Experimental analysis of symbiosis of Orientia tsutsugamushi and Leptorombidium.

本研究采用微生物学和实验相结合的方法对恙虫病东方体和田鼠的共生情况进行了分析。1.建立了用免疫荧光显微镜观察立克次体的方法，极大地改进了维持立克次体阳性菌落的繁琐工作。2.用类型特异性的单抗可以用上述方法分析单只螨体中立克次体的亚型。结果表明，每只螨类及其家系均含有单一血清型的立克次体。这与目前的观点相反。3.为了了解携带钩端螺旋体的种群只由雌性组成的原因，用注射了杀立克次体抗生素的米诺环素的实验室小鼠饲养该种群中未取食的幼虫。成功地消灭了尘螨中的立克次体，并在子代中观察到了性别比。P、F1代均为雌性，F2~F5代以雄性为主。结果表明，立克次体可导致携带立克次体的人群中雌雄比例偏大。4.对日本地区分离的钩端螺旋体菌株进行了单抗和编码该株特异性抗原蛋白基因的RFLP分析，结果表明，各血清型的钩端螺旋体菌株可进一步划分为亚型。

We analyzed the symbiosis of Orientia tsutsugamushi and Trombiculid mite by microbiological and experimentaltechniques.1.We developed a method to observe rickettsiae in the mites by immunofluorescent microscopy, which largely improved a laborious work to maintain rickettsia-positive colonies of Leptotrombidium.2.Secrotype of the rickettsiae in a single mite could be analyzed by the above-mentioned method with type-specific monoclonal antibodies. It was demonstrated that each mite and each family line of the mites harbor rickettsiae of a single serotype. This is the contrary to an opinion so far claimed.3.To know the reason why the colony of O.tsutsugamushi-harboring L.fletcheri consists only from females, unfed larvae in the colony were fed on laboratory mice which had been injected with minocycline, a rickettsiacidal antibiotic agent. The rickettsiae in the mites were successfully eliminated from the mites, and sex ratio was observed in the descendants. All the mites at the P and F1 generations were females, but males appeared and dominated at F2 through F5 generations. This suggests that the rickettsia causes female-biased sex ratio in the rickettsia-harboring colony of L.fletcheri.4.Strains of O.tsutsugamushi isolated isolated in Japan were analyzed by monoclonal antibodies and RFLP of a gene cording the strain specific antigen protein.It was indicated that strains in each serotype of O.tsutsutgamushi could be further classified into subtypes.