Comparison on mice' immunoreaction induced by different vector-associated mimic epitopes of HCV hypervariable region 1 / 解放军医学杂志

ABSTRACT

Objective To compare the cellular immune responses induced by two different vectors,eukaryotic plasmid pcDN3.1(+) and attenuated typhia live vaccine Ty21a,-associated mimic epitopes of HCV hypervariable region 1,so to find a better way for vaccine immunization.Methods The DNA sequence based on the peptides' sequence of HCV hypervariable region 1 related consensus polymimotopes was synthesize and then inserted into plasmid pcDN3.1(+) to construct recombinant plasmid pcDN3.1(+)-SP,which then was transfected into live attenuated typhia vaccine Ty21a to construct Ty21a-SP.The mice were immunized orally with Ty21a-SP and intramuscularly with pcDN3.1(+)-SP,respectively,and then sacrificed by exsanguination.The splenocytes were separated and restimulated with pooled synthesized peptides,and then collected.Flow cytometry was employed to identify CD8+IFN-?+ T cells,and non-radioactive MTS method was adopted to test T cell proliferation,and non-radioactive LDH method was used to test cytotoxic T cytolytic reaction(CTL).Results Compared with control groups,the proliferation of splenocytes was apparently enhanced,the proportion of CD8+IFN-?+ cells obviously increased,and CTL responses also significantly increased after the spenocytes of mice immunized by pcDN3.1-SP and Ty21a-SP were restimulated with synthesized peptides.And the responses mentioned above in the mice immunized by Ty21a-SP were stronger than those mice immunized by pcDN3.1-SP.Conclusion Using attenuated typhia live vaccine Ty21a as DNA vector is an effective way to induce cellular immune responses.