Immune Response To Polysaccharide-protein Conjugate Vacc

对多糖-蛋白缀合物疫苗的免疫反应

• 批准号: 6541154
• 负责人: RACHEL SCHNEERSON
• 金额: --
• 依托单位: EUNICE KENNEDY SHRIVER NATIONAL INSTITUTE OF CHILD HEALTH & HUMAN DEVELOPMENT
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6541154
• 关键词: Bacillus; Bordetella pertussis; Borrelia; Clostridium difficile; Corynebacterium diphtheriae; Neisseria meningitidis vaccine; Pseudomonas aeruginosa; Shigella vaccines; Streptococcus vaccine; active immunization; adult human (21+); bacterial polysaccharides; bacterial vaccines; bactericidal immunity; clinical research; drug screening /evaluation; human subject; human therapy evaluation; immunoconjugates; lipopolysaccharides; membrane transport proteins; middle childhood (6-11); preschool child (1-5); tetanus toxoid

Surface polysaccharides of pathogenic bacteria, including capsular polysaccharides (CPS) or lipopolysaccharides (LPS), serve both as essential virulence factors and as protective antigens. The age-related and T-cell independent immunogenicity of CPS limit their use as vaccines especially in infants and young children. LPS are too toxic to be administered. Accordingly, their O-specific polysaccharide (O-SP), that share the virulence promoting and protectiveness of CPS, must be purified: O-SP are too small to be immunogenic (haptens). Covalent binding of CPS or of O-SP to medically-useful proteins to form conjugates both increases their immunogenicity and confers T-cell dependence to these saccharides. The O-SP of Shigella sonnei and of Shigella flexneri 2a were bound to bacterial toxoids. In adults and then in 4-7 year-olds, both conjugates were safe and induced statistically significant and long-lived rises of IgG antibodies to the homologous LPS. Similar, though lesser rises of IgM and IgA anti-LPS were also induced. Re-injection of S. flexneri 2a conjugate induced a booster response in the recruits and the 4-7 years old. A Phase 3 trial showed that one injection of S. sonnei O-SP, bound to a non-toxic recombinant Pseudomonas aeruginosa exoprotein A (rEPA) protected army recruits against outbreaks with this pathogen. Importantly, there was a statistically-significant correlation between the levels of serum IgG anti-LPS and the efficacy of the conjugate. Two methods were developed that increased the immunogenicity of the Shigella conjugates in mice: another carrier protein, a genetically-inactivated Corynebacterium diphtheriae toxin (CRM9) was a superior carrier for S. sonnei O-SP and treatment of rEPA with succinic anhydride, a non-toxic mild akylating agent that converts amino groups of proteins to carboxyls, increased the immunogenicity of S. flexneri 2a O-SP. A phase 1 study in adults of these Shigella conjugates confirmed their safety and immunogenicity; the improved immunogenicity was less marked than in mice. A phase 2 study in 1-4 years old showed an improved immunogenicity of the new S.flexneri 2a conjugate but lesser immunogenicity of the S.sonnei conjugate. A phase 3 study of the modified S.flexneri 2a and the original S. sonnei conjugates are in preparation. In collaboration with the Lanzhou Vaccine Institute and Provincial Medical Center in Henan, China, a clinical trial of these two conjugates is being planned. To investigate if concurrent administration of a cross-reacting along with a homologous CPS has an advantage over the use of the homologous CPS alone, the cell wall polysaccharide (PS) of Bacillus pumilus, SH18, reported to cross react with the CPS of haemophilus influenzae type b (Hib), was isolated by conventional methods and it?s structure investigated using GC-MS. It was shown to contain glycerol, ribitol and 2-acetamido-2-deoxyglucose in a molar ratio of 0.2:1.0:0.2 and 17% phosphate. Besides with the anti Hib it cross reacted with anti Staphilococcus epidermidis. Methods to prepare a conjugate of this PS are investigated. Neisseria meningitidis group A causes endemic and epidemic meningitis, notably in the meningitis belt of Africa. A CPS vaccine , effective and available, is underutilized. To further improve it?s immunogenicity, as was done for other CPS, methods of binding it to a carrier protein are being investigated. A double mutant of Bordetella pertussis, producing a genetically-inactivated toxin and deficient in FHA synthesis was developed. Effort is directed towards increasing production of this B. pertussis strain as a more easily purified pertussis toxin for a monocomponent vaccine and as a carrier protein for pneumococcal type 14 CPS. Clostridium difficile is a major cause of hospital-acquired diarrhea following antibiotic usage: the diarrhea is mediated by two exotoxins, A and B. Toxin A, considered to be the major toxin, in the extreme form will cause pseudomembranous colitis. A genetically-derived toxin mutant (rARU) induces both antitoxin and protects animals from infection with C. difficile. The succinylation of rARU improved its solubility and did not detectably affects its antigenicity. Techniques to prepare the mutant toxins A for clinical use have been worked out. Three polysaccharide of varying composition, pneumococcus type 14, Escherichia coli K1 and S. flexneri 2a were conjugated to succinylated rARU. The resultant conjugates induced high levels of both anti-polysaccharide and antitoxin. Preparation of toxin A conjugates for clinical evaluation is underway. Borrelia burgdorferi, a spirochete transmitted though the bite of infected Ixodes ticks, is the etiologic agent of Lyme disease. A protein vaccine against it is available but is not effective below the age of 12 years. LPS has been described in other spirochetes but it's presence in B. burgdorferi has been debated. So far we have not been able to confirm it's presence. The search for LPS revealed a unique glycolipid cosisting of glycerol and galactose as the carbohydrate moiety. There is evidence that this glycolipid is surface exposed Injected in complete Freund's adjuvant it induced specific antibodies.

病原菌表面多糖，包括衣壳多糖(CPS)和脂多糖(LPS)，既是重要的毒力因子，又是保护性抗原。CPS的年龄相关和T细胞非依赖性免疫原性限制了其作为疫苗的使用，特别是在婴幼儿中。脂多糖毒性太大，不能用药。因此，它们的O-特异性多糖(O-SP)具有CPS的毒力促进和保护作用，必须进行纯化：O-SP太小而不能产生免疫原性(半抗原)。CPS或O-SP的共价结合到医学上有用的蛋白质上形成偶联物，既增加了它们的免疫原性，又使T细胞对这些糖类产生依赖。宋内氏志贺氏菌和福氏2a志贺氏菌的O-SP与细菌类毒素结合。在成人和4-7岁儿童中，这两种结合物都是安全的，并诱导了具有统计学意义的同源内毒素抗体的长期升高。类似地，尽管IgM和IgA抗内毒素的升高幅度较小，但也是如此。重新注射福氏2a结合菌在新兵和4-7岁儿童中诱导了增强反应。3期试验表明，一次注射宋内氏链球菌O-SP，与无毒的重组铜绿假单胞菌外蛋白A(REPA)结合，可保护新兵免受这种病原体的爆发。重要的是，血清中抗内毒素抗体的水平与结合物的疗效之间存在统计学上的显著相关性。研究了两种提高志贺氏菌结合物免疫原性的方法：另一种载体蛋白是基因灭活的白喉棒状杆菌毒素(CRM9)，它是宋内氏志贺氏菌O-SP的优良载体；琥珀酸酐处理REPA可提高福氏2a志贺氏菌O-SP的免疫原性。丁二酸酐是一种无毒的温和烷化剂，可将蛋白质的氨基转化为羧基。这些志贺氏菌结合物在成人中的第一阶段研究证实了它们的安全性和免疫原性；改善的免疫原性不如在小鼠身上明显。1-4岁儿童的2期研究表明，新的福氏2a结合物免疫原性增强，但宋内氏志贺氏菌结合物的免疫原性较低。改良的福氏2a志贺氏菌和原始宋内氏志贺氏菌结合物的3期研究正在准备中。在兰州疫苗研究所和河南省医学中心中国的合作下，这两种结合物的临床试验正在计划中。为了研究交叉反应与同源CPS同时给予是否比单独使用同源CPS更有优势，用常规方法分离了短小芽孢杆菌SH18与b型流感嗜血杆菌CPS交叉反应的胞壁多糖，并用GC-MS对其S结构进行了研究。甘油、核糖醇和2-乙酰氨基-2-脱氧葡萄糖的摩尔比为0.2：1.0：0.2，磷酸盐含量为17%。此外，它还与抗Hib抗体发生交叉反应。研究了该多聚糖偶联物的制备方法。A组脑膜炎奈瑟菌引起地方性和流行性脑膜炎，特别是在非洲的脑膜炎地带。一种有效和可用的CPS疫苗没有得到充分利用。为了进一步提高其免疫原性，就像对其他CP所做的那样，正在研究将其与载体蛋白结合的方法。百日咳杆菌产生一种FHA合成缺陷的基因失活毒素，是百日咳杆菌的双突变株。致力于提高百日咳杆菌菌株的产量，将其作为一种更容易提纯的百日咳毒素用于单组分疫苗，并作为14型肺炎球菌CPS的载体蛋白。艰难梭菌是抗生素使用后医院获得性腹泻的主要原因：腹泻由两种外毒素A和B介导，A毒素被认为是主要毒素，极端情况下会引起伪膜性结肠炎。一种基因衍生的毒素突变体(RARU)既能诱导抗毒素，又能保护动物免受艰难梭菌的感染。RARU的琥珀酸化改善了其溶解性，并且没有明显影响其抗原性。制备突变毒素A用于临床的技术已经制定出来。将肺炎球菌14型、大肠杆菌K1和福氏2a菌三种不同组成的多糖与琥珀酸化的RARU偶联。生成的结合物诱导了高水平的抗多糖和抗毒素。用于临床评估的A毒素结合物的制备工作正在进行中。伯氏疏螺旋体是莱姆病的病原体，是一种通过受感染的硬蜱叮咬传播的螺旋体。目前有一种针对这种疾病的蛋白质疫苗，但在12岁以下无效。脂多糖曾在其他螺旋体中被描述过，但它在伯氏杆菌中的存在一直存在争议。到目前为止，我们还无法确认它的存在。对脂多糖的搜索揭示了一种独特的糖脂，它是由甘油和半乳糖组成的碳水化合物部分。有证据表明，这种糖脂是表面暴露的，注射在完全弗氏佐剂中，它会诱导特异性抗体。