title: G2 rotavirus infections in an infantile population of the South of Italy: variability of viral strains over time.
abstract: 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.
authors.affiliation: Dipartimento di Igiene e Microbiologia, Università di Palermo, Palermo, Italy. arista@unipa.it
authors.forename: Serenella
authors.initials: S
authors.lastname: Arista
authors.forename: Giovanni M
authors.initials: GM
authors.lastname: Giammanco
authors.forename: Simona
authors.initials: S
authors.lastname: De Grazia
authors.forename: Claudia
authors.initials: C
authors.lastname: Colomba
authors.forename: Vito
authors.initials: V
authors.lastname: Martella
authors.forename: Antonio
authors.initials: A
authors.lastname: Cascio
authors.forename: Miren
authors.initials: M
authors.lastname: Iturriza-Gòmara
mesh_terms: 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
chemical_list: D000956:Antigens, Viral; D036022:Capsid Proteins; C060339:VP4 protein, Rotavirus; C050779:VP7 protein, Rotavirus