[Objective] The paper was to determine the genomic sequence of a very virulent strain of infectious bursal disease virus（IBDV）,and study its molecular characteristics.[Method] A very virulent strain（vvIBDV）（HLJ-0...[Objective] The paper was to determine the genomic sequence of a very virulent strain of infectious bursal disease virus（IBDV）,and study its molecular characteristics.[Method] A very virulent strain（vvIBDV）（HLJ-0504） of infectious bursal disease virus（IBDV） with special characters was isolated in China and its genome was sequenced.[Result] Sequence analysis showed that segment A of HLJ-0504 was derived from vvIBDV,while segment B was from a distinct ancestor.The morbidity and mortality of HLJ-0504 was 100% and 86.7%to SPF chickens,respectively.[Conclusion] vvIBDV with distinct segment B were still circulating and the evolution of IBDV was diversified in China.Besides,it is hard to imagine that the virulence of IBDV is determined solely by segment A or B.展开更多
Infectious bursal disease virus（IBDV）is responsible for the highly contagious infectious bursal disease of chickens.Further understanding the gene-function is necessary to design the tailored vaccine.The amino acid ...Infectious bursal disease virus（IBDV）is responsible for the highly contagious infectious bursal disease of chickens.Further understanding the gene-function is necessary to design the tailored vaccine.The amino acid residue 279,located on strand P_F of VP2,is one of the three residues that have been reported to be involved in cell-tropism but with some inconsistency.In this study,to further clarify the amino acids involved in the cell tropism of IBDV,a series of mutations about residue 279were introduced into the VP2 of vv IBDV Gx strain.With the reverse genetic system,we found single mutation of D279N,double mutations of D279N/A284T or Q253H/D279N were not enough to adapt IBDV to chicken embryo fibroblast（CEF）cell.To evaluate whether residue 279 could influence the replication and virulence of IBDV,the virus r Gx HT-279 with three mutations（Q253H/D279N/A284T）was rescued and evaluated.Results showed that the mutation of residue 279 in VP2had no efficient effects on both the replication efficiency in vitro and the virulence to SPF chickens of IBDV.In summary,the results demonstrated that residue 279 of VP2 did not contribute efficiently to cell tropism,replication efficiency,and virulence of IBDV at least in some strains.These findings provided further information for understanding the gene function of IBDV.展开更多
Garlic(Allium sativum,Liliaceae)has been safely used for more than 5000 years,and research on garlic extract is rapidly increasing because of its multiple biological functions.The in vivo effects of oral administratio...Garlic(Allium sativum,Liliaceae)has been safely used for more than 5000 years,and research on garlic extract is rapidly increasing because of its multiple biological functions.The in vivo effects of oral administration of garlic mixture(GM,water-soluble extract)on infectious bursal disease virus(IBDV)-infected specific pathogen free male white leghorn chicken were examined through histopathological,immunohistochemical,and Western blot analyses,and enzyme-linked immunosorbent assay.The results confirmed the protective effects of oral administration of 5 mg·kg^(–1) BW GM(Group GM1)on bursal lesions after IBDV infection.In particular,protein expression of IBDV in the bursa decreased in Group GM1,indicating that GM administration decreased IBDV replication in the bursa.Furthermore,immunoglobulin M-and A-bearing B lymphocytes significantly increased 7 days post infection in bursae in Group GM1(P<0.01),suggesting that the oral administration of 5 mg·kg^(–1) GM offers moderate protection against B cell destruction after IBDV infection.During infection,the concentration of bursal interferon gamma(IFN-g)increased and peaked in Group GM1 earlier than in Group T(IBDV-exposed),demonstrating that GM administration prompted the production of IFN-g to protect against IBDV infection.展开更多
Two hundred and forty specific pathogen free leghorn chickens were randomly divided into four groups and reared in isolated pens. The tested chickens were negative to infectious bursal disease virus （IBDV） at 25 d o...Two hundred and forty specific pathogen free leghorn chickens were randomly divided into four groups and reared in isolated pens. The tested chickens were negative to infectious bursal disease virus （IBDV） at 25 d old. Group 1 was treated with saline, whereas Groups 2, 3, and 4 were inoculated with 0.3 mL IBDV suspension intranasally the next day. Groups 3 and 4 were also administered with Astragalus polysaccharides （APS） intramuscularly twice daily at 5 or 10 mg kg-1 BW, respectively, until 31 d old. The erythrocyte-C3b receptor rosette rate （E-C3bRR） and the erythrocyte-C3b immune complex rosette rate （E-ICRR） were measured at 25, 29, 32, 35, and 38 d old. The results showed that IBDV significantly reduced E-C3bRR and E-ICRR when compared with the control group （P 〈 0.05）, while simultaneous administration of APS with 1BDV maintained E-C3bRR at similar levels to the control group （P 〉 0.05） and increased E-ICRR when compared with the control group and the group non-treated with APS （P 〈 0.05）. APS treatment reduced the morbidity and mortality of chickens inoculated with IBDV （P 〈 0.05）. The results suggest that APS may enhance the immune adherence of chickens erythrocytes by affecting the activity and/or the number of complement receptors on the erythrocyte membrane. These findings can be beneficial in providing an understanding of the basic mechanisms required for the rational application of APS in modern medicine.展开更多
基金Supported by National 973 Project(2005CB523202)National Natural Science Foundation of China (30901083)China PostdoctoralScience Foundation(20080440921)~~
文摘[Objective] The paper was to determine the genomic sequence of a very virulent strain of infectious bursal disease virus（IBDV）,and study its molecular characteristics.[Method] A very virulent strain（vvIBDV）（HLJ-0504） of infectious bursal disease virus（IBDV） with special characters was isolated in China and its genome was sequenced.[Result] Sequence analysis showed that segment A of HLJ-0504 was derived from vvIBDV,while segment B was from a distinct ancestor.The morbidity and mortality of HLJ-0504 was 100% and 86.7%to SPF chickens,respectively.[Conclusion] vvIBDV with distinct segment B were still circulating and the evolution of IBDV was diversified in China.Besides,it is hard to imagine that the virulence of IBDV is determined solely by segment A or B.
