一种KBMA炭疽疫苗候选株的研制

Development of a killed but metabolically active anthracis vaccine candidate strain

摘要:

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。

Abstract:

Anthrax is a zoonosis caused by Bacillus anthracis, which seriously affects human health. In recent years, a special phenomenon is found that the metabolic active of a bacterium remains after it is killed. To development of a KBMA (killed but metabolically active) Bacillus anthracis vaccine candidate strain, a plasmid pMAD and a recombinase system Cre-loxP were used to knockout the uvrAB gene of B. anthracis AP422 which lacks both of two plasmids pXO1 and pXO2. The results of PCR and RT-PCR shows that uvrAB genes were deleted from B. anthracis AP422 chromosome successfully. The constructed B. anthracis AP422△uvrAB was inactivated by photochemical treatment (PCT) including an exposure in a long-wave-length ultraviolet (UVA) light and a treatment of 8-Methoxypsoralen (8-MOP), then the metabolic activity were detected by the method of MTS. The results showed that the killed B. anthracis AP422△uvrAB maintained a highly metabolic activity for at least 4 hours, showing a state of KBMA. The KBMA strain of B. anthracis AP422△uvrAB provides the prospective vaccine candidate strain for anthrax.