Alterations in the HLA-B57:01 Immunopeptidome by Flucloxacillin and Immunogenicity of Drug-Haptenated Peptides

• Published in: Frontiers in immunology 2021-02, Vol.11, p.629399
• Main Authors: Puig, Montserrat, Ananthula, Suryatheja, Venna, Ramesh, Kumar Polumuri, Swamy, Mattson, Elliot, Walker, Lacey M, Cardone, Marco, Takahashi, Mayumi, Su, Shan, Boyd, Lisa F, Natarajan, Kannan, Abdoulaeva, Galina, Wu, Wells W, Roderiquez, Gregory, Hildebrand, William H, Beaucage, Serge L, Li, Zhihua, Margulies, David H, Norcross, Michael A
• Format: Article
• Language: English
• Subjects: drug hypersensitivity; flucloxacillin; hapten; HLA-B57:01; immunogenicity; Immunology; transgenic mice
• ISSN: 1664-3224; 1664-3224
• DOI: 10.3389/fimmu.2020.629399

Neoantigen formation due to the interaction of drug molecules with human leukocyte antigen (HLA)-peptide complexes can lead to severe hypersensitivity reactions. Flucloxacillin (FLX), a β-lactam antibiotic for narrow-spectrum gram-positive bacterial infections, has been associated with severe immune-mediated drug-induced liver injury caused by an influx of T-lymphocytes targeting liver cells potentially recognizing drug-haptenated peptides in the context of HLA-B*57:01. To identify immunopeptidome changes that could lead to drug-driven immunogenicity, we used mass spectrometry to characterize the proteome and immunopeptidome of B-lymphoblastoid cells solely expressing HLA-B*57:01 as MHC-I molecules. Selected drug-conjugated peptides identified in these cells were synthesized and tested for their immunogenicity in HLA-B*57:01-transgenic mice. T cell responses were evaluated by immune assays. The immunopeptidome of FLX-treated cells was more diverse than that of untreated cells, enriched with peptides containing carboxy-terminal tryptophan and FLX-haptenated lysine residues on peptides. Selected FLX-modified peptides with drug on P4 and P6 induced drug-specific CD8 T cells . FLX was also found directly linked to the HLA K146 that could interfere with KIR-3DL or peptide interactions. These studies identify a novel effect of antibiotics to alter anchor residue frequencies in HLA-presented peptides which may impact drug-induced inflammation. Covalent FLX-modified lysines on peptides mapped drug-specific immunogenicity primarily at P4 and P6 suggesting these peptide sites as drivers of off-target adverse reactions mediated by FLX. FLX modifications on HLA-B*57:01-exposed lysines may also impact interactions with KIR or TCR and subsequent NK and T cell function.