H9N2亚型禽流感病毒对鸡的免疫抑制机制

摘要

通过评价H9N2亚型禽流感病毒(AIVs)感染对于鸡新城疫和传染性支气管炎活疫苗免疫效力的影响,研究了H9N2 AIVs的免疫抑制机理.结果显示,H9N2 AIVs感染可降低鸡对鸡新城疫和传染性支气管炎活疫苗的抗体应答,但与对照组相比差异并不显著;而流式分析结果显示,与对照组相比H9N2 AIVs感染可显著降低鸡外周血中CD4+T淋巴细胞和CD8+T淋巴细胞的比率(P<0.05);抗原特异性的T淋巴细胞增殖试验结果显示,与对照组相比H9N2 AIVs感染鸡的外周血T淋巴细胞增殖活性显著下降(P<0.05);另外,H9N2 AIV感染还导致鸡血清中细胞因子IFN-γ和IL-4应答水平的下降,其中IFN-γ的应答水平与对照组相比差异显著(P<0.05).说明H9N2 AIVs感染可抑制鸡的免疫应答,其中对细胞免疫应答的抑制更为明显.%The influence of H9N2 subtype avian influenza viruses(H9N2 AIVs) infection on the immune efficacy of newcastle disease virus (NDV) and infectious bronchitis virus (IBV) vaccine was assessed to determine the immune sup-pressive mechanism for H9N2 virus. The results showed that the infection of H9N2 virus reduced the antibody titers to the live vaccine of NDV and IBV,but this difference was not significant compared with the control group. However, the flow cytometric analysis of peripheral blood lymphocyte subpopulations showed that H9N2 virus infection resulted in a significantly decrease in CD4+T lymphocyte and CD8+T lymphocyte proportion, and the antigen specific proliferation ability of peripheral blood T lymphocyte in H9N2 virus infection group was also obviously suppressed compared with that of the control group.Moreover,the lev-el of cytokines IFN-γ and IL-4 in serum of H9N2 virus infection chickens was also lower than that of control group,and the difference of IFN-γ was significant. The results suggested that H9N2 AIVs infection could suppress the immune response to vaccine in chickens,and the cellular immune response was more significantly suppressed.