Human Immune Response To Polysaccharide-protein Conjugat

人体对多糖-蛋白质缀合物的免疫反应

• 批准号: 6840683
• 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/6840683
• 关键词: Bacillus; Bordetella pertussis; Borrelia; Clostridium difficile; Corynebacterium diphtheriae; Neisseria meningitidis vaccine; Pseudomonas aeruginosa; Shigella vaccines; Streptococcus vaccine; active immunization; bacterial polysaccharides; bacterial vaccines; bactericidal immunity; clinical research; drug screening /evaluation; human subject; human therapy evaluation; immunoconjugates; laboratory mouse; lipopolysaccharides; membrane transport proteins; tetanus toxoid; vaccine development

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 S.flexneri 2a were bound to bacterial toxoids. Both conjugates were safe and induced statistically significant and long-lived rises of IgG antibodies to the homologous LPS in adults, 4-7 and 1-4 year-olds. 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 all age groups,of the S. sonnei conjugate only in the 1-4 year 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 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: 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. In a phase 2 study in 1-4 years old the S.flexneri 2a conjugate induced a 4-fold rise in 92% of the children, the S.sonnei conjugate in 85%. 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,NMR, fast atom bombardment and several sugar degrading techniques. It was shown to be composed of polyribitolphosphate bound to polyglycerolphosphate and likely through the latter to the muramic acid of the cell wall. Both polyols are partially substituted at C2 with N-acetylglucosamine.Besides with the anti Hib it cross reacted with anti Staphylococcus epidermidis. The polysaccharide was conjugated to carrier proteins and it's immunogenicity evaluated in GP mice. Conjugate-induced antibodies reacted with the homologous and several cross-reacting polysaccharides. 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 it was conjugated to BSA . Contrary to the CPS alone it was immunogenic in mice, with booster responses after 2nd and 3rd injections. Conjugates of the cross reactive polysaccharides, e.coli K93 and B.pumilus SH17,did not induce anti Men. A CPS. 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 composed of C16, C18fatty acids possibly 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. The immunogenicity of this glycolipid in various formulations and the biological effect of the antibodies are being ingestigated. Bacillus anthracis, a potential cause of lethal human infection, has 2 essential virulence factors without either of which it is not pathogenic for humans. these factors are: 1.anthrax toxin, 2.a capsule. The toxin is composed of 3 peptides: Lethal Factor, Edema Factor and Protective Antigen, each by itself non toxic. PA is the toxin part that binds to mammalian cells. It has to have a 20 KDa peptide hydrolyzed off exposing a site to which LF or EF may bind rendering toxins that enzymatically modify substrates in mammalian cell cytosol. The capsule is composed of poly-D-gamma-glutamic acid.It is non-immunogenic and it's protective effect unknown. The licensed vaccine is safe and protective but has limitations that justify development of improved vaccines. A recombinant PA was isolated from an unencapsulated strain grown in a fermenter. Several formulations with formaldehyde treated and alum adsorbed materials were found to be immunogenic in mice. Clinical lots are being prepared. The capsule has been isolated from a non toxic strain and methods to conjugate it to carrier proteins are being investigated.

