Genetic heterogeneity of the hexon gene of adenovirus type 3 over a 9-year period in Korea

Abstract

Hexon sequences were analyzed in 29 epidemiologically unrelated adenovirus type 3 (Ad3) isolates from the 7 genome types to understand the molecular basis of the genome-type diversity of Ad3 associated with childhood pneumonia in Korea during the period 1991-1999. Nine nucleotide substitutions were observed among the 29 Ad3 strains. Five of the 9 involved amino acid changes in loops 1 (Gly to Val at codon 205 and Thr to Ile at 211) and loop 2 (His to Asn at 417, Thr to Ala at 429, and Ala to Asp at 439). The predicted hydropathic characteristics of this region have been affected by these amino acid changes. The region surrounding codons from 417 to 439 of Ad3a16 and Ad3a18 manifested greater hydrophobicity than the region of other genome types (Ad3a, Ad3a13, Ad3a14, Ad3a15, and Ad3a17). In particular, three amino acid changes in loop 2 were associated with two new genome types, namely, Ad3a16 and Ad3a18, which were recognized during later epidemics in 1998-1999. Phylogenetic relatedness revealed that these two genome types clustered into distinct lineages in the phylogenetic tree. This result suggests that the genetic heterogeneity of Ad3 hexon could play a potential role in the appearance of new genome types and that it could affect the antigenic characteristics of Ad3.

Clinical severity of respiratory adenoviral infection by serotypes in Korean children over 17 consecutive years (1991–2007)

“…Actually, the genome type analysis showed that only two genome types among HAdV-7 were identified, but seven genome types, meanwhile, were detected among HAdV-3 in Korean children. 1,9,16,17 However, this has not been the case for HAdV-3 associated lower respiratory tract infections. Continuous circulation of HAdV-3 and the relative diversity of the HAdV-3 genome types might have produced steady state of herd immunity, 1 which resulted in persistent HAdV-3 outbreaks and showed no change of clinical severity over time.…”

“…1,2 Among the known 53 HAdV serotypes, 3-5 particular serotypes are more commonly associated with specific diseases and multiple genetic variants exist that often have quite different geographical distributions and associated virulence. [6][7][8] During a surveillance period of 1991-2007, major respiratory viruses isolated from nasopharyngeal aspirates have been collected and comprehensive typing of respiratory HAdVs was performed in our institute.…”

Comprehensive serotyping and epidemiology of human adenovirus isolated from the respiratory tract of Korean children over 17 consecutive years (1991–2007)

“…Molecular epidemiology or genome analysis focusing on specific serotypes such as 3, 7, or 21 have been reported previously [Kajon and Wadell, 1994;Hong et al, 2001;Kim et al, 2003;Choi et al, 2005Choi et al, , 2006a. However, a longitudinal epidemiological study of respiratory HAdVs, at the serotype level for an observational period extending 17 years has not been reported previously.…”

Human adenoviruses in respiratory infections: Sequencing of the hexon hypervariable region reveals high sequence variability

“…A phylogenetic separation into two genetic lineages has also been described for Korean hAdV-3 isolates. 19 The authors of this study hypothesize that these sequence variations account for an alteration of antigenic characteristics and therefore might be causative for the occurrence of hAdV-3 epidemics in the Korean population.…”