T Cell Cross-Reactivity between a Highly Immunogenic EBV Epitope and a Self-Peptide Naturally Presented by HLA-B*18:01+ Cells.Rist, M.J., Hibbert, K.M., Croft, N.P., Smith, C., Neller, M.A., Burrows, J.M., Miles, J.J., Purcell, A.W., Rossjohn, J., Gras, S., Burrows, S.R.
(2015) J Immunol 194: 4668-4675
- PubMed: 25855358
- DOI: https://doi.org/10.4049/jimmunol.1500233
- Primary Citation of Related Structures:
- PubMed Abstract:
T cell cross-reactivity underpins the molecular mimicry hypothesis in which microbial peptides sharing structural features with host peptides stimulate T cells that cross-react with self-peptides, thereby initiating and/or perpetuating autoimmune disease. EBV represents a potentially important factor in the pathogenesis of several T cell-mediated autoimmune disorders, with molecular mimicry a likely mechanism. In this study, we describe a human self-peptide (DELEIKAY) that is a homolog of a highly immunogenic EBV T cell epitope (SELEIKRY) presented by HLA-B*18:01. This self-peptide was shown to bind stably to HLA-B*18:01, and peptide elution/mass spectrometric studies showed it is naturally presented by this HLA molecule on the surface of human cells. A significant proportion of CD8(+) T cells raised from some healthy individuals against this EBV epitope cross-reacted with the self-peptide. A diverse array of TCRs was expressed by the cross-reactive T cells, with variable functional avidity for the self-peptide, including some T cells that appeared to avoid autoreactivity by a narrow margin, with only 10-fold more of the self-peptide required for equivalent activation as compared with the EBV peptide. Structural studies revealed that the self-peptide-HLA-B*18:01 complex is a structural mimic of the EBV peptide-HLA-B*18:01 complex, and that the strong antiviral T cell response is primarily dependent on the alanine/arginine mismatch at position 7. To our knowledge, this is the first report confirming the natural presentation of a self-peptide cross-recognized in the context of self-HLA by EBV-reactive CD8(+) T cells. These results illustrate how aberrant immune responses and immunopathological diseases could be generated by EBV infection.
QIMR Berghofer Medical Research Institute, Brisbane, Queensland 4029, Australia; School of Medicine, University of Queensland, Brisbane, Queensland 4072, Australia; Institute of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, United Kingdom.