1996 Fiscal Year Final Research Report Summary
Molecular biological study on immunosuppresion mechanism by infectious bursal disease virus
| Project/Area Number |
07660402
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Basic veterinary science/Basic zootechnical science
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| Research Institution | Gifu University |
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Principal Investigator |
HIRAI Katsuya Gifu University Faculty of Agriculture, Professor, 農学部, 教授 (30021702)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Tsuyoshi Gifu University Faculty of Agriculture, Research Associate, 農学部, 助手 (70210367)
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| Project Period (FY) |
1995 – 1996
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| Keywords | Immunosuppression / IBDV / Avian virus |
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| Research Abstract |
The IBD virus (IBDV) causes severe immunosuppression in young chickens. The immunosuppression presumably results from the destruction of differentiating lymphocytes however, the mechanism is not fully understood. In this study, IBDV receptor on target cells and nucleotide sequence of the virus genome were analyzed to understand the mechanism of immunosuppression.
1.Characterization of IBDV receptor
The attachment of IBDV to chicken lymphocyte and lymphoblastiod cell lines was quantitated by a fluorescencee-activated cell sorter assay in which binding of biotinylated virus was detected with streptoavidinfluorescein isothiocyanate. To determine the nature of the cell surface component to which IBDV vinds, chicken lymphoblastoid cells susceptible to virulent IBDV were treated with some proteases, phospholipases, glycosidases, tunicamysin and sodium periodic acid. Treatment of cells with any of several proteases abolished IBDV binding, whereas phospholipases and glycosidases had not effect, indicating that one or more membrane proteins were involved in virus attachment. However, the virus did not bound to cells grown in tunicamycin. It may show that IBDV attachment to chicken lymphoblastoid cell is mediated by glycoprotein (s).
2.Molecular basis of virulence of IBDV
Attenuated strains of IBDV increased in virulence during several passages in susceptible chickens, as judged by damage to the bursa of Fabricius. To reveal the molecular basis of virulence of IBDV,the nucleotide and the predicted amino acid sequences of VP2 hyper variable region of the attenuated and the passaged strains were compared. An amino acid substitution at position 253 (His->Gln) was predicted. This finding may show that the amino acid residue at position 253 is important for virulence and propagation in target cell.
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