基金supported by a grant from National Natural Science Foundation of China(31430087)the Scientific and Technological Research Project of Harbin,China(2014AB3AN058)+2 种基金the Special Fund for Scientific and Technological Innovative Talents of Harbin,China(2014RFQYJ129)China-France Cai-Yuanpei Program(2011008007)the Modern Agro-industry Technology Research System of China(nycytx-42-G3-01)
文摘Infectious bursal disease virus（IBDV）is responsible for the highly contagious infectious bursal disease of chickens.Further understanding the gene-function is necessary to design the tailored vaccine.The amino acid residue 279,located on strand P_F of VP2,is one of the three residues that have been reported to be involved in cell-tropism but with some inconsistency.In this study,to further clarify the amino acids involved in the cell tropism of IBDV,a series of mutations about residue 279were introduced into the VP2 of vv IBDV Gx strain.With the reverse genetic system,we found single mutation of D279N,double mutations of D279N/A284T or Q253H/D279N were not enough to adapt IBDV to chicken embryo fibroblast（CEF）cell.To evaluate whether residue 279 could influence the replication and virulence of IBDV,the virus r Gx HT-279 with three mutations（Q253H/D279N/A284T）was rescued and evaluated.Results showed that the mutation of residue 279 in VP2had no efficient effects on both the replication efficiency in vitro and the virulence to SPF chickens of IBDV.In summary,the results demonstrated that residue 279 of VP2 did not contribute efficiently to cell tropism,replication efficiency,and virulence of IBDV at least in some strains.These findings provided further information for understanding the gene function of IBDV.
基金This work was supported by the Twelfth Five-Year-Plan of the National Science and Technology Support Project(2011BAD34B01)National Natural Science Foundation of China(31502025).
文摘Garlic(Allium sativum,Liliaceae)has been safely used for more than 5000 years,and research on garlic extract is rapidly increasing because of its multiple biological functions.The in vivo effects of oral administration of garlic mixture(GM,water-soluble extract)on infectious bursal disease virus(IBDV)-infected specific pathogen free male white leghorn chicken were examined through histopathological,immunohistochemical,and Western blot analyses,and enzyme-linked immunosorbent assay.The results confirmed the protective effects of oral administration of 5 mg·kg^(–1) BW GM(Group GM1)on bursal lesions after IBDV infection.In particular,protein expression of IBDV in the bursa decreased in Group GM1,indicating that GM administration decreased IBDV replication in the bursa.Furthermore,immunoglobulin M-and A-bearing B lymphocytes significantly increased 7 days post infection in bursae in Group GM1(P<0.01),suggesting that the oral administration of 5 mg·kg^(–1) GM offers moderate protection against B cell destruction after IBDV infection.During infection,the concentration of bursal interferon gamma(IFN-g)increased and peaked in Group GM1 earlier than in Group T(IBDV-exposed),demonstrating that GM administration prompted the production of IFN-g to protect against IBDV infection.
文摘Two hundred and forty specific pathogen free leghorn chickens were randomly divided into four groups and reared in isolated pens. The tested chickens were negative to infectious bursal disease virus （IBDV） at 25 d old. Group 1 was treated with saline, whereas Groups 2, 3, and 4 were inoculated with 0.3 mL IBDV suspension intranasally the next day. Groups 3 and 4 were also administered with Astragalus polysaccharides （APS） intramuscularly twice daily at 5 or 10 mg kg-1 BW, respectively, until 31 d old. The erythrocyte-C3b receptor rosette rate （E-C3bRR） and the erythrocyte-C3b immune complex rosette rate （E-ICRR） were measured at 25, 29, 32, 35, and 38 d old. The results showed that IBDV significantly reduced E-C3bRR and E-ICRR when compared with the control group （P 〈 0.05）, while simultaneous administration of APS with 1BDV maintained E-C3bRR at similar levels to the control group （P 〉 0.05） and increased E-ICRR when compared with the control group and the group non-treated with APS （P 〈 0.05）. APS treatment reduced the morbidity and mortality of chickens inoculated with IBDV （P 〈 0.05）. The results suggest that APS may enhance the immune adherence of chickens erythrocytes by affecting the activity and/or the number of complement receptors on the erythrocyte membrane. These findings can be beneficial in providing an understanding of the basic mechanisms required for the rational application of APS in modern medicine.
