John A Paulson School of Engineering and Applied Sciences , Harvard University , Cambridge , Massachusetts 02138 , United States.
Wyss Institute for Biologically Inspired Engineering , Harvard University , Boston , Massachusetts 02115 , United States.
Bioconjug Chem. 2018 Mar 21;29(3):733-741. doi: 10.1021/acs.bioconjchem.7b00656. Epub 2018 Jan 10.
Short peptides are the minimal modality of antigen recognized by cellular immunity and are therefore considered a safe and highly specific source of antigen for vaccination. Nevertheless, successful peptide immunotherapy is limited by the short half-life of peptide antigens in vivo as well as their weak immunogenicity. We recently reported a vaccine strategy based on dendritic cell-recruiting Mesoporous Silica Rod (MSR) scaffolds to enhance T-cell responses against subunit antigen. In this study, we investigated the effect of covalently conjugating peptide antigens to MSRs to increase their retention in the scaffolds. Using both stable thioether and reducible disulfide linkages, peptide conjugation greatly increased peptide loading compared to passive adsorption. In vitro, Bone Marrow derived Dendritic Cells (BMDCs) could present Ovalbumin (OVA)-derived peptides conjugated to MSRs and induce antigen-specific T-cell proliferation. Stable conjugation decreased presentation in vitro while reducible conjugation maintained levels of presentation as high as soluble peptide. Compared to soluble peptide, in vitro, expansion of OT-II T-cells was not affected by adsorption or stable conjugation to MSRs but was enhanced with reversible conjugation to MSRs. Both conjugation schemes increased peptide residence time in MSR scaffolds in vivo compared to standard bolus injections or a simple adsorption method. When MSR scaffolds loaded with GM-CSF and CpG-ODN were injected subcutaneously, recruited dendritic cells could present antigen in situ with the stable conjugation increasing presentation capacity. Overall, this simple conjugation approach could serve as a versatile platform to efficiently incorporate peptide antigens in MSR vaccines and potentiate cellular responses.
短肽是细胞免疫识别的最小抗原模式，因此被认为是一种安全且高度特异的疫苗抗原来源。然而，肽免疫疗法的成功受到肽抗原在体内半衰期短以及免疫原性弱的限制。我们最近报道了一种基于树突状细胞募集介孔硅棒（MSR）支架的疫苗策略，以增强针对亚单位抗原的 T 细胞反应。在这项研究中，我们研究了将肽抗原共价连接到 MSR 上以增加其在支架中保留的效果。使用稳定的硫醚和可还原的二硫键连接，与被动吸附相比，肽偶联大大增加了肽的负载量。体外，骨髓来源的树突状细胞（BMDCs）可以呈递与 MSR 偶联的卵清蛋白（OVA）衍生肽，并诱导抗原特异性 T 细胞增殖。稳定偶联在体外降低了呈递，而可还原偶联则保持了与可溶性肽一样高的呈递水平。与可溶性肽相比，在体外，吸附或稳定偶联到 MSR 对 OT-II T 细胞的扩增没有影响，但与可还原偶联到 MSR 则增强了扩增。与标准的推注或简单的吸附方法相比，这两种偶联方案都增加了肽在 MSR 支架中的体内停留时间。当负载 GM-CSF 和 CpG-ODN 的 MSR 支架被皮下注射时，募集的树突状细胞可以原位呈递抗原，而稳定偶联则增加了呈递能力。总的来说，这种简单的偶联方法可以作为一种有效的平台，将肽抗原高效地整合到 MSR 疫苗中，并增强细胞反应。
