Influences And Mechanixm On Erythrocyte Immune And IFN-γ MRNA Expression Of Ducks Infected With Avain Influenza Virus

Avian influenza (AI) is an infection and/or syndrome disease of birds cause by influenza virus type A, mainly infringe the respiratory, reproductive system and digestive system of poultry. Since 1990s, the high pathogenic avian influenza occurred frequently, cause seriously loss of economy in poultry industry and become a threat to the human health. Duck, as one kind of waterfowl, plays an important role in AIV epidemic and variation. Red blood cell(RBC) not only has the physiological function of transferring oxygen, but also has many immunity related substances, such as CR₁, CR₃. CD₅₈. CD₅₉, DAF, SOD and so on. Erythrocytes are the most important natural immune cells in the blood circulation. RBC has the ability of identification, adherence, concentrate, killing antigen and clearing immune complex, and takes an important part in acquired immune cells (T cells and B cells) activation and specific immune response, it also has self adjusting system. There is wide and close relationship between erythrocyte immune system and leukocyte immune system. Till now, the changes of erythrocyte immune function in ducks infected with avian influenza virus have not been comprehensively and systematically reported. In this study, cell culture technique and MTT method, semi quantitative reverse transcription polymerase chain reaction(RT-PCR) and other techniques of modern cellular immunology and molecular immunology were used to discover the dynamic changes of erythrocyte immune adherence function, erythrocyte immune self-regulation ability, regulative ability of erythrocyte acting on lymphocyte proliferation and expression of IFN-γmRNA in peripheral blood lymphocyte of ducks infected with AIV at 21 days old, which were to reveal the mechanism and regulation of erythrocyte immune function and IFN-γmRNA expression of ducks infected with AIV. The results were as follows:1. Compared with controls, the ability of erythrocyte promoting lymphocyte proliferation of ducks infected with AIV was significantly decreased at 3-9 days post infection (PI). It indicated that AIV infection can hinder the immunity regulation function. Immune function imbalance could be an important element of leading death of ducks infected with AIV at initial period.2. The erythrocyte immune function of ducks infected with AIV at 21 days old was secondary decreased at initial period, which could be the main reason of antigen-antibody complex clearance decreased in ducks infected with AIV. As the development of the disease, the erythrocyte C_3b receptor rosette rate and erythrocyte immune complex rosette rate were recovered in different degree, and it showed that the effect of AIV infection on the erythrocyte immune adherence function of ducks was reversible.3. Compared with controls, the activity of erythrocyte immune promoting factor in the serum of ducks infected with AIV was significantly decrease at 3-21 days PI, while the activity of erythrocyte immune inhibitor factor was increased obviously at 1-21 days PI. This results indicated that AIV infection could lead to regulation disorder of erythrocyte immune function of ducks.4. The expression of IFN-γmRNA in peripheral blood lymphocyte of ducks infected with AIV at 21 days old was significantly decreased in initial stage and rise again in later stage compared with that of controls. The results revealed that during the early period, the molecular immune function of ducks infected with AIV was inhibited, and it lead to the cellular immunity and humoral immunity weakened, which may be an important reason of ducks death in the early stage. The experiment also revealed that the effect of AIV on the expression of IFN-γmRNA in peripheral blood lymphocyte of ducklings was reversible.