The calcineurin inhibitor tacrolimus allows the induction of functional CD4CD25 regulatory T cells by rabbit anti-thymocyte globulins.
Rabbit anti-thymocyte globulins (rATG) induce CD4(+)CD25(+)forkhead box P3 (FoxP3(+)) regulatory T cells that control alloreactivity. In the present study, we investigated whether rATG convert T cells into functional CD4(+)CD25(+)FoxP3(+)CD127(-/low) regulatory T cells in the presence of drugs that may hamper their induction and function, i.e. calcineurin inhibitors. CD25(neg) T cells were stimulated with rATG or control rabbit immunoglobulin G (rIgG) in the absence and presence of tacrolimus for 24 h. Flow cytometry was performed for CD4, CD25, FoxP3 and CD127 and the function of CD25(+) T cells was examined in suppression assays. MRNA expression profiles were composed to study the underlying mechanisms. After stimulation, the percentage CD4(+)CD25(+)FoxP3(+)CD127(-/low) increased (from 2% to 30%, mean, P < 0.01) and was higher in the rATG samples than in control rIgG samples (2%, P < 0.01). Interestingly, FoxP3(+)T cells were also induced when tacrolimus was present in the rATG cultures. Blockade of the interleukin (IL)-2 pathway did not affect the frequency of rATG-induced FoxP3(+) T cells. The rATG tacrolimus-induced CD25(+) T cells inhibited proliferative responses of alloantigen-stimulated effector T cells as vigorously as rATG-induced and natural CD4(+)CD25(+)FoxP3(+)CD127(-/low) T cells (67% +/- 18% versus 69% +/- 16% versus 45% +/- 20%, mean +/- standard error of the mean, respectively). At the mRNA-expression level, rATG-induced CD25(+) T cells abundantly expressed IL-10, IL-27, interferon (IFN)-gamma, perforin and granzyme B in contrast to natural CD25(+) T cells (all P = 0.03), while FoxP3 was expressed at a lower level (P = 0.03). These mRNA data were confirmed in regulatory T cells from kidney transplant patients. Our findings demonstrate that tacrolimus does not negatively affect the induction, phenotype and function of CD4(+)CD25(+) T cells, suggesting that rATG may induce regulatory T cells in patients who receive tacrolimus maintenance therapy.
Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands.
V D K D
VD
Sewgobind
L J W
LJ
van der Laan
M M L
MM
Kho
R
R
Kraaijeveld
S S
SS
Korevaar
W
W
Mol
W
W
Weimar
C C
CC
Baan
D000818:Animals; D000961:Antilymphocyte Serum / Q000276:immunology* / Q000627:therapeutic use; D002454:Cell Differentiation / Q000187:drug effects / Q000276:immunology; D002478:Cells, Cultured; D018920:Coculture Techniques; D003602:Cytotoxicity, Immunologic / Q000276:immunology; D051858:Forkhead Transcription Factors / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics / Q000276:immunology; D053804:Granzymes / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology; D007371:Interferon-gamma / Q000235:genetics; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism*; D053699:Interleukin-7 Receptor alpha Subunit / Q000378:metabolism; D007378:Interleukins / Q000235:genetics; D007519:Isoantigens / Q000276:immunology; D016030:Kidney Transplantation / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology*; D015778:Minor Histocompatibility Antigens; D054353:Perforin / Q000235:genetics; D010766:Phosphorylation / Q000187:drug effects / Q000276:immunology; D011817:Rabbits; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D016559:Tacrolimus / Q000494:pharmacology* / Q000627:therapeutic use; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D000961:Antilymphocyte Serum; C097732:EBI3 protein, human; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C508017:IL2RA protein, human; D053645:Interleukin-2 Receptor alpha Subunit; D053699:Interleukin-7 Receptor alpha Subunit; D007378:Interleukins; D007519:Isoantigens; D015778:Minor Histocompatibility Antigens; D054353:Perforin; D007371:Interferon-gamma; D048051:p38 Mitogen-Activated Protein Kinases; D053804:Granzymes; D016559:Tacrolimus