Republic of Korea.
Ji Eun
JE
Han
Department of Bioscience & Biotechnology, College of Bioscience, Sejong University, Seoul, Republic of Korea.
Seo Ri
SR
Wui
Research & Development Center, EyeGene, Seoul, Republic of Korea.
Kwang Sung
KS
Kim
Research & Development Center, EyeGene, Seoul, Republic of Korea.
Yang Je
YJ
Cho
Yonsei University Gangnam Severance Hospital, Seoul, Republic of Korea.
Wan Je
WJ
Cho
Department of Bioscience & Biotechnology, College of Bioscience, Sejong University, Seoul, Republic of Korea.
Na Gyong
NG
Lee
D000215:Acylation; D000276:Adjuvants, Immunologic / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured; D016207:Cytokines / Q000097:blood / Q000276:immunology / Q000378:metabolism; D003713:Dendritic Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D015151:Immunoblotting; D008070:Lipopolysaccharides / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology*; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D015394:Molecular Structure; D009000:Monocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000172:deficiency / Q000235:genetics / Q000276:immunology; D014612:Vaccines / Q000276:immunology
D000276:Adjuvants, Immunologic; D016207:Cytokines; D008070:Lipopolysaccharides; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D014612:Vaccines; C023023:lipid-linked oligosaccharides