T cell receptor usage in autoimmune disease

T cell receptor gene usage of BP180-specific T lymphocytes from patients with bullous pemphigoid and pemphigoid gestationis

BP180 is the autoantigen of different immunobullous diseases, including bullous pemphigoid (BP) and pemphigoid gestationis (PG). Previously, we demonstrated that the NC16A domain of this autoantigen harbors key epitopes of autoantibodies and T cells, indicating that it plays an essential role in the pathogenesis of diseases. Moreover, NC16A-specific T cell clones derived from these patients were shown to express a CD4+ memory T cell phenotype and secrete cytokines that may promote autoantibody production. In this study, we further characterize the properties of these T cells by analyzing their epitope specificity and T cell receptor (TCR) gene usage. We discovered that 83% of T cell clones obtained from BP patients preferentially express TCRBV13, while clones derived from a PG patient express the TCRBV3 gene. However, no preferential TCRBJ gene usage was identified. In conclusion, our results provide an advanced understanding of the characteristics of autoimmune T cells in immunobullous diseases.

T cell receptor gene usage in desmoglein-3-specific T lymphocytes from patients with pemphigus vulgaris

Pemphigus vulgaris (PV) is an autoimmune disease mediated by autoantibodies against desmoglein-3 (Dsg3). It has been documented that both humoral and cellular autoimmunity play essential roles in the development of PV. Recently, we identified that T cells from PV patients respond to three antigenic fragments on the ectodomain of Dsg3. These T cells are CD4 alpha/beta cells secreting a Th2-like cytokine profile, and responding of Dsg3 in a restriction to HLA-DRBI*0402 or 1401 alleles. Other characteristics of these cells, such as detailed epitope(s) and T cell receptors (TCRs) usage, however, have not been investigated. The purpose of this study is to determine detailed T cell epitope(s) and TCR genes utilized by Dsg3-specific T cells. Here, we found that Dsg3(AA145-192)-specific cells preferentially utilize the TCRVbeta13 gene, while Dsg3(AA240-303)- and Dsg3 (AA570-614)-specific cells utilize Vbeta7 and Vbeta17 genes, respectively. Analysis of TCRValpha gene expression, it appears that Valpha22 gene is expressed by Dsg3(AA145-192)-specific cells, whereas the Valpha10 gene is predominantly utilized by Dsg3(AA240-303)-specific T cells. There are no specific utilization of Valpha gene in the group of cells proliferate to Dsg3 (AA570-614). We believe that this information will further our understanding of the properties of autoimmune T cells in patients with PV.

Conserved TCR beta chain usage in reactive arthritis; evidence for selection by a putative HLA-B27-associated autoantigen

Previous work suggested that expanded CD8+ T-cell clones in the synovial fluid (SF) of HLA-B27+ patients with reactive arthritis (ReA) preferentially use the T-cell receptor variable region (TCRBV) 1, similar CDR3 sequences, and joining region (BJ) 2S3. To determine the range of conservation and disease-specificity of CDR3-sequences, we analyzed the TCRBV1-J2S3 repertoire from 33 healthy HLA-B27+ individuals, patients with various types of spondyloarthropathies (SpA), and with rheumatoid arthritis (RA) by CDR3-spectratyping. After collection and database submission of all available TCRB-CDR3 from HLA-B27-restricted or SpA-derived T cells, we systematically screened the entire human sequence database for sequences similar to the B27/SpA-related CDR3. Spectratyping revealed expanded T cell clones using conserved TCRBV1J2S3 in the SF from 5/6 of the patients with acute ReA but not among the controls. In database searches, 50 HLA-B27 or SpA-related CDR3-sequences generated similar clusters of matched sequences, and matched reciprocally. Identical or closely related sequences were identified in 15 different individuals and a canonical ReA-associated TCRB was defined [BV1-CASSVG(V/I/L)(Y/F)STDTQYF-J2S3]. All but one patient-derived conserved sequences originated from acute stage ReA-patients, and were not present among approximately 3800 other human TCRB sequences in the database. Five of the conserved sequences originated from T cell clones that recognized uninfected cells in an HLA-B27-restricted fashion, implying a role of HLA-B27-restricted CD8+ T cells specific for a ubiquitous self- or cross-reactive microbial determinant in the early phase of ReA. Related sequences were independently identified in four different laboratories. The consensus TCRB motif could be a helpful diagnostic marker in HLA-B27-associated 'undifferentiated arthritis'.