The evaluation of a novel multi-epitope vaccine against human papillomavirus and Candida albicans

The purpose of this study was to design and evaluate a multiepitope peptide vaccine against Human papillomavirus (HPV) and Candida albicans (C. albicans) on human dendritic cells (hDC).

To determine the antigenic epitopes for C. albicans and HPV, the FASTA format of protein targets was extracted from NCBI. Then, all epitopes were analyzed using ABCpred, Vaxijen, AllerTOP, ToxinPred, and molecular docking. Then, selected peptides were first synthesized using the solid phase method, mixed with cationic lipids, and characterized by DLS, Zetasizer, and nanodrop at 280 nm. In the next step, hDCs were obtained from peripheral blood and confirmed by flow cytometry. Then, they were exposed to vaccine candidates at 1 mg/mL. Next, the activation of hDC was checked by the expression and concentration of interleukin-12 (IL-12) and interferon-ɣ (IFN-ɣ). Also, the functionality of hDCs and antigen-loaded hDCs was evaluated by their ability to induce the proliferation of allogeneic T cells by mixed lymphocyte reaction (MLR). Finally, antibody titration against vaccine candidates was investigated on Syrian male mice using the ELISA method.

Here, KDIDLDLQEL, GPVLALNVAL, and KDIDLDLQELKKKGPVLALNVAL peptides were selected as E7, HYR1, and merged E7-HYR1 peptides, respectively. We found that more than 85 % of the isolated hDCs were positive for HLA-DR, CD86, and CD209 and less than 5 % were positive for CD14. After treatment of hDCs with vaccine candidates, we found that peptides E7, HYR1, and merged E7-HYR1 could stimulate hDCs to express IL-12 and IFN-ɣ and when the selected peptides integrated into nanoliposomes, they were significantly more capable to stimulate hDC (P < 0.05). Also, we found that the stimulation index of vaccine-loaded hDCs was higher than unloaded hDCs. The antibody titer in mice exposed to nanoliposomes was significantly higher than in mice exposed to specific peptide vaccines. ^a P < 0.05 compared with other groups.

Here, a multiepitope peptide vaccine against HPV and C. albicans was designed and evaluated on hDC. Real efficacy and side effects of this vaccine must be analyzed in future studies.