iDali C, Foged N T, Frandsen P L, Nielsen M H, Elling F
Institute of Pathological Anatomy, University of Copenhagen II, Denmark.
J Gen Microbiol. 1991 May;137(5):1067-71. doi: 10.1099/00221287-137-5-1067.
Toxigenic strains of Pasteurella multocida produce the 147 kDa protein Pasteurella multocida toxin (PMT) which is responsible for the osteoclastic bone resorption in progressive atrophic rhinitis in pigs and induces such resorption in all experimental animals tested so far. In the present study we have carried out immunocytochemistry on formaldehyde- and glutaraldehyde-fixed ultracryocut P. multocida using a pool of monoclonal antibodies against different epitopes on PMT as the first layer and affinity purified rabbit anti-mouse IgG as the second layer. Goat anti-rabbit IgG conjugated with 5 nm gold particles was used as marker. The gold particles were silver-enhanced prior to examination in the transmission electron microscope. Whole bacteria were also immunostained after fixation and critical point drying and examined by scanning transmission electron microscopy. The results showed that PMT was located in the cytoplasm of P. multocida. PMT could not be detected on intact, undamaged P. multocida by scanning electron microscopy. Neither pili nor flagella could be detected on the surface of the negatively stained P. multocida strains investigated. PMT has a series of characteristics encompassed in the definition of an exotoxin. However, that PMT was not secreted by living intact P. multocida is unexpected for an exotoxin.
多杀巴斯德菌的产毒菌株可产生147 kDa的多杀巴斯德菌毒素（PMT），该毒素与猪进行性萎缩性鼻炎中的破骨细胞性骨吸收有关，并且在迄今为止所有测试的实验动物中均可诱导这种骨吸收。在本研究中，我们使用针对PMT上不同表位的单克隆抗体池作为第一层，以亲和纯化的兔抗小鼠IgG作为第二层，对甲醛和戊二醛固定的多杀巴斯德菌超低温切片进行了免疫细胞化学研究。与5 nm金颗粒偶联的山羊抗兔IgG用作标记物。在透射电子显微镜检查之前对金颗粒进行银增强。固定和临界点干燥后，对完整细菌也进行免疫染色，并通过扫描透射电子显微镜检查。结果表明，PMT位于多杀巴斯德菌的细胞质中。通过扫描电子显微镜在完整、未受损的多杀巴斯德菌上未检测到PMT。在所研究的经负染色的多杀巴斯德菌菌株表面未检测到菌毛或鞭毛。PMT具有外毒素定义中包含的一系列特征。然而，对于一种外毒素而言，活的完整多杀巴斯德菌不分泌PMT是出乎意料的。
