Immune Netw.  2013 Feb;13(1):25-29. 10.4110/in.2013.13.1.25.

Ribavirin Does Not Impair the Suppressive Activity of Foxp3+CD4+CD25+ Regulatory T Cells

• Lee J
• Choi YS
• Shin EC

• KMID: 2150767
• DOI: http://doi.org/10.4110/in.2013.13.1.25

Abstract

Ribavirin is an antiviral drug used in combination with pegylated interferon-alpha (IFN-alpha) for the treatment of hepatitis C virus (HCV) infection. Recently, ribavirin was reported to inhibit the suppressive activity of regulatory T (Treg) cells. In the present study, we re-evaluated the effect of ribavirin on Foxp3+CD4+CD25+ Treg cells from normal donors. First, we examined the expression of CTLA-4 and CD39, which are known to play a role in the suppressive function of Treg cells. We found that ribavirin treatment did not modulate the expression of CTLA-4 and CD39 in Treg cells. We also studied the effect of ribavirin on Treg cells in the presence of IFN-alpha; however, the expression of CTLA-4 and CD39 in Treg cells was not changed by ribavirin in the presence of IFN-alpha. Next, we directly evaluated the effect of ribavirin on the suppressive activity of Treg cells in the standard Treg suppression assay, by co-culturing CFSE-labeled non-Treg CD4+ T cells with purified Treg cells. We found that ribavirin did not attenuate the suppressive activity of Treg cells. Taken together, while ribavirin reversed Treg cell-mediated suppression of effector T cells in the previous study, we herein demonstrate that ribavirin does not impair the suppressive activity of Treg cells.

Keyword

Regulatory T cells; Ribavirin; Suppressive activity; Hepatitis C virus

MeSH Terms

Hepacivirus
Humans
Interferon-alpha
Ribavirin
T-Lymphocytes
T-Lymphocytes, Regulatory
Tissue Donors
Interferon-alpha
Ribavirin

Figure

• 

  Figure 1 The effect of ribavirin on the expression of CTLA-4 and CD39. (A, B) PBMCs were isolated from whole blood of normal donors and treated with 2.5µg/ml of ribavirin for 3 days. The percentage of CTLA-4+ or CD39+ cells in Foxp3+CD4+CD25+ Treg cells and Foxp3-CD25- non-Treg CD4+ T cells was analyzed by flow cytometry (A). Representative histograms illustrate CTLA-4+ or CD39+ cells within the Foxp3+CD4+CD25+ Treg cell gate (B). (C, D) PBMCs were treated with 2.5µg/ml of ribavirin and 100 U/ml of IFN-α for 3 days. The percentage of CTLA-4+ or CD39+ cells in Foxp3+CD4+CD25+ Treg cells and Foxp3-CD25- non-Treg CD4+ T cells was analyzed by flow cytometry (C). Representative histograms illustrate CTLA-4+ or CD39+ cells within the Foxp3+CD4+CD25+ Treg cell gate (D). The experiment was performed with PBMCs of multiple donors, and data from a single donor is presented as representative data.

• 

  Figure 2 The effect of ribavirin on the suppressive activity of Treg cells. (A) Direct effect of ribavirin on the proliferation of non-Treg CD4+ T cells. Non-Treg CD4+ T cells were labeled with CFSE and stimulated with anti-CD3/anti-CD28 with or without 2.5µg/ml of ribavirin for 4 days, and the percentage of CFSElo dividing cells were analyzed by flow cytometry. (B, C) Foxp3+CD4+CD25+ Treg cells and non-Treg CD4+ T cells were isolated from PBMCs of normal donors, and the standard Treg suppression assay was performed by co-culture of the isolated Treg cells and CFSE-labeled non-Treg CD4+ T cells at the indicated ratio. The percentage of CFSElo dividing cells among non-Treg CD4+ T cells were analyzed by flow cytometry, and the percentage of suppression was calculated as [1-(% T cell proliferation with Treg cells/% T cell proliferