Structural determination of lipid antigens captured at the CD1d-T-cell receptor interface

Research output: Contribution to journalArticle

Authors

  • Patrick J Brennan
  • Tan-Yun Cheng
  • Daniel G Pellicci
  • Gerald F M Watts
  • David C Young
  • Jamie Rossjohn
  • Dale I Godfrey
  • Michael B Brenner
  • D Branch Moody

Colleges, School and Institutes

Abstract

Glycolipid antigens recognized by αβ T-cell receptors (TCRs) drive the activation of invariant natural killer T (iNKT) cells, a specialized subset of innate T lymphocytes. Glycolipids with α-linked anomeric carbohydrates have been identified as potent microbial lipid antigens for iNKT cells, and their unusual α-anomeric linkage has been thought to define a "foreign" lipid antigen motif. However, mammals use endogenous lipids to select iNKT cells, and there is compelling evidence for iNKT cell responses in various types of sterile inflammation. The nature of endogenous or environmental lipid antigens encountered by iNKT cells is not well defined. Here, we sought to identify lipid antigens in cow's milk, a prominent part of the human diet. We developed a method to directly capture lipid antigens within CD1d-lipid-TCR complexes, while excluding CD1d bound to nonantigenic lipids, followed by direct biochemical analysis of the lipid antigens trapped at the TCR-CD1d interface. The specific antigens captured by this "TCR trap" method were identified as α-linked monohexosylceramides by mass spectrometry fragmentation patterns that distinguished α- from β-anomeric monohexosylceramides. These data provide direct biochemical evidence for α-linked lipid antigens from a common dietary source.

Details

Original languageEnglish
JournalNational Academy of Sciences. Proceedings
Early online date17 Jul 2017
Publication statusE-pub ahead of print - 17 Jul 2017

Keywords

  • NKT, iNKT, lipid antigen, CD1d, glycolipid