Koch Institute for Integrative Cancer Research, MIT, Cambridge, Massachusetts.
Department of Biological Engineering, MIT, Cambridge, Massachusetts.
Cancer Immunol Res. 2018 Sep;6(9):1025-1038. doi: 10.1158/2326-6066.CIR-17-0607. Epub 2018 Jun 18.
Antitumor T-cell responses have the potential to be curative in cancer patients, but the induction of potent T-cell immunity through vaccination remains a largely unmet goal of immunotherapy. We previously reported that the immunogenicity of peptide vaccines could be increased by maximizing delivery to lymph nodes (LNs), where T-cell responses are generated. This was achieved by conjugating the peptide to 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-PEG (DSPE-PEG) to promote albumin binding, which resulted in enhanced lymphatic drainage and improved T-cell responses. Here, we expanded upon these findings and mechanistically dissected the properties that contribute to the potency of this amphiphile-vaccine (amph-vaccine). We found that multiple linkage chemistries could be used to link peptides with DSPE-PEG, and further, that multiple albumin-binding moieties conjugated to peptide antigens enhanced LN accumulation and subsequent T-cell priming. In addition to enhancing lymphatic trafficking, DSPE-PEG conjugation increased the stability of peptides in serum. DSPE-PEG peptides trafficked beyond immediate draining LNs to reach distal nodes, with antigen presented for at least a week , whereas soluble peptide presentation quickly decayed. Responses to amph-vaccines were not altered in mice deficient in the albumin-binding neonatal Fc receptor (FcRn), but required -dependent dendritic cells (DCs). Amph-peptides were processed by human DCs equivalently to unmodified peptides. These data define design criteria for enhancing the immunogenicity of molecular vaccines to guide the design of next-generation peptide vaccines. .
抗肿瘤 T 细胞反应有可能治愈癌症患者,但通过疫苗接种诱导有效的 T 细胞免疫仍然是免疫治疗的一个未满足的主要目标。我们之前报道过,通过最大限度地将肽疫苗递送至淋巴结(LN)中,可以提高其免疫原性,T 细胞反应就是在 LN 中产生的。这是通过将肽与 1,2-二硬脂酰-sn-甘油-3-磷酸乙醇胺-N-聚乙二醇(DSPE-PEG)偶联来实现的,这促进了白蛋白结合,从而增强了淋巴引流并改善了 T 细胞反应。在这里,我们扩展了这些发现,并从机制上剖析了促成这种两亲体疫苗(amph-vaccine)效力的特性。我们发现可以使用多种连接化学方法将肽与 DSPE-PEG 连接,并且进一步发现,连接到肽抗原上的多个白蛋白结合部分增强了 LN 聚集和随后的 T 细胞启动。除了增强淋巴转运外,DSPE-PEG 缀合还增加了肽在血清中的稳定性。DSPE-PEG 肽会运送到除了直接引流 LN 之外的更远端的节点,并且至少在一周内呈现抗原,而可溶性肽的呈现则迅速衰减。在缺乏白蛋白结合新生 Fc 受体(FcRn)的小鼠中,amph-vaccines 的反应没有改变,但需要 FcγR 依赖性树突状细胞(DCs)。amph-肽与人 DCs 的处理方式与未修饰的肽相同。这些数据为增强分子疫苗的免疫原性定义了设计标准,以指导下一代肽疫苗的设计。