Induction of mucosal immune responses by DNA vaccine encoding Porphyromonas gingivalis fimbriae

为了开发针对侵入粘膜上皮的口腔和咽部病原体的疫苗，已经诱导分泌和血清伊加/IgG抗体和细胞毒性T淋巴细胞。我们采用了一种新的方法，靶向唾液腺（TSG）免疫，使用质粒pcDNA 3/fimA编码牙龈卟啉单胞菌菌毛。转染pcDNA 3/fimA后，在体外生长的真核细胞中观察到亚基蛋白fimbrillin的表达。本研究采用TSG免疫BALB/c小鼠，获得了良好的体液免疫和细胞免疫应答。TSG免疫可显著刺激唾液中6 f菌毛特异性伊加和IgG抗体的产生及血清中IgG抗体的产生。唾液腺内注射DNA疫苗可诱导产生高水平的抗原特异性IgG抗体，与肌肉内免疫诱导的结果相似。pcDNA 3/fimA免疫小鼠血清中识别菌毛的主要IgG亚类为IgG 2a。用RT-PCR分析唾液腺单个核细胞时，免疫组中Th 2细胞特异性mRNA水平高于非免疫组。此外，TSG DNA免疫导致脾中抗原特异性CTL的产生。这些结果表明，TSG免疫与质粒DNA可能代表了一种遗传免疫策略，对感染的口腔和咽部病原体，可能会侵入局部，粘膜表面。

For the development of vaccines against oral and pharyngeal pathogens invading the mucosal epithelia, both secretory and serum IgA/IgG antibodies and cytotoxic T lymphocytes have been induced. We employed a novel approach, targeted salivary gland (TSG) immunization, using a plasmid pcDNA3/fimA coding for Porphyromonas gingivalis fimbriae. Expression of subunit protein, fimbrillin, was observed in eukaryotic cells growing in vitro following transfection, with pcDNA3/fimA. In this study, we obtained good humoral and cell-mediated immune responses in BALB/c mice by TSG administration using the above mentioned DNA vaccine. The production 6f fimbriae-specific IgA and IgG antibodies in saliva and serum IgG antibody was significantly stimulated by TSG immunization. Injection of DNA vaccine into salivary gland elicited high level production of antigen-specific IgG antibody, similar to that induced following intramuscular immunization. The major IgG subclass that recognized fimbriae was IgG2a in serum from pcDNA3/fimA immunized mice. When mononuclear cells from salivary glands^were analyzed by RT-PCR, higher levels of Th2 cytokine-specific mRNA were seen in the immunized group than non-immunized group. In addition, TSG DNA immunization resulted in the generation of antigen-specific CTL in spleen. These results indicate that TSG immunization with plasmid DNA may represent a genetic immunization strategy against infection by oral and pharyngeal pathogens that may invade local, mucosal surfaces.