论文部分内容阅读
以往的志贺菌自然感染能对同型菌的再感染提供高度的免疫力.抗感染免疫是由针对O多糖(O-PS)成分的抗脂多糖(LPS)抗体所介导的,这就导致了一系列含O-PS菌苗的构建.霍乱弧菌染色体上的rfb基因座编码霍乱弧菌O-PS,而宋内志贺菌的rfb基因座则位于质粒上,其脂多糖具有Rl型核心.在宋内志贺菌中,rfc基因(一种rfb连锁基因)编码O抗原聚合酶,此酶能将二糖装配成长链重复体.研究证实两种O-PS的共表达不理想,最佳方法是在载体菌株中只表达异源性O-PS.本试验的主要程序是:(1)自霍乱弧菌减毒株CVD103-HgR(汞抗性)中克隆rfb_(Inaba)基因座;(2)构建仅有重组rfb/rfc_(sonnei)基因座或结合rfa_Rl基因座的rfb_(Inaba)缺失的CVD103-HgR突变株,测定缺失突变株中同源性和异源性LPS的表达;(3)检测缺失突变株的生物学特性,选择菌苗候选株CH21株(既表达R1型核心,又表达宋内志贺菌O-PS)和CH22株(仅表达宋内志贺菌O-PS)作进一步鉴定.
Previously natural Shigella infection provided a high degree of immunity to re-infection of the same bacteria, which is mediated by anti-lipopolysaccharide (LPS) antibodies directed against the O-PS component, resulting in A series of constructs containing the O-PS vaccine were constructed.The rfb locus on the cholerae Vibrio cholerae encodes Vibrio cholerae O-PS, whereas the rfb locus on Shigella sonnei is located on the plasmid with lipopolysaccharide Rl Core.In the Shigella sonnei, the rfc gene, an rfb-linked gene, encodes an O antigen polymerase that can assemble disaccharides into long chain repeats.The study demonstrated that co-expression of the two O-PSs was not ideal, The best method is to express only heterologous O-PS in the vector strain.The main procedures of this experiment are: (1) cloning the rfb_ (Inaba) locus from Vibrio cholerae attenuated strain CVD103-HgR (mercury resistance) ; (2) Construction of a rdb_ (Inaba) deleted CVD103-HgR mutant with only the rfb / rfc sonnei locus or the rfa_Rl locus, to determine the homologue and heterologous LPS expression in the deletion mutant; (3) To detect the biological characteristics of the mutant without mutation, select the candidate strain of vaccine strain CH21 (express both the R1 core and Shigella sonnei O-PS) and CH22 strain Shigella O-PS) for further identification.