1. Unique and common TCR repertoire features of Ni2+‐, Co2+‐, and Pd2+‐specific human CD154 + CD4+ T cells.
- Author
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Riedel, Franziska, Aparicio‐Soto, Marina, Curato, Caterina, Münch, Lucas, Abbas, Amro, Thierse, Hermann‐Josef, Peitsch, Wiebke K., Luch, Andreas, and Siewert, Katherina
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T cells , *MONONUCLEAR leukocytes , *T cell receptors , *CD4 antigen , *IMMUNOLOGIC memory - Abstract
Background: Apart from Ni2+, Co2+, and Pd2+ ions commonly trigger T cell‐mediated allergic contact dermatitis. However, in vitro frequencies of metal‐specific T cells and the mechanisms of antigen recognition remain unclear. Methods: Here, we utilized a CD154 upregulation assay to quantify Ni2+‐, Co2+‐, and Pd2+‐specific CD4+ T cells in peripheral blood mononuclear cells (PBMC). Involved αβ T cell receptor (TCR) repertoires were analyzed by high‐throughput sequencing. Results: Peripheral blood mononuclear cells incubation with NiSO4, CoCl2, and PdCl2 increased frequencies of CD154 + CD4+ memory T cells that peaked at ~400 μM. Activation was TCR‐mediated as shown by the metal‐specific restimulation of T cell clones. Most abundant were Pd2+‐specific T cells (mean 3.5%, n = 19), followed by Co2+‐ and Ni2+‐specific cells (0.6%, n = 18 and 0.3%, n = 20) in both allergic and non‐allergic individuals. A strong overrepresentation of the gene segment TRAV9‐2 was unique for Ni2+‐specific TCR (28% of TCR) while Co2+ and Pd2+‐specific TCR favorably expressed TRAV2 (8%) and the TRBV4 gene segment family (21%), respectively. As a second, independent mechanism of metal ion recognition, all analyzed metal‐specific TCR showed a common overrepresentation of a histidine in the complementarity determining region 3 (CDR3; 15% of α‐chains, 34% of β‐chains). The positions of the CDR3 histidine among metal‐specific TCR mirrored those in random repertoires and were conserved among cross‐reactive clonotypes. Conclusions: Induced CD154 expression allows a fast and comprehensive detection of Ni2+‐, Co2+‐, and Pd2+‐specific CD4+ T cells. Distinct TCR repertoire features underlie the frequent activation and cross‐reactivity of human metal‐specific T cells. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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