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Transgenic antigen-specific, HLA-A*02:01-allo-restricted cytotoxic T cells recognize tumor-associated target antigen STEAP1 with high specificity

Item Type:Article
Title:Transgenic antigen-specific, HLA-A*02:01-allo-restricted cytotoxic T cells recognize tumor-associated target antigen STEAP1 with high specificity
Creators Name:Schirmer, D. and Grünewald, T.G.P. and Klar, R. and Schmidt, O. and Wohlleber, D. and Rubio, R.A. and Uckert, W. and Thiel, U. and Bohne, F. and Busch, D.H. and Krackhardt, A.M. and Burdach, S. and Richter, G.H.S.
Abstract:Pediatric cancers, including Ewing sarcoma (ES), are only weakly immunogenic and the tumor-patients' immune system often is devoid of effector T cells for tumor elimination. Based on expression profiling technology, targetable tumor-associated antigens (TAA) are identified and exploited for engineered T-cell therapy. Here, the specific recognition and lytic potential of transgenic allo-restricted CD8(+) T cells, directed against the ES-associated antigen 6-transmembrane epithelial antigen of the prostate 1 (STEAP1), was examined. Following repetitive STEAP1(130) peptide-driven stimulations with HLA-A*02:01(+) dendritic cells (DC), allo-restricted HLA-A*02:01(-) CD8(+) T cells were sorted with HLA-A*02:01/peptide multimers and expanded by limiting dilution. After functional analysis of suitable T cell clones via ELISpot, flow cytometry and xCELLigence assay, T cell receptors' (TCR) {alpha}- and {beta}-chains were identified, cloned into retroviral vectors, codon optimized, transfected into HLA-A*02:01(-) primary T cell populations and tested again for specificity and lytic capacity in vitro and in a Rag2(-/-){gamma}c(-/-) mouse model. Initially generated transgenic T cells specifically recognized STEAP1(130)-pulsed or transfected cells in the context of HLA-A*02:01 with minimal cross-reactivity as determined by specific interferon-{gamma} (IFN{gamma}) release, lysed cells and inhibited growth of HLA-A*02:01(+) ES lines more effectively than HLA-A*02:01(-) ES lines. In vivo tumor growth was inhibited more effectively with transgenic STEAP1(130)-specific T cells than with unspecific T cells. Our results identify TCRs capable of recognizing and inhibiting growth of STEAP1-expressing HLA-A*02:01(+) ES cells in vitro and in vivo in a highly restricted manner. As STEAP1 is overexpressed in a wide variety of cancers, we anticipate these STEAP1-specific TCRs to be potentially useful for immunotherapy of other STEAP1-expressing tumors.
Keywords:Allo-Restricted T Cells, Ewing Sarcoma, STEAP1, TCR-Transgenic T Cells
Publisher:Taylor & Francis
Page Range:e1175795
Date:25 April 2016
Official Publication:https://doi.org/10.1080/2162402X.2016.1175795
PubMed:View item in PubMed

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