Genetic variability of respiratory syncytial virus subgroup a strain in 15 successive epidemics in one city

Abstract

The genetic variability of 125 respiratory syncytial virus (RSV) subgroup A isolates over 15 successive epidemics from 1980 to 1995 in an urban population of Japan was determined. Allocation of isolates into lineages was archived by reverse transcriptase-polymerase chain reaction amplification of selected regions of the nucleoprotein (NP) and attachment (G) protein gene followed by restriction fragment length polymorphism (RFLP) analysis. Three and seven distinct restriction patterns of the NP and G gene were observed, respectively. When the NP and G gene RFLP analyses were combined, ten different genetic lineages were identified in the 125 isolates. The strains with the same genotype were isolated in each epidemic and the dominant lineages were replaced by others after every one to three consecutive epidemics. Nucleotide and amino acid sequencing of the variable region of G gene of these predominant isolates revealed differences of 5--28% between strains. There was, however, no apparent accumulation of diversity with age to indicate progressive changes. The dominant strains were often closely related to those isolated in other parts of the world at a similar time. These observations suggest that dominant RSV strains are replaced frequently by others that have been co-circulating or have recently entered the community from a worldwide reservoir. The change of dominant strains may be influenced by the buildup of immunological resistance in the community to successive epidemics of the same strain.

Molecular epidemiology and genetic variability of respiratory syncytial virus (RSV) in Stockholm, 2002–2003

“…In all 12 patients, sequences from the sequential sampling were identical and no genetic variation in the N-terminal region of the G gene could be demonstrated during the phase of illness. International data from molecular epidemiological studies of RSV are derived from long-term studies with 100 or more isolates [Peret et al, 1998;Choi and Lee, 2000;Seki et al, 2001;Venter et al, 2001;Scott et al, 2004;Kuroiwa et al, 2005;Sato et al, 2005;Viegas and Mistchenko, 2005], from long-term studies with a more limited number if isolates [Cane et al, 1994;Garcia et al, 1994;Zambon et al, 2001;Venter et al, 2002;Frabasile et al, 2003;Rafiefard et al, 2004;Galiano et al, 2005;Parveen et al, 2006], and also from shortterm studies like this one from Stockholm [Peret et al, 2000;Moura et al, 2004]. This study provides data from a complete season.…”

Genetic Variability and Molecular Epidemiology of Respiratory Syncytial Virus Subgroup A Strains in Japan Determined by Heteroduplex Mobility Assay

“…RSV identification and subgrouping were performed by enzyme-linked immunosorbent assay with subgroup-specific monoclonal antibodies to the F and G proteins of the Long strain of RSV as described previously (34 RNA extraction and cDNA synthesis. RNA extraction and cDNA synthesis were described previously (26). Briefly, the frozen RSV isolates were inoculated on HEp-2 cells in 24-well plates and total RNA was extracted by adding 0.8 ml of RNAzol B (TEL-TEST, Inc., Friendswood, Tex.)…”

“…PCR was performed as described previously with minor modifications (26). Primers used in this PCR amplified the sequence between nucleotides (nt) 1 and 584 of the G gene of the Long strain, which covers the first hypervariable region of the G gene.…”

“…The procedure of RFLP was described previously (26). Briefly, 8 l of each PCR product was digested with AluI, TaqI, and NdeII at 37°C for 90 min.…”

“…The G-protein variability is concentrated in its ectodomain, which contains two hypervariable regions separated by a conserved 11-amino-acid motif (4,7,19,29). Recent molecular epidemiological studies suggest that many distinct RSV genotypes circulate worldwide and that similar genetic variants are clustered by time rather than by geographic location (6,8,17,26).Genetic variability of RSV has most often been studied by using restriction fragment length polymorphism (RFLP) analysis and DNA sequencing (4, 30). RFLP analysis is relatively easy to perform, although genotypes obtained by this method provide limited information.…”