RT Journal Article SR Electronic T1 Residue substitution enhances the immunogenicity of neoepitopes from gastric cancers JF Cancer Biology & Medicine JO Cancer Biol Med FD China Anti-Cancer Association SP 1053 OP 1065 DO 10.20892/j.issn.2095-3941.2021.0022 VO 18 IS 4 A1 Huahui Yu A1 Jieyu Li A1 Yuan Yuan A1 Yu Chen A1 Jingwen Hong A1 Chunmei Ye A1 Wansong Lin A1 Huijing Chen A1 Zengqing Guo A1 Bo Li A1 Yunbin Ye YR 2021 UL http://www.cancerbiomed.org/content/18/4/1053.abstract AB Objective: Neoantigens arising from gene mutations in tumors can induce specific immune responses, and neoantigen-based immunotherapies have been tested in clinical trials. Here, we characterized the efficacy of altered neoepitopes in improving immunogenicity against gastric cancer.Methods: Raw data of whole-exome sequencing derived from a patient with gastric cancer were analyzed using bioinformatics methods to identify neoepitopes. Neoepitopes were modified by P1Y (the first amino acid was replaced by tyrosine) and P2L (the second amino acid was replaced by leucine). T2 binding and stability assays were used to detect the affinities between the neoepitopes and the HLA molecules, as well as the stabilities of complexes. Dendritic cells (DCs) presented with neoepitopes stimulated naïve CD8+ T cells to induce specific cytotoxic T lymphocytes. ELISA and carboxyfluorescein succinimidyl ester were used to detect IFN-γ and TNF-α levels, and T cell proliferation. Perforin was detected by flow cytometry. The cytotoxicity of T cells was determined using the lactate dehydrogenase assay.Results: Bioinformatics analysis, T2 binding, and stability assays indicated that residue substitution increased the affinity between neoepitopes and HLA molecules, as well as the stabilities of complexes. DCs presented with altered neoepitopes stimulated CD8+T cells to release more IFN-γ and had a greater effect on promoting proliferation than wild-type neoepitopes. CD8+T cells stimulated with altered neoepitopes killed more wild-type neoepitope-pulsed T2 cells than those stimulated with wild-type neoepitopes, by secreting more IFN-γ, TNF-α, and perforin.Conclusions: Altered neoepitopes exhibited greater immunogenicity than wild-type neoepitopes. Residue substitution could be used as a new strategy for immunotherapy to target neoantigens.