G2 rotavirus infections in an infantile population of the South of Italy: variability of viral strains over time.
Rotavirus positive samples collected in Palermo, Italy, during 2002-2004 did not react with the G2 type-specific RV5:3 monoclonal antibodies (MAbs) and could be identified as G2 only by RT-PCR genotyping. The genetic variation of VP7 and VP4 antigenic proteins was studied in 14 G2 samples including a selection of both those successfully characterized by serotyping and those failing to be serotyped. The phylogenetic analysis performed on partial VP7 sequences showed a temporal clustering of these strains, with those isolated in Palermo in 2003 belonging to the same lineage of G2 MAbs-unreactive strains identified in UK in 1996-1997 and in Bari, Italy, in 2003-2004. A single amino acid substitution in VP7 antigenic region A, at position 96 (Asp-->Asn), was consistently associated with the loss of antigenic reactivity. Five of the G2 strains were further characterized by sequencing of VP4-encoding genes as belonging to the P[4] type, and separate lineages clustering the strains according to a temporal distribution could be described. VP7 and VP4 antigenic proteins analysis provided evidence that over the last 11 years, at least two different populations of G2P[4] rotavirus strains have been infecting the infant population in Palermo. Considering the role of anti-VP7 and anti-VP4 neutralizing antibodies in rotavirus immunity, the emergence of new VP7-VP4 gene combinations might influence rotavirus circulation in the infant population and should be taken into consideration when devising vaccination strategies.
Arista
Serenella
S
Dipartimento di Igiene e Microbiologia, Università di Palermo, Palermo, Italy. arista@unipa.it
Giammanco
Giovanni M
GM
De Grazia
Simona
S
Colomba
Claudia
C
Martella
Vito
V
Cascio
Antonio
A
Iturriza-Gòmara
Miren
M
D000956:Antigens, Viral / Q000737:chemistry / Q000235:genetics*; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics*; D002675:Child, Preschool; D005243:Feces / Q000821:virology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007558:Italy / Q000453:epidemiology; D010802:Phylogeny; D012401:Rotavirus / Q000145:classification / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D012400:Rotavirus Infections / Q000453:epidemiology* / Q000821:virology; D012703:Serotyping; D013997:Time Factors
D000956:Antigens, Viral; D036022:Capsid Proteins; C060339:VP4 protein, Rotavirus; C050779:VP7 protein, Rotavirus