Understanding the constitutive presentation of MHC class I immunopeptidomes in primary tissues.
iScience 2022;
25:103768. [PMID:
35141507 PMCID:
PMC8810409 DOI:
10.1016/j.isci.2022.103768]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 06/15/2021] [Accepted: 01/11/2022] [Indexed: 12/20/2022] Open
Abstract
Understanding the molecular principles that govern the composition of the MHC-I immunopeptidome across different primary tissues is fundamentally important to predict how T cells respond in different contexts in vivo. Here, we performed a global analysis of the MHC-I immunopeptidome from 29 to 19 primary human and mouse tissues, respectively. First, we observed that different HLA-A, HLA-B, and HLA-C allotypes do not contribute evenly to the global composition of the MHC-I immunopeptidome across multiple human tissues. Second, we found that tissue-specific and housekeeping MHC-I peptides share very distinct properties. Third, we discovered that proteins that are evolutionarily hyperconserved represent the primary source of the MHC-I immunopeptidome at the organism-wide scale. Fourth, we uncovered new components of the antigen processing and presentation network, including the carboxypeptidases CPE, CNDP1/2, and CPVL. Together, this study opens up new avenues toward a system-wide understanding of antigen presentation in vivo across mammalian species.
Tissue-specific and housekeeping MHC class I peptides share distinct properties
HLA-A, HLA-B, and HLA-C allotypes contribute very unevenly to the pool of class I peptides
MHC-I immunopeptidomes are represented by evolutionarily conserved proteins
An extended antigen processing and presentation pathway is uncovered
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