Tetramer visualization of gut-homing gluten-specific T cells in the peripheral blood of celiac disease patients

Abstract

Tetramers of MHC-peptide complexes are used for detection and characterization of antigen-specific T cell responses, but they require knowledge about both antigenic peptide and the MHC restriction element. The successful application of these reagents in human diseases involving CD4 ؉ T cells is limited. Celiac disease, an intestinal inflammation driven by mucosal CD4 ؉ T cells recognizing wheat gluten peptides in the context of disease-associated HLA-DQ molecules, is an ideal model to test the potential clinical use of these reagents. We investigated whether gluten-specific T cells can be detected in the peripheral blood of celiac disease patients using DQ2 tetramers. Nine DQ2 ؉ patients and six control individuals on a gluten-free diet were recruited to the study. Participants consumed 160 g of gluten-containing bread daily for 3 days. After bread-challenge, gluten-specific T cells were detectable in the peripheral blood of celiac patients but not controls both directly by tetramer staining and indirectly by enzyme-linked immunospot. These T cells expressed the ␤7 integrin indicative of gut-homing properties. Most of the cells had a memory phenotype, but many other phenotypic markers showed a heterogeneous pattern. Tetramer staining of gluten-specific T cells has the potential to be used for diagnosis of celiac disease. tetramers T he development of multimeric MHC-peptide complexes has revolutionized the analysis of antigen-specific T cell responses. Tetramers are such reagents consisting of four soluble recombinant MHC molecules, each loaded with a single peptide and bound to a streptavidin molecule that is coupled with a fluorogenic marker (1). Multivalent engagement of the MHCpeptide complexes leads to a stable binding of the tetramer to T cell receptors on the T cell surface, allowing direct visualization of T cells with a defined specificity.MHC class I tetramer technology has greatly facilitated our understanding of CD8 ϩ T cell responses in viral infections and cancer (2). The benefit of tetramers for characterization and diagnosis of human autoimmune and infectious diseases has, however, been modest (3-6). This particularly relates to MHC class II tetramers used for the characterization of antigen-specific CD4 ϩ T cells. Only a few studies of relevance to autoimmunity exist (7-9). MHC class II tetramers are more difficult to produce than MCH class I tetramers (10, 11), and CD4 ϩ T cells of a given specificity appear to be present at much lower frequencies than their CD8 ϩ counterparts (12, 13). Several criteria have to be met to be able to detect antigen-reactive T cells with MHC II tetramers: both the peptide epitope and HLA-restriction element have to be identified, and sufficient frequency and relative high avidity of reactive T cells are needed (14).Celiac disease, a chronic inf lammatory disorder of the small intestine precipitated by ingestion of cereal gluten proteins, presents as an ideal model to test the potential clinical use of MHC class II tetramers. The disorder is driven by intestinal glu...

Dietary gluten triggers concomitant activation of CD4 + and CD8 + αβ T cells and γδ T cells in celiac disease

“…S1). This aspect is similar to the absence of gluten-specific CD4 + T cells in peripheral blood of patients with active celiac disease (4,5). Also, although plasma cells secreting anti-gluten and autoantibodies are present in celiac intestinal lesions (17-19), we did not detect a similar increase in intestinal-homing B cells (not shown).…”

“…The mobilization of specific lymphocytes into the peripheral blood 6 d after antigenic challenge, as has been reported in CD (4,5) and in the context of influenza vaccination (52), has provided an invaluable window into antigen-specific responses in human subjects. It will be interesting to see whether other such migrations are occurring at specific times in other autoimmune diseases.…”

“…Reintroducing dietary gluten to celiac patients who are on a gluten-free diet induces large numbers of gluten-specific CD4 + T cells in the peripheral blood 6 d later (4,5,13). These cells express the β7 integrin receptor, indicating that they will home to the intestine (5).…”

“…CD4 + T cells bearing αβ T-cell receptors (TCRs) are critical in the pathogenesis of the disease, as it occurs almost exclusively in HLA-DQ2-or HLA-DQ8-positive individuals (1,2). CD-associated gluten peptide CD4 + T-cell epitopes have been discovered, and HLA-DQ2/8-restricted gluten-reactive CD4 + T cells have been identified in individuals with CD (3)(4)(5). Nonetheless, no gluten-induced enteropathy is seen in humanized mouse models expressing HLA-DQ2 and a gluten-specific TCR (6, 7), suggesting that CD4 + T cells alone are unable to induce tissue damage in CD (1,2).…”

Recurrence of autoreactive antigen-specific CD4+ T cells in autoimmune diabetes after pancreas transplantation

“…MHC tetramers have been used to detect autoreactive antigen-specific CD4+ T cells in human subjects associated with T1D, MS, pemphigus vulgaris, and celiac disease [2,4,6,11,[16][17][18][19]. Because construction of appropriate MHC tetramers requires knowledge both of the HLA restriction element and of a suitable peptide epitope, diseases that have dominant HLA gene associations and dominant autoantigen targets are well suited for application of this technology, whereas other autoimmune disorders with more heterogeneous genetics or antigen targets are less optimal.…”