Ali M A
Environmental Virology Lab, Department of Water Pollution Researches, National Research Centre, 12311 Dokki, Cairo, Egypt.
J Egypt Public Health Assoc. 2002;77(1-2):101-16.
More than 20 hepatitis A virus (HAV) strains that can be distinguished from each other are known till now. In the present study, a cytopathic strain of HAV (HA-10) was isolated in Egypt from stool of acute sporadic cases. The isolated strain showed CPE in early stages of adaptation in cell culture. Accordingly, the first step in the work was to confirm the presence of HAV, the second step was to prove that no enteric virus is associated with the isolate and finally to try to know the reason for that rapid adaptation in cell culture. So, RT-PCR was carried out for different regions of the viral RNA (5'ntr, VP1, VP1/2A, 2B and 2B/2C) also, enterovirus primers (5'ntr) were used. Reference HAV strains such as HM-175, HAS-15, MBB and 18F were used for comparison. Segment of 2BC region of the viral RNA was sequenced and compared with the nucleotide sequence of the reference HAV strains at the same region. The results revealed that HA-10 isolate react with all HAV primers and similar in this behavior with 18F and HM-175 strains. The nucleotide sequencing showed that there are 16 mutations in HA-10, two of them in 2B and the others in 2C region which may explain the reason for the highly adaptation of HA-10 isolate than 18F. As a result of this study, HA-10 may give us a highlight on HAV replication and also, the isolated strain may be useful for vaccine development.
到目前为止，已知有20多种彼此可区分的甲型肝炎病毒（HAV）毒株。在本研究中，从埃及急性散发病例的粪便中分离出一株具有细胞病变效应的HAV毒株（HA - 10）。该分离株在细胞培养适应的早期阶段就表现出细胞病变效应。因此，研究工作的第一步是确认HAV的存在，第二步是证明该分离株不伴有肠道病毒，最后试图了解其在细胞培养中快速适应的原因。于是，对病毒RNA的不同区域（5'非编码区、VP1、VP1/2A、2B和2B/2C）进行了逆转录聚合酶链反应（RT-PCR），同时也使用了肠道病毒引物（5'非编码区）。使用参考HAV毒株如HM - 175、HAS - 15、MBB和18F进行比较。对病毒RNA的2BC区域片段进行测序，并与相同区域的参考HAV毒株的核苷酸序列进行比较。结果显示，HA - 10分离株与所有HAV引物反应，在这一行为上与18F和HM - 175毒株相似。核苷酸测序表明，HA - 10有16个突变，其中两个在2B区域，其他的在2C区域，这可能解释了HA - 10分离株比18F具有更高适应性的原因。作为本研究的结果，HA - 10可能为我们深入了解HAV复制提供线索，而且该分离株可能对疫苗研发有用。
