Wiker H G, Harboe M
Institute of Immunology and Rheumatology, University of Oslo, Norway.
Microbiol Rev. 1992 Dec;56(4):648-61. doi: 10.1128/mr.56.4.648-661.1992.
The large number of different proteins synthesized by the mycobacterial cell are currently classified and studied in terms of groups of proteins with certain common properties such as physical and chemical characteristics, function, and localization in the mycobacterial cell. Proteins that are actively secreted during culture on synthetic media represent a particular group of great current interest. At least eight proteins secreted by Mycobacterium tuberculosis have been isolated and characterized to various extents. The genes coding for five proteins secreted from M. tuberculosis and/or Mycobacterium bovis BCG have been cloned and sequenced. All of them contain typical signal sequences. The proteins of the antigen 85 complex, which form the main subject of this review, are often the most common proteins in M. tuberculosis culture fluid. The constituents denoted 85A, 85B, and 85C are encoded by three genes located at different sites in the mycobacterial genome and show extensive cross-reactivity as well as homology at amino acid and gene levels. The proteins differ slightly in molecular mass in the 30- to 31-kDa region, and all of them are fibronectin-binding proteins, but the significance of the latter observation and the role of these proteins in mycobacterial physiology and interaction with the infected host remain to be elucidated. The antigen 85 complex proteins are strongly immunogenic in natural and experimental mycobacterial infections in terms of both induction of antibody synthesis and T-cell-mediated reactions. The well-recognized difference in the efficacy of live and dead mycobacterial vaccines should be considered in relation to the group of secreted antigens. After inoculation, live bacteria in vaccines such as BCG multiply in the host, probably releasing several constituents belonging to the class of secreted proteins and hence resulting in more efficient stimulation of the immune system. Secreted mycobacterial antigens are expected to be of particular significance in induction of various immune responses that are responsible for development of protective immunity in some individuals and for clinical symptoms and complications of the ensuing disease in others.
分枝杆菌细胞合成的大量不同蛋白质，目前是根据具有某些共同特性（如理化特征、功能以及在分枝杆菌细胞中的定位）的蛋白质组进行分类和研究的。在合成培养基上培养期间被主动分泌的蛋白质，是当前备受关注的一个特殊类别。结核分枝杆菌分泌的至少8种蛋白质已被分离出来，并在不同程度上进行了表征。编码从结核分枝杆菌和/或牛分枝杆菌卡介苗分泌的5种蛋白质的基因已被克隆和测序。它们都含有典型的信号序列。作为本综述主要研究对象的抗原85复合体蛋白，通常是结核分枝杆菌培养液中最常见的蛋白质。分别命名为85A、85B和85C的组分，由位于分枝杆菌基因组不同位点的3个基因编码，在氨基酸和基因水平上表现出广泛的交叉反应性以及同源性。这些蛋白质在30至31 kDa区域的分子量略有不同，并且它们都是纤连蛋白结合蛋白，但后一观察结果的意义以及这些蛋白质在分枝杆菌生理学和与受感染宿主相互作用中的作用仍有待阐明。就抗体合成的诱导和T细胞介导的反应而言，抗原85复合体蛋白在自然和实验性分枝杆菌感染中具有很强的免疫原性。在考虑分泌抗原类别时，应考虑到活的和死的分枝杆菌疫苗在效力上已得到充分认识的差异。接种后，卡介苗等疫苗中的活细菌在宿主体内繁殖，可能释放出几种属于分泌蛋白类别的成分，从而更有效地刺激免疫系统。预计分泌的分枝杆菌抗原在诱导各种免疫反应中具有特殊意义，这些免疫反应在一些个体中负责保护性免疫的发展，而在另一些个体中则导致随后疾病的临床症状和并发症。
