Wiker H G, Nagai S, Hewinson R G, Russell W P, Harboe M
Institute of Immunology and Rheumatology, University of Oslo, Norway.
Scand J Immunol. 1996 Apr;43(4):374-80. doi: 10.1046/j.1365-3083.1996.d01-61.x.
MPB70 and MPB83 are homologous cross-reactive secreted mycobacterial proteins with very limited species distribution. The expression of these two proteins was compared between several substrains of Mycobacterium bovis BCG, virulent M. bovis and Mycobacterium tuberculosis H37Rv. A polyclonal antibody specific for MPB70 in Western blotting, and a monoclonal antibody, MBS43, found to be specific for MPB83 in ELISA and Western blotting, were used for the comparison. The previously established pattern of high- and low-producing substrains of BCG for MPB70 is only partially applicable for MPB83. MPB70 low-producing strains are also MPB83 low-producing, but the expression of MPB83 is much more variable than the expression of MPB70 in the MPB70 high-producing strains. Purified MPB83 (23 kDa) was found to be glycosylated. A band in SDS-PAGE at 1-2 kDa lower than that of purified MPB83 may represent unglycosylated MPB83. Furthermore, it was confirmed that purified MPB70 (22 kDa) is unglycosylated. There is cross-reactive antigen at 26 kDa. The MPB83 related antigen at 26 kDa was found to be the most abundant. These findings indicate greater heterogeneity between different substrains of BCG than previously realized. Virulent M. bovis produce and secrete large amounts of MPB70 and MPB83 while both these proteins occur in a far lower concentration in M. tuberculosis.
MPB70和MPB83是同源的交叉反应性分泌型分枝杆菌蛋白，其物种分布非常有限。比较了牛分枝杆菌卡介苗的几个亚菌株、强毒牛分枝杆菌和结核分枝杆菌H37Rv中这两种蛋白的表达情况。在蛋白质印迹法中使用对MPB70特异的多克隆抗体，以及在酶联免疫吸附测定法和蛋白质印迹法中发现对MPB83特异的单克隆抗体MBS43进行比较。先前确立的卡介苗MPB70高产和低产亚菌株模式仅部分适用于MPB83。MPB70低产菌株也是MPB83低产菌株，但在MPB70高产菌株中，MPB83的表达比MPB70的表达变化大得多。发现纯化的MPB83（23 kDa）是糖基化的。在十二烷基硫酸钠聚丙烯酰胺凝胶电泳中，比纯化的MPB83低1 - 2 kDa处的条带可能代表未糖基化的MPB83。此外，已证实纯化的MPB70（22 kDa）未糖基化。在26 kDa处有交叉反应性抗原。发现26 kDa处与MPB83相关的抗原最为丰富。这些发现表明卡介苗不同亚菌株之间的异质性比以前认识到的更大。强毒牛分枝杆菌产生并分泌大量的MPB70和MPB83，而这两种蛋白在结核分枝杆菌中的浓度要低得多。
