Development of a Non-Tolerogenic Anti-DEC-205 Vaccine Delivery Platform

本U19 TRIAD技术开发提案描述了一项旨在开发 基于树突状细胞的高效、促炎和非致耐受性疫苗递送系统 靶向抗DEC-205抗体。抗DEC-205作为强炎症免疫刺激剂的成功 应答取决于非特异性树突细胞成熟因子的共同施用。在他们缺席的情况下，反 DEC-205诱导抗原特异性耐受而不是免疫。由于与非特异性相关的危险 激活免疫系统，我们建议开发一种改良的促炎性和非耐受性 抗DEC-205抗体。我们发现了一组天然的调节性T细胞表位， 通过刺激调节性T细胞诱导耐受性人免疫球蛋白。我们已经验证 实验上，这些表位产生调节性T细胞的抗原特异性扩增并抑制 炎症免疫反应。我们推测，抗DEC-205抗体中含有的调节性T细胞表位 促进致耐受性反应，该致耐受性反应仅通过非特异性免疫刺激剂的共施用来克服。 我们预期这些表位的修饰将显著降低致耐受性，使得能够使用 抗DEC-205作为独立的高性能抗原递送系统。我们将通过以下方式消除抗DEC-205的耐受性： 表位修饰在两阶段过程中首先在（人源化）小鼠模型系统中开始， 发展到人类血液样本使用TRIAD Toolkit Core免疫信息学算法， 抗DEC-205，使得其调节性T细胞表位中的关键氨基酸被替换为 在实验上显示会干扰HLA结合。然后，我们将（1）产生一组抗体变体 与试验抗原重组偶联，包括TRIAD研究项目中鉴定的候选疫苗， (2)鉴定不干扰树突细胞靶向的去耐受性突变，和（3）评估变体 用于降低疫苗抗原的致耐受性以及用于增强疫苗抗原的免疫原性。

This U19 TRIAD Technology Development proposal describes an innovative program aimed at developing a high-performance, pro-inflammatory and non-tolerogenic vaccine delivery system based on the dendritic cell targeting anti-DEC-205 antibody. The success of anti-DEC-205 as a stimulator of strong inflammatory immune responses depends on co-administration of non-specific dendritic cell maturation factors. In their absence, anti- DEC-205 induces antigen-specific tolerance rather than immunity. Because of the dangers associated with nonspecific activation of the immune system, we propose to develop a modified pro-inflammatory and nontolerogenic anti-DEC-205 antibody. We have discovered a set of natural regulatory T-cell epitopes derived from human immunoglobulins that induce tolerance by stimulating regulatory T cells. We have verified experimentally that these epitopes generate antigen-specific expansion of regulatory T cells and suppress inflammatory immune responses. We hypothesize that regulatory T-cell epitopes contained in anti-DEC-205 promote a tolerogenic reaction that is only overcome through co-administration of non-specific immunostimulators. We expect that modification of these epitopes will significantly diminish tolerogenicity, enabling use of anti-DEC-205 as a stand-alone, high performance antigen delivery system. We will de-tolerize anti-DEC-205 by epitope modification in a two-stage process beginning first in a (humanized) mouse model system and progressing to human blood samples. Using TRIAD Toolkit Core immuno-informatics algorithms, we will reengineer anti-DEC-205 such that key amino acids in its regulatory T-cell epitopes are replaced with those that are experimentally shown to interfere with HLA binding. We will then (1) produce a set of antibody variants recombinantly conjugated to test antigens including vaccine candidates identified in TRIAD Research Projects, (2) identify de-tolerizing mutations that do not interfere with dendritic cell targeting, and (3) evaluate variants for reduced tolerogenicity, as well as for enhanced immunogenicity for vaccine antigens.