The Inlfuence Of Infectious Bursal Disease Virus To The TGF-β₁mRNA Expression And Immune Function In Immune Organs Of SPF Chicks

Infectious bursal disease （IBD） is an immunosuppressive disease of chicks by infectiousbursal disease virus （IBDV）.TGF-β₁is a kind of cytokine with multiple biological functions andstrong immunosuppression in person and any other animals. In this experiment，the technologies ofcells culture，MTT，immunohistochemical staining，real-time fluorescence quantitative PCR andflow cytometry were used to respectively research the following details in immune organs （bursaof Fabricius，spleens，thymus）of SPF chicks infected with IBDV：the proliferative function of Tand B lymphocytes，the number of antibody-producing cells，the TGF-β₁mRNA expression and thenumber of CD₄⁺T and CD₈⁺T lymphocytes.Our objective is to comprehensive understand theinfluence to the cellular immune function and the humoral immune function and the TGF-β₁mRNA expression caused by IBDV in chicks.The results were as follows：1) Compared with controls，the TGF-β₁mRNA expression in thymus and spleens was remarkablyincreased at3⁷days （P<0.01）；and that in bursa of Fabricius was significantly increased at1¹4days（P<0.05or P<0.01）.These results indicated that the latent transforming growth factor wereactivated and the TGF-β₁mRNA expression were remarkably increased in immune organs ofchicks infected with IBDV，then lead to immunosuppressive of chicks infected with IBDV at firststage，and gradually restored at later stage.2) Compared with controls， the B lymphocytes proliferative function and the number ofantibody-producing cells in bursa of Fabricius and spleens were lower than these in controls chicksat1²8days，but the B lymphocytes proliferative function of infectious chicks were remarkablyreduced at3²8days（P<0.01）.These results indicated that the humoral immune function inimmune organs of chicks infected with IBDV was reduced.3) Compared with controls，the T lymphocytes proliferative function in thymus and spleens wereremarkably reduced at3⁷days （P<0.01） of chicks infected with IBDV；the number of CD₄⁺Tcells in spleens was remarkably reduced at7days（P<0.05） and the number of CD₈⁺T cells wasdecreased at1¹4days（P<0.05or P<0.01） in chicks of infected with IBDV；the number of CD₄⁺Tcells in thymus of chicks infected with IBDV was much weaker than that of controls chicks anddiffered remarkably at1¹4days （P<0.01or P<0.05），the number of CD₈⁺T cells in that was decreased and differed remarkably at5⁷days （P<0.01）.These results indicated that the cellularimmune function in immune organs was also immunosuppressed caused by IBDV.