Clonal analysis of SepSecS-specific B and T cells in autoimmune hepatitis
Michael Kramer, … , Benedetta Terziroli Beretta-Piccoli, Federica Sallusto
Michael Kramer, … , Benedetta Terziroli Beretta-Piccoli, Federica Sallusto
Published January 16, 2025
Citation Information: J Clin Invest. 2025;135(2):e183776. https://doi.org/10.1172/JCI183776.
View: Text | PDF
Research Article Autoimmunity Immunology

Clonal analysis of SepSecS-specific B and T cells in autoimmune hepatitis

Abstract

Autoimmune hepatitis (AIH) is a rare chronic inflammatory liver disease characterized by the presence of autoantibodies, including those targeting O-phosphoseryl-tRNA:selenocysteine-tRNA synthase (SepSecS), also known as soluble liver antigen (SLA). Anti-SepSecS antibodies have been associated with a more severe phenotype, suggesting a key role for the SepSecS autoantigen in AIH. To analyze the immune response to SepSecS in patients with AIH at the clonal level, we combined sensitive high-throughput screening assays with the isolation of monoclonal antibodies (mAbs) and T cell clones. The anti-SepSecS mAbs isolated were primarily IgG1, affinity-matured compared with their germline versions, and recognized at least 3 nonoverlapping epitopes. SepSecS-specific CD4+ T cell clones were found in patients with AIH who were anti-SLA-positive and anti-SLA-negative,and, to a lesser extent, in patients with non-AIH liver diseases and in healthy individuals. SepSecS-specific T cell clones from patients with AIH produced IFN-γ, IL-4, and IL-10, targeted multiple SepSecS epitopes, and, in one patient, were clonally expanded in both blood and liver biopsy. Finally, SepSecS-specific B cell clones, but not those of unrelated specificities, were able to present soluble SepSecS to specific T cells. Collectively, our study provides the first detailed analysis of B and T cell repertoires targeting SepSecS in patients with AIH, offering a rationale for improved targeted therapies.

Authors

Michael Kramer, Federico Mele, Sandra Jovic, Blanca Maria Fernandez, David Jarrossay, Jun Siong Low, Christiane Sokollik, Magdalena Filipowicz Sinnreich, Sylvie Ferrari-Lacraz, Giorgina Mieli-Vergani, Diego Vergani, Antonio Lanzavecchia, Antonino Cassotta, Benedetta Terziroli Beretta-Piccoli, Federica Sallusto

×

Figure 4

SepSecS proliferative response of memory CD4+ T cells in the blood of patients with AIH and individuals in the control groups.

Options: View larger image (or click on image) Download as PowerPoint
SepSecS proliferative response of memory CD4+ T cells in the blood of pa...
Total memory CD4+ T cells from the blood of patients with AIH, patients with non-AIH liver diseases in the PC group and individuals in the HC group were labeled with CFSE and stimulated with autologous monocytes in the presence or absence of the SepSecS peptide pool. On day 7, cells were collected and stained with anti–CD25-PE and anti–ICOS-APC mouse mAbs. (A) Histograms represent CFSE profile and contour plots represent CD25 and ICOS staining on gated CFSElo cells from AIH12 (anti-SLA positive), PC3 and HC2. Red lines, no SepSecS; gray lines, SepSecSpp. (B) Pooled data from all study participants shown as the percentage of CFSEloCD25+ICOS+ cells in the SepSecS stimulated cultures. Lines represent the median values. Blue dots represent anti-SLA positive patients with AIH. *P < 0.05 when determined by 2-tailed Mann-Whitney test and < 0.01 when determined by Spearman Partial correlation considering age as a covariable. (C) Number of total CD4+ T cell clones (left) isolated by limiting dilution from sorted CFSEloCD25+ICOS+ cells from ex vivo cultures of memory CD4+ T cells from patients with AIH, and individuals in the PC and HC groups. The right plot shows the frequency of SepSecS-specific CD4+ T cell clones among the isolated clones for each donor. Specificity was tested by stimulation with irradiated autologous B cells untreated or pulsed with SepSecS peptide pool. Proliferation was measured on day 3 after a 16 hour incubation with 1 μCi/mL methyl-3H-thymidine. (D) Epitope mapping of SepSecS-specific CD4+ T cell clones from patients with AIH and individuals in the control groups. Epitopes were identified by stimulating the clones with individual SepSecS peptides. Patients with AIH are represented in blue, patients in the PC group are in orange and individuals in the HC group are in black. Predicted binding peptides are shown as shaded blue (DRB1*03:01) and shaded green (DRB1*0401) squares in patients carrying the AIH predisposing HLA alleles DRB1*0301 and DRB1*0401, respectively. Anti-SLA status and disease activity are shown on the left-hand side; number of CD4+ T cell autoreactive clones are shown on the right-hand side.