Characterization of human CD4+ T-cell clones recognizing conserved and variable epitopes of the Lassa virus nucleoprotein
Characterization of human CD4+ T-cell clones recognizing conserved and variable epitopes of the Lassa virus nucleoprotein
复制标题
DOI：
10.1128/jvi.74.5.2186-2192.2000
复制
发表时间：
2000-03-01
影响因子：
5.4
通讯作者：
Hoerauf, A
中科院分区：
文献类型：
--
作者：
ter Meulen, J;Badusche, M;Hoerauf, A
T细胞必须在控制急性人类拉沙病毒感染中发挥主要作用，因为患者在缺乏可测量的中和抗体应答的情况下从急性拉沙热中恢复。T细胞本身似乎可以保护动物免受致命的拉沙病毒的攻击，因为在实验性疫苗接种后，检测不到中和抗体。为了研究人T细胞对单一拉沙病毒蛋白的反应性，克隆拉沙病毒Josiah株的核蛋白（NP），在大肠杆菌中表达，并亲和纯化。外周血单核细胞（PBMC）获自生活在西非几内亚共和国的13名健康拉沙病毒抗体阳性个体中的8名，被发现响应重组蛋白而增殖（增殖指数大于或等于10）。从具有特别高的增殖反应的一个个体获得的PBMC用于产生50个NP特异性T细胞克隆（TCC）。对于其中的六个，表位用源自NP序列的重叠合成肽作图。这些CD 4（+）TCC显示出高特异性增殖，并且在用NP刺激时主要产生γ干扰素。因为已经观察到天然存在的拉沙病毒变体的结构蛋白的氨基酸序列中高达15%的变异，所以测试了TCC与源自拉沙病毒的尼日利亚株和东非沙粒病毒Mopeia的同源表位的肽的反应性。对于拉沙病毒的尼日利亚株，这些表位中的两个的同源性水平为100%，其中三个为85%，而与相应的Mopeia表位的同源性范围为92 - 69%。TCC与源自尼日利亚株和Mopeia的可变表位的肽的反应性降低或完全消除。本报告首次表明，来自流行地区的血清阳性个体对拉沙病毒的NP具有非常强的记忆性CD 4（+）T细胞应答，这种应答部分具有毒株特异性，部分与其他拉沙病毒毒株交叉反应。我们的研究结果可能对设计针对这种主要由T细胞控制的人沙粒病毒感染的重组疫苗的策略具有重要意义。
T cells must play the major role in controlling acute human Lassa virus infection, because patients recover from acute Lassa fever in the absence of a measurable neutralizing antibody response. T cells alone seem to protect animals from a lethal Lassa virus challenge, because after experimental vaccination no neutralizing antibodies are detectable. In order to study human T-cell reactivity to single Lassa virus proteins, the nucleoprotein (NP) of Lassa virus, strain Josiah, was cloned, expressed in Escherichia coli, and affinity purified, Peripheral blood mononuclear cells (PBMC) obtained from 8 of 13 healthy, Lassa virus antibody-positive individuals living in the Republic of Guinea, western Africa, were found to proliferate in response to the recombinant protein (proliferation index greater than or equal to 10). PBMC obtained from one individual with a particularly high proliferative response were used to generate 50 NP-specific T-cell clones (TCC), For six of these the epitopes were mapped with overlapping synthetic peptides derived from the sequence of the NP. These CD4(+) TCC displayed high specific proliferation and produced mainly gamma interferon upon stimulation with NP, Because variation of up to 15% in the amino acid sequences of the structural proteins of naturally occurring Lassa virus variants has been observed, the reactivity of the TCC with peptides derived from the homologous epitopes of the Nigeria strain of Lassa virus and of the eastern Africa arenavirus Mopeia was tested. With the Nigeria strain of Lassa virus the levels of homology were 100% for two of these epitopes and 85% for three of them, whereas homology with the respective Mopeia epitopes ranged from 92 to 69%, Reactivity of the TCC with peptides derived from the variable epitopes of the Nigeria strain and of Mopeia was reduced or completely abolished. This report shows for the first time that seropositive individuals from areas of endemicity have very strong memory CD4(+) T-cell responses against the NP of Lassa virus, which are partly strain specific and partly cross-reactive with other Lassa virus strains. Our findings may have important implications for the strategy of designing recombinant vaccines against this mainly T-cell controlled human arenavirus infection.