Coadministration of gene adjuvant MIP-1α and Flt3l to enhance the immunological effect of DNA vaccine to HPV16E7

Objective:To study the possibility for enhancing the immunological effects of DNA vaccine to HPV16E7 by combination of gene adjuvant macrophage inflammatory protein-1α(MIP-1α) and Flt3 ligand(Flt3l).Methods:The eukaryotic expressing plasmids,which in-cluded pcDNA3/MIP-1α,pcDNA3/HPV16E7 and pcDNA3/Flt3l.C57BL/6 mice were divided into 8 groups randomly.The groups were pcDNA3 group,pcDNA3/MIP-1α group,pcDNA3/Flt3l group,pcDNA3/MIP-1α and pcDNA3/Flt3l mixed group,pcDNA3/HPV16E7 group,pcDNA3/MIP-1α and pcDNA3/HPV16E7 mixed group,pcDNA3/Flt3l and pcDNA3/HPV16E7 mixed group,pcDNA3/MIP-1α and pcDNA3/Flt3l and pcDNA3/HPV16E7 mixed group,respectively.Each group contained 14 mice.Plasmids were performed to mice by intramuscular injection at 3 week intervals for 3 times.6 mice of each group were sacrificed randomly 2 weeks after the last immunization event with collection of lymphocyte suspension from spleens.Specific cytotoxic T lymphocytes(CTLs) targeting to TC-1 cells were tested by CCK-8 kit.The rest mice were challenged with 5×104 TC-1 cells via subcutaneous injection in fold inguen.The growth of tumours was observed.Results:The eukaryotic expressing plasmids of pcDNA3/MIP-1α,pcDNA3/HPV16E7 and pcDNA3/Flt3l were constructed successfully.The CTL level of pcDNA3/MIP-1α and pcDNA3/Flt3l and pcDNA3/HPV16E7 three plasmids mixed groups was higher than those of the other groups remarkably(P0.01).16 days after challenge by tumour cells,all mice of pcDNA3 group formed tumors,while the tumor-forming rate of pcDNA3/MIP-1α and pcDNA3/Flt3l and pcDNA3/HPV16E7 three plasmids mixed group was 12.5%,which was lower than the other groups markedly.The difference of tumor-forming rate among 8 groups was significant by statistics analysis(P=0.007).60 days after the challenge,the difference among all groups had no statistic significance(P=0.229).Conclusion:The immunological effect of DNA vaccine to HPV16E7 is enhanced by coadmin-istration of gene adjuvant MIP-1α and Flt3l.They delay the tumor growth to a certain extent.