肺炎球菌表面蛋白的克隆表达与免疫原性研究

从肺炎球菌YF05中扩增了肺炎球菌表面蛋白A（PspA）和肺炎球菌表面黏附素A（PsaA）基因,以pET27b(+)为载体构建了重组表达质粒的表达系统后，转化入大肠杆菌BL21，IPTG诱导表达，表达的重组蛋白约占菌体总蛋白的75％，结果显示：表达的PspA蛋白和PsaA蛋白，分子量分别约为75kDa和37kDa。成功表达的重组蛋白具有较强的免疫活性和交叉免疫效果。

Study of expression of Pneumococcal surface protein and Immunogenicity

The specific fragment of Pneumococcal surface protein A( PspA) and Pneumococcal Surface Adhesin A(PsaA) gene was amplified by PCR from Streptococcus pneumonia 5. The amplified fragnent of PspA and PsaA gene was ligated into pET- 27b (+) vector and transformed into BL 21 E.coli for expression and obtain the expressive production of PspA and PsaA. Induced by IPTG, the expression level was as high as 75 % of total protein. The result showed that the recombinant plasmid could express a specific 75 kDa and 37 kDa fusion protein in E. coli BL 21, which showed the good immunogenicity and a broadly cross reactivity with the other serotypes.