In the development of cancer vaccines, antigens are delivered to elicit potent and specific T-cell responses to eradicate tumour cells. Nonetheless, successful vaccines are often hampered by the poor immunogenicity of tumour antigens, rapid clearance by the innate immunity, and limited cross-presentation on MHC-I to activate CD8⁺ T-cells arm. To address these issues, we developed dextran-based nanogels to promote antigen uptake, storage, and cross-presentation on MHC-I, while directing immunogenic maturation of the antigen-presenting cells (APCs). To promote the nanocarriers interaction with cells, we modified DX with L-arginine (Arg), whose immunomodulatory activities have been well documented. The ArgDX nanogel performance was compared with the nanogel modified with L-histidine (His) and L-glutamate (Glut). Moreover, we introduced pH-sensitive hydrazone crosslinking during the nanogel formation for the conjugation and controlled release of antigen ovalbumin (OVA). The OVA-laden nanogels have an average size of 325 nm. We demonstrated that the nanogels could rapidly release cargoes upon a pH change from 7 to 5 within 8 days, indicating the controlled release of antigens in the acidic cellular compartments upon internalization. Our results revealed that the ArgDX nanogel could promote greater antigen uptake and storage in DCs in vitro and promoted a stronger immunogenic maturation of DCs and M1 polarization of the macrophages. The OVA signals were co-localized with lysosomal compartments up till 96 hours post-treatment and washing, suggesting the nanogels could facilitate prolonged antigen storage and supply from endo-lysosomal compartments. Furthermore, all the tested nanogel formulations retained antigens at the skin injection sites until day 21. Such delayed clearance could be due to the formation of micron-sized aggregates of OVA-laden nanogels, extending the interactions with the resident DCs. Amongst the amino acid modifications, ArgDX nanogels promoted the highest level of lymph node homing signal CCR7 on DCs. The nanogels also showed higher antigen presentation on both MHC-I and II than DX in vitro. In the in vivo immune studies, ArgDX nanogels were more superior in inducing cellular and humoral immunity than the other treatment groups on day 21 post-treatment. These results suggested that ArgDX nanogel is a promising self-adjuvanted nanocarrier for vaccine delivery.

中文翻译：

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自佐L-精氨酸修饰的葡聚糖纳米凝胶可将局部抗原蛋白持续递送至抗原呈递细胞并增强细胞和体液免疫反应

在癌症疫苗的开发过程中，抗原被传递以引发有效且特异性的 T 细胞反应，从而根除肿瘤细胞。^{尽管如此，成功的疫苗常常受到以下因素的阻碍：肿瘤抗原的免疫原性差、先天免疫的快速清除以及MHC-I上激活CD8 +} T细胞臂的交叉呈递有限。为了解决这些问题，我们开发了基于葡聚糖的纳米凝胶，以促进 MHC-I 上的抗原摄取、储存和交叉呈递，同时指导抗原呈递细胞 (APC) 的免疫原性成熟。为了促进纳米载体与细胞的相互作用，我们用L-精氨酸 (Arg) 修饰 DX，其免疫调节活性已得到充分记录。将ArgDX纳米凝胶的性能与用L-组氨酸(His)和L-谷氨酸(Glut)修饰的纳米凝胶进行比较。此外，我们在纳米凝胶形成过程中引入了 pH 敏感的腙交联，用于抗原卵清蛋白 (OVA) 的结合和控制释放。负载 OVA 的纳米凝胶的平均尺寸为 325 nm。我们证明，当 pH 在 8 天内从 7 变化到 5 时，纳米凝胶可以快速释放负载物，这表明内化后酸性细胞区室中抗原的受控释放。我们的结果表明，ArgDX 纳米凝胶可以在体外促进 DC 更大的抗原摄取和储存，并促进 DC 更强的免疫原性成熟和巨噬细胞的 M1 极化。OVA 信号与溶酶体区室共定位，直至处理和清洗后 96 小时，这表明纳米凝胶可以促进内溶酶体区室的抗原储存和供应的延长。此外，所有测试的纳米凝胶制剂直到第 21 天都在皮肤注射部位保留抗原。这种延迟的清除可能是由于含有 OVA 的纳米凝胶形成微米级聚集体，从而延长了与驻留 DC 的相互作用。在氨基酸修饰中，ArgDX 纳米凝胶促进 DC 上淋巴结归巢信号 CCR7 的最高水平。在体外，纳米凝胶在 MHC-I 和 II 上也表现出比 DX 更高的抗原呈递。在体内免疫研究中，在治疗后第21天，ArgDX纳米凝胶在诱导细胞和体液免疫方面比其他治疗组更优越。这些结果表明 ArgDX 纳米凝胶是一种有前途的用于疫苗递送的自佐纳米载体。