Letters in Drug Design & Discovery | 2021
In silico and in vitro analysis of a multiepitope L1-E7 fusion construct for vaccine development against human papillomaviruses
Abstract
\n\nHuman papillomavirus (HPV) infection is the major risk factor for cervical cancer. Current prophylactic HPV vaccines provide immunity against most genital and carcinogenic HPV types. However, these vaccines failed to produce immune responses against already established HPV infections. \n\n\n\nFor the design of a therapeutic vaccine candidate, we utilized immunoinformatics tools to design a potential multiepitope fusion construct based on L1 and E7 genes from different high- and low-risk HPV types. After determination of CD4+ and CD8+ T cell epitopes, the allergenicity, toxicity, immunogenicity, conservancy, and population coverage were analyzed for epitope selection. Then, the hemolytic probability of the selected epitopes, and molecular docking between major histocompatibility complex (MHC) and the chosen epitopes were performed by different web servers. Next, a multiepitope peptide construct consisting of 12 epitopes linked by the AAY proteasomal sequence was designed. After that, physicochemical properties, solubility, secondary and tertiary structures of this construct were evaluated by bioinformatics tools. Finally, after amino acid reverse translation of the multiepitope peptide construct, expression of the L1-E7 DNA construct (pEGFP-L1-E7) was investigated in HEK-293T cells using fluorescent microscopy, flow cytometry, and western blotting. \n\n\n\nConsidering various parameters, the immunodominant peptides such as L1(MHC-I)-DLDQFPLGRKFLLQ, L1(MHC-II)-NQLFVTVVDTTRSTN, E7-HPV16(MHC-I)-AEPDRAHYNIVTF, E7-HPV18(MHC-I)-HGPKATVQDIVLHL, E7-HPV31(MHC-I)-KPDTSNYNIVTF, E7-HPV33(MHC-I)-RPDGQAQPATADYYI, E7-HPV45(MHC-I)- RTLQQLFLSFV, E7-HPV16(MHC-II)-TLHEYMLDLQPETTD, E7-HPV18(MHC-II)-LRAFQQLFLNTLSFV, E7-HPV31(MHC-II)-PTLQDYVLDLQPEAT, E7-HPV33(MHC-II)-LKEYVLDLYPEPTDL and E7-HPV45(MHC-II)-LQQLFLSTLSFVCPW were determined to design the vaccine construct. The results indicated efficient expression of the L1-E7 DNA construct (74 ± 2.19%) in vitro. Moreover, the polyepitope peptide generated in the cells was detected as a clear band of ~ 50 kDa in western blotting. \n\n\n\nRegarding the favorable transfection efficiency of the designed L1-E7 multiepitope construct, in vivo validation study on its therapeutic potential is underway. \n