Assessment of genetic, antigenic and pathotypic criteria for the characterization of IBDV strains.
The aim of this work was the selection and comparison of representative infectious bursal disease virus (IBDV) strains. Nine strains of IBDV, isolated at different times and from different geographic regions of Europe and China, were characterized. Batches of all strains were prepared following standardized protocols and checked for the absence of contaminating viruses. Criteria used for their characterization were: (i) the nucleotide sequence of the VP2 variable region, (ii) binding to a panel of neutralizing monoclonal antibodies in antigen capture enzyme-linked immunosorbent assays, and (iii) virulence in specific pathogen free chickens after infection with a standardized number of median embryo infective doses. Based on the first two criteria, two of nine strains were classified as classical virulent (cv) IBDV (F52/70, Cu-1wt), and five as very virulent (vv) IBDV (849VB, 96108, HK46, GX, Harbin). Remarkably, although a clear-cut difference was demonstrable between European cvIBDV (F52/70 and Cu-1wt) and vvIBDV (849VB and 96108) strains, there was a continuum in the pathogenicity of Chinese vvIBDVs. Our results indicate the probable existence of differences in virulence within IBDV lineages determined on the basis of antigenic typing using monoclonal antibodies and the alignment of the VP2 sequences. This indicates limitations in the analysis of IBDV pathotypes based on the VP2 variable region and emphasizes that these criteria may not be sufficient for the classification of IBDV strains.
van den Berg
T P
TP
Avian Virology & Immunology Unit, Veterinary and Agrochemical Research centre Groeselenberg 99 1180 Brussels, Belgium. thvan@var.fgov.be
Morales
D
D
Eterradossi
N
N
Rivallan
G
G
Toquin
D
D
Raue
R
R
Zierenberg
K
K
Zhang
M F
MF
Zhu
Y P
YP
Wang
C Q
CQ
Zheng
H J
HJ
Wang
X
X
Chen
G C
GC
Lim
B L
BL
Müller
H
H
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D001483:Base Sequence; D002645:Chickens / Q000821:virology; D002681:China; D016000:Cluster Analysis; D017931:DNA Primers; D004797:Enzyme-Linked Immunosorbent Assay; D005060:Europe; D007243:Infectious bursal disease virus / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity*; D008969:Molecular Sequence Data; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013047:Specific Pathogen-Free Organisms; D015678:Viral Structural Proteins / Q000235:genetics*; D014774:Virulence
D000911:Antibodies, Monoclonal; D017931:DNA Primers; C082513:VP2 protein, infectious bursal disease virus; D015678:Viral Structural Proteins