Development of effective immunization by DNA vaccine against iron-acquisition protein of periodontopathic bacteria

牙龈卟啉单胞菌赖氨酸特异性半胱氨酸蛋白酶(KGP)是一种重要的牙周病致病细菌，它既具有与血红蛋白结合的活性，又具有蛋白酶活性，在牙周病的发病机制中起着重要作用。以前我们曾报道，肌肉注射抗KGP DNA疫苗免疫小鼠，可诱导血清中特异性的抗KGP抗体，DNA疫苗可预防炎症反应，延长免疫小鼠对抗牙龈假单胞菌感染的生存率。本研究的目的是通过肌肉注射DNA疫苗或口服寄生于宿主细胞的携带DNA疫苗的无毒细菌免疫小鼠，探讨是否可以引入体液免疫和细胞免疫，从而形成有效的免疫。我们构建了口服kgp基因疫苗(pCMV/kgp)，并将其转化到沙门氏菌…中。More himuriuin SL7207，这是一种无毒细菌，被用作DNA疫苗的载体。每周用携带编码KGP-DNA疫苗的质粒的细菌口服免疫小鼠，共接种四次。免疫后，用ELISA法可明显诱导血清中特异性抗KGP-Ig G抗体。肌肉注射DNA疫苗免疫小鼠后，血清中抗KGP-Ig G抗体的滴度明显低于口服免疫小鼠。此外，口服DNA疫苗免疫小鼠也可在唾液中引入抗KGP IgA抗体，而肌肉注射免疫小鼠则未观察到这些抗体。我们目前正致力于开发有效的免疫方法，并引入细胞免疫和粘膜免疫。提示KGP-DNA疫苗口服免疫可能是预防牙周炎的一种有效方法。较少

Lysine-specific cysteine proteinase (KGP) of Porphyromonas gingivalis, which is a prominent periodontopathic bacterium, is considered to play an important role in its pathogenesis, since it possesses protease activity as well as hemoglobin-binding activity. Previously, we reported that immunization of mice by injection of DNA vaccine against KGP into the muscle induced specific anti-KGP IgG antibodies in serum and that the DNA vaccine prevented inflammatory responses and prolonged the survival rate of the immunized mice against P gingivalis infection. The aim of this study was to investigate whether humoral immunity and cell-mediated immunity could be introduced when mice were immunized by injection of DNA vaccine into muscle or by oral administration of DNA vaccine-harboring avirulent bacterium that parasitizes in host cells; consequently to develop effective immunization. We constructed kgp-DNA vaccine (pCMV/kgp) for oral administration and transformed the plasmid into Salmonella typ … More himuriuin SL7207, which is an avirulent bacterium and was used as a vehicle for the DNA vaccine. Mice were immunized orally with the bacterium harboring the plasmid encoding kgp-DNA vaccine weekly for a total of four inoculations. Following the immunization, it was shown that specific anti-KGP IgG antibodies in serum were clearly induced by ELISA. Although induction of anti-KGP IgG antibodies in serum was observed when mice were immunized by injection of the DNA vaccine into muscle, the titers were lower than those when mice were orally immunized. Moreover, anti-KGP IgA antibodies in saliva were also introduced by immunization by oral administration of the DNA vaccine, while those were not observed when mice were immunized by intramuscular injection. We are now working on development of effective immunization methods and ion introduction of cell-mediated immunity and mucosal immunity. The present study indicates that immunization of kgp-DNA vaccine by oral administration may be a useful method to prevent periodontitis. Less