IMMUNE RESPONSE TO POLYSACCHARIDE AND CONJUGATE VACCINES

对多糖和结合疫苗的免疫反应

• 批准号: 6161340
• 负责人: KE E STEIN
• 金额: --
• 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/6161340
• 关键词: Neisseria meningitidis vaccine; antibacterial antibody; antibody formation; antibody specificity; autoantibody; bacterial antigens; bacterial polysaccharides; bacterial vaccines; bactericidal immunity; gene mutation; genetic recombination; immunoconjugates; immunogenetics; immunoglobulin genes; laboratory mouse; monoclonal antibody; northern blottings; nucleic acid sequence; site directed mutagenesis; structural genes; tetanus toxoid; thymus; western blottings

The immune response to polysaccharide (PS) antigens is highly regulated and has several distinguishing features including restricted subclass, variable region gene usage, fine specificity, and avidity. Simple PS not conjugated to protein (such as Neisseria meningitidis group C (MCPS)) elicit a thymus-independent (TI) response. PS conjugated to proteins (such as MCPS coupled to tetanus toxoid, (MCPS-TT)), on the other hand, elicit a different type of response, termed thymus-dependent (TD). Previous analyses of anti-MCPS mAb reveal that VH gene family usage is dominated by VHJ558. Sequence comparisons support the conclusion that several germline VHJ558 genes are used in response to MCPS. The sequence of 1705.18, 1846.13 and 1863.5 are encoded by the same germline. The sequence for 1863.5, an IgM mAb, has more mutations in its VH region than 1705.18 and 1846.13, both IgG3 antibodies likely generated from the same clone as they came from the same fusion. Genes used by 3006.18 and 177.16 resemble those anti-Dextran of group 45.21.1. The 2055.5 mAb utilizes yet another VHJ558 germline gene. Sequence analysis of VL genes from the anti-MCPS mAb revealed that the VkOX1 light chain of the Vk4/5 family was the VL most commonly paired with the VHJ558 genes. The sequences of1705.18 and 1863.5 are similar to 26.4.1 an anti-dextran mAb and 2055.5 is identical to 26.4.1 but uses Jk4 instead of Jk2. Three mAb utilize two different germline genes belonging to the VHQ52 family. 1702.10 and 3079.6 utilize the VHOx1 heavy chain denoted VH101. The 1922.2 mAb utilizes the VHOx2 germline. The fine specificities of 1702.10 and 1922.2 mAb are the same although they utilize different VL genes.Other VH-VL pairs are seen in this response in a restricted fashion. The expression of VH3609-Vk23 correlates with reactivity to native MCPS. This fine specificity is only seen in anti-MCPS TI-2 mAb, not in the anti-C2 or anti-CP panel. The sequence of these mAbs are very similar to the 3609.3 germline sequence. The VL gene is similar to a Vk23 sequene specific for a spin-labeled dinitrophenyl hapten (DNP-SL). Sequence analysis in progress will determine if somatic mutation can account for the increased diversity and increased avidity . Previous mouse model studies in our laboratory indicated a developmental delay in the immune response to MCPS even when they were administered as a TD antigen; MCPS-TT. In order to understand whether this delay in the response to TD conjugates in neonatal mice is due to defective antigen presentation, TT specific T cell clones were generated from mice that were immunized with MCPS-TT. One of these T cell clones showed 2-3 fold higher proliferative response to MCPS-TT than TT in vitro, suggesting this T cell clone might be specific to a glycosylated moiety of TT. In future studies, these T cell clones will be used to identify the antigen presenting cells involved in the presentation of MCPS-TT conjugates to T cells.

对多糖（PS）抗原的免疫应答是高度调节的 并且具有几个区别特征，包括受限子类， 可变区基因的使用、良好的特异性和亲合力。简单PS注释 与蛋白质结合（如C组脑膜炎奈瑟菌（MCPS）） 引起胸腺非依赖性（TI）反应。PS与蛋白质（如 另一方面，如与破伤风类毒素偶联的MCPS（MCPS-TT））， 一种不同类型的反应，称为胸腺依赖性（TD）。先前 抗MCPS mAb的分析显示VH基因家族的使用主要是由 VHJ 558。序列比较支持以下结论： VHJ 558基因用于响应MCPS。1705.18的序列， 1846.13和1863.5由相同的种系编码。的序列 1863.5，一种IgM mAb，在其VH区中具有比1705.18更多的突变， 1846.13，这两种IgG 3抗体可能产生自相同的克隆，因为它们 都来自于同一次融合3006.18和177.16使用的基因类似于 组45.21.1的抗葡聚糖。2055.5 mAb利用另一种VHJ 558 生殖系基因抗MCPS mAb VL基因的序列分析 显示Vk 4/5家族的VkOX 1轻链是VL最多的 通常与VHJ 558基因配对。1705.18和1863.5的序列 与26.4.1抗葡聚糖mAb相似，2055.5与 26.4.1，但使用Jk 4而不是Jk 2。三种mAb利用两种不同的 属于VHQ 52家族的种系基因。1702.10和3079.6使用 VHOx 1重链表示为VH 101。1922.2 mAb利用VHOx 2 生殖系1702.10和1922.2 mAb的精细特异性相同 尽管它们利用不同的VL基因。 这种反应是有限的。VH 3609-Vk 23的表达 与对天然MCPS的反应性相关。这种精细的特异性只是 在抗MCPS TI-2 mAb中观察到，而在抗C2或抗CP组中未观察到。的 这些mAb的序列与3609.3种系序列非常相似。 VL基因类似于对自旋标记寡核苷酸特异性的Vk 23序列。 二硝基苯基半抗原（DNP-SL）。正在进行的序列分析将 确定体细胞突变是否可以解释增加的多样性， 增加的贪婪。 我们实验室以前的小鼠模型研究表明， 对MCPS的免疫应答延迟，即使当它们作为 TD抗原; MCPS-TT。为了了解这种延迟是否 新生小鼠对TD缀合物的应答是由于缺陷抗原 在呈现中，TT特异性T细胞克隆从以下小鼠产生： 用MCPS-TT免疫。这些T细胞克隆中的一个显示出2-3倍高的 MCPS-TT的增殖反应比TT在体外，表明这种T细胞 克隆可能特异于TT的糖基化部分。在未来的研究中， 这些T细胞克隆将用于鉴定抗原呈递细胞 参与MCPS-TT缀合物向T细胞的呈递。