Memory T cells specific to citrullinated α-enolase are enriched in the rheumatic joint.

Memory T cells specific to citrullinated α-enolase are enriched in the rheumatic joint. J Autoimmun. 2018 May 28;: Authors: Pieper J, Dubnovitsky A, Gerstner C, James EA, Rieck M, Kozhukh G, Tandre K, Pellegrino S, Gebe JA, Rönnblom L, Sandalova T, Kwok WW, Klareskog L, Buckner JH, Achour A, Malmström V Abstract ACPA-positive rheumatoid arthritis (RA) is associated with distinct HLA-DR alleles and immune responses to many citrullinated self-antigens. Herein we investigated the T cell epitope confined within α-enolase326-340 in the context of HLA-DRB1*04:01 and assessed the corresponding CD4+ T cells in both the circulation and in the rheumatic joint. Comparative crystallographic analyses were performed for the native and citrullinated α-enolase326-340 peptides in complex with HLA-DRB1*04:01. HLA-tetramers assembled with either the native or citrullinated peptide were used for ex vivo and in vitro assessment of α-enolase-specific T cells in peripheral blood, synovial fluid and synovial tissue by flow cytometry. The native and modified peptides take a completely conserved structural conformation within the peptide-binding cleft of HLA-DRB1*04:01. The citrulline residue-327 was located N-terminally, protruding towards TCRs. The frequencies of T cells recognizing native eno326-340 were similar in synovial fluid and peripheral blood, while in contrast, the frequency of T cells recognizing cit-eno326-340 was significantly elevated ...
Source: Journal of Autoimmunity - Category: Allergy & Immunology Authors: Tags: J Autoimmun Source Type: research