Zinc supplementation induces CD4+CD25+Foxp3+antigen-specific regulatory T cells and suppresses IFN-γ production by upregulation of Foxp3 and KLF-10 and downregulation of IRF-1.
OBJECTIVE
The essential trace element zinc plays a fundamental role in immune function and regulation since its deficiency is associated with autoimmunity, allergies, and transplant rejection. Thus, we investigated the influence of zinc supplementation on the Th1-driven alloreaction in mixed lymphocyte cultures (MLC), on generation of antigen-specific T cells, and analyzed underlying molecular mechanisms.


METHODS
Cell proliferation and pro-inflammatory cytokine production were monitored by [3H]-thymidine proliferation assay and ELISA, respectively. Analysis of surface and intracellular T cell marker was performed by flow cytometry. Western blotting and mRNA analysis were used for Foxp3, KLF-10, and IRF-1 expression.


RESULTS
Zinc supplementation on antigen-specific T cells in physiological doses (50 µM) provokes a significant amelioration of cell proliferation and pro-inflammatory cytokine production after reactivation compared to untreated controls. Zinc administration on MLC results in an increased induction and stabilization of CD4+CD25+Foxp3+and CD4+CD25+CTLA-4+T cells (p < 0.05). The effect is based on zinc-induced upregulation of Foxp3 and KLF-10 and downregulation of IRF-1. However, in resting lymphocytes zinc increases IRF-1.


CONCLUSIONS
In summary, zinc is capable of ameliorating the allogeneic immune reaction by enhancement of antigen-specific iTreg cells due to modulation of essential molecular targets: Foxp3, KLF-10, and IRF-1. Thus, zinc can be seen as an auspicious tool for inducing tolerance in adverse immune reactions.
Faculty of Medicine, Institute of Immunology, RWTH Aachen University, University Hospital, Pauwelsstr. 30, 52074, Aachen, Germany.
Martina
M
Maywald
Faculty of Medicine, Institute of Immunology, RWTH Aachen University, University Hospital, Pauwelsstr. 30, 52074, Aachen, Germany. LRink@UKAachen.de.
Lothar
L
Rink
D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D015536:Down-Regulation; D051765:Early Growth Response Transcription Factors / Q000235:genetics / Q000378:metabolism*; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D050856:Interferon Regulatory Factor-1 / Q000235:genetics / Q000378:metabolism*; D007371:Interferon-gamma / Q000096:biosynthesis*; D051741:Kruppel-Like Transcription Factors / Q000235:genetics / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000378:metabolism; D007959:Lymphocyte Culture Test, Mixed; D050378:T-Lymphocytes, Regulatory / Q000378:metabolism*; D015854:Up-Regulation; D015032:Zinc / Q000494:pharmacology*
D016207:Cytokines; D051765:Early Growth Response Transcription Factors; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C573415:IFNG protein, human; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; C098111:KLF10 protein, human; D051741:Kruppel-Like Transcription Factors; D007371:Interferon-gamma; D015032:Zinc
Foxp3; IRF-1; KLF-10; Mixed lymphocyte culture (MLC); Regulatory T cells; Zinc