Cholera conjugates designed to prevent colonization and induce B cell memory

在过去的3个世纪和之前，霍乱弧菌（Vc），一种革兰氏阴性细菌一直困扰着人类， 导致了七次大流行，霍乱流行性和地方性霍乱，其特点是， 如果不治疗的话，会导致严重的腹泻和高死亡率。非洲的地方性霍乱和海地的流行病强调， 如何控制霍乱的问题尚未解决。一种短期霍乱控制方法是通用疫苗。 通用霍乱疫苗的主要挑战是迅速为最易感的共同感染者提供免疫力。 霍特：幼儿（2-5岁）。目前的共识是，口服霍乱疫苗（OCV）的42%， 对幼儿的保护效力不能实现这一点。我们将扩大和改善我们的实验 通过引入新的临床相关载体，结合霍乱疫苗。目前的BSA载体不适用于- 用于人类疫苗。我们开发的结合物含有一种高度免疫原性的酸- 解毒的稻叶LPS（pmLPS），其用一个剂量诱导杀弧菌滴度，用一个剂量诱导高度保护性Ab， 第二。我们需要优化pmLPS结合物，以达到我们的目标，即为年轻人提供一剂霍乱疫苗 孩子单个Vc鞭毛蛋白（FlaPr）将充当载体。霍乱现有数据的综合 文献提出了一种假设：纯化的重组Vc FlaPr将诱导保护性抗体（Abs） 并且还用作最佳Ab诱导所需的TLR 5激动剂。文献表明，两个亲- pm-LPS-FlaPr缀合物中的保护性Ag将促进协同的Ab效应，从而提供 一剂小儿霍乱疫苗口服或鼻内给药后，基于FlaPr的疫苗和 将比较灭活的全细胞Vc疫苗的免疫原性、诱导保护性免疫和B细胞 记忆成年小鼠将用于初始免疫原性研究，但在选择的研究中， 将新生小鼠与成年小鼠进行比较。与年幼的儿童一样，用天然LPS免疫的新生小鼠也是如此。 可怜的回复者。我们建议通过使用结合疫苗来克服这一缺陷， 新生儿滤泡B细胞，而不是边缘区B细胞，主要产生抗LPS IgM抗体。重定向的 应答应增强类别转换并诱导LPS特异性记忆B细胞。在我们的研究中，如果成人和 新生小鼠对缀合物产生类似的Ab应答，但只有成年小鼠对LPS应答， 提供了一个关键的证据，显示了缀合物的价值和新生小鼠的实用性 模型使用pmLPS-FlaPr缀合物克服新生儿对LPS表位的无反应性 小鼠对于霍乱疫苗研究来说无疑是新的。在临床上，荚膜多糖是典型的前体， 广泛用于儿童接种的缀合物疫苗的保护性表位（例如，气，气 球菌）。胶囊结合疫苗是如此有效，他们重新配置了循环的血清型， 儿童病原体pmLPS-缀合物可以具有相同的效果。

During the last 3 centuries and before, Vibrio cholerae (Vc), a Gram negative bacterium has plagued humans, causing 7 pandemics of the disease, cholera. Cholera in both epidemic and endemic form, features intracta- ble diarrhea and high mortality if not treated. Endemic cholera in Africa and the Haiti epidemic underscore the unresolved issue of how to control cholera. One short term cholera control approach is a universal vaccine. The main challenge of a universal cholera vaccine is to provide immunity quickly to the most susceptible co- hort: young children (2-5 years old). The consensus is that the current oral cholera vaccine (OCV) with its 42% protective efficacy for young children does not accomplish this. We will expand and improve our experimental conjugate cholera vaccine by introducing a new clinically relevant carrier. The current BSA carrier is not ap- propriate for human vaccines. The conjugates we developed contain a highly immunogenic form of acid- detoxified Inaba LPS (pmLPS) that induces vibriocidal titers with one dose and highly protective Ab with a sec- ond. We need to optimize the pmLPS conjugate to reach our goal of a one dose cholera vaccine for young children. Individual Vc flagellar proteins (FlaPr) will serve as carriers. Synthesis of existing data in the cholera literature suggest a hypothesis: a purified, recombinant, Vc FlaPr will induce protective antibodies (Abs) and also serve as a TLR5 agonists required for optimal Ab induction. The literature indicates the two pro- tective Ag in pm-LPS-FlaPr conjugates will prompt synergistic Ab effects thus providing the final component of a one dose, pediatric cholera vaccine. Following oral or intranasal administration, FlaPr-based vaccine and a killed, whole-cell Vc vaccine will be compared for immunogenicity, induction of protective immunity, and B cell memory. Adult mice will serve for initial immunogenicity studies but in select studies, the vaccine response of neonatal mice will be compared to adults. Like young children, neonatal mice immunized with native LPS are poor repsonders. We propose to overcome this defect by using a conjugate vaccine that preferentially target neonatal follicular B cells rather than marginal zone B cells that mainly make anti-LPS IgM Abs. The redirected response should enhance class switching and induce LPS-specific memory B cells. In our studies, if adult and neonatal mice produce similar Ab responses to the conjugates, but only adults respond to the LPS, it would supply a critical piece of evidence showing the value of the conjugates and the utility of the neonatal mouse model. The use of pmLPS-FlaPr conjugates to overcome non-responsiveness to LPS epitopes in neonatal mice is decidedly novel for cholera vaccine research. In the clinic, capsular polysaccharides are the typical pro- tective epitopes of the conjugate vaccine that are used extensively for childhood vaccination (e.g., pneumo- coccal). Capsular conjugate vaccines are so effective they have reconfigured the circulating serotypes of childhood pathogens. pmLPS-conjugates could have the same effect.