In vitro proteasome processing of neo-splicetopes does not predict their presentation in vivo.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 33875134.
- Also identified by DOI 10.7554/eLife.62019 and PMC identifier 8154032.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Proteasome-catalyzed peptide splicing (PCPS) of cancer-driving antigens could generate attractive neoepitopes to be targeted by T cell receptor (TCR)-based adoptive T cell therapy. Based on a spliced peptide prediction algorithm, TCRs were generated against putative KRAS<sup>G12V</sup>- and RAC2<sup>P29L</sup>-derived neo-splicetopes with high HLA-A*02:01 binding affinity. TCRs generated in mice with a diverse human TCR repertoire specifically recognized the respective target peptides with high efficacy. However, we failed to detect any neo-splicetope-specific T cell response when testing the in vivo neo-splicetope generation and obtained no experimental evidence that the putative KRAS<sup>G12V</sup>- and RAC2<sup>P29L</sup>-derived neo-splicetopes were naturally processed and presented. Furthermore, only the putative RAC2<sup>P29L</sup>-derived neo-splicetopes was generated by in vitro PCPS. The experiments pose severe questions on the notion that available algorithms or the in vitro PCPS reaction reliably simulate in vivo splicing and argue against the general applicability of an algorithm-driven 'reverse immunology' pipeline for the identification of cancer-specific neo-splicetopes.
Medical subject headings
- Antigens, Neoplasm
- CD8-Positive T-Lymphocytes
- Epitopes
- Neoplasms
- Proteasome Endopeptidase Complex
- Protein Processing, Post-Translational
- Proto-Oncogene Proteins p21(ras)
- Receptors, Antigen, T-Cell
- rac GTP-Binding Proteins