Development of novel vaccine adjuvant for infectious disease

我们通过将常规脂质体与紫外线灭活的仙台病毒融合来制备融合脂质体。融合脂质体可以以仙台病毒融合依赖的方式将包封的内容物直接递送到细胞质中。基于进入细胞质的高递送速率，我们检查了融合脂质体作为抗原递送载体的用途。使用融合脂质体的抗原的鼻给药有效地将抗原递送到鼻咽相关淋巴网状组织中的抗原取样M细胞。此外，融合脂质体还有效地将抗原递送到鼻咽相关淋巴网状组织和鼻通道中的上皮细胞和巨噬细胞中。体外抗原呈递试验清楚地表明，融合脂质体通过上皮细胞以及巨噬细胞的MHC II类依赖性途径有效地呈递包封的抗原。融合脂质体还具有针对粘膜上皮细胞的佐剂活性以增强MHC II类表达。根据融合脂质体的这些高递送和佐剂活性，用OVA包封的融合脂质体进行鼻免疫诱导高水平的OVA特异性CD4（+）Th1和Th2细胞应答。此外，通过用抗原包封的融合脂质体鼻免疫，还在粘膜和全身部位引起抗原特异性CTL应答和抗体产生。这些结果表明，融合脂质体是一种通用的和有效的系统，用于刺激抗原特异性免疫反应在粘膜和全身隔室。

We prepared fusogenic liposomes by fusing conventional liposomes with an ultra-violet inactivated Sendai virus. Fusogenic liposomes can deliver encapsulated contents into the cytoplasm directly in a Sendai virus fusion-dependent manner. Based on the high delivery rates into the cytoplasm, we examined the use of fusogenic liposomes as an antigen delivery vehicle. Nasal administration of antigens using fusogenic liposome efficiently delivered antigens to antigen-sampling M cells in nasopharyngeal-associated lymphoreticular tissue. Additionally, fusogenic liposomes also effectively delivered the antigens into epithelial cells and macrophages in nasopharyngeal-associated lymphoreticular tissue and nasal passages. In vitro Antigen presentation assays clearly showed that fusogenic liposomes effectively presented encapsulated antigens via the MHC class II-dependent pathway of epithelial cells as well as macrophages. Fusogenic liposomes also have an adjuvant activity against mucosal epithelial cells to enhance MHC class II expression. According to these high delivery and adjuvant activities of fusogenic liposomes, nasal immunization with OVA-encapsulated fusogenic liposomes induced high levels of OVA-specific CD4(+) Th1 and Th2 cell responses. Furthermore, Antigen-specific CTL responses and antibody productions were also elicited at both mucosal and systemic sites by nasal immunization with antigen-encapsulated fusogenic liposomes. These results indicate that fusogenic liposome is a versatile and effective system for the stimulation of antigen-specific immune responses at both mucosal and systemic compartments.