Immunologic Function Suppression And TGF-β1 MRNA Expression In Immune Organs Of Ducks Infected With H5N1 Influenza Virus

In this study,technology of hematoxylin and eosin stain, TdT-mediated X-dUTP nick end labling and real-time fluorescence quantitative PCR(SYBR GreenⅠ) were used to discover the damage of immune organ , the dynamic changes of the quantity of cell apoptosis and the expression of TGF-β1 mRNA in immune organs (thymus, bursa of Fabricius and spleen) of ducks infected with avian influenza virus (A IV) at 21days old, which were to reveal the mechanism and suppression of immune function in immune organs of ducks infected with AIV at 21days old. The experiment provided scientific evidence of experiment for the mechanism of morbidity and useful effective prevention in influenza. The results were as follows:1.Following the ducks infected with H5N1 AIV, immune organs(thymus, bursa of Fabricius and spleen) of ducks were suffer serious damage , the pathologic changes were obviously at 3~5 days post infection (PI). The serious damage of immune organs of ducks infected with AIV should be significance reason of immunologic function suppression in initial period of AIV infection.2.Following the ducks infected with H5N1 AIV, compared with controls,the quality of apoptosis cells in immune organs of duck infected with AIV was persistently increased at 1~21 days PI at different degree, remarkablely at 1~5 days in spleen and 3~5 days PI in thymus and bursa of Fabricius. The results of the histopathology observation showed that the cells of apoptosis in thymus, bursa of Fabricius, and spleen of ducks infected with AIV were mainly lymphocyte. The cells of apoptosis in thymus, bursa of Fabricius, and spleen of ducks infected with AIV could be mian reason of immunologic function suppression.3.Following the ducks infected with H5N1 AIV, compared with controls, the expression of TGF-β1 mRNA in immune organs dramatic increased at 24h PI, meanwhile continue to 7days PI, then the expression returned to control values. The dramatic increasion of the expression of TGF-β1 mRNA in thymus and spleen of ducks infected with AIV, which inhibited the proliferation function of T-lymphocytes to ConA and weakened the activity of CD8+T. The elements above were the mian reasons of descreasion and suppression of immunologic function.Meanwhile, this study cloned duck TGF-β1 mature firstly and elucidated its genomic structure. The results show that duck TGF-β1 mature shares a 93.6% nucleotide acids homology and a 94.2% amino acids homology with chicken .