IMMUNE RESPONSE TO POLYSACCHARIDE AND CONJUGATE VACCINES

对多糖(PS)抗原的免疫反应是高度调节的 并且具有包括受限子类在内的几个区别特征， 可变区基因使用，良好的特异性和亲和力。简单PS备注 与蛋白质结合(如C群脑膜炎奈瑟氏菌(MCPS)) 诱导胸腺非依赖性(TI)反应。PS与蛋白质(如 另一方面，由于MCPS与破伤风类毒素(MCPS-TT)偶联，诱导 一种不同类型的反应，称为胸腺依赖(TD)。上一首 对抗MCPS单抗的分析表明，VH基因家族的使用主要由 VHJ558。序列比较支持这样的结论：几个生殖系 VHJ558基因被用来响应MCPS。1705.18的序列， 1846.13和1863.5由相同的生殖系编码。的顺序 1863.5是一种免疫球蛋白单抗，在其VH区有比1705.18更多的突变 1846.13，这两种IgG3抗体很可能是从同一个克隆产生的 来自相同的融合。3006.18和177.16使用的基因与 抗右旋糖酐45.21.1组。2055.5单抗利用的是另一株VHJ558 生殖系基因。抗MCPS单抗中VL基因的序列分析 揭示了Vk4/5家族的VkOX1轻链是VL最多的 通常与VHJ558基因配对。1705.18和1863.5的序列 类似于26.4.1抗葡聚糖单抗，而2055.5与26.4.1相同 26.4.1，但使用Jk4而不是Jk2。三种单抗利用两种不同的 胚系基因属于VHQ52家族。1702.10和3079.6的利用率 VHOx1重链表示为VH101。1922.2单抗利用VHox2 生殖系。1702.10单抗和1922.2单抗的特异性相同 尽管它们使用不同的VL基因。其他VH-VL对在 这是一种受限的反应。VH3609-Vk23的表达 与对原生MCP的反应性相关。这种细致入微的特异性只是 在抗MCPS TI-2单抗中可见，在抗C2或抗CP组中未见。这个 这些单抗的序列与3609.3个生殖系序列非常相似。 VL基因类似于自旋标记的Vk23序列 二硝基苯半抗原(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多样性的增加和 增加了亲和力。 我们实验室以前的小鼠模型研究表明， 对MCPS的免疫反应延迟，即使当它们作为 一种TD抗原；MCPS-TT。为了了解这一延迟是否 新生小鼠对TD结合物的反应是由于抗原缺陷引起的 目前，TT特异性T细胞克隆是从小鼠中产生的 用MCPS-TT免疫。这些T细胞克隆中的一个显示出2-3倍的高 体外对MCPS-TT的增殖反应优于TT，提示该T细胞 克隆可能是TT糖基化部分的特异性。在未来的研究中， 这些T细胞克隆将用于识别抗原提呈细胞 参与将MCPS-TT偶联物呈递给T细胞。

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.