Genetic Variations In The GB, UL144 And UL133 Genes Of Human Cytomegal Ovirus Clinical Strains

Human cytomegalovirus (HCMV) is one of the most complex DNA virus, and also an important pathogen capable of establishing lifelong prsistent infections, witch normally remain asymptimatic. 50-100% of the normal people all over the world were infected. For the immunocompromised population (AIDS patients, organ transplant patients, infants and young children, etc.), cytomegalovirus infection often leads to various clinical symptoms, and even life-threatening diseases. At present, the relationship between cytomegalovirus genetic polymorphism and the clinical symptoms is still poorly understood. Human cytomegalovirus will show different levels of virulence, cell tropism after mamy times’ subcultures. Compared with low passage clinical strain Toledo, the high-passage strain AD169 lack of 19 open reading frame (ORF), these 19 genes were considered a set of genes most likely related to the HCMV pathogenicity.To explore a possible role for viral genes as determinants of virulence, the full-length of UL144 gene and partial sequence of gB gene from clinical children with congenital cytomegalovirus infection or acquired infection were sequenced. We did not find any association between the gB and UL144 genotypes and clinical outcome. Of the 23 patients, 13 (57%) had UL144 group 1A, 3 patients(13%) had UL144 group 2, and 7 patients (30%) had UL144 group 3. UL144 group 1B and 1C genotypes were not found in this study, although these genotypes were common in USA trains. All the genotypes found in this study could be vertically transmitted from mother to fetus.UL133 gene is one of these 19 ORF, we analysis the UL133 gene genetic polymorphism with low passage clinical strain Toledo and Merlin as a control. Sequence analysis showed that, all sequences of UL133 in clinical isolates including Toledo and Merlin strain could be divided into three groups(Group1, Group2 and Group3). We found that either group2 strains or group3 strains could lead to congenital infection, and did not find any significant relationships between UL133 genotypes and clinical outcome in this study.