Magurano F, Nicoletti L
Laboratorio di Virologia, Istituto Superiore di Sanità, Rome, Italy.
Clin Diagn Lab Immunol. 1999 Jan;6(1):55-60. doi: 10.1128/CDLI.6.1.55-60.1999.
The Toscana virus (family Bunyaviridae, genus Phlebovirus) is the only sandfly-transmitted virus that demonstrates neurotropic activity. Clinical cases ranging from aseptic meningitis to meningoencephalitis caused by Toscana virus are yearly observed in central Italy during the summer, and several cases have been reported among tourists returning from zones of endemicity (Italy, Portugal, Spain, and Cyprus). In Toscana virus patients, immunoglobulin M (IgM) antibodies, usually present at the onset of symptoms, can reveal elevated titers by enzyme-linked immunosorbent assay and can persist for at least 1 year. IgG antibodies can be absent at the onset of symptoms: titers rise in convalescent sera and persist for many years. At least five proteins have been identified in Toscana virus-infected cells: nucleoprotein N, glycoproteins G1 and G2, a large protein (L) assumed to be a component of the polymerase, and two nonstructural proteins, NSm and NSs. We report results of a study on the antibody response to individual viral proteins in patients with Toscana virus-associated acute neurologic disease. Immunoblotting and semiquantitative radioimmunoprecipitation assay (RIPA) allow identification of nucleoprotein N as the major antigen responsible for both IgM and IgG responses. Antibodies to proteins other than nucleoprotein N are detected only by RIPA. Antibodies to glycoproteins are detected in about one-third of patients, and whereas their presence always predicts neutralization, some serum samples with neutralizing activity have undetectable levels of antibodies to G1-G2. Antibodies to nonstructural proteins NSm and NSs are also identified. The results obtained raise some questions about antigenic variability and relevant neutralization epitopes of Toscana virus.
托斯卡纳病毒（布尼亚病毒科白蛉病毒属）是唯一一种具有嗜神经活性的白蛉传播病毒。每年夏季在意大利中部都会观察到由托斯卡纳病毒引起的从无菌性脑膜炎到脑膜脑炎的临床病例，并且在从流行区（意大利、葡萄牙、西班牙和塞浦路斯）返回的游客中也报告了几例病例。在托斯卡纳病毒患者中，免疫球蛋白M（IgM）抗体通常在症状出现时就已存在，通过酶联免疫吸附测定可显示其滴度升高，并且可以持续至少1年。IgG抗体在症状出现时可能不存在：滴度在恢复期血清中升高并持续多年。在感染托斯卡纳病毒的细胞中至少鉴定出了五种蛋白质：核蛋白N、糖蛋白G1和G2、一种被认为是聚合酶成分的大蛋白（L）以及两种非结构蛋白NSm和NSs。我们报告了一项关于托斯卡纳病毒相关急性神经疾病患者对单个病毒蛋白抗体反应的研究结果。免疫印迹和半定量放射免疫沉淀测定（RIPA）可确定核蛋白N是引发IgM和IgG反应的主要抗原。仅通过RIPA才能检测到针对核蛋白N以外蛋白质的抗体。约三分之一的患者检测到针对糖蛋白的抗体，虽然其存在总是预示着中和作用，但一些具有中和活性的血清样本中针对G1 - G2的抗体水平却无法检测到。还鉴定出了针对非结构蛋白NSm和NSs的抗体。所获得的结果引发了一些关于托斯卡纳病毒抗原变异性和相关中和表位的问题。
