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炭疽病是由炭疽芽胞杆菌Bacillus anthracis引起的一种人畜共患传染病,严重影响着人类的健康。近年来在细菌疫苗的研究中发现一种特殊的现象:细菌被杀死后,体内的代谢活性却仍然维持(Killed but metabolically active,KBMA)。此发现为炭疽新型疫苗候选株的研制提供了新思路。先通过同源重组的方法,利用pMAD质粒和Cre-loxP重组酶系统完成对缺失两个毒性大质粒的炭疽芽胞杆菌减毒株AP422的uvrAB基因的敲除,得到AP422△uvrAB菌株,然后通过光化学处理(包括长波紫外光的照射和8-甲氧基补骨脂素处理),使炭疽芽胞杆菌AP422△uvrAB失去繁殖能力。利用四氮唑化合物MTS检测其代谢活性,表明光化学处理杀死后的炭疽芽胞杆菌AP422△uvrAB在至少4 h内维持一个很高的代谢活性水平,即具备典型的KBMA特性。炭疽杆菌AP422△uvrAB的KBMA菌株的成功研制为我们提供了一种新型炭疽疫苗候选株。
Anthrax is a zoonosis caused by Bacillus anthracis, which seriously affects human health. In recent years, a special phenomenon has been found in bacterial vaccine research: Killing but metabolically active (KBMA) remains after the bacteria are killed. This discovery provides a new idea for the development of candidate anthrax new vaccine strains. The first knockdown of uvrAB gene of attenuated B. anthracis strain AP422 with two virulent large plasmids was accomplished by homologous recombination using the pMAD plasmid and the Cre-loxP recombinase system to obtain the AP422ΔuvrAB strain, which was then purified by photochemistry Treatment (Including long-wave UV irradiation and 8-methoxy psoralen treatment), so that B. anthracis AP422 △ uvrAB loss of reproductive capacity. The activity of tetrazolium compound (MTS) was assayed by MTT assay. The results showed that AP422 △ uvrAB after killing by photochemical treatment maintained a high level of metabolic activity for at least 4 h, that is, typical KBMA characteristics. The successful development of the KBMA strain of Bacillus anthracis AP422ΔuvrAB provided us with a new anthrax vaccine candidate strain.