Development of a multimeric CD40 ligand vaccine adjuvant

描述（由申请人提供）：CD40配体（CD40L或CD154）被广泛认为是免疫系统最重要的内源性激活剂之一。特别是，CD40L刺激树突状细胞（dc）启动强烈的CD8+ T细胞反应。然而，尽管进行了多次尝试，但没有一种形式的CD40L被许可用于临床。为了解决这一问题，本项目将推进一种高活性、可溶形式的CD40L的开发。这种新型蛋白是通过Acrp30（一种天然血清蛋白）与CD40L的细胞外结构域融合而成的。最终蛋白Acrp30-CD40L或“MegaCD40L”已被证实为疫苗诱导的CD8+ T细胞反应的高效佐剂。在SBIR一期项目中，MegaCD40L将通过开发cGMP CHO细胞的研究细胞库向临床推进，这些细胞库可生产人和小鼠MegaCD40L。所得到的蛋白质将被纯化到均匀使用的方法，可以扩大到工业生产。为了证明这种新佐剂的效用，MegaCD40L将在一个名为“交叉启动-短间隔增强”的小鼠疫苗接种系统中进行测试，该系统是由该项目的顾问John Harty博士（爱荷华大学）开发的。在该疫苗接种方案中，小鼠首先接种抗原包被的PLGA微球，7天后再接种抗原+ MegaCD40L + poly（I:C）。预计这将产生真正巨大的抗原特异性CD8+ T细胞反应，这将对流感、疟疾和生物防御剂引起的感染的疫苗很重要。在这个项目结束时，MegaCD40L将准备进行bla支持的cGMP蛋白制造和正式的毒性测试，作为这种令人兴奋的新疫苗佐剂的人体试验的下一步。

DESCRIPTION (provided by applicant): CD40 ligand (CD40L or CD154) is widely recognized as one of the most important endogenous activators of the immune system. In particular, CD40L stimulates dendritic cells (DCs) to initiate strong CD8+ T cell responses. However, despite several attempts, no form of CD40L has been licensed for clinical use. To solve this problem, this project will advance the development of a highly active, soluble form of CD40L. This novel protein is made by fusing the body of Acrp30 (a natural serum protein) with the extracellular domain of CD40L. The final protein, Acrp30-CD40L or "MegaCD40L," has been validated as a highly effective adjuvant for vaccine-induced CD8+ T cell responses. In this SBIR Phase 1 project, MegaCD40L will be advanced toward the clinic by developing research cell banks of cGMP CHO cells that produce human and murine MegaCD40L. The resulting proteins will be purified to homogeneity using methods that can be scaled up to industrial production. To prove the utility of this new adjuvant, MegaCD40L will be tested in a mouse vaccination system called "cross-prime-short interval boost" as developed by Dr. John Harty (University of Iowa), a Consultant to the project. In this vaccination protocol, mice are first vaccinated with PLGA microspheres coated with antigen followed 7 days later by boosting with antigen plus MegaCD40L plus poly(I:C). This is anticipated to generate a truly enormous antigen-specific CD8+ T cell response that would be important for vaccines against influenza, malaria, and infections caused by biodefense agents. At the conclusion of this project, MegaCD40L will be ready for BLA-enabling cGMP protein manufacturing and formal toxicity testing as the next steps toward a human trial with this exciting new vaccine adjuvant.