0000000000476610
AUTHOR
Monika Arenz
Autoreactive CD4+ LKM-specific and anticlonotypic T-cell responses in LKM-1 antibody-positive autoimmune hepatitis
Peripheral blood mononuclear cells (PBMC) of patients with autoimmune hepatitis (AIH) and controls were studied for their proliferative response to six overlapping synthetic peptides covering the 33-amino acid immunodominant region of cytochrome P450IID6, the main target antigen of LKM-1 antibody-positive type II AIH. PBMC from 8 of 8 type II AIH patients (100%), 6 of 12 LKM-1 antibody-negative type I AIH patients (50%), but only 4 of 31 patients with chronic hepatitis C (12.9%) reacted with a 23-amino acid LKM peptide and mainly with a shorter 18-amino acid LKM peptide. Follow-up showed that LKM-specific T-cell responses decreased after immunosuppression had started. Fine specificity, HLA …
Limited T cell receptor Vbeta-chain repertoire of liver-infiltrating T cells in autoimmune hepatitis.
Abstract Background/Aims: To characterize the cellular immune reactions in autoimmune hepatitis, the T cell receptor repertoire of livre-infiltrating and circulating T cells was studied. Methods: Nucleic acids of liver-tissue and peripheral blood-derived T cells from 12 patients with untreated autoimmune hepatitis, four patients with chronic hepatitis C and three patients with toxic liver injury were extracted and analysed using a semiquantitative RT-PCR with a panel of T cell receptor Vβ family specific primers. After agarose gel electrophoresis, the distribution of T cell receptor (TCR) Vβ molecules was assessed by densitometry. Furthermore, results were compared to the TCR Vβ distributio…
The viral clearance in interferon-treated chronic hepatitis C is associated with increased cytotoxic T cell frequencies
Abstract Background/Aims: Cytotoxic T lymphocytes have been demonstrated in peripheral blood and liver tissue of patients with chronic hepatitis C virus infection, but their significance for viral clearance is unknown. Therefore, we analyzed hepatitis C virus-specific cytotoxic T lymphocyte precursor frequencies in chronic hepatitis C virus carriers during interferon-α treatment. Methods: Blood mononuclear cells or CD8+ T cells from HLA-A2 positive and negative patients and controls were analyzed in chromium-release assays using a panel of 18 synthetic peptides from the HCV core, E1 and NS4 antigens bearing HLA-A2 binding motifs. Specific cytotoxic T lymphocyte precursor frequencies were st…
Pyruvate dehydrogenase specific T cells in primary biliary cirrhosis show restricted antigen recognition sites
: Background/Aims: The aim was to characterise the antigen recognition sites of the variable T cell receptor α-chain (TCRAV) and β-chain (TCRBV) of T cells specific to the pyruvate dehydrogenase (PDC) in primary biliary cirrhosis. Methods: In 21 PDC-specific T cell clones isolated from five patients we analysed TCRAV and TCRBV usage by RT-PCR and sequenced the CDR3 regions. Results: Preferential expression of the TCR elements BV6 (6 clones), BV12 (4 clones) and BV1 (3 clones), and frequent usage of the joining elements JB2.3 and JB2.1 were seen. Analysis of the α chain revealed rearrangement of AV2 in 7 clones (35%) and AV7 in 3 clones, however, distribution of the joining elements was het…
Antigen-independent in vitro expansion of T cells does not affect the T cell receptor V beta repertoire.
Analysis of the variable chains (V alpha/V beta) of the specific T cell receptor (TCR) of organ-infiltrating T cells may provide further insights into the pathogenesis of many infectious diseases, malignancies, and autoimmune disorders. To determine the TCR V beta repertoire of these small T cell populations antigen-independent in vitro expansion is necessary but may select for certain T cell subpopulations. In this study various antigen independent T cell activation protocols were used to stimulate peripheral blood mononuclear cells (PBMC) of six healthy blood donors, and TCR V beta molecules were analyzed by flow cytometry and semiquantitative reverse-transcriptase polymerase chain reacti…
T cell receptor Vβ chain restriction and preferred CDR3 motifs of liver-kidney microsomal antigen (LKM-1)-reactive T cells from autoimmune hepatitis patients
Aims/Background : The liver-kidney-microsomal antigen (LKM-1) has been recognized as a major CD4 + T cell antigen in autoimmune hepatitis (AIH). The aim of this study was to characterize the antigen recognition sites of the variable T cell receptor β-chain (TCRBV) of T cells specific to LKM-1. Methods: By repeated stimulation of T cells with a recombinant LKM-1 antigen or an LKM-derived peptide followed by limited dilution, we generated T cell clones. Usage of TCRBV was analyzed by RT-PCR and CDR3 antigen recognition sites were sequenced. Results: The 18 LKM-1 specific T cell clones isolated from six AIH patients preferentially expressed the TCR elements BV9, BV5S2+S3, BV6, and BV13S1. Four…