Targeting hepatitis B virus antigens to dendritic cells by heat shock protein to improve DNA vaccine

AIM: To investigate a novel DNA vaccination based upon expression of the HBV e antigen fused to a heat shock protein (HSP) as a strategy to enhance DNA vaccine potency.METHODS: A pCMV-HBeAg-HSP DNA vaccine and a control DNA vaccine were generated. Mice were immunized with these different construct. Immune responses were measured 2 wk after a second immunization by a T cell response assay, CTL cytotoxicity assay, and an antibody assay in C57BL/6 and BALB/c mice. CT26-HBeAg tumor cell challenge test in vivo was performed in BALB/c mice to monitor anti-tumor immune responses.RESULTS: In the mice immunized with pCMV-HBe-HSP DNA, superior CTL activity to target HBV-positive target cells was observed in comparison with mice immunized with pCMV-HBeAg (44% ± 5% vs 30% ± 6% in E: T > 50:1, P < 0.05).="" elispot="" assays="" showed="" a="" stronger="" t-cell="" response="" from="" mice="" immunized="" with="" pcmv-hbe-hsp="" than="" that="" from="" pcmv-hbeag="" immunized="" animals="" when="" stimulated="" either="" with="" mhc="" class="" ⅰ="" or="" class="" ⅱ="" epitopes="" derived="" from="" hbeag="" (74%="" ±="" 9%="" vs="" 31%="" ±="" 6%,="" p="">< 0.01).="" elisa="" assays="" revealed="" an="" enhanced="" hbeag="" antibody="" response="" from="" mice="" immunized="" with="" pcmv-hbe-hsp="" than="" from="" those="" immunized="" with="" pcmv-hbeag.="" the="" lowest="" tumor="" incidence="" and="" the="" slowest="" tumor="" growth="" were="" observed="" in="" mice="" immunized="" with="" pcmv-hbe-hsp="" when="" challenged="" with="" ct26-hbeag.conclusion:="" the="" results="" of="" this="" study="" demonstrate="" a="" broad="" enhancement="" of="" antigen-specific="" cd4+="" helper,cd8+="" cytotoxic="" t-cell,="" and="" b-cell="" responses="" by="" a="" novel="" dna="" vaccination="" strategy.="" they="" also="" proved="" a="" stronger="" antigen-specific="" immune="" memory,="" which="" may="" be="" superior="" to="" currently="" described="" hbv="" dna="" vaccination="" strategies="" for="" the="" treatment="" of="" chronic="" hbv="" infection.="">