The Interaction Of Co-infection Of Cav And Other Immunosuppressive Disease

Chicken anemia virus(CAV) is the most important pathogen which can destroy chick hematopoietic system and make lymphoid organ wither,and also cause immunosuppression to adult chicken. CAV is widely distributed in the world and is one the most important pathogens in poultry industry,which will cause co-infection or a secondary affection after its infection,and cause considerable economic losses in poultry industry.Therefore,the more in-depth we study the pathogenicity of CAV,the more benefit we have from the practical producing and to prevent and to cure the desease.In the experiment,we cultured CAV-SDLY08(isolated from ShanDong Province)in MSB1 cells and determined the virus titer.we used 103 TCID50-CAV to infect 1-day-old chicks in order to study the dynamic changes in chickens infected by CAV and to study the Synergic inhibitory effect of the co-infection of CAV and Marek′s disease virus(MDV) or CAV and Avian Leukosis virus subgroup J(ALV-J).In order to study the synergic inhibitory effect of co-infection of Chicken infectious anemia virus(CAV) and Marek′s disease virus(MDV) in SPF chickens,CAV and MDV were used to infect 1-day-old SPF chickens, the H'crit of which were alternately detected in 14days,21days,28days and 35days.And the antibody titers of which were detected in 3 weeks after these chicken were immunized.The result showed that the H'crit of the co-infected chickens were the lowest,and the antibody titers of the co-infected chickens immunized by the vaccinum of NDV,AIV(H5/H9) and IBDV were also the lowest.Above these datas mentioned,the experiment confirmed that the effect of co-infection of CAV and MDV not only aggravated the symptom of anaemia in SPF chickens,but also extended the symttom for many days longer.Moreover,there were 6 chickens died in these co-infected chickens(6/25),which also indicated that the effect of co-infection increased the mortality.These results confirmed that the effect of co-infectin of CAV and MDV was synergic inhibitory effect.In order to study the synergic inhibitory effect of co-infection of Chicken infectious anemia virus(CAV) and Avian Leukosis virus subgroup J(ALV-J) in SPF chickens,CAV and ALV-J were used to infect 1-day-old SPF chickens, the H'crit of which were alternately detected in 14days,21days,28days and 35days.And the antibody titers of which were detected in 3 weeks after these chicken were immunized.The result showed that the H'crit of the co-infected chickens were the lowest,and the antibody titers of the co-infected chickens immunized by the vaccinum of NDV,AIV(H5/H9) and IBDV were also the lowest.Above these datas mentioned,the experiment confirmed that the effect of co-infection of CAV and ALV-J not only aggravated the symptom of anaemia in SPF chickens,but also extended the symttom for many days longer.Besides,the bodies of co-infected chickens were the smallest.These results confirmed that the effect of co-infectin of CAV and MDV was synergic inhibitory effect.According to the genomic sequences of VP1 gene of Chicken anemia virus (CAV-C14) published in Genbank,we designed a pairs of primers to amplify CAV-VP1 gene.PCR product was cloned into pGEX-6p-1 down to its GST gene for expression of fusion protein.The E.coli BL21 was transformed with recombinant expressing plasmid,and induced to express the fusion protein.Fusion protein was collected from SDS-PAGE and used to immunize mice to achieve the positive mouse sera to anti-CAV-VP1.And we collected the fresh tissue of chicken infected by CAV, and made Paraffin through fixxing tissue with 4% Paraformaldehyde.we used the positive sera to detect CAV antigen in paraffin through Immunohistochemistry.The result indicated that the positive antibody could be used as monovalent antisera for diagnosis purpose,but the techniques and conditions still need to improve.