HLA A*24:02–restricted T cell receptors cross-recognize bacterial and preproinsulin peptides in type 1 diabetes
Garry Dolton, … , Pierre J. Rizkallah, Andrew K. Sewell
Garry Dolton, … , Pierre J. Rizkallah, Andrew K. Sewell
Published September 17, 2024
Citation Information: J Clin Invest. 2024;134(18):e164535. https://doi.org/10.1172/JCI164535.
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Research Article Autoimmunity Immunology

HLA A*24:02–restricted T cell receptors cross-recognize bacterial and preproinsulin peptides in type 1 diabetes

Abstract

CD8+ T cells destroy insulin-producing pancreatic β cells in type 1 diabetes through HLA class I–restricted presentation of self-antigens. Combinatorial peptide library screening was used to produce a preferred peptide recognition landscape for a patient-derived T cell receptor (TCR) that recognized the preproinsulin-derived (PPI-derived) peptide sequence LWMRLLPLL in the context of disease risk allele HLA A*24:02. Data were used to generate a strong superagonist peptide, enabling production of an autoimmune HLA A*24:02–peptide–TCR structure by crystal seeding. TCR binding to the PPI epitope was strongly focused on peptide residues Arg4 and Leu5, with more flexibility at other positions, allowing the TCR to strongly engage many peptides derived from pathogenic bacteria. We confirmed an epitope from Klebsiella that was recognized by PPI-reactive T cells from 3 of 3 HLA A*24:02+ patients. Remarkably, the same epitope selected T cells from 7 of 8 HLA A*24+ healthy donors that cross-reacted with PPI, leading to recognition and killing of HLA A*24:02+ cells expressing PPI. These data provide a mechanism by which molecular mimicry between pathogen and self-antigens could have resulted in the breaking of self-tolerance to initiate disease.

Authors

Garry Dolton, Anna Bulek, Aaron Wall, Hannah Thomas, Jade R. Hopkins, Cristina Rius, Sarah A.E. Galloway, Thomas Whalley, Li Rong Tan, Théo Morin, Nader Omidvar, Anna Fuller, Katie Topley, Md Samiul Hasan, Shikha Jain, Nirupa D’Souza, Thomas Hodges-Hoyland, the TIRID Consortium, Owen B. Spiller, Deborah Kronenberg-Versteeg, Barbara Szomolay, Hugo A. van den Berg, Lucy C. Jones, Mark Peakman, David K. Cole, Pierre J. Rizkallah, Andrew K. Sewell

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Figure 5

K. oxytoca peptides are real epitopes and prime PPI-reactive T cells from a healthy donor.

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K. oxytoca peptides are real epitopes and prime PPI-reactive T cells fr...
(A) Genes encoding enterochelin esterase (also known as DUF3327 containing protein) (gene: fes) or glutathione ABC transporter ATP-binding protein (gene: gsiA) from K. oxytoca were expressed in C1R cells (with or without HLA A*24:02) using lentivirus, then used in overnight activation assays with PPI LWMRLLPLL peptide–reactive CD8+ T cell clone 4C6. Irrelevant protein IMP2 (gene: IGF2BP2) was used as a negative control. Peptides (10–5 M) RYPRLFGIV from enterochelin esterase and SLPRLFPLL from glutathione ABC transporter ATP-binding protein were used as positive controls. Supernatants used for MIP-1β and TNF ELISA. Error bars represent standard deviation of triplicate conditions. (B) Purified CD8+ T cells from an HLA A*24+ healthy donor (BB51) were primed with K. oxytoca (Kleb) SLPRLFPLL or PPI LWMRLLPLL peptides at 10–5 M. Unprimed T cells were cultured without peptide. The lines were stained with HLA A*24:02–irrelevant (AYAAAAAAL), Kleb SLPRLFPLL, and PPI tetramers. Percentages are for viable CD3+ tetramer+ cells.