HUMAN IMMUNE RESPONSE TO POLYSACCHARIDE-PROTEIN CONJUGATE VACCINES

多糖蛋白结合疫苗的人体免疫反应

• 批准号: 6290219
• 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/6290219
• 关键词: Shigella vaccines; Streptococcus vaccine; active immunization; bacterial polysaccharides; bactericidal immunity; chronic renal failure; clinical research; clinical trial phase I; drug screening /evaluation; human subject; immunoconjugates; immunoglobulins; infant human (0-1 year); laboratory mouse; sickle cell anemia; tetanus toxoid

Surface polysaccharides of pathogenic bacteria, including capsular polysaccharides (CPS) or lipopolysaccharides (LPS), may 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 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). Covalently binding 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 IgG anti-LPS were also induced. The levels of serum IgG anti-LPS were equal to or greater that those in recruits that recovered from shigellosis. Re-injection of S. flexneri 2a conjugate induced a booster response in the recruits. 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. First another carrier protein, a genetically-inactivated Corynebacterium diphtheriae toxin (CRM9) was a superior carrier for S. sonnei O-SP. Second 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 of these improved Shigella conjugates confirmed their immunogenicity and these new products will be evaluated for their clinical efficacy in a Phase 3 trial in Israel.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. In its extreme form. Toxin A, considered to be the major toxin, in its extreme form will cause pseudomembranous colitis. A genetically-derived toxin mutant (rARU) induces both antitoxin and protects animals from infection with C. difficile. The solubility of rARU improved its solubility and did not detectable affects its reaction with antiserum. 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. Clinical evaluation of these conjugates, designed to protect two diseases, is planned. - Human Subjects

病原菌的表面多糖，包括荚膜多糖（CPS）或脂多糖（LPS），既可以作为基本的毒力因子，也可以作为保护性抗原。CPS的年龄相关性和T细胞非依赖性免疫原性限制了其作为疫苗的使用，特别是在婴儿和幼儿中。LPS毒性太大，无法给药。因此，它们的O-特异性多糖（O-SP）（其具有CPS的毒力促进和保护性）必须被纯化：O-SP太小而不能是免疫原性的（半抗原）。将CPS或O-SP结合到医学上有用的蛋白质上以形成缀合物的缀合物既增加了它们的免疫原性，又赋予T细胞对这些蛋白质的依赖性。在成人中，然后在4-7岁的孩子，这两种共轭物是安全的，并诱导统计学显着和长期的上升IgG抗体同源LPS。类似地，也诱导了IgM和IgG抗LPS的较小升高。血清IgG抗LPS的水平等于或大于那些新兵从志贺氏菌病恢复。再注射S.弗氏2A缀合物在新兵中诱导加强应答。一项3期试验表明，一次注射S。Sonnei O-SP，结合到无毒的重组铜绿假单胞菌胞外蛋白A（rEPA）保护新兵免受这种病原体的爆发。重要的是，血清IgG抗LPS水平与偶联物功效之间存在统计学显著相关性.开发了两种方法来增加志贺氏菌缀合物在小鼠中的免疫原性。首先，另一种载体蛋白，一种遗传失活的白喉棒状杆菌毒素（CRM 9）是S.用琥珀酸酐（一种将蛋白质的氨基转化为羧基的无毒温和烷基化剂）对rEPA进行第二次处理，增加了S.这些改良的志贺氏菌偶联物的1期研究证实了它们的免疫原性，这些新产品将在以色列的3期试验中评价它们的临床功效。努力的方向是增加这种B的产量。百日咳菌株作为单组分疫苗的更容易纯化的百日咳毒素和作为肺炎球菌14型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。以其极端的形式。毒素A被认为是主要毒素，其极端形式会导致伪膜性结肠炎。一种遗传衍生毒素突变体（rARU）诱导抗毒素并保护动物免受C.很难rARU的溶解性提高了其溶解性，并且未检测到其与抗血清的反应。三种不同组成的多糖，肺炎球菌14型，大肠杆菌K1和S。福氏2a与琥珀酰化的rARU缀合。所得缀合物诱导高水平的抗多糖和抗毒素。计划对这些旨在保护两种疾病的结合物进行临床评价。- 人类受试者