Development of a novel nasal vaccine having wide spectrum activity for upper respiratory infections

1. 磷酸胆碱（PC）的免疫原性。采用ELISA法检测急性会厌炎和扁桃体周围脓肿患者血清pc特异性抗体活性。结果显示，抗PC抗体滴度升高，提示PC具有免疫原性和诱导保护性抗体的能力。PC表达与细菌毒力的关系。酶联免疫吸附法检测PC在细菌表面的表达在滞期显著升高，在滞期显著降低。此外，高表达PC的细菌的粘附能力比低表达PC的细菌强。这些结果表明，PC与细菌的相变化和细菌的毒力有关。小鼠经鼻给药，观察其粘膜免疫反应和全身免疫反应。结果表明，PC能够诱导鼻黏膜的IgA免疫应答。免疫反应对包括流感嗜血杆菌和肺炎链球菌在内的广谱细菌有影响。然而，接种PC后，对霍乱毒素、粘膜佐剂以及PC的IgE免疫应答均降低，表明PC作为粘膜疫苗是安全的。新的粘膜佐剂CpG和flt3配体的发展被认为可以激活树突状细胞，是粘膜佐剂的候选物。当CpG和flt3配体同时经鼻给药给卵清蛋白小鼠时，诱导Th1和th2型免疫反应，并观察到持久的IgA和IgG免疫反应。结果表明，PC可能是一种对流感嗜血杆菌和肺炎链球菌等引起上呼吸道感染的大多数细菌具有广谱活性的粘膜疫苗。

1. Immunogenicity of phosphorylcholine (PC). PC-specific antibody activities in serum obtained from patients with acute epiglottitis and peri-tonsillar abscess were examined by ELISA. The results showed increased antibody titers against PC, suggesting that PC has immunogenicity and an ability to induce protecting antibodies.2. Relationship between the expression of PC and bacterial virulence. The expression of PC on bacterial surfaces determined by ELISA was significantly increased in log-phase and decreased in lag-phase. Further, the adherence ability of bacteria highly expressing PC was greater than that of bacteria scarcely expressing PC. Those findings indicate that PC is associated with the phase variation of bacteria and the virulence of bacteria.3. Mucosal immune responses against PC PC was intra-nasally administered to mice and mucosal as well as systemic immune responses were investigated. The results demonstrated that PC is capable of inducing IgA immune responses in nasal mucosa. The immune responses had impact on wide spectrum of bacteria including Haemophilus influenzae and Streptococcus pneumonia. However, IgE immune responses against cholera toxin, mucosal adjuvant administered with PC, as well as PC were reduced, indicating the safety of PC as mucosal vaccine.4. Development of new mucosal adjuvant CpG and Flt3-ligand are known to activate dendritic cell and are candidates of mucosal adjuvant. When both CpG and Flt3-ligand were intra-nasally administered to mice with ovalbumin, Th1- and Th2-type immune responses were induced and long-lasting IgA as well as IgG immune responses were observed. The results suggest that PC might be a candidate of mucosal vaccine having wide spectrum activity against most bacteria such as Haemophilus influenzae and Streptococcus pneumonia causing upper respiratory infections.