In Vitro Generation of Interleukin 10–producing Regulatory CD4+ T Cells Is Induced by Immunosuppressive Drugs and Inhibited by T Helper Type 1 (Th1)– and Th2-inducing Cytokines

Abstract

We show that a combination of the immunosuppressive drugs, vitamin D3 and Dexamethasone, induced human and mouse naive CD4+ T cells to differentiate in vitro into regulatory T cells. In contrast to the previously described in vitro derived CD4+ T cells, these cells produced only interleukin (IL)-10, but no IL-5 and interferon (IFN)-γ, and furthermore retained strong proliferative capacity. The development of these IL-10–producing cells was enhanced by neutralization of the T helper type 1 (Th1)- and Th2–inducing cytokines IL-4, IL-12, and IFN-γ. These immunosuppressive drugs also induced the development of IL-10–producing T cells in the absence of antigen-presenting cells, with IL-10 acting as a positive autocrine factor for these T cells. Furthermore, nuclear factor (NF)-κB and activator protein (AP)-1 activities were inhibited in the IL-10–producing cells described here as well as key transcription factors involved in Th1 and Th2 subset differentiation. The regulatory function of these in vitro generated IL-10–producing T cells was demonstrated by their ability to prevent central nervous system inflammation, when targeted to the site of inflammation, and this function was shown to be IL-10 dependent. Generating homogeneous populations of IL-10–producing T cells in vitro will thus facilitate the use of regulatory T cells in immunotherapy.

1,25‐dihydroxyvitamin D3 promotes IL‐10 production in human B cells

“…Activation of B cells via BCR, TLR-9, CD40 and IL-4 initiates expression of Cyp1a, enabling B cells to convert pro-vitamin D into calcitriol. Thus, human B lymphocytes can regulate immunity by auto-and paracrine provision of calcitriol, enhancing IL-10 expression by themselves, and by T lymphocytes [11] and dendritic cells [10] in their vicinity. In addition, as we have shown previously, calcitriol in B lymphocytes also suppresses the generation of IgE germline transcripts, and thus antibody class switching to IgE [7].…”

“…Patients with overproduction of calcitriol due to uncontrolled extrarenal CYP1a expression, e.g., sarcoidosis patients [31][32][33][34], suffer from peripheral immunological anergy and show enhanced numbers of Treg cells [35]. In vitro, calcitriol-stimulated dendritic cells can promote the development of Treg cells [10] and calcitriol directly enhances expression of IL-10 by Th cells [11]. Acquired vitamin D deficiency has been correlated to increased prevalence and severity of inflammatory immune-mediated diseases, such as rheumatoid arthritis [2,36], multiple sclerosis [37,38], but also is discussed in context with allergic asthma [4] and atopic dermatitis [5,39].…”

“…Calcitriol-mediated inhibition of IgE expression may indirectly result from up-regulation of IL-10 expression. It has been shown that IL-10 inhibits IL-4-driven IgE production in human PBMC [8] and purified B cells [9], and that calcitriol induces IL-10 expression in dendritic cells [10] and enhances it in T cells [11]. Nutritional supplementation with the calcitriol precursor 25-hydroxyvitamin D 3 , leads to increased serum IL-10 levels in vivo [12].…”

Cytokine gene-modulated dendritic cells protect against allergic airway inflammation by inducing IL-10+IFN-γ+CD4+ T cells

“…[9][10][11][12] IL-10 was also shown to be produced by specialized subsets of regulatory T cells (Tregs), such as CD25 + FoxP3 + Tregs and T-regulatory 1 cells (Tr1), and the regulatory activities of T cells were found to be closely related to their IL-10-producing ability. [13][14][15][16] These findings led to the hypothesis that the expression of IL-10 in the airway environment may inhibit the development of airway inflammation. Another key cytokine produced by DCs involved in Th polarization is IL-12.…”

Budesonide increases TLR4 and TLR2 expression in Treg lymphocytes of allergic asthmatics

“…Corticosteroids act on Tregs increasing IL-10 production [14] and enhancing IL-10 Treg function [5]. Corticosteroids inhibit T-cell activation and production of Th2 cytokines [15] and increase T cell apoptosis [16].…”