Schetters Sjoerd T T, Li R J Eveline, Kruijssen Laura J W, Engels Steef, Ambrosini Martino, Garcia-Vallejo Juan J, Kalay Hakan, Unger Wendy W J, van Kooyk Yvette
Department of Molecular Cell Biology and Immunology, Amsterdam UMC, Location VUmc, Amsterdam, Netherlands.
Department of Molecular Cell Biology and Immunology, Amsterdam UMC, Location VUmc, Amsterdam, Netherlands.
Biomaterials. 2020 Dec;262:120342. doi: 10.1016/j.biomaterials.2020.120342. Epub 2020 Aug 28.
Injection of antigenic peptides has been widely used as a vaccine strategy to boost T cell immunity. However, the poor immunogenicity of single peptides can potentially be strengthened through modification of the tertiary structure and the selection of the accompanying adjuvant. Here, we generated antigenic peptides into non-linear trimers by solid phase peptide synthesis, thereby enhancing antigen presentation by dendritic cells to CD8 T cells in vitro and in vivo. CD8 T cells from mice vaccinated with trimers showed an KLRG1 effector phenotype and were able to recognize and kill antigen-expressing tumor cells ex vivo. Importantly, trimers outperformed synthetic long peptide in terms of T cell response even when equal number of epitopes were used for immunization. To improve the synthesis of trimers containing difficult peptide sequences, we developed a novel small molecule that functions as conjugation platform for synthetic long peptides. This platform , termed Antigen MAtriX (AMAX) improved yield, purity and solubility of trimers over conventional solid phase synthesis strategies. AMAX outperformed synthetic long peptides in terms of both CD8 and CD4 T cell responses and allowed functionalization with DC-SIGN-binding carbohydrates for in vivo dendritic cell targeting strategies, boosting T cell responses even further. Moreover, we show that agonistic CD40 antibody combined with MF59 (AddaVax) emulsion synergistically improves the antigen-specific T cell response of the AMAX in vivo. Also, tumor-associated antigens and neo-antigens could be incorporated in AMAX for tumor-specific CD8 T cell responses. Importantly, immunization with a mix of neoantigen AMAX could reduce tumor growth in a pre-clinical syngeneic mouse model. Hence, we provide pre-clinical support for the induction of effector CD8 T cells through the adaptable AMAX platform as easy implementable peptidic vaccination strategy against any antigen of choice, including neoantigens for anti-tumor immunity.
注射抗原肽已作为一种疫苗策略被广泛用于增强T细胞免疫力。然而，单一肽的免疫原性较差，可通过修饰三级结构和选择合适的佐剂来潜在地增强其免疫原性。在此，我们通过固相肽合成将抗原肽生成非线性三聚体，从而在体外和体内增强树突状细胞向CD8 T细胞的抗原呈递。用三聚体免疫的小鼠的CD8 T细胞表现出KLRG1效应子表型，并且能够在体外识别并杀伤表达抗原的肿瘤细胞。重要的是，即使使用等量的表位进行免疫，三聚体在T细胞应答方面也优于合成的长肽。为了改进包含难合成肽序列的三聚体的合成，我们开发了一种新型小分子作为合成长肽的偶联平台。这个平台称为抗原基质（AMAX），与传统的固相合成策略相比，提高了三聚体的产率、纯度和溶解度。AMAX在CD8和CD4 T细胞应答方面均优于合成长肽，并允许用与DC-SIGN结合的碳水化合物进行功能化修饰以用于体内树突状细胞靶向策略，进一步增强T细胞应答。此外，我们表明激动性CD40抗体与MF59（AddaVax）乳液协同作用可在体内协同改善AMAX的抗原特异性T细胞应答。此外，肿瘤相关抗原和新抗原可掺入AMAX中以引发肿瘤特异性CD8 T细胞应答。重要的是，用新抗原AMAX混合物进行免疫可在临床前同基因小鼠模型中减少肿瘤生长。因此，我们为通过适应性强的AMAX平台诱导效应性CD8 T细胞提供了临床前支持，这是一种易于实施的肽疫苗接种策略，可针对任何选择的抗原，包括用于抗肿瘤免疫的新抗原。
