Constructing conjugate vaccine against Salmonella Typhimurium using lipid-A free lipopolysaccharide

作者：Tzu-Wei Chiu, Chi‐Jiun Peng, Ming-Cheng Chen, Mei‐Hua Hsu, Yihua Liang, Cheng‐Hsun Chiu, Jim‐Min Fang, Yuan Chuan Lee · 发表于：Journal of Biomedical Science · 年份：2020 · DOI：10.1186/s12929-020-00681-8 · 被引用次数：29 · 研究领域：Salmonella and Campylobacter epidemiology、Immune Response and Inflammation、Cancer Research and Treatments

BACKGROUND: Salmonella enterica serotype Typhimurium is a nontyphoidal and common foodborne pathogen that causes serious threat to humans. There is no licensed vaccine to prevent the nontyphoid bacterial infection caused by S. Typhimurium. METHODS: To develop conjugate vaccines, the bacterial lipid-A free lipopolysaccharide (LFPS) is prepared as the immunogen and used to synthesize the LFPS-linker-protein conjugates 6a-9b. The designed bifunctional linkers 1-5 comprising either an o-phenylenediamine or amine moiety are specifically attached to the exposed 3-deoxy-D-manno-octulosonic acid (Kdo), an α-ketoacid saccharide of LFPS, via condensation reaction or decarboxylative amidation. In addition to bovine serum albumin and ovalbumin, the S. Typhimurium flagellin (FliC) is also used as a self-adjuvanting protein carrier. RESULTS: The synthesized conjugate vaccines are characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and fast performance liquid chromatography (FPLC), and their contents of polysaccharides and protein are determined by phenol-sulfuric acid assay and bicinchoninic acid assay, respectively. Enzyme-linked immunosorbent assay (ELISA) shows that immunization of mouse with the LFPS-linker-protein vaccines at a dosage of 2.5 μg is sufficient to elicit serum immunoglobulin G (IgG) specific to S. Typhimurium lipopolysaccharide (LPS). The straight-chain amide linkers in conjugates 7a-9b do not interfere with the desired immune response. ...