title: Genetic heterogeneity of small ruminant lentiviruses involves immunodominant epitope of capsid antigen and affects sensitivity of single-strain-based immunoassay.
abstract: The pol and gag gene fragments of small ruminant lentivirus field isolates collected in the last decade in Italy were amplified, sequenced, and analyzed. Phylogenetic analysis revealed that the majority of ovine isolates form a distinct cluster more similar to caprine lentivirus prototypes than to the visna virus prototype. These findings confirm and extend those reported by Leroux et al. (Arch. Virol., 142:1125-1137, 1997). Moreover, we observed that a variable region of Gag, included in the fragment analyzed, corresponded to one of the three major capsid antigen epitopes, which suggests that the antibody response to this epitope may be type specific. To test this hypothesis, two recombinant peptides, derived from the Icelandic prototype K1514 and this novel genotype, were expressed and used in an enzyme-linked immunosorbent assay to screen a panel of ovine and caprine sera collected from different geographical locations in Italy. Several sera reacted in a type-specific manner, indicating that in a diagnostic setting the combination of at least these two type-specific peptides is necessary to cover a wide range of infections. Additionally, these results support the hypothesis of cross-species transmission based on the phylogenetic analysis described above. This has implications for the control and eradication of small ruminant lentivirus infections.
authors.affiliation: Dipartimento di Produzioni Animali, Epidemiologia ed Ecologia, Facoltà di medicina Veterinaria, Università di Torino, 10095 Grugliasco, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Grego
authors.forename: Margherita
authors.initials: M
authors.lastname: Profiti
authors.forename: Monica
authors.initials: M
authors.lastname: Giammarioli
authors.forename: Laura
authors.initials: L
authors.lastname: Giannino
authors.forename: Domenico
authors.initials: D
authors.lastname: Rutili
authors.forename: Chris
authors.initials: C
authors.lastname: Woodall
authors.forename: Sergio
authors.initials: S
authors.lastname: Rosati
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000235:genetics; D016088:Arthritis-Encephalitis Virus, Caprine / Q000235:genetics / Q000276:immunology; D002213:Capsid / Q000276:immunology*; D018740:Genetic Heterogeneity; D006041:Goats; D007118:Immunoassay / Q000592:standards; D016056:Immunodominant Epitopes / Q000235:genetics*; D007558:Italy; D016086:Lentivirus / Q000235:genetics* / Q000276:immunology; D008969:Molecular Sequence Data; D010802:Phylogeny; D012418:Ruminants / Q000821:virology*; D012680:Sensitivity and Specificity; D012756:Sheep; D014790:Visna-maedi virus / Q000235:genetics / Q000276:immunology
chemical_list: D000956:Antigens, Viral; D016056:Immunodominant Epitopes