[Preparation of HPV18 E7 peptide plus CpG vaccine and its immunologic effects in vitro].

OBJECTIVE:To screen and prepare the vaccine of human papillomavirus (HPV) 18 E7 peptide target at human leukocyte antigen (HLA)-A2 plus CpG through SYFPEITHI. METHODS:(1) The SYFPEITHI database was employed for predicting and screening of HPV18 E7 HLA-A2 restricted T cell epitopes.(2) The peripheral blood and tumor tissue sample of HLA-A2 positive and HPV18 positive/negative patients were collected and randomly divided into 7 groups, i.e. E7PA + CpG, E7PB + CpG, E7PC + CpG, E7PD + CpG, CpG, IR-T + CpG and control groups respectively. T cell proliferation was detected by thiazolyl blue tetrazolium bromide (MTT) assay at different timepoints. Lactate dehydrogenase delivery method (LDH) was used to test the cytolytic t lymphocyte (CTL) activity of peripheral blood mononuclear cell (PBMC) in different ratios of effect and target (E:T). And the level of activity T cells was evaluated by interferon gamma (IFN-γ)-related enzyme-linked immuno-spot assay (ELISPOT). RESULTS:(1) Four peptides named E7PA, E7PB, E7PC and E7PD were obtained separately with high levels of affinity and specificity. (2) During continuous observations after vaccination, the E7PA + CpG group had the most pronounced proliferation rate. When E:T = 100:1, the E7PA + CpG group had more powerful CTL effect than the control group with statistic significance (P < 0.00). E:T was concentration-dependent. Except for IR-T + CpG, all other groups had great difference than control group with statistic significance (P < 0.05) but no significant difference between the groups. The levels of IFN-γ spot-forming T cells were higher in the E7PA + CpG group than the control group with statistic significance (P < 0.01). In terms of specificity, E7PA + CpG in the HPV18 positive group could induce the proliferation of IFN-γ-secreting T cells. And there was statistical difference with the control group (P < 0.05). CONCLUSION:Screening the HPV18 E7 peptide target at HLA-A2 plus CpG as the candidate targets by SYFPEITHI may active specific immunological cellular responses to HPV18 positive disease.