Lipidomic scanning of self-lipids identifies headless antigens for natural killer T cells

Cheng, Tan-Yun, Praveena, T., Govindarajan, Srinath, Almeida, Catarina F., Pellicci, Daniel G., Arkins, Wellington C., Van Rhijn, Ildiko, Venken, Koen, Elewaut, Dirk, Godfrey, Dale I., Rossjohn, Jamie ORCID: https://orcid.org/0000-0002-2020-7522 and Moody, D. Branch 2024. Lipidomic scanning of self-lipids identifies headless antigens for natural killer T cells. Proceedings of the National Academy of Sciences 121 (34) , e2321686121. 10.1073/pnas.2321686121

Preview

PDF - Published Version Available under License Creative Commons Attribution. Download (1MB) | Preview

Abstract

To broadly measure the spectrum of cellular self-antigens for natural killer T cells (NKT), we developed a sensitive lipidomics system to analyze lipids trapped between CD1d and NKT T cell receptors (TCRs). We captured diverse antigen complexes formed in cells from natural endogenous lipids, with or without inducing endoplasmic reticulum (ER) stress. After separating protein complexes with no, low, or high CD1d–TCR interaction, we eluted lipids to establish the spectrum of self-lipids that facilitate this interaction. Although this unbiased approach identified fifteen molecules, they clustered into only two related groups: previously known phospholipid antigens and unexpected neutral lipid antigens. Mass spectrometry studies identified the neutral lipids as ceramides, deoxyceramides, and diacylglycerols, which can be considered headless lipids because they lack polar headgroups that usually form the TCR epitope. The crystal structure of the TCR–ceramide–CD1d complex showed how the missing headgroup allowed the TCR to predominantly contact CD1d, supporting a model of CD1d autoreactivity. Ceramide and related headless antigens mediated physiological TCR binding affinity, weak NKT cell responses, and tetramer binding to polyclonal human and mouse NKT cells. Ceramide and sphingomyelin are oppositely regulated components of the “sphingomyelin cycle” that are altered during apoptosis, transformation, and ER stress. Thus, the unique molecular link of ceramide to NKT cell response, along with the recent identification of sphingomyelin blockers of NKT cell activation, provide two mutually reinforcing links for NKT cell response to sterile cellular stress conditions.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Medicine
Publisher:	National Academy of Sciences
ISSN:	0027-8424
Date of First Compliant Deposit:	7 March 2025
Date of Acceptance:	12 June 2024
Last Modified:	10 Mar 2025 09:45
URI:	https://orca.cardiff.ac.uk/id/eprint/176728

Actions (repository staff only)

Edit Item