Ag85B核酸疫苗的免疫原性和保护性研究

扩增结核分枝杆菌的Ag85B基因并克隆于真核表达载体 pJW4 30 4 ,转染COS - 7细胞后 ,Westernblot检测表明该基因在细胞内得到了正确表达。用该质粒免疫C5 7BL/ 6小鼠 ,免疫三次后 ,用纯化的重组蛋白Ag85B检测小鼠血清中的抗体 ,抗体滴度达到 1:10 2 4 0 0 ,(γ -干扰素测定表明 ,免疫动物的干扰素含量达到 116 0 3± 10 4 pg /ml。实验结果说明Ag85B核酸疫苗在实验动物体内引起了较强的免疫应答。三次免疫后经静脉强毒攻击 ,免疫组小鼠肺脏和脾脏的细菌数比对照空载体组分别减少了 1 5和 15倍以上。本研究表明 ,该核酸疫苗能同时诱导机体产生细胞和体液免疫应答并获得较高的保护效率。

Study on the Immunogenicity and protective efficacy of Ag85B DNA Vaccine

The gene encoding Ag85B protein from M tuberculosis was amplified by PCR and cloned into the eukaryotic expression vector pJW4303 The expression of the recombinant protein in COS7 cells was demonstrated by Western blot using antiserum of M TB H37Rv and the specific antibody titers were determined after C57BL/6 mice were vaccinated by this Ag85B DNA vaccine It was found that the specific antibody up to 1∶102400 was detected in sera harvested from immunized mice 21days after the third injection and antigen specific IFN γ level of Ag85B reached to 11603±104 pg/ml After the last boost with the DNA vaccine,mice were challenged with 10 6 CFU of M tuberculosis H37Rv via a lareral tail veil Vaccination with Ag85B DNA vaccine caused a more than 1 5 folds of decrease of bacterial CFUs in the lung and speens in comparison with the control group This study indicates that Ag85B DNA vaccine can induced the productions of cell mediated and humoral immune responses to obtain higher protective response against M TB