Tagawa Y, Haritani M, Ishikawa H, Yuasa N
National Institute of Animal Health, Ibaraki, Japan.
Infect Immun. 1993 May;61(5):1750-5. doi: 10.1128/iai.61.5.1750-1755.1993.
In immunoblot analysis, a murine monoclonal antibody (MAb), 27-1, which was produced to an outer membrane protein (OMP) of Haemophilus somnus, showed that a major OMP is heat modifiable, having a molecular mass of 28 kDa when the N-lauroylsarcosine-insoluble OMP preparation was solubilized at 60 degrees C and a mass of 37 kDa when the OMP preparation was solubilized at 100 degrees C. The heat-modifiable OMP reacted intensely with convalescent sera obtained from calves with experimental H. somnus pneumonia in immunoblot analysis. Immunoelectron microscopic and antibody absorption studies revealed that the MAb 27-1 epitope was not surface exposed on the intact bacterium. However, a decrease in antibody reactivity to the heat-modifiable OMP in immunoblot analysis after absorption of convalescent serum with intact bacterial cells of H. somnus suggests that a surface-exposed portion of the heat-modifiable OMP is expressed on the intact bacterium. MAb 27-1 reacted with 45 of 45 strains of H. somnus tested in immunoblot analysis. The apparent molecular mass of the antigen varied among strains, and five reactivity patterns demonstrated by MAb 27-1 were observed. MAb 27-1 also reacted with six species in the family Pasteurellaceae, Escherichia coli, and Salmonella dublin, but not with the other eight species of gram-negative bacteria. The heat-modifiable OMP of H. somnus showed immunological cross-reactivity with the OmpA protein of E. coli K-12 and significant N-terminal amino acid sequence homology with the OmpA proteins of gram-negative bacteria. We conclude that a major, 37-kDa heat-modifiable OMP of H. somnus, which elicits an antibody response in H. somnus-infected animals, is a common antigen among H. somnus strains tested and is structurally related to the OmpA protein of E. coli.
在免疫印迹分析中，一种针对睡眠嗜血杆菌外膜蛋白（OMP）产生的鼠单克隆抗体（MAb）27-1显示，一种主要的OMP具有热可修饰性，当N-月桂酰肌氨酸不溶性OMP制剂在60℃溶解时，其分子量为28 kDa，而当OMP制剂在100℃溶解时，其分子量为37 kDa。在免疫印迹分析中，这种热可修饰性OMP与从患有实验性睡眠嗜血杆菌肺炎的犊牛获得的恢复期血清发生强烈反应。免疫电子显微镜和抗体吸收研究表明，MAb 27-1表位在完整细菌表面未暴露。然而，用睡眠嗜血杆菌完整细菌细胞吸收恢复期血清后，免疫印迹分析中对热可修饰性OMP的抗体反应性降低，这表明热可修饰性OMP的一个表面暴露部分在完整细菌上表达。在免疫印迹分析中，MAb 27-1与所测试的45株睡眠嗜血杆菌中的45株发生反应。抗原的表观分子量在不同菌株间有所不同，观察到MAb 27-1显示出五种反应模式。MAb 27-1还与巴斯德菌科的六个种、大肠杆菌和都柏林沙门氏菌发生反应，但不与其他八种革兰氏阴性菌发生反应。睡眠嗜血杆菌的热可修饰性OMP与大肠杆菌K-12的OmpA蛋白显示出免疫交叉反应，并且与革兰氏阴性菌的OmpA蛋白具有显著的N端氨基酸序列同源性。我们得出结论，睡眠嗜血杆菌的一种主要的、37 kDa的热可修饰性OMP在感染睡眠嗜血杆菌的动物中引发抗体反应，是所测试的睡眠嗜血杆菌菌株中的一种共同抗原，并且在结构上与大肠杆菌的OmpA蛋白相关。