病原菌的表面多糖，包括荚膜多糖（CPS）或脂多糖（LPS），既可作为必需的毒力因子，又可作为保护性抗原。 CPS 与年龄相关且与 T 细胞无关的免疫原性限制了其作为疫苗的用途，尤其是在婴儿和幼儿中。 LPS 毒性太大，无法施用。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 太小而无法产生免疫原性（半抗原）。 CPS 或 O-SP 与医学上有用的蛋白质共价结合形成缀合物，既增加了它们的免疫原性，又赋予了 T 细胞对这些糖的依赖性。宋内志贺氏菌和弗氏志贺氏菌2a 的O-SP 与细菌类毒素结合。两种缀合物都是安全的，并且能够在成人、4-7 岁和 1-4 岁儿童中诱导针对同源 LPS 的 IgG 抗体的统计显​​着且持久的升高。类似地，尽管也诱导了 IgM 和 IgA 抗 LPS 的较小升高。重新注射福氏链霉菌2a结合物在所有年龄组中均诱导了加强反应，而宋内链霉菌结合物仅在1-4岁儿童中引起了加强反应。一项 3 期试验表明，注射一次宋内链球菌 O-SP 与无毒重组铜绿假单胞菌外蛋白 A (rEPA) 结合，可以保护新兵免受这种病原体的感染。重要的是，血清 IgG 抗 LPS 水平与缀合物的功效之间存在显着相关性。开发了两种方法来增加小鼠志贺氏菌缀合物的免疫原性：基因灭活的白喉棒状杆菌毒素（CRM9）是宋内氏志贺氏菌 O-SP 的优质载体，并且用琥珀酸酐（一种无毒的温和烷基化剂，可将蛋白质的氨基转化为羧基）处理 rEPA，增加了志贺氏菌的免疫原性。 弗氏 2a O-SP。对这些志贺氏菌缀合物的成人进行的 1 期研究证实了它们的安全性和免疫原性；免疫原性的改善不如小鼠显着。在一项针对 1-4 岁儿童的 2 期研究中，S.flexneri 2a 结合物在 92% 的儿童中诱导了 4 倍的升高，而 S.sonnei 结合物则在 85% 的儿童中诱导了 4 倍的升高。改良的 S.flexneri 2a 和原始 S. sonnei 结合物的 3 期研究正在准备中。与中国河南省兰州疫苗研究所和省医学中心合作，正在计划对这两种结合物进行临床试验。 为了研究交叉反应与同源 CPS 的同时施用是否比单独使用同源 CPS 更具优势，通过常规方法分离了短小芽孢杆菌 SH18 的细胞壁多糖 (PS)（据报道与 b 型流感嗜血杆菌 (Hib) 的 CPS 发生交叉反应），并使用 GC-MS、NMR、快原子轰击和多种方法研究了其结构。 糖降解技术。它被证明是由与聚甘油磷酸结合的聚核糖醇磷酸组成，并可能通过后者与细胞壁的胞壁酸结合。两种多元醇的 C2 部分均被 N-乙酰氨基葡萄糖取代。除了与抗 Hib 抗体发生交叉反应外，它还与抗表皮葡萄球菌发生交叉反应。将多糖与载体蛋白缀合，并在 GP 小鼠中评估其免疫原性。缀合物诱导的抗体与同源多糖和几种交叉反应多糖发生反应。 A 组脑膜炎奈瑟菌引起地方性和流行性脑膜炎，特别是在非洲脑膜炎带。有效且可用的 CPS 疫苗尚未得到充分利用。为了进一步提高其免疫原性，将其与 BSA 缀合。与单独的 CPS 相反，它在小鼠中具有免疫原性，在第 2 次和第 3 次注射后产生增强反应。交叉反应性多糖、大肠杆菌 K93 和短小芽孢杆菌 SH17 的结合物不会诱导抗 Men。一个 CPS。 伯氏疏螺旋体是一种通过受感染的硬蜱叮咬传播的螺旋体，是莱姆病的病原体。目前已有针对该病的蛋白质疫苗，但对 12 岁以下儿童无效。 LPS 已在其他螺旋体中被描述，但它在伯氏疏螺旋体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 LPS 的研究揭示了一种独特的糖脂，由 C16、C18 脂肪酸组成，可能是甘油和半乳糖作为碳水化合物部分。有证据表明这种糖脂是表面暴露的，注射到完全弗氏佐剂中会诱导特异性抗体。这种糖脂在各种制剂中的免疫原性和抗体的生物效应正在被研究。 炭疽杆菌是导致人类致命感染的潜在原因，它具有 2 个基本毒力因子，如果没有其中任何一个，它都不会对人类致病。这些因素是：1.炭疽毒素，2.胶囊。该毒素由 3 种肽组成：致死因子、水肿因子和保护性抗原，每种肽本身都是无毒的。 PA是与哺乳动物细胞结合的毒素部分。它必须有一个 20 KDa 的肽水解，暴露出 LF 或 EF 可能结合的位点，从而产生酶促修饰的毒素 哺乳动物细胞胞浆中的底物。该胶囊由聚-D-γ-谷氨酸组成，无免疫原性，其保护作用未知。获得许可的疫苗是安全且具有保护性的，但有其局限性，因此需要开发改进的疫苗。 从发酵罐中生长的未封装菌株中分离出重组 PA。发现几种含有甲醛处理和明矾吸附材料的制剂在小鼠中具有免疫原性。临床批次正在准备中。该胶囊已从无毒菌株中分离出来 并将其与载体蛋白缀合的方法正在研究中。