Design of artificial immunogens containing melanoma-associated T-cell epitopes.

OBJECTIVE: Immunotherapy based on induction of T-cell response is a promising approach to treatment of oncological diseases that currently attracts particular attention of researchers. The study aims to design artificial epitope-based immunogens, DNA vaccine candidates against melanoma and evaluate their antitumor response within the system of T-cell response induction ex vivo.

METHODS: The study used computer methods for predicting T-cell epitopes and designing polyepitope antigens, DNA vaccine candidates against melanoma. Evaluating target gene expression was carried out using two methods: (1) detection of synthesis of specific mRNA in HEK-293T cells transfected with DNA-vaccine constructs; and (2) immunochemical staining of transfected cell preparations using MAb. Analysis of cytotoxic activity of autologous effector lymphocytes generated in the system of T-cell response induction ex vivo involved detecting the content of lactate dehydrogenase released from the damaged target cells.

RESULTS: Using original software we have predicted T-cell epitopes and designed two DNA vaccine constructs - pMEL-TCI and pMEL-A0201 - encoding T-cell epitopes of six immunodominant melanoma antigens (NY-ESO-1, MART1, MAGE-A1, MAGE-A11, MAGE-A3, and MAGE-C1). We have demonstrated that the designed genetic constructs provide synthesis of respective mRNAs and proteins in a culture of transfected eukaryotic HEK-293T cells. Dendritic cells from HLA-A*02:01+ donors transfected with DNA vaccine constructs induce autologous T-lymphocytes to develop a specific cytotoxic activity to Mel Is melanoma cells in the model of T-cell response induction ex vivo.

CONCLUSION: The described approach may become a common platform for designing not only vaccines against oncological diseases but also immunoprophylactic vaccines against infectious diseases.