Characterization of Proteasome-Generated Spliced Peptides Detected by Mass Spectrometry.
J Immunol
; 208(12): 2856-2865, 2022 06 15.
Article
en En
| MEDLINE
| ID: mdl-35623660
ABSTRACT
CD8+ T cells recognize peptides displayed by HLA class I molecules and monitor intracellular peptide pools. It is known that the proteasome splices two short peptide fragments. Recent studies using mass spectrometry (MS) and bioinformatics analysis have suggested that proteasome-generated spliced peptides (PSPs) may account for a substantial proportion of HLA class I ligands. However, the authenticity of the PSPs identified using bioinformatics approaches remain ambiguous. In this study, we employed MS-based de novo sequencing to directly capture cryptic HLA ligands that were not templated in the genome. We identified two PSPs originating from the same protein in a human colorectal cancer line with microsatellite instability. Healthy donor-derived CD8+ T cells readily responded to the two PSPs, showing their natural HLA presentation and antigenicity. Experiments using minigene constructs demonstrated proteasome-dependent processing of two PSPs generated by standard and reverse cis splicing, respectively. Our results suggest a broader diversity of HLA class I Ag repertoires generated by proteasomal splicing, supporting the advantage of MS-based approaches for the comprehensive identification of PSPs.
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Linfocitos T CD8-positivos
/
Complejo de la Endopetidasa Proteasomal
Límite:
Humans
Idioma:
En
Revista:
J Immunol
Año:
2022
Tipo del documento:
Article
País de afiliación:
Japón