Deshpande R G, Khan M B, Bhat D A, Navalkar R G
Department of Microbiology and Immunology, Morehouse School of Medicine, Atlanta, Georgia 30310.
Tuber Lung Dis. 1993 Dec;74(6):388-94. doi: 10.1016/0962-8479(93)90082-9.
To determine the superoxide dismutase (SOD) activity from clinical isolates of Mycobacterium tuberculosis and to study the seroreactivity of SOD from M. tuberculosis H37Rv.
Crude cell extracts of 16 strains of M. tuberculosis isolated from tuberculosis (TB) patients were assayed for SOD activity. SOD from H37Rv was partially purified and characterized, and the seroreactivity was studied by ELISA using sera from 36 active pulmonary TB and 31 leprosy patients.
SOD activity was detected in all the 16 strains of M. tuberculosis and also in the medium of logarithmic and stationary cultures of H37Rv. SOD activity from H37Rv extract was not affected by 1 mM KCN or by 5 mM H2O2 and was only 20% inhibited by 10 mM NaN3, suggesting that it is a Mn-containing enzyme. SOD was partially purified from H37Rv extract by gel filtration chromatography as a tetramer of molecular weight (MW) of 80,000 and a subunit MW of approximately 23,000. A delayed type hypersensitivity was elicited by SOD in guinea pigs sensitized with H37Rv or M. leprae sonicate. ELISA using SOD as antigen indicated 100% positivity with TB sera, while 84% positivity was observed with leprosy sera. Western blotting with pooled TB and leprosy sera indicated the presence of antibodies to the 23 kD SOD protein.
Our data indicate that M. tuberculosis strains are rich in SOD, and the secretion of SOD may play a valuable role in the pathogenesis of M. tuberculosis.
测定结核分枝杆菌临床分离株中超氧化物歧化酶（SOD）的活性，并研究结核分枝杆菌H37Rv菌株SOD的血清反应性。
对从结核病（TB）患者中分离出的16株结核分枝杆菌的粗细胞提取物进行SOD活性检测。对H37Rv菌株的SOD进行部分纯化和特性鉴定，并使用36例活动性肺结核患者和31例麻风病患者的血清通过酶联免疫吸附测定（ELISA）研究其血清反应性。
在所有16株结核分枝杆菌中以及在H37Rv菌株的对数期和稳定期培养物培养基中均检测到SOD活性。H37Rv提取物中的SOD活性不受1 mM氰化钾（KCN）或5 mM过氧化氢（H2O2）的影响，仅受10 mM叠氮化钠（NaN3）抑制20%，提示其为含锰酶。通过凝胶过滤色谱从H37Rv提取物中部分纯化出SOD，其为分子量（MW）80,000的四聚体，亚基MW约为23,000。在用H37Rv或麻风分枝杆菌超声裂解物致敏的豚鼠中，SOD引发了迟发型超敏反应。以SOD作为抗原的ELISA显示，结核病血清的阳性率为100%，而麻风病血清的阳性率为84%。用结核病和麻风病混合血清进行的蛋白质免疫印迹法表明存在针对23 kD SOD蛋白的抗体。
我们的数据表明，结核分枝杆菌菌株富含SOD，SOD的分泌可能在结核分枝杆菌的发病机制中发挥重要作用。
