Changes Of Immunologic Function And Tgf-β1Mrna Expression In Peripheral Blood Of Chicks Infected With Ibdv

Infectious bursal disease (IBD) was an immunosuppressive disease of chickens by infectious bursal disease virus (IBDV). TGF-β1was a kind of cytokine with multiple biological functions and strong immunosuppression. The technologies of MTT, histochemical staining, ELISA, flow cytometry and realtime fluorescence quantitative PCR were used respectively to detect the following details in peripheral blood of chicks infected with IBDV:the proliferative function of lymphocyte, TANAE+cells, the content of Igs (IgG, IgM, IgA), the number of CD4+T cells and CD8+T cells and the expression of T lymphocyte’s TGF-β1mRNA. Our objective was to understand preferably the immunosuppression mechanism of IBDV. The results were as follows:1. Compared with controls, the number of TANAE+cells of chicks decreased and differed remarkably at5-7days (P<0.01); the T lymphocytes proliferative function of chicks was much weakener than that of controls and differed remarkably at3-7days (P<0.01or P<0.05); the number of CD4+T cells and CD8+T cells in peripheral blood of chicks was decreased than that of controls and differed remarkably at7-14days (P<0.05) and7th day (P<0.05), respectively. These results indicated that the function of cellular immunity in peripheral blood of chickens infected with IBDV was reduced.2. Compared with controls, the content of IgA of infected chicks was decreased and differed remarkably at3-5days and the14th day (P<0.01or P<0.05); the content of IgM was decreased and differed remarkably at1th and42th day (P<0.01or P<0.05); the content of IgG decreased and differed remarkably at1th and42th day (P<0.01or P<0.05); B lymphocytes proliferative function of infected chicks was much weakener and differed remarkably at3-5days (P<0.05). These results indicated that the function of humoral immunity in peripheral blood of chickens infected with IBDV was reduced and the immunosuppression caused by IBDV lasted for long time.3. Compared with controls, the expression of lymphocyte’s TGF-β1mRNA in peripheral blood of chickens was increased and differed remarkably at3-28days (P<0.01or P<0.05). And at42th day after infection, the expression of TGF-β1mRNA was same compared with control. And the tendency of expression of TGF-β1mRNA was increased first and then decreased. These results indicated that the expression of TGF-β1mRNA of chicks infected with IBDV was reversible and the expression of TGF-β1mRNA had an suppressive effect on chickens immunity.