Kim H Y, Rikihisa Y
Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio 43210-1093, USA.
J Clin Microbiol. 1998 Nov;36(11):3278-84. doi: 10.1128/JCM.36.11.3278-3284.1998.
The major outer membrane proteins (OMPs) of the human granulocytic ehrlichiosis (HGE) agent, with molecular sizes of 44 to 47 kDa, are immunodominant antigens in human infection. Monoclonal antibodies (MAbs) to the OMPs were made by immunizing BALB/c mice with the purified HGE agent and then by fusing spleen cells with myeloma cells. The immunologic specificities of three MAbs (3E65, 5C11, and 5D13) were examined with five human HGE agent isolates and one tick isolate. By Western blot analysis, all three MAbs recognized the HGE agent but not Ehrlichia chaffeensis, Ehrlichia sennetsu, Ehrlichia canis, or their host cells. MAb 3E65 reacted with a 44-kDa protein in the homologous human isolate but not in the remaining five isolates. The two remaining MAbs recognized proteins with molecular sizes of 44 to 47 kDa in all six isolates. Western blot results with the OMP fraction of the six isolates were consistent with results with the whole HGE agent. Immunofluorescent-antibody staining and immunogold labeling with these MAbs showed that these antigens were primarily present on the membrane of the HGE agent. MAbs 5C11 and 5D13 recognized the recombinant 44-kDa protein by Western immunoblot analysis, but MAb 3E65 did not. Passive immunization with MAb 3E65 was more effective in protecting mice from HGE agent infection than with MAbs 5C11 and 5D13. These MAbs would be useful for analyzing the role of the major OMP antigens in HGE agent infection and for serodiagnosis.
人粒细胞埃立克体病（HGE）病原体的主要外膜蛋白（OMPs），分子大小为44至47 kDa，是人类感染中的免疫显性抗原。通过用纯化的HGE病原体免疫BALB/c小鼠，然后将脾细胞与骨髓瘤细胞融合，制备了针对OMPs的单克隆抗体（MAbs）。用5株人HGE病原体分离株和1株蜱分离株检测了3种单克隆抗体（3E65、5C11和5D13）的免疫特异性。通过蛋白质印迹分析，所有3种单克隆抗体都能识别HGE病原体，但不能识别恰菲埃立克体、腺热埃立克体、犬埃立克体或它们的宿主细胞。单克隆抗体3E65与同源人分离株中的一种44 kDa蛋白发生反应，但与其余5种分离株不发生反应。其余两种单克隆抗体在所有6种分离株中都能识别分子大小为44至47 kDa的蛋白。6种分离株的OMP组分的蛋白质印迹结果与整个HGE病原体的结果一致。用这些单克隆抗体进行免疫荧光抗体染色和免疫金标记显示，这些抗原主要存在于HGE病原体的膜上。通过蛋白质印迹免疫分析，单克隆抗体5C11和5D13能识别重组44 kDa蛋白，但单克隆抗体3E65不能。用单克隆抗体3E65进行被动免疫在保护小鼠免受HGE病原体感染方面比用单克隆抗体5C11和5D13更有效。这些单克隆抗体将有助于分析主要OMP抗原在HGE病原体感染中的作用以及用于血清学诊断。
