Abstract: Objectives To explore the possibility to utilize unrelated donors' cells as sources for adoptive T cell anti-tumor therapy, thus we need to identify HLA restriction for neoantigens and evaluate neoantigen induced reactive T cells' cytolysis ability. Methods 16 neoantigen peptides were used to induce 18 unrelated donors' (group 1) PBMC (peripheral blood mononuclear cells) into reactive T cells, and HLA typing was performed, the affinity between peptides' and HLA molecule was predicted by NetMHC database, then neoantigen with HLA-A2 restriction was selected to induce another group (group 2) of 17 unrelated donors' PBMC into reactive T cells, these cells would act as effectors, tumor cell line T2 cells or the tumor cells with the same source of this neoantigen would act as targets either, LDH release tests and RTCA (real time celluar analysis) were performed to evaluate the effectors' anti-tumor ability. Then these results were compared between HLA-A2+ and HLA-A2- samples. Results NetMHC database predicted neoantigen LM7 showed high affinity with HLA-A2+ antigens, 5/11 of HLA-A2+ samples can successfully be induced into reactive T cells, including 3/3 homozygous HLA-A2+ samples, while 2/7 of HLA-A2- samples with more reactive T cells. Induced T cells from A2+ samples showed higher percentages of tumor cells killed than those A2- samples(60.72±11.28 vs 47.2± 4.46, P=0.03). Conclusions Our study suggests prediction by NetMHC is more helpful in homozygous samples, neoantigens LM7 is confirmed as HLA-A2 restrictive, which can induce some HLA-A2+ PBMC into reactive T cells which can kill tumor cells more efficiently, unrelated donors should be screened not only by HLA-typing but also cell function tested, thus induced reactive T cells can take the roles as the source for adoptive anti-tumor T cells therapy.

Key words: HLA restriction, Neoantigen, Reactive T cell, Adoptive T cell therapy