Enhancing the Potency of Viral Vectors with C3d

描述（由申请人提供）：疫苗接种是一种有效且具有成本效益的应对生物恐怖主义制剂威胁的对策，人们对设计和使用佐剂以增强对疫苗的免疫反应非常感兴趣。这对于基于来自生物恐怖剂的亚基的疫苗特别重要，因为这些抗原本身通常不是高度免疫原性的。最近的研究表明，细胞补体途径的C3 d组分可以作为佐剂选择性地增强抗体对外源抗原的应答，以及加速抗体的亲和力成熟。 我们的中心假设是，病毒载体可以通过表达与C3 d共价连接的抗原而变得更有效。增强的效力将允许病毒载体以较低和较安全的剂量使用，以获得比在较高剂量的常规病毒载体下所见的更好的应答。此外，这种方法将允许病毒载体被减毒到更高的程度，并且仍然保持效力。我们将通过确定C3 d在从基于非致细胞病变副粘病毒猿猴病毒5（SV 5）的载体表达时是否作为分子佐剂发挥作用来检验这一假设。我们最近发表的工作表明，rSV 5具有固有的特性，可以用来创建新的疫苗载体。 在目的1中，我们将测试C3 d可以作为增强对Y的呼吸道抗体应答的选择性佐剂的假设。鼠疫F1抗原，表达Y.将在我们开发良好的小鼠模型系统中测试单独的鼠疫F1抗原或与C3 d连接的F1的病毒生长特性、呼吸道炎症程度以及细胞因子表达和细胞浸润。时间进程试验和剂量反应实验将通过测定呼吸道感染后的抗体应答和T辅助应答来检测表达F1或F1-C3 d的rSV 5载体的效力。在目标2中，小鼠将用可溶性F1或F1-C3 d沿着rSV 5-F1或rSV 5-F1-C3 d的各种组合感染，以建立最适合C3 d的呼吸道初免-加强方案的阶段：仅初免、仅加强或两个阶段。在目的3中，我们将比较当通过病毒载体或通过DNA疫苗接种递送时C3 d的相对佐剂效应。 在这些研究的结论中，我们将开发出一种强大的新型病毒载体，以在呼吸道中引发更快速和更有效的抗原特异性抗体应答。

DESCRIPTION (provided by applicant): Vaccination is a potent and cost-effective countermeasure to the threat of bioterrorism agents, and there is intense interest in the design and use of adjuvants to enhance immune responses to vaccines. This is particularly important for vaccines that are based on subunits from bioterrorism agents, since these antigens are usually not highly immunogenic by themselves. Recent work has shown that the C3d component of the cellular complement pathway can function as an adjuvant to selectively enhance antibody responses to a foreign antigen, as well as accelerated affinity maturation of antibodies. Our central hypothesis is that viral vectors can be engineered to be more potent by expressing antigen covalently linked to C3d. Enhanced potency would allow viral vectors to be used at lower and safer doses to obtain better responses than that seen at higher doses of conventional viral vectors. In addition, this approach would allow viral vectors to be attenuated to a higher degree and still maintain potency. We will test this hypothesis by determining if C3d functions as a molecular adjuvant when expressed from vectors based on the noncytopathic paramyxovirus Simian Virus 5 (SV5). Our recent published work has shown that rSV5 has inherent properties that could be exploited to create novel vaccine vectors. In Aim 1, we will test the hypothesis that C3d can function as a selective adjuvant for enhancing respiratory tract antibody responses to Y. pestis F1 antigen when delivered by an rSV5 vector, rSV5 vectors expressing either Y. pestis F1 antigen alone or F1 linked to C3d will be tested in our well-developed mouse model system for viral growth properties, the degree of respiratory tract inflammation, and for cytokine expression and cellular infiltration. Timecourse assays and dose-response experiments will test the potency of rSV5 vectors that express F1 or F1-C3d by determining the antibody response and T helper response following respiratory tract infection. In Aim 2, mice will be infected with various combinations of soluble F1 or F1-C3d along with rSV5-F1 or rSV5-F1-C3d to establish the stage of respiratory tract prime-boost protocols that is best served by C3d: prime only, boost only or both stages. In Aim 3, we will compare the relative adjuvant effect of C3d when delivered by virus vector or by DNA vaccination. At the conclusion of these studies, we will have developed a powerful new class of viral vectors to elicit a more rapid and potent antigen-specific antibody response in the respiratory tract.