title: Immuno-Stimulatory Activity of Escherichia coli Mutants Producing Kdo2-Monophosphoryl-Lipid A or Kdo2-Pentaacyl-Monophosphoryl-Lipid A.
abstract: Lipid A is the active center of lipopolysaccharide which also known as endotoxin. Monophosphoryl-lipid A (MPLA) has less toxicity but retains potent immunoadjuvant activity; therefore, it can be developed as adjuvant for improving the strength and duration of the immune response to antigens. However, MPLA cannot be chemically synthesized and can only be obtained by hydrolyzing lipopolysaccharide (LPS) purified from Gram-negative bacteria. Purifying LPS is difficult and time-consuming and can damage the structure of MPLA. In this study, Escherichia coli mutant strains HWB01 and HWB02 were constructed by deleting several genes and integrating Francisella novicida gene lpxE into the chromosome of E. coli wild type strain W3110. Compared with W3110, HWB01 and HWB02 synthesized very short LPS, Kdo2-monophosphoryl-lipid A (Kdo2-MPLA) and Kdo2-pentaacyl-monophosphoryl-lipid A (Kdo2-pentaacyl-MPLA), respectively. Structural changes of LPS in the outer membranes of HWB01 and HWB02 increased their membrane permeability, surface hydrophobicity, auto-aggregation ability and sensitivity to some antibiotics, but the abilities of these strains to activate the TLR4/MD-2 receptor of HKE-Blue hTLR4 cells were deceased. Importantly, purified Kdo2-MPLA and Kdo2-pentaacyl-MPLA differed from wild type LPS in their ability to stimulate the mammalian cell lines THP-1 and RAW264.7. The purification of Kdo2-MPLA and Kdo2-pentaacyl-MPLA from HWB01 and HWB02, respectively, is much easier than the purification of LPS from W3110, and these lipid A derivatives could be important tools for developing future vaccine adjuvants.
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.|School of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.
authors.forename: Biwen
authors.initials: B
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.
authors.forename: Yaning
authors.initials: Y
authors.lastname: Han
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, China.|Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi, China.
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Wang
mesh_terms: D000276:Adjuvants, Immunologic / Q000235:genetics; D001428:Bacterial Vaccines / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics* / Q000276:immunology / Q000378:metabolism*; D005603:Francisella / Q000235:genetics; D008050:Lipid A / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D008070:Lipopolysaccharides / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology; D014614:Vaccines, Synthetic / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D001428:Bacterial Vaccines; C506188:Kdo2-lipid A; D008050:Lipid A; D008070:Lipopolysaccharides; D008565:Membrane Proteins; D014614:Vaccines, Synthetic; C048436:monophosphoryl lipid A