Immune surveillance for ERAAP dysfunction

Niranjana A. Nagarajan, Nilabh Shastri

Research output: Contribution to journalReview article

Abstract

The ER aminopeptidase associated with antigen processing, ERAAP (or ERAP1), is essential for trimming peptides that are presented by MHC class I molecules. ERAP1 is inhibited by human cytomegalovirus, and ERAP1 polymorphisms are associated with autoimmune diseases. How the immune system detects ERAAP dysfunction, however, is unknown. We have shown previously that ERAAP-deficient cells present an immunogenic pMHC I repertoire, that elicits CD8+ T cell response in WT mice. Additionally, we discovered that the WT CD8+ T cells recognized novel peptides presented by non-classical, or MHC class Ib, molecules on ERAAP-deficient cells. The MHC Ib restricted WT CD8 T cells eliminated ERAAP-deficient cells in vitro and in vivo. We identified the FL9 peptide, presented by Qa-1b, a MHC class Ib molecule exclusively on ERAAP-deficient cells. Remarkably, T cells specific for the FL9-Qa-1b complex were frequent in naïve WT mice, and had an antigen-experienced phenotype. Thus, novel non-classical pQa-1b complexes direct cytotoxic T cells to target cells with defective peptide processing in the endoplasmic reticulum. Here, we discuss the implications of our findings, and the possible roles of pMHC Ib-specific T cells in immune surveillance for ERAAP dysfunction.

Original languageEnglish (US)
Pages (from-to)120-122
Number of pages3
JournalMolecular Immunology
Volume55
Issue number2
DOIs
StatePublished - Sep 1 2013
Externally publishedYes

Keywords

  • Antigen processing
  • CD8+ T cells
  • Immune surveillance
  • MHC class I

ASJC Scopus subject areas

  • Immunology
  • Molecular Biology

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