Genetic diversity in the G protein gene of group A human respiratory syncytial viruses circulating in Riyadh, Saudi Arabia

ABSTRACTWorldwide G-glycoprotein phylogeny of human respiratory syncytial virus (hRSV) group A sequences revealed diversification in major clades and genotypes over more than 50 years of recorded history. Multiple genotypes cocirculated during prolonged periods of time, but recent dominance of the GA2 genotype was noticed in several studies, and it is highlighted here with sequences from viruses circulating recently in Spain and Panama. Reactivity of group A viruses with monoclonal antibodies (MAbs) that recognize strain-variable epitopes of the G glycoprotein failed to correlate genotype diversification with antibody reactivity. Additionally, no clear correlation was found between changes in strain-variable epitopes and predicted sites of positive selection, despite both traits being associated with the C-terminal third of the G glycoprotein. Hence, our data do not lend support to the proposed antibody-driven selection of variants as a major determinant of hRSV evolution. Other alternative mechanisms are considered to account for the high degree of hRSV G-protein variability.IMPORTANCEAn unusual characteristic of the G glycoprotein of human respiratory syncytial virus (hRSV) is the accumulation of nonsynonymous (N) changes at higher rates than synonymous (S) changes, reaching dN/dS values at certain sites predictive of positive selection. Since these sites cluster preferentially in the C-terminal third of the G protein, like certain epitopes recognized by murine antibodies, it was proposed that immune (antibody) selection might be driving the apparent positive selection, analogous to the antigenic drift observed in the influenza virus hemagglutinin (HA). However, careful antigenic and genetic comparison of the G glycoprotein does not provide evidence of antigenic drift in the G molecule, in agreement with recently published data which did not indicate antigenic drift in the G protein with human sera. Alternative explanations to the immune-driven selection hypothesis are offered to account for the high level of G-protein genetic diversity highlighted in this study.

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Genetic variability among group A and B respiratory syncytial viruses in Mozambique: identification of a new cluster of group B isolates

Journal of General Virology ◽

10.1099/0022-1317-82-1-103 ◽

2001 ◽

Vol 82 (1) ◽

pp. 103-111 ◽

Cited By ~ 46

Author(s):

Anna Roca ◽

Mari-Paz Loscertales ◽

Llorenç Quintó ◽

Pilar Pérez-Breña ◽

Neide Vaz ◽

...

Keyword(s):

Genetic Variability ◽

Protein Gene ◽

N Protein ◽

Glycosylation Sites ◽

Rsv Infection ◽

Group A ◽

Respiratory Syncytial Viruses ◽

Syncytial Virus ◽

Group B ◽

Vulnerable Adults

Respiratory syncytial virus (RSV) is the major cause of acute lower respiratory tract infection in children and vulnerable adults, but little is known regarding RSV infection in Africa. In this report, a recent RSV outbreak in Mozambique was studied and results showed that 275 of 3192 (8·6%) nasopharyngeal aspirates tested were RSV-positive by ELISA. RSV presents two antigenic groups (A and B) with a high genetic and antigenic variability between and within them. Analysis by a new RFLP assay of RT–PCR amplified N protein gene products showed a higher prevalence of group B RSV than that of group A (85% versus 15%). However, genetic variability of the G protein gene was higher among group A RSV strains. The frequency and pattern of glycosylation sites were also quite different between both groups. In addition, two different phylogenetic clusters of Mozambican viruses were found within each group, but only sequences from cluster B-I were relatively distinct from previously described isolates. The implications of such differences in the antigenic and immunogenic characteristics of each group are discussed.

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Unusual Antigenic and Genetic Characteristics of Human Respiratory Syncytial Viruses Isolated in Cuba

Journal of Virology ◽

10.1128/jvi.72.9.7589-7592.1998 ◽

1998 ◽

Vol 72 (9) ◽

pp. 7589-7592 ◽

Cited By ~ 9

Author(s):

Odalys Valdés ◽

Isidoro Martínez ◽

Angel Valdivia ◽

Reynel Cancio ◽

Clara Savón ◽

...

Keyword(s):

G Protein ◽

Protein Gene ◽

Temperate Climate ◽

Nucleotide Difference ◽

Genetic Characteristics ◽

Socioeconomic Characteristics ◽

Genetic Level ◽

Respiratory Syncytial Viruses ◽

Syncytial Virus ◽

Extra Nucleotide

ABSTRACT The G protein of 23 strains of human respiratory syncytial virus isolated in Havana, Cuba, between October 1994 and January 1995 was analyzed at the antigenic and genetic level. All viruses reacted with 10 of 11 antibodies specific for the Long strain. Moreover, the G protein gene of the Cuban isolates had only five nucleotide differences from the sequence of the Long gene. The homogeneity of the Cuban isolates and their resemblance to an ancient strain, such as Long, are at odds with previous findings for viruses isolated in countries with a temperate climate and different socioeconomic status. The G proteins of three of four other viruses isolated in Havana 2 years later (1996) were also identical to those of the 1994-to-1995 isolates, and the fourth virus had a single extra nucleotide difference. This, again, is unusual, since no identical viruses had been isolated in different epidemics previously. The singular characteristics of the Cuban isolates reported here are discussed in terms of the epidemiological, climatic, and socioeconomic characteristics of Cuba.

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