【摘要】 iss基因是鸡大肠杆菌的毒力基因,与菌株的血清抗性有关。本研究采用GST-Iss融合蛋白免疫4~6周龄小鼠,间接ELISA检测抗血清效价,并检测鸡致病性大肠杆菌O2(O2血清型)、CVCC1553(O78血清型)菌株Iss蛋白的表达。通过体外血清抗性抑制试验及iss、ybtA、chuA基因实时荧光定量PCR,检测2株菌株的血清抗性变化及mRNA转录水平的改变。结果表明,鼠源抗Iss抗血清能够在体外试验中抑制O2、CVCC1553菌株的血清抗性,并降低iss、ybtA及chuA基因的转录,并且对不同血清型菌株均有效。由此推测,抗Iss抗血清可能通过降低血清抗性相关基因的转录,使致病性菌株的血清抗性下降。Iss蛋白可能具有制备亚单位疫苗的潜力。更多还原

【Abstract】 The iss gene is the virulence gene of avian E. coli, which is related to its serum resistance. However, there are few reports regarding immune protection of the Iss protein. In the present study, the GST-Iss fusion protein was used to immunize 4-6 week-old mice. The indirect ELISA was used to detect the titer of the antiserum and the expression of Iss protein in pathogenic E. coli strains CVCC1553 and O2. The changes of serum resistance and mRNA transcription level were detected in these two strains as detected using in vitro serum resistance inhibition and real-time fluorescence quantitative PCR assay for iss, ybtA, chuA genes. The results concluded that the anti-Iss serum inhibited the serum resistance of O2 and CVCC1553 strains in vitro and reduced the transcription of iss, ybtA and chuA genes in different serotype strains. The mechanism for the anti-Iss serum may be due to its role in decreasing the serum resistance of pathogenic bacteria by reducing the transcription of the serum resistance related genes. In addition, Iss protein may have the potential for development of the subunit vaccine.更多还原