猪γ干扰素和胸腺肽α1基因的共表达及其调节免疫活性的效果与机理

Animal Viral diseases had increasingly severe harm to livestock and poultry breeding and were prevented and crued by vaccines.The traditional vaccines could activate organism to produce high titer antibody, but they Couldn't stimulate enough cellular immunity. However, cellular immunity was most important to clear away virus infections. So there was much academic and industrial interest in the cytokines. Interferon gamma(IFNγ) and thymosin α1(Tα1) were the two cytokines and could enhance T-cell, dendritic cell and antibody responses, modulate cytokines and chemokines production and block steroid-induced apoptosis of thymocytes. Due to their pleiotropic biological activities, IFN and Tα1 have gained increasing interest in recent years and have been used for the treatment of various diseases in clinic. Accordingly, there is an increasing need for the production of these peptides. In our study, the IFNγ gene and Tα1 gene were cloned into Eukaryotic expression vector pIRES simultaneously obtaining the recombinant plasmid pIRES-IFNγ，pIRES-Tα1 and IFNγ-pIRES-Tα1 respectively. Then the three recombinant plasmids were transfected into COS-7 cells. Endo-free plasmids were extracted, and then these plasmids were inoculated to pigs as vaccines for an animal immunization trial to investigate whether and how they could have great immunity promotion on foot-and-mouth disease vaccine. Further, we want to know if there have considerable immune protection achieving as well synergy emerged between the two genes, which had satisfactory effect when expressed in one same system(IFNγ-pIRES-Tα1). This opens the new way to prevent foot-and-mouth disease and thus laying down the foundation for the further research and clinical applications.

病毒性疾病对畜禽养殖业的危害有逐年扩大的趋势。传统的灭活疫苗具有较强的免疫原性，可刺激机体产生高滴度的抗体，但诱生的细胞免疫有限。然而，细胞免疫应答在清除病毒感染中起重要作用，干扰素和胸腺肽作为免疫应答的自然介导物和调节物之一，具有广谱的抗病毒活性、抑制细胞分化和增殖及广泛的免疫调节能力，在临床上具有良好的应用前景。本项目欲采用新型真核表达载体pIRES同时表达猪IFNγ和Tα1并制备无内毒素的DNA佐剂，和猪口蹄疫疫苗共同免疫猪只后，对其免疫增进的效果进行系统研究。同时，采用分子生物学技术、流式细胞术、RT-PCR、ELISA等技术研究IFNγ和Tα1基因对淋巴细胞增殖及亚类分化、细胞信号转导途径的影响，从分子水平探讨其免疫调节机理。该研究考察IFNγ和Tα1是否具有协同作用，为口蹄疫的预防和治疗探索一条新途径，也为将IFNγ和Tα1更好地应用于畜禽养殖业奠定基础。