炭疽芽孢杆菌PA蛋白的表达及免疫保护效果研究

Cloning and immunoprotection of PA recombinant protein of Bacillus anthracis

扩增了炭疽芽孢杆菌PA基因,构建了原核表达质粒pET-28a-PA,并对其进行了诱导表达,对表达产物免疫原性和免疫保护效果进行了研究。结果表明,PA基因的长度约为2 205 bp,PA蛋白的相对分子质量为83 ku;rPA蛋白具有良好的免疫原性,初免后10 d即可检测到特异性抗体,第3次免疫后抗体水平明显升高,可达1∶12 800;rPA蛋白刺激小鼠产生的特异性抗体亚型以IgG 1为主;rPA蛋白在体外对小鼠脾脏细胞有促进生长和增殖作用。rPA免疫组小鼠脾脏中CD4+细胞显著增加,免疫应答趋向T h2型反应,说明rPA介导的免疫反应以体液免疫为主。rPA具有一定的免疫保护作用,保护率达到50%。

PA gene amplified was from Bacillus anthracis by PCR and then cloned into pET28a （＋） vector. The recombinant plasmid pET28a （＋）-PA was constructed and expressed and the immunogenicity and immunoprotection were studied. The results show that the length of PA gene is about 2 205 bp and relative molecular mass of the expressed protein is 83 ku ;the rPA has good immunogenicity,and specificity of antibody could be detected after 10 d immunization,and the antibody levels rise markedly, 3rd to 1 ： 12 800;the rPA protein stimulates the specificity of antibody binding to mouse IgG1-based ;the rPA protein can promote the growth and multiplication of the mouse spleen cells in vitro. The rPA immunization group can significantly increase CD4^＋ mouse spleen cells and the immune responses tend to Th2-type response, showing that the rPA most mediate to humoral immunity. The rPA is fairly immune protective,the protection rate being 50%.