Shigellae

病原菌表面多糖，包括CPS或脂多糖的O-特异性多糖(OSP)，既是基本的毒力因子，又是保护性抗原。这些糖与医学上有用的蛋白质共价结合形成结合物，增加了它们的免疫原性，使它们对T细胞产生依赖，使它们适合婴儿和儿童的疫苗。结合重组无毒铜绿假单胞菌外蛋白A(REPA)的宋内氏志贺氏菌O-SP对6-14%发病率的青壮年有超过70%的疗效。该结合物和结合琥珀酸化外蛋白A的福氏2a志贺菌结合物(REPA-Succ)是安全的，可在1~4岁儿童中诱导抗同源内毒素的抗体。一项对1至4岁儿童进行的随机、盲目、第三阶段的研究表明，这些疫苗是安全的。免疫原性和有效性与年龄有关，在1至2岁的儿童中几乎没有效果，但在3至4岁的儿童中约有70%。和以前一样，抗体水平的成倍增长与成人相似，但实际达到的水平更低。 我们已经证明，合成的1型痢疾杆菌O-SP寡糖，通过它们的还原末端结合到载体蛋白上(SUN构型)，诱导的抗体水平显著高于通过几个点连接(晶格构型)结合到蛋白质上的天然O-SP的结合物。松内螺旋藻低聚糖的合成没有成功。因此，我们分离了天然O-SP的低分子质量O-SP-核心(O-SPC)片段，并利用它们通过还原末端核心末端Kdo残基与BSA或无毒重组白喉毒素或艰难梭菌毒素B结合的氨基连接物之间的肟键与蛋白质结合。偶联反应在中性pH、室温下进行，时间短。抗原性水平。O-SP结合物在幼龄杂交小鼠体内诱导的Sonnei-LPSIg G显著高于O-SP全长结合物诱导的Sonnei-LPSG。 志贺氏邻单胞菌O17的O-SP在结构上与宋内氏副单胞菌完全相同，但仅公布了宋内氏副单胞菌的核心结构。我们用核磁共振和质谱仪研究了志贺氏假单胞菌O17的核心结构，包括它与O-SP的连接。指定了一个不同于S.sonnei核心的核心结构。

Surface polysaccharides of pathogenic bacteria, including CPs or the O-specific polysaccharide (OSP) of lipopolysaccharides (LPS), function as both essential virulence factors and protective antigens. Covalent binding of these saccharides to medically useful proteins to form conjugates increases their immunogenicity and confers on them T cell dependence, making them suitable vaccines for infants and children. The O-SP of Shigella sonnei bound to recombinant non-toxic P. aeruginosa exoprotein A (rEPA) exhibited an efficacy of over 70 percent in young adults exposed to 6 to 14 percent attack rates. This conjugate and that of S. flexneri 2a bound to the succinylated exoprotein A (rEPA-succ) were safe and induced IgG antibodies to the homologous LPS in 1- to 4-year-olds. A randomized, blinded, Phase 3 study of the conjugates in 1- to 4-year-olds, with each conjugate serving as a control for the other, showed the vaccines to be safe. Immunogenicity and efficacy were age-related with little efficacy in 1- to 2-year-olds but with about 70 percent in 3- to 4-year-olds. As before, fold increases in antibody levels were similar to those for adults, but the actual achieved levels were lower. We have shown that synthetic oligosaccharides of S. dysenteriae type 1 O-SP, bound by their reducing end to a carrier protein (sun configuration), induced significantly higher antibody levels than conjugates of the native O-SP bound to protein by several point attachments (lattice configuration). Synthesis of S. sonnei oligosaccharides was not successful. Therefore, we isolated lowmolecular mass O-SP-core (O-SPC) fragments of the native O-SP and used them to bind to proteins by oxime linkages between the terminal Kdo residues of the reducing end core and the aminoxy linkers bound to either BSA or to non-toxic recombinant diphtheria toxin or C.difficile toxin B. The coupling reaction was performed at a neutral pH, at room temperature, and in a short time. Levels of antiS. sonnei LPS IgG induced by these conjugates in young outbred mice were significantly higher than those induced by the full-length O-SP conjugates. The O-SP of Plesiomonas shigelloides O17 is structurally identical to that of S. sonnei, but only the core structure of S. sonnei has been published. We investigated the core structure of P. shigelloides O17, including its linkage to the O-SP, by nuclear magnetic resonance (NMR) and mass spectroscopy. A core structure, different form the S. sonnei core, was assigned.