Genetic and antigenic variation of capsid protein VP7 of serotype G1 human rotavirus isolates.

242

203

Section: Resultsmentioning

confidence: 99%

Reassortment In Vivo: Driving Force for Diversity of Human Rotavirus Strains Isolated in the United Kingdom between 1995 and 1999

Iturriza‐Gómara

Isherwood

Desselberger

et al. 2001

242

203

“…A number of studies have investigated the genetic and antigenic variations in the VP7 gene of G1 HRVs (7,21,37,42,45,47,54,64). These studies revealed a high genetic homogeneity of G1 strains isolated in a single outbreak and the concomitant occurrence of G1 strains belonging to the same lineage in different parts of the world, suggesting a lack of defined geographical or temporal patterns.…”

Section: Discussionmentioning

confidence: 99%

“…By contrast, the amino acid substitution 94-Asn3Ser was present only in Italian strains belonging to sublineage Ic. Residue 94 is considered to be essential for discrimination of G1 monotypes (18) and for distinguishing between lineages I and II (21). Also, the presence in convalescent-phase sera of antibodies blocking the binding of a VP7 serotype-specific MAb mapping to aa 94 has been correlated with resistance to disease in adult volunteers challenged with virulent G1 strain D (29).…”

Section: Discussionmentioning

confidence: 99%

Heterogeneity and Temporal Dynamics of Evolution of G1 Human Rotaviruses in a Settled Population

Arista

Giammanco

Grazia

et al. 2006

118

106

A rotavirus sample collection from 19 consecutive years was used to investigate the heterogeneity and the dynamics of evolution of G1 rotavirus strains in a geographically defined population. Phylogenetic analysis of the VP7 gene sequences of G1P[8] human rotavirus strains showed the circulation of a heterogeneous population comprising three lineages and seven sublineages. Increases in the circulation of G1 rotaviruses were apparently associated with the introduction of novel G1 strains that exhibited multiple amino acid changes in antigenic regions involved in rotavirus neutralization compared to the strains circulating in the previous years. The emergence and/or introduction of G1 antigenic variants might be responsible for the continuous circulation of G1 rotaviruses in the local population, with the various lineages and sublineages appearing, disappearing, or cocirculating in an alternate fashion under the influence of immune-pressure mechanisms. Sequence analysis of VP4-encoding genes of the G1 strains revealed that the older strains were associated with a unique VP4 lineage, while a novel VP4 lineage emerged after 1995. The introduction of human rotavirus vaccines might alter the forces and balances that drive rotavirus evolution and determine the spread of novel strains that are antigenically different from those included in the vaccine formulations. The continuous emergence of VP7-VP4 gene combinations in human rotavirus strains should be taken into consideration when devising vaccination strategies.

“…Sequence analysis has also revealed the existence of genetic lineages within the P and G types. For example, the strains of type P [8] form at least three lineages (23,29,36), and four lineages of type G1 have been found so far (15,29,30,36,55). Genetic clustering is also evident at least for segments 5 (16), 7 (44), 8 (41), and 10 (12,17,28).…”

mentioning

confidence: 92%

Frequent Reassortments May Explain the Genetic Heterogeneity of Rotaviruses: Analysis of Finnish Rotavirus Strains

Maunula

Bonsdorff

2002

The predominant rotavirus electropherotypes (e-types) during 17 epidemic seasons (1980 through 1997) in Finland were established, and representative virus isolates were studied by nucleotide sequencing and phylogenetic analysis. The virus isolates were either P[8]G1 or P[8]G4 types. The G1 and G4 strains formed one G1 lineage (VP7-G1-1) and one G4 lineage, respectively. Otherwise, they belonged to two P[8] lineages (VP4-P[8]-1 and -2) unrelated to their G types. Phylogenetic analysis of partial sequences of all 11 RNA segments obtained from the strains also revealed genetic diversity among gene segments other than those defining P and G types. With the exception of segments 1, 3, and 10, the sequences of the other segments could be assigned to 2 to 4 different genetic clusters. The results of this study suggest that, in addition to the RNA segments encoding VP4 and VP7, the other RNA segments may segregate independently as well. In total, the 9 predominant e-types represented 7 different RNA segment combinations when the phylogenetic clusters of their 11 genes were determined. The extensive genetic diversity and number of e-types among rotaviruses are best explained by frequent genetic reassortment.