Multifunctional T cell reactivity with native and glycosylated type II collagen in rheumatoid arthritis

Abstract

Objective Type II collagen (CII) is a cartilage-specific protein to which a loss of immune tolerance may trigger autoimmune reactions and cause arthritis. The major T cell epitope on CII, aa259-273, can be presented by several HLA-DRB1*04 alleles in its native or posttranslational-glycosylated form. Here, we aimed to functionally explore and compare CII-autoreactive T cells from blood and synovial fluid of patients with rheumatoid arthritis (RA). Methods Peripheral blood were obtained from HLA-DRB1*04 RA and control subjects (n=10 each), then stimulated in vitro with several variants of the CII259-273 epitope: (a) unmodified, or glycosylated on (b) lysine-264, (c) lysine-270, or (d) both lysine-264 and 270. Upregulation of CD154 was used to identify responding T cells. These cells were further characterized by intracellular staining for IL-17, IFNγ and IL-2 by flow cytometry. For RA patients, synovial T cells were investigated in parallel. Results Multifunctional T cell responses towards all examined variants of the CII259-273 peptide could be detected in RA patients and to a lesser extent also in healthy HLA-matched individuals (p<0.001). In RA, a comparison between blood and joint-derived T cell function revealed a significant increase of the proinflammatory cytokine IFNγ (p=0.027) in synovial T cells. Studies of longitudinal samples show that T cell responses were sustained over the course of disease, and even included epitope spreading. Conclusions The identification of inflammatory T cell responses to both glycosylated and non-glycosylated variants of the major CII epitope in RA patients suggests that CII autoreactivity may be more common than previously appreciated.

Pathogenesis and prevention of rheumatic disease: focus on preclinical RA and SLE

“…92 Furthermore, the presence of anti-carbamylated antibodies has been detected in serum samples collected before the onset of RA, 93 and emerging data in patients with established RA suggests that neutrophil extracellular trap (NET) formation are a source of citrullinated autoantigens in RA. 94 In addition, although emerging data is available regarding T-cell reactivity to specific citrullinated proteins and other antigens in patients with established RA, 95,96 no studies to date have directly evaluated the antigen specificity of T-cell and/or B-cell subsets during the preclinical stage of RA and compared this with the ACPA responses. Hope fully, well-designed prospective studies that methodically isolate and analyse peripheral blood mononuclear cells, including utilization of emerging technologies such as single-cell analyses that can identify antigen reactivity of specific immune cells, 97 will address this important question in the near future.…”

Immunological evaluation of rheumatoid arthritis patients treated with itolizumab

“…12 Previous reports have shown high numbers of activated CD4+ T cells in the inflamed joint. 13,14 Once activated, T lymphocytes stimulate macrophages and fibroblasts to secrete proinflammatory cytokines such as tumor necrosis factor (TNF), interleukin (IL)-1 and IL-6, as well as IL-17 and interferon (IFN)-g, 12,15 which constitute the key soluble factors in the inflammatory process of RA. However, no differences have been observed in IL-10 levels when RA patients are compared with healthy individuals.…”

Comparative analysis of collagen type II-specific immune responses during development of collagen-induced arthritis in two B10 mouse strains

“…The T cell responses in RA patients carrying HLA-DRB*04 alleles show a diverse pattern of CII259-273 epitope recognition, that is, toward both non-modified and glycosylated CII259-273; only few patients exclusively responded to K264 but most of them to GalOK264 [5,6]. A longitudinal analysis of CII-specific T cell responses showed a consistent reactivity but variable magnitude and specificity of the response over time [6].…”

“…We have identified a T cell immunodominant epitope from collagen type II (CII259-273) that plays a major role in CIA development in mice with H-2 q haplotype [10]. Subsequently, it was shown that this epitope also binds to human DR4 and DR1 molecules, associated with RA [11,12] and immunity to CII259-273 was detected also in RA patients [5,6,13]. Interestingly, the CII259-273 epitope could be posttranslationally modified (at position 264 and 270) by lysine hydroxylation and glycosylation.…”