肿瘤纳米疫苗(NVs)的研究已经获得了兴趣,因为它们特异性识别和消除肿瘤细胞。然而,树突状细胞(DCs)的识别和内化能力差以及免疫原性不足限制了疫苗的效力。在这里,我们提取了两种分子量的黄芪多糖(APS,12.19kD;APSHMw,135.67kD)来自黄芪,并使它们与OVA257-264自组装,通过微流体方法直接形成OVA/APS整合的纳米复合物。用可脱落的磷酸钙层包裹纳米复合物以提高稳定性。形成的纳米复合物中的APS用作有效的肿瘤免疫治疗的药物载体和免疫佐剂。最佳APS-NV约为160nm,粒径分布均匀,在生理盐水溶液中保持稳定。APS-NV中的FITC-OVA可以被DC有效地吸收,APS-NVs可以刺激DCs的成熟,在体外提高抗原交叉呈递效率。可能的机制是APS可以通过多种受体如dectin-1和Toll样受体2和4诱导DC活化。皮下注射后观察到在引流和远端淋巴结中APS-NVs的增强积累。较小的APS-NVs可以容易地进入淋巴结。此外,APS-NVs可以显著促进抗原向DC的递送效率并激活细胞毒性T细胞。此外,与OVA+明矾治疗组相比,APS-NVs在已建立的B16-OVA黑色素瘤肿瘤中实现更好的抗肿瘤效果。抗肿瘤机制与肿瘤区域中细胞毒性T细胞的增加有关。随后,APS-NVs对黑色素瘤裸鼠模型的抑瘤效果较差,也证实了NVs诱导的抗肿瘤适应性免疫反应的参与。因此,这项研究开发了一种有前途的基于APS的肿瘤NV,这是一种有效的肿瘤免疫疗法,没有全身副作用。
The study of tumor nanovaccines (NVs) has gained interest because they specifically recognize and eliminate tumor cells. However, the poor recognition and internalization by dendritic cells (DCs) and insufficient immunogenicity restricted the vaccine efficacy. Herein, we extracted two molecular-weight Astragalus polysaccharides (APS, 12.19 kD; APSHMw, 135.67 kD) from Radix Astragali and made them self-assemble with OVA257-264 directly forming
OVA/APS integrated nanocomplexes through the microfluidic method. The nanocomplexes were wrapped with a sheddable calcium phosphate layer to improve stability. APS in the formed nanocomplexes served as drug carriers and immune adjuvants for potent tumor immunotherapy. The optimal APS-NVs were approximately 160 nm with uniform size distribution and could remain stable in physiological saline solution. The FITC-
OVA in APS-NVs could be effectively taken up by DCs, and APS-NVs could stimulate the maturation of DCs, improving the antigen cross-presentation efficiency in vitro. The possible mechanism was that APS can induce DC activation via multiple receptors such as dectin-1 and Toll-like receptors 2 and 4. Enhanced accumulation of APS-NVs both in draining and distal lymph nodes were observed following s.c. injection. Smaller APS-NVs could easily access the lymph nodes. Furthermore, APS-NVs could markedly promote antigen delivery efficiency to DCs and activate cytotoxic T cells. In addition, APS-NVs achieve a better antitumor effect in established B16-
OVA melanoma tumors compared with the
OVA+Alum treatment group. The antitumor mechanism correlated with the increase in cytotoxic T cells in the tumor region. Subsequently, the poor tumor inhibitory effect of APS-NVs on the nude mouse model of melanoma also confirmed the participation of antitumor adaptive immune response induced by NVs. Therefore, this study developed a promising APS-based tumor NV that is an efficient tumor immunotherapy without systemic side effects.