Yu Yuefei, Wen Bohai, Wen Bogui, Niu Dongsheng, Chen Meiling, Qiu Ling
Beijing Institute of Microbiology and Epidemiology, Fengtai, Beijing, People's Republic of China.
Am J Trop Med Hyg. 2005 Apr;72(4):458-64.
A partial gene sequence encoding the 56-kD scrub typhus antigen (Sta56) was amplified from genomic DNA of the Orientia tsutsugamushi Karp strain by a polymerase chain reaction (PCR). The PCR product was ligated with the 47-kD scrub typhus antigen (Sta47) gene in the pQE30/47 expression vector, and the resulting recombinant expression vector was designated pQE30/56-47. A fusion antigen (Sta56-47) was expressed in Escherichia coli cells transformed with pQE30/56-47 after induction with isopropyl-beta-d-thiogalactopyranoside. The Sta56-47 antigen was recognized by both Sta47 and Sta56 immune sera and by immune serum to Sta56-47 in an immunoblot assay. This antigen was purified and used to immunize BALB/c mice. The animals immunized with Sta56-47 exhibited profound humoral and cellular immune responses, as well as increased resistance to O. tsutsugamushi Karp compared with mice immunized with Sta56 or Sta47. These results strongly suggest that Sta56-47 contains antigenic epitopes of the Sta56 and Sta47 antigens of O. tsutsugamushi Karp, and is a more suitable candidate for replacing whole-cell antigen of O. tsutsugamushi Karp to induce protective immunity against scrub typhus.
通过聚合酶链反应（PCR）从恙虫病东方体Karp株的基因组DNA中扩增出编码56-kD恙虫病抗原（Sta56）的部分基因序列。将该PCR产物与pQE30/47表达载体中的47-kD恙虫病抗原（Sta47）基因连接，所得重组表达载体命名为pQE30/56-47。用异丙基-β-D-硫代半乳糖苷诱导后，在经pQE30/56-47转化的大肠杆菌细胞中表达融合抗原（Sta56-47）。在免疫印迹分析中，Sta56-47抗原可被Sta47和Sta56免疫血清以及Sta56-47免疫血清识别。纯化该抗原并用其免疫BALB/c小鼠。与用Sta56或Sta47免疫的小鼠相比，用Sta56-47免疫的动物表现出强烈的体液免疫和细胞免疫反应，以及对恙虫病东方体Karp的抵抗力增强。这些结果强烈表明，Sta56-47包含恙虫病东方体Karp的Sta56和Sta47抗原的抗原表位，并且是替代恙虫病东方体Karp全细胞抗原以诱导抗恙虫病保护性免疫的更合适候选物。
