pcDNAL1 genetic immunization can induce specific cell-mediated immune responses in C57BL/6 mice

Objective. To investigate the specific cell-mediated immune efficacy of the an HPV16 prophylactic vaccine. Methods. C57BL/6 mice were randomly divided into 3 groups: experimental group I (treated with pcDNA L1), control group II (treated with pcDNA3. 1) and control group III (treated with PBS buffer). The mice were immunized three times during a three-week interval. Ten to fourteen days after the third inoculation, a footpad swelling test was used to detect delayed-type hypersensitivity (DTH) responses. Antigen-specific splenocyte proliferation assay and quantitation of IFN-γ cells in splenocytes were performed by FACS assay. Results. In the experimental group, splenocytes actively proliferated after stimulation with HPV16 VLP, and had developed a markedly larger amount of CD8⁺ IFN-γ⁺ cells, which is an index for special CTL. Also, the footpad was significantly thickened upon inoculation with HPV16 VLP. Conclusion. Naked DNA vaccine of HPV16 L1 can induce specific cell-mediated immune responses in mice, which should be considered for evaluation of HPV16 DNA vaccine feasibility.