Lundkvist A, Vapalahti O, Plyusnin A, Sjölander K B, Niklasson B, Vaheri A
Swedish Institute for Infectious Disease Control, Stockholm, Sweden.
Virus Res. 1996 Nov;45(1):29-44. doi: 10.1016/0168-1702(96)01360-3.
Tula virus was recently discovered by RT-PCR in lung samples from European common voles (Microtus arvalis and M. rossiaemeridionalis). Since virus isolation attempts had been unsuccessful, no antigen was available for analysis or for use in immunoassays. To circumvent this, complete Tula virus nucleocapsid protein (bac-TUL-N) was expressed in recombinant baculovirus. Rodent antibody end-point titers to bac-TUL-N and to truncated N fragments indicated that the NH2-terminal region is the major antigenic target and revealed a high cross-reactivity to Puumala virus N. Immunizations with crude bac-TUL-N preparations evoked high antibody responses to native hantavirus N in Balb/c mice and six monoclonal antibodies (Mabs) were generated. Epitope mapping of the Mabs, based on a competitive assay, reactivities to truncated recombinant N fragments, and reactivity patterns to different hantavirus strains, identified five recognition sites on Tula virus N. One epitope, which was identified as specific for Tula virus, was located in a region of N which is highly variable among the hantaviruses (aa 226-293), and four epitopes were mapped to the NH2-terminal region of the protein (aa 1-61). One epitope was expressed only in Tula and Prospect Hill viruses, one epitope in Tula, Prospect Hill, Khabarovsk, and Sin Nombre viruses, while two epitopes were conserved in all examined hantaviruses carried by rodents within the subfamily Arvicolinae of the Muridae family.
图拉病毒最近通过逆转录聚合酶链反应（RT-PCR）在欧洲普通田鼠（草原田鼠和南俄田鼠）的肺样本中被发现。由于病毒分离尝试未成功，没有抗原可用于分析或免疫测定。为了克服这一问题，完整的图拉病毒核衣壳蛋白（bac-TUL-N）在重组杆状病毒中表达。啮齿动物针对bac-TUL-N和截短的N片段的抗体终点滴度表明，NH2末端区域是主要的抗原靶点，并显示出与普马拉病毒N的高交叉反应性。用粗制的bac-TUL-N制剂进行免疫在Balb/c小鼠中引发了对天然汉坦病毒N的高抗体反应，并产生了六种单克隆抗体（Mab）。基于竞争试验、对截短的重组N片段的反应性以及对不同汉坦病毒株的反应模式对Mab进行表位定位，确定了图拉病毒N上的五个识别位点。一个被确定为图拉病毒特异性的表位位于N的一个区域，该区域在汉坦病毒中高度可变（氨基酸226 - 293），四个表位定位于该蛋白的NH2末端区域（氨基酸1 - 61）。一个表位仅在图拉病毒和展望山病毒中表达，一个表位在图拉病毒、展望山病毒、哈巴罗夫斯克病毒和辛诺柏病毒中表达，而两个表位在鼠科田鼠亚科啮齿动物携带的所有检测汉坦病毒中保守。
