Abstract：
The mucosal barrier and scavenging effect of the mucosal layer are two main obstacles in inducing mucosal immunization. To overcome these obstacles, we synthesized a bio-inspired mucoadhesive material, chitosan-catechol (ChiC), for surface modification of inactive porcine epidemic diarrhea virus (PEDV). Studies have revealed that PEDV particles can be facilely and mildly modified by Chi-C forming Chi-C-PEDV nanoparticles (Chic-Ps) through the covalent and electrostatic bond, which effectively prolongs the retention time of PEDV in the nasal mucosa. The cell co-culture model demonstrated that Chic-Ps exhibit enhanced recruitment of dendritic cells via the secretion of stimulating chemokine CCL20 and improving antigen permeability by disruption the distribution of ZO-1 protein in epithelial cells. Additionally, the flow cytometry (FCM) analysis revealed that Chic-Ps facilitate trafficking to lymph nodes and induce stronger cellular and humoral immune responses compared to unmodified PEDV. Notably, Chic-Ps induced a higher level of PEDV neutralizing antibody was induced by Chic-Ps in the nasal washes, as confirmed by a plaque reduction neutralization test. These results demonstrate that Chi-C is a promising nasal delivery system for vaccines. Proof of principle was obtained for inactivated PEDV, but similar delivery mechanisms could be applied in other vaccines when intranasal administration is needed.
摘要：
粘膜层的粘膜屏障和清除作用是诱导粘膜免疫的两个主要障碍。为了克服这些障碍,我们合成了一种受生物启发的粘膜粘附材料，壳聚糖-邻苯二酚（ChiC），用于非活性猪流行性腹泻病毒（PEDV）的表面修饰。研究表明，通过Chi-C形成Chi-C-PEDV纳米颗粒（Chic-Ps），可以通过共价键和静电键轻松温和地修饰PEDV颗粒，有效延长PEDV在鼻黏膜中的滞留时间。细胞共培养模型表明，Chic-P通过分泌刺激趋化因子CCL20并通过破坏ZO-1蛋白在上皮细胞中的分布来改善抗原通透性，从而增强了树突状细胞的募集。此外,流式细胞术（FCM）分析显示，与未修饰的PEDV相比，Chic-Ps促进运输到淋巴结并诱导更强的细胞和体液免疫反应。值得注意的是,Chic-Ps诱导较高水平的PEDV中和抗体由Chic-Ps在鼻洗液中诱导，通过斑块减少中和试验证实。这些结果表明,Chi-C是用于疫苗的有前景的鼻递送系统。获得了灭活PEDV的原理证明，但是当需要鼻内给药时，类似的递送机制可以应用于其他疫苗。
