GENETIC VARIATION AMONG DENGUE VIRUSES

黄病毒家族的登革热病毒亚群由4个亚组组成。 不同的血清型(类型1到类型4)。典型内变异一直是 寡核苷酸指纹分析在几种血清型中的检测 通过病毒中和。来自加勒比海的4型登革热变异株 1981-1982年期间恢复的登革热似乎与登革热4不同 1956年和最近在菲律宾分离到的原型(H241) 来自东南亚的分离物。在过去两年中，4型登革热 相比之下，曼谷登革热出血性休克最常见的原因 到早期的流行模式，其中登革2型病毒最多 经常被牵连。出于这些原因，重要的是在分子中定义 条件：(A)登革4型病毒分离株的遗传稳定性和多样性 间隔30年和(B)可能涉及特定病毒 严重登革热疾病中的毒株，即“强毒力病毒”。两名登革热患者 4型变异体，原型菌株H241和菌株2123分离自 失血性休克患者，分别进行克隆和DNA测序 分析。几个与该基因相对应的特异性寡核苷酸引物 对已建立的登革热4序列(多米尼克株)进行了测试 启动逆转录的能力。至少一种寡核苷酸 有效地引发了每个登革热基因组RNA，并产生了5,000个DNA 核苷酸的长度。然后，这些cdna产物将被克隆 早些时候建立的程序。克隆的DNA随后将被分析以 确定两种保护性抗原的编码序列，即包膜 糖蛋白和NS1非结构蛋白。最后，序列将是 比较以试图确定E和NS1中的高变区 糖蛋白。

The dengue virus subgroup of the flavivirus family is comprised of 4 distinct serotypes (type 1 to type 4). Intratypic variations have been detected within several serotypes by oligonucleotide fingerprint analysis and by virus neutralization. Dengue type 4 variants from the Caribbean recovered during 1981-1982 appear to be different from the dengue 4 prototype (H241) isolated in the Phillipines in 1956 as well as recent isolates from Southeast Asia. During the past two years, dengue type 4 was the most frequent cause of dengue hemorrhagic shock in Bangkok, in contrast to the earlier epidemic pattern in which dengue type 2 viruses were most often implicated. For these reasons it is important to define in molecular terms: (a) genetic stability and diversity of dengue 4 viruses isolated over a 30 year interval and (b) the possible involvement of specific virus strains, i.e., "virulent viruses", in severe dengue disease. Two dengue type 4 variants, the prototype strain H241 and strain 2123 isolated from a hemorrhagic shock patient, were chosen for cloning and DNA sequence analysis. Several specific oligonucleotide primers corresponding to the established dengue 4 sequence (Dominica strain) were tested for their ability to prime reverse-transcription. At least one oligonucleotide effectively primed each dengue genomic RNA and yielded cDNA 5,000 nucleotides in length. These cDNA products will then be cloned by the procedure established earlier. Cloned DNA will then be analyzed to determine the sequence coding for the two protective antigens, the envelope glycoprotein and the NS1 nonstructural protein. Finally, sequences will be compared in an attempt to identify hypervariable regions in the E and NS1 glycoproteins.