鼠伤寒沙门氏菌SL7207 SifA^-突变株的构建和鉴定

Construction and characterization ofSalmonella typhimurium SL7207 SifA^- mutant strain

鼠伤寒沙门氏菌SifA- 基因突变株的特点是能进入真核细胞的胞液。利用P2 2噬菌体转导技术构建了鼠伤寒沙门氏菌疫苗株SL72 0 7的SifA- 突变株SL72 0 7 ,该突变株与SL72 0 7有着相似的体外生长曲线和细胞侵袭力,SL72 0 7 在MDCK上皮细胞中的增殖能力增强,但在RAW2 6 4 7巨噬细胞中的生存能力减弱。小鼠毒力试验显示SL72 0 7 在BALB c小鼠体内毒力下降。仅SL72 0 7 在体外可向RAW2 6 4 7巨噬细胞递送真核表达质粒。SL72 0 7

One characteristic ofSalmonella typhimuriumSifA - mutant strain is to enter the cytosol of eukaryotic cells. TheSifA - mutation ofS. typhimurium P3H6 was transferred intoS. typhimurium vaccine vector SL7207 by P22 phage transduction and the new strain was named as SL7207 *. SL7207 * had similar growth curve in LB medium and similar invasiveness for eukaryotic cells. It was found that SL7207 * replicates within MDCK cells at a higher rate than SL7207, but is defective for replication in macrophage cell line RAW264.7. SL7207 * was more attenuated than SL7207 in BALB/c mice when innoculated intraperitoneally or intravenously. SL7207 *, but not SL7207, could transfer eukaryotic expression plasmid into RAW264.7 cells. These results showed that SL7207 * could be a promising candidate vaccine vector to express foreign antigen or act as a eukaryotic expression plasmid carrier.