Lundkvist A, Kallio-Kokko H, Sjölander K B, Lankinen H, Niklasson B, Vaheri A, Vapalahti O
Department of Defense Microbiology, Swedish Institute for Infectious Disease Control, Stockholm, Sweden.
Virology. 1996 Feb 15;216(2):397-406. doi: 10.1006/viro.1996.0075.
B-cell epitopes in the nucleocapsid protein (N) of Puumala (PUU) virus were investigated by use of truncated recombinant proteins and overlapping peptides. Six of seven epitopes, recognized by bank vole monoclonal antibodies, were localized within the amino-terminal region of the protein (aa 1-79). Polyclonal antibodies from wild-trapped or experimentally infected bank voles identified epitopes located over the entire protein. Antibody end-point titers to different N fragments indicated that the amino-terminal region is the major antigenic target in PUU virus-infected bank voles. To investigate the role of PUU virus N in protective immunity, we analyzed the immunogenicity of truncated recombinant N and developed an animal model based on colonized bank voles. No PUU virus N antigen, nor any glycoprotein-specific antibodies, could be detected after virus challenge in animals immunized with an amino-terminal fragment (aa 1-118), a fragment covering two thirds of the animals immunized with shorter N fragments displayed either N antigen, or glycoprotein-specific antibodies, suggestive of partial protection. Prechallenge sera from all groups of immunized animals were found negative or only weakly positive for neutralizing antibodies when assayed by focus reduction neutralization test, which indicated an important role for cell-mediated immunity in protection.
通过使用截短的重组蛋白和重叠肽，对普马拉（PUU）病毒核衣壳蛋白（N）中的B细胞表位进行了研究。被田鼠单克隆抗体识别的七个表位中的六个位于该蛋白的氨基末端区域（氨基酸1-79）。来自野外捕获或实验感染田鼠的多克隆抗体识别出位于整个蛋白上的表位。针对不同N片段的抗体终点滴度表明，氨基末端区域是PUU病毒感染田鼠的主要抗原靶点。为了研究PUU病毒N在保护性免疫中的作用，我们分析了截短的重组N的免疫原性，并建立了基于圈养田鼠的动物模型。在用氨基末端片段（氨基酸1-118）免疫的动物中，病毒攻击后未检测到PUU病毒N抗原，也未检测到任何糖蛋白特异性抗体，而用较短N片段免疫的动物中有三分之二的动物显示出N抗原或糖蛋白特异性抗体，提示有部分保护作用。通过蚀斑减少中和试验检测时，所有免疫动物组的攻击前血清对中和抗体呈阴性或仅弱阳性，这表明细胞介导的免疫在保护中起重要作用。
