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

1.磷胆碱(PC)的免疫原性。用双抗体夹心法检测急性会厌炎和扁桃体周围脓肿患者血清中PC特异性抗体活性。结果：1.抗PC抗体效价升高，提示PC具有免疫原性和诱导保护性抗体的能力。PC基因的表达与细菌毒力的关系酶联免疫吸附试验检测到细菌表面PC的表达在对数生长期显著增加，在迟滞期显著降低。此外，高表达PC的细菌的黏附能力强于几乎不表达PC的细菌。这些发现表明PC与细菌的时相变化和细菌的毒力有关。给小鼠鼻腔注射抗PC-PC的黏膜免疫应答，并观察其黏膜免疫应答和全身免疫应答。结果表明，PC能诱导鼻黏膜产生IgA免疫应答。免疫应答对流感嗜血杆菌和肺炎链球菌等广谱细菌产生影响。但对霍乱毒素、PC和PC黏膜佐剂的免疫应答均降低，表明PC作为黏膜疫苗是安全的。新的粘膜佐剂CpG和Flt3配体的开发被认为可以激活树突状细胞，是黏膜佐剂的候选药物。用CpG和Flt3配体同时鼻腔注射卵白蛋白小鼠，可诱导Th1和Th2型免疫应答，并观察到持久的IgA和Ig G免疫应答。结果表明，PC可能是一种对大多数引起上呼吸道感染的细菌如流感嗜血杆菌和肺炎链球菌具有广谱活性的黏膜疫苗。

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.