Levisohn S, Rosengarten R, Yogev D
Division of Avian Diseases, Kimron Veterinary Institute, Bet Dagan, Israel.
Vet Microbiol. 1995 Jul;45(2-3):219-31. doi: 10.1016/0378-1135(95)00039-d.
The antigen expression profiles of Mycoplasma gallisepticum isolates obtained from tracheal swabs of chickens after aerosol-inoculation with M. gallisepticum strain R or clonal variant R/E were examined in western immunoblots. A reference anti-M. gallisepticum chicken antiserum and antisera from individual infected chickens as well as monoclonal antibodies (mAbs) specific for surface proteins were used to monitor in vivo antigenic variation. mAbs 1E5 and 12D8, recognizing PvpA and p67a, recently shown to undergo high-frequency in vitro phase variation, were used for consecutive staining of colony and western immunoblots in order to distinguish between the resultant phenotypes with respect to the corresponding epitopes. Marked differences in the expression of major immunogenic proteins, including p67a, were observed between the two inocula as well as among reisolates recovered at different times of infection. Comparative western immunoblot analysis of the rapidly changing chicken serum antibody response and reisolates recovered during the course of an experimental infection with M. gallisepticum R or clonal variant R/E suggest that immune modulation may have a key role in generating surface diversity. In addition, comparison of colony immunoblots of strain R inoculum and of reisolated colonies from tracheas of birds 8 days post infection indicated an in vivo selection of the PvpA+p67a- phenotype. This study established that surface antigens of M. gallisepticum are subjected in vivo to rapid alteration in their expression. This variability may function as a crucial adaptive mechanism, enabling the organism to escape from the host immune defense and to adapt to the changing host environment at different stages of a natural infection.
用鸡毒支原体R株或克隆变异株R/E对鸡进行气溶胶接种后，从鸡气管拭子中分离得到鸡毒支原体菌株，通过蛋白质免疫印迹法检测其抗原表达谱。使用参考抗鸡毒支原体鸡抗血清、来自个体感染鸡的抗血清以及针对表面蛋白的单克隆抗体（mAb）来监测体内抗原变异。识别PvpA和p67a的单克隆抗体1E5和12D8最近显示在体外会发生高频相变，用于对菌落和蛋白质免疫印迹进行连续染色，以便区分关于相应表位的所得表型。在两种接种物之间以及在感染不同时间回收的再分离株之间，观察到包括p67a在内的主要免疫原性蛋白表达存在显著差异。对鸡毒支原体R株或克隆变异株R/E实验感染过程中快速变化的鸡血清抗体反应和回收的再分离株进行蛋白质免疫印迹比较分析表明，免疫调节可能在产生表面多样性中起关键作用。此外，对R株接种物的菌落免疫印迹与感染后8天从鸟类气管中重新分离的菌落进行比较，表明在体内选择了PvpA + p67a-表型。本研究证实，鸡毒支原体的表面抗原在体内其表达会迅速改变。这种变异性可能作为一种关键的适应性机制，使该生物体能够逃避宿主免疫防御，并在自然感染的不同阶段适应不断变化的宿主环境。
