A killed whole-cell one dose cholera vaccine

 描述(申请人提供)：霍乱弧菌(VC)，一种革兰氏阴性细菌，已导致超过200年的霍乱，这是一种EP流行性和地方性腹泻疾病。巴基斯坦(霍乱的古老发源地)的流行病和海地(霍乱的新发源地)的流行病突出了如何控制霍乱的悬而未决的问题。短期内控制的一个方面是通用疫苗。通用霍乱疫苗的主要挑战是提供持续时间最长的快速免疫(˜7天)，使用最小剂量免疫Vc抗原(Ag)，免疫幼稚或生活在霍乱流行地区的幼儿(2-5岁)。目前世界卫生组织推荐的口服霍乱疫苗(OCV)在幼儿中实现这一目标的程度并不高或一致。一种新的实验性霍乱疫苗配方，部分基于OCV疫苗，将被测试其提供霍乱免疫的能力与一个鼻腔(I.N.)剂量。现有OCV配方的新添加剂是3种经过验证的保护性VC AGS(TCPA、TcpF和CBP-1)，它们对霍乱的发病至关重要。结果表明，TCPA和TcpF一次给药即可诱导小鼠产生免疫应答。这些蛋白的加入以及CBP-A(一种不那么强健的保护性抗原)将增加保护性AGS，这是OCV免疫原谱的一部分。这些AGS将通过壳聚糖纳米颗粒(Chitnp)靶向于粘膜上皮细胞，这一过程也将优化B细胞的启动。我们还将使用强大的粘膜辅助CT。一种新的基于CT的佐剂(CC-TD)正在临床前人类免疫方案中进行测试。霍乱感染的CT和其他标准因素与幼儿对VC-LPS的较好血清转换有关，因此，有必要观察是否有更多的Ag(与感染相关)以更好的数量提供给粘膜启动区域，并提供正确的辅助刺激信号，将OCV转变为一剂疫苗。我们将测试的假设是，重新配制的、灭活的全细胞(kW-C)霍乱疫苗能否最大限度地诱导免疫，是否能够激发足够的保护性抗体(Ab)，仅用一剂就能提供对霍乱的保护。霍乱免疫力在接种疫苗后的第一年就已经下降，在第三年继续对使用最广泛使用的OCV-Shanchol免疫的幼儿几乎没有免疫力。这种具有3种保护性蛋白AGS的新型OCV配方的长期目标是诱导更广泛的B细胞记忆(预防霍乱的生物标志物)，在众所周知对疫苗蛋白AGS比疫苗相关的LPSAGS反应更好的幼儿中，这种记忆将持续至少3年甚至更长时间。

 DESCRIPTION (provided by applicant): Vibrio cholerae (Vc), a Gram negative bacterium that has caused over 200 years of cholera that is both an ep- idemic and endemic diarrheal disease. Endemics in Pakistan (ancient home of cholera) and epidemics in Haiti (new home of cholera) underscore the unresolved issue how to control cholera. One aspect of control in the short term is a universal vaccine. The main challenges of a universal cholera vaccine are to provide fast im- munity (˜7 days) with the longest duration using the minimal number of doses to immunize the Vc antigen (Ag) immunologically naïve or young children (2-5 years) living in endemic cholera areas. The current oral cholera vaccines (OCV) recommended by the WHO do not accomplish this in young children to a high or consistent degree. A novel experimental cholera vaccine formulation, based in part on the OCV inoculum will be tested for its ability to provide cholera immunity with one intranasal (i.n.) dose. The new additions to the existing OCV formulation are 3 proven, protective Vc Ags (TcpA, TcpF and CBP-1) that are critical for cholera pathogenesis. We showed that TcpA and TcpF were able to induce immunity after one dose. The addition of these proteins, as well as CBP-A (a less robust protective Ag) will add to the protective Ags that are part of the immunogen profile of OCV. These Ags will be targeted to the mucosal epithelia by chitosan nanoparticles (Chitnp) a pro- cess which should also optimize priming of B cells. We will also use the powerful mucosal adjuvant CT. A new CT-based adjuvants (CC-TD) is being tested in preclinical human immunization protocols. CT and other normative elements of a cholera infection are associated with better sero-conversion of young children to Vc LPS, so it makes sense to see if more Ag (associated with infection), provided in better quantity to the areas of mucosal priming with the correct attending co-stimulations signals can change an OCV into a one dose vac- cine. The hypothesis we will test is whether `maximal' induction of immunity by a reformulated, killed whole-cell (kW-C) cholera vaccine can stimulate enough protective antibody (Ab) to provide protection against cholera with just one dose. Cholera immunity is already in decline in the first year after vaccination and continues to essentially no immunity in year three for young children immunized with the Shanchol, the most widely used OCV. The long term goal for this novel OCV formulation that features 3 protective protein Ags is, the induction of broader B cell memory (a biomarker of protection against cholera) that will endure for at least 3years and perhaps longer in young children who are well known to respond to vaccine protein Ags better than vaccine-associated LPS Ags.