Infectious bursal disease virus persistently infects bursal B-lymphoid DT40 cells

Abstract

Infectious bursal disease virus (IBDV), an important avian pathogen, exhibits a specific tropism for immature B-lymphocyte populations. We have investigated the ability of IBDV to replicate in chicken B-lymphoid DT40 cells, a tumour cell line derived from the bursa of Fabricius of a chicken infected with avian leukosis virus. Our results show that IBDV persistently infects DT40 cells. Establishment of the persistent infection is associated with an extensive remodelling of the hypervariable region of the VP2 capsid polypeptide, accumulating 14 amino acid changes during the first 60 days of the persistent infection. The amino acid sequence of the non-structural VP5 polypeptide, involved in virus dissemination, is not altered during the persistent infection. Results described in this report constitute the first demonstration of the ability of IBDV to establish a persistent infection in vitro.Infectious bursal disease virus (IBDV), an avian pathogen responsible for a highly contagious immunosuppressive disease, is the best-characterized member of the family Birnaviridae. Birnaviruses are naked, icosahedral viruses with bipartite, double-stranded RNA genomes (Dobos et al., 1979). Although the last few years have witnessed major progress in the understanding of IBDV molecular and structural biology aspects, key issues concerning the virus replication programme remain poorly characterized. This lack of information is exemplified by the fact that, although the tropism of IBDV for bursal B-lymphocyte populations was first described and characterized extensively over 25 years ago (Becht, 1980;Kibenge et al., 1988), the discovery of the mechanism(s) governing this phenomenon still represents the holy grail of IBDV biology.Propagation of IBDV field isolates in tissue culture requires previous adaptation involving serial virus passage, a process that invariably leads to the introduction of mutations at specific residues on the VP2 capsid polypeptide, as well as a significant reduction of virus virulence (Cursiefen et al., 1979; Hassan et al., 1996;Lange et al., 1987; Yamaguchi et al., 1996a, b). This phenomenon constitutes a major obstacle to characterizing the interaction of pathogenic IBDV strains with susceptible host cells.In a recent report, Terasaki et al. (2008) showed that very virulent IBDV isolates can be grown directly in chicken lymphoid DT40 tumour cells infected persistently with avian leukosis virus (ALV) (Baba et al., 1985), without the requirement for a preliminary adaptation process. Most importantly, serial passage in this cell line does not result in the incorporation of mutations at the specific VP2 residues. Additionally, DT40 cells show an extremely high frequency of homologous recombination (Buerstedde & Takeda, 1991). This property has been exploited widely for the generation of derivative cell lines in which selected target genes are inactivated (Winding & Berchtold, 2001). Accordingly, DT40 cells appear to be an excellent candidate system to undertake a systematic analysis aimed at determining the ...

Adaptation and Molecular Characterization of Two Malaysian Very Virulent Infectious Bursal Disease Virus Isolates Adapted in BGM-70 Cell Line

“…The molecular analyses using RT-PCR, sequence, and sequence analysis revealed that the two isolates are phylogenetically related to the vvIBDV found in Asia, Europe, Middle East, and Africa due to the presence of A222 [ 51 , 52 ] and I242, I256, I294, and S299 [ 51 ] in their VP2 hypervariable amino acid composition compared to the caIBDV or vaIBDV that possessed V222, VA, or E256 or the serotype 2 viruses that possessed P222, V242, I or S256, N or F294 and T or P299 [ 51 ] in the same region. The presence of the 233–236 IDA motif in our strains just like other IBDV indicates that these viruses could adapt to cell culture because these amino acids were reported to be important for cell culture adaptation [ 51 , 53 ] via the integrin receptors. Furthermore, during the CEE passaging, UPM190 isolate acquired a mutation at D279N at EP12, a mutation that was reported to be part of the two changes observed in attenuated and/or cell culture adapted IBD viruses [ 7 , 54 – 56 ].…”

Infectious Bursal Disease Virus Hijacks Endosomal Membranes as the Scaffolding Structure for Viral Replication

“…We next sought to decipher the functional role of VP3 association with endosomal membranes in the context of the viral replication cycle. Noticeably, our first idea was to profit from the reverse genetic approach developed in the laboratory of J. F. Rodríguez and previously described (57) to generate P2-mutated viral progeny. To this end, a plasmid harboring a mutant version of segment A cDNA containing the P2 substitutions was constructed, but unfortunately, mutated viral progeny was not generated.…”

Effective multiple oral administration of reverse genetics engineered infectious bursal disease virus in mice in the presence of neutralizing antibodies

“…The amount of neutralizing antibody in the blood did not prevent virus delivery to the tissues. In the present study, we did not explore the means of virus delivery to tissues, although it is possible that IBDV is picked up by gut macrophages or other lymphoid cells and then dispersed throughout the body .…”