Abstract 019: T Cell Recognition Of Isolevuglandin-adducted Proteins In Hypertension Is Mhc Class 1-restricted

Abstract

Introduction: Isolevuglandins (isoLGs) are peroxidized lipids that covalently bond lysine residues to modify self-antigens in hypertension. We hypothesized that isoLG-adduction restricts peptide presentation to specific class 1 major histocompatibility complexes (MHC) in mice and humans. Methods and Results: We developed 2 mouse strains expressing either his-tagged class 1 MHC-I H-2D b or H-2K b with truncated membrane binding domains. Shed MHC-I from cultured splenoctyes was adsorbed onto nickel-agarose beads and used to stimulate T cells. We found that CD8+ T cell proliferation is restricted to H-2D b and not H-2K b (Fig 1A) and occurs only if both T-cells and soluble H-2D b are from hypertensive (angiotensin II-treated) mice. Proliferation was blocked if donors received an isoLG-scavenger or by an isoLG specific antibody added during the proliferation assay (Fig 1B). Fluorescence resonance energy transfer (FRET) demonstrated that isoLG-adducts associate with MHC-1 H-2D b and not H-2K b . We transfected HLA-null K562 cells with 18 common human HLA subtypes, and induced isoLG formation with tert-butyl hydroperoxide. Using FRET we identified human HLAs that are high, intermediate and low presenters of isoLG adducts (Fig 1C). Unique modeling software identified candidate peptides and showed that structural characteristics of H-2D b cause lysines at positions 4-7 to project from the MHC groove and present isoLGs (Fig 1D-E). Conclusion: IsoLG adduct presentation is MHC-1 restricted. This may explain differences in the degree of inflammation and end-organ damage observed between populations with hypertension and provides a possible new approach to personalized care.