禽IL-2与传染性法氏囊VP2融合蛋白免疫学特性

Influence of fusion protein of IBDV VP2 and chicken Interleukin-2 on immune response in chicken

摘要:

为研究禽细胞因子IL-2与IBDV主要保护性抗原VP2基因融合蛋白的免疫学特性，将重组的rVP2-IL-2融合蛋白免疫鸡，通过IBDV-VP2 ELISA抗体效价、抗体亚型 (IgG1和IgG2a)、淋巴细胞增殖、INF-γ和IL-4细胞因子的分泌水平、中和抗体以及动物攻毒试验检测评价其对鸡体免疫水平的影响。抗体滴度测定和淋巴细胞增殖试验结果显示，rVP2-IL-2融合蛋白免疫鸡体的体液和细胞免疫应答水平均明显高于单独的VP2蛋白免疫组。抗体亚型测定结果显示，rVP2-IL-2融合蛋白免疫组鸡体能产生一个平衡的IgG1和IgG2a抗体反应。细胞因子ELISA试验结果表明rVP2-IL-2融合蛋白能有效平衡Th1(?-IFN) 和Th2(IL-4) 类型的细胞免疫反应。动物攻毒试验rVp2-IL-2融合蛋白免疫组鸡体获得了85％的保护率，表明构建的rVP2-IL-2融合蛋白对IBDV的攻击具有较好的免疫保护作用。本研究为进一步研制IBD高效的基因工程疫苗奠定了基础。

Abstract:

In order to research immunogenicity of the recombinant rVP2-IL-2 fusion protein, we obtained the rVP2-IL-2 fusion protein using Pichia pastoris expression system, and then evaluated its potential to induce immune responses in chicken. The effect was determined in the form of protective anti-IBDV VP2 titers, antibodies (IgG1 and IgG2a), lymphocyte proliferation, the levels of interferon-γ and interleukin-4 cytokines, and challenge experiment. Antibody titers and proliferation lymphocyte level suggested that the fusion protein could elicit specific humoral immune and cellular immune responses. antibody sub-type results indicated that the rVP2-IL-2 fusion protein induced secretion both of IgG1 and IgG2a. The seem result elicited from cytokines ELISA test, secretion of both of Th1 (?-IFN) and Th2 (IL-4) were induced by the rVP2-IL-2 fusion protein. Challenge experiment result shown that chicken immunized the rVP2-IL-2 fusion protein obtained 85% protection. These results confirm that the fusion protein enhances the protection against IBDV through both humoral and cell-mediated immunity, and thus could serve as a candidate for the development of IBDV subunit vaccine.