猪IL-2与IL-6的原核表达及其对伪狂犬病基因缺失疫苗的佐剂效应研究

 将猪白细胞介素2(pIL-2)与猪白细胞介素6(pIL-6)的cDNA序列克隆到大肠杆菌表达载体pET-28a及pGEX-KG上,转化BL21(DE3)表达菌,经IPTG诱导产生重组蛋白pIL-2与pIL-6,表达量分别占菌株总蛋白的43.45％和28.37％,经提纯后含量可分别达到97.06％和86.37％。将提纯后不同剂量的两种重组蛋白以单独或组合的方式,加入伪狂犬病(Ea株)TK~-/gG~-双基因缺失疫苗中,使每头份疫苗分别含2、5和10μg·ml~(-1)的pIL-2或(和)pIL-6,用此疫苗免疫伪狂犬病抗体阴性猪。同时设试验对照组。初次免疫30d后加强免疫,测定中和抗体,观察试验猪的日增重情况,进行统计分析。发现各试验组的抗体水平均高于不含重组蛋白的基因缺失疫苗组;其中,含2μg·ml~(-1)pIL-2试验组与含10μg·ml~(-1)pIL-2/pIL-6试验组抗体水平和基因缺失疫苗对照组之间呈显著差异(P=0.019)与极显著差异(P=0.009)。结果表明,大肠杆菌表达的pIL-2、pIL-6对伪狂犬病鄂A株基因缺失疫苗(TK~-/gG~-/LacZ~+)有较强的佐剂效应,且呈剂量相关性。不同试验组日增重比较结果表明,免疫效果高低与猪的生长速度呈正相关。本试验为重组pIL-2与pIL-6作为新型疫苗佐剂应用提供了重要的试验依据。     

Porcine Interleukin-2 Expression in Insect Cells and Its Enhancement of Pig Immunity to Swine Influenza Virus Inactivated Vaccine

Mature porcine interleukin-2 （pIL-2） gene was amplified by PCR from the plasmid pGEM-T-pIL2 and cloned into the baculovirus pFastBacTM Dual vector of the Bac-to-Bac baculovirus expression system under the control of the PH promoter. Recombinant plL-2 （rpIL-2） expressed in Sf9 insect cells was detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunofluorescence assay. Western blot analysis confirmed that the rpIL-2 protein had a molecular mass of 20 kDa, which was larger than the molecular mass of the mature protein predicted based on its peptide sequence. The rpIL-2 protein induced in vitro proliferation of ConA-stimulated porcine splenocytes and enhanced in vivo protective immune responses induced by vaccinating the pigs with inactivated oil emulsion vaccine against swine influenza virus. The results showed that the rpIL-2 expressed in Sf9 insect cells has immunoenhancement effects; the finding lays the foundation for the preparation of a specific recombinant IL-2 protein and the development of a novel immune adjuvant of vaccines against various infectious porcine pathogens to increase the immunoprotective efficacy of vaccines.     

PCV2和猪伪狂犬病弱毒疫苗体外共接种对猪PBMC中IL-2及IL-6 mRNA表达的影响

将猪圆环病毒2型（PCV2）与猪伪狂犬病弱毒疫苗（PRV）体外单接种和共接种仔猪外周血单个核细胞（PB-MC）,采用real-time PCR技术定量检测接种后不同时间PBMC细胞因子IL-2和IL-6的mRNA表达水平,以分析PCV2对PRV免疫反应的影响。结果显示,PRV接种组PBMC中IL-2与IL-6的mRNA表达均出现显著上调（P〈0.05）,PCV2接种组IL-2与IL-6的mRNA表达在接种后的部分时间也出现显著上调,但PCV2与PRV共接种组的IL-2与IL-6的mRNA表达较PRV组均出现显著下调,表明PCV2能够抑制PRV促进猪PBMC中IL-2与IL-6的mRNA表达上调作用,提示PCV2可能会对PRV的免疫反应产生不利影响。