Identification of new HLA-A*0201-restricted cytotoxic T lymphocyte epitopes from LDHC in lung adenocarcinoma.

BACKGROUND

Lactate dehydrogenase C (LDHC) is a kind of cancer-testis antigen (CTA) that has been reported to be a biomarker for diagnosis, efficacy evaluation, and recurrence monitoring of lung adenocarcinoma (LUAD). This study aims to assess the value of LDHC in peptide-based vaccines for LUAD immunotherapy.

METHODS

The LDHC recombinant protein was purified and its effect on PC9 cells was evaluated by wound healing assay, Transwell invasion, and migration assay. Ten HLA-A2-restricted LDHC-derived peptides were predicted and synthesized, and the affinity for the HLA-A2 molecule was analyzed by T2 binding assay and molecule docking. Enzyme-linked immunospot (ELISpot) and LDH cytotoxicity assay were performed to determine the interferon-γ (IFN-γ) release level and tumor cell lysis ability of peptide-induced specific cytotoxic T lymphocytes (CTLs).

RESULTS

The LDHC recombinant protein promoted invasion and migration of PC9 cells. Three HLA-A2-restricted LDHC-derived peptides P2 (LDHC170-180, FRYLIGEKLGV), P5 (LDHC116-124, IMKSIIPAI), and P6 (LDHC172-180, YLIGEKLGV) had high affinity for the HLA-A2 molecule at 50 μg/mL. P6 (LDHC172-180, YLIGEKLGV) elicited the strongest IFN-γ-secreting cytotoxic T lymphocyte (CTL) response and exhibited potent cytotoxicity against HLA-A2-positive cells with high LDHC expression.

CONCLUSIONS

LDHC may serve as a targetable biomarker for peptide-based immunotherapy of LUAD.