Transcutaneous and oral-transcutaneous cholera immunization with TcpA and Peru15

描述(申请人提供)：霍乱弧菌是霍乱的起因，是B类病原体。对霍乱弧菌的保护性免疫知之甚少，高效霍乱疫苗的开发也一直存在问题。我们有初步证据表明，在野生型霍乱之后，针对毒素共调节菌毛(TCPA)的主要亚单位的免疫反应显著，TCPA是霍乱弧菌在人类肠道定植所需的一种毒力因子。TCPA在感染期间在体内表达；非肠道和口服灭活霍乱疫苗不含TCPA，非肠道和口服灭活霍乱疫苗对霍乱的保护作用相对较短(30-80%；3-6个月)。此外，我们有初步证据表明，口服减毒活霍乱疫苗(如Peru15)后，尽管接种后诱导了显著的杀弧性免疫反应，但抗TCPA反应并不显著。我们也有初步证据表明，TCPA经皮免疫具有高度的免疫原性，包括用减毒霍乱活疫苗粘膜(口服)接种，然后用纯化的抗原经皮增强的联合免疫，可诱导非常强大的粘膜和系统免疫反应。我们假设，Peru15口服免疫和提纯TCPA经皮免疫将诱导显著的保护性粘膜和系统免疫反应，更接近于反映野生型霍乱后发生的情况。在这个修订的R21开发项目中，我们有两个具体的目标：(1)进一步研究经皮应用TCPA在小鼠模型中作为霍乱保护性免疫原的潜力(评估剂量、时机、间隔和安全性问题)。(2)研究Peru15口服免疫和提纯TCPA经皮免疫的联合免疫，检测小鼠攻击模型的全身和粘膜免疫反应及对霍乱的保护作用。该项目将提供关键的初步信息，即诱导抗TCPA反应是否会补充现有霍乱疫苗诱导的免疫反应，以及粘膜-经皮联合免疫策略是否可以诱导针对粘膜病原体的显著粘膜和系统免疫反应。这一发展中的R21项目产生的数据将为更详细的联合免疫机制免疫学分析奠定基础，并有助于后续的人类评估，并可能为针对粘膜病原体的联合免疫方案的新范例奠定基础。相关：霍乱弧菌是霍乱的起因，是B类病原体。该项目将调查针对霍乱的粘膜-经皮联合免疫策略是否能够诱导针对粘膜病原体的显著的粘膜和系统免疫反应。这一发展中的R21项目产生的数据将为更详细的联合免疫机制免疫学分析奠定基础，并有助于后续的人类评估，并可能为针对粘膜病原体的联合免疫方案的新范例奠定基础。

DESCRIPTION (provided by applicant): Vibrio cholerae is the cause of cholera and a category B agent. Protective immunity to V. cholerae is poorly understood, and development of highly effective cholera vaccines has been problematic. We have preliminary evidence that following wild type cholera, immune responses are prominent against the main subunit of toxin co-regulated pilus (TcpA), a V. cholerae virulence factor required for intestinal colonization of humans. TcpA is expressed in vivo during infection; parenteral and oral killed cholera vaccines do not contain TcpA, and parenteral and killed oral cholera vaccines are only moderately protective against cholera for relatively short periods of time (30-80%; 3-6 months). In addition, we have preliminary evidence that anti-TcpA responses are not prominent following oral immunization with live attenuated cholera vaccines (such as Peru15), despite induction of prominent vibriocidal immune responses following vaccination. We also have preliminary evidence that transcutaneous immunization with TcpA is highly immunogenic, and that combination immunization that includes mucosal (oral) vaccination with live attenuated cholera vaccines followed by transcutaneous boosting with purified antigen induces very robust mucosal and systemic immune responses. We hypothesize that oral immunization with Peru15 and transcutaneous boosting with purified TcpA would induce prominent and protective mucosal and systemic immune responses that more closely mirror what occurs after wild type cholera. In this revised R21 developmental project, we have two Specific aims: (1) To further investigate the potential of transcutaneously applied TcpA to act as a protective immunogen against cholera in a mouse model (evaluating issues of dosing, timing, interval, and safety). (2) To investigate combination immunization of oral priming with Peru15 and transcutaneous boosting with purified TcpA in mice, measuring systemic and mucosal immune responses and protection against cholera in the mouse challenge model. This project would provide pivotal preliminary information on whether induction of anti-TcpA responses would complement immune responses induced by a currently available cholera vaccine, and whether mucosal-transcutaneous combination immunization strategies can induce prominent mucosal and systemic immune responses protective against a mucosal pathogen. Data generated by this developmental R21 project would lay the foundation for a more detailed mechanistic immunological analysis of combination immunization, as well as facilitate subsequent evaluation in humans, and could possibly lay the foundation for a new paradigm of combination immunization regimens against mucosal pathogens. Relevance: Vibrio cholerae is the cause of cholera and a category B agent. This project would investigate whether mucosal-transcutaneous combination immunization strategies against cholera can induce prominent mucosal and systemic immune responses protective against a mucosal pathogen. Data generated by this developmental R21 project would lay the foundation for a more detailed mechanistic immunological analysis of combination immunization, as well as facilitate subsequent evaluation in humans, and could possibly lay the foundation for a new paradigm of combination immunization regimens against mucosal pathogens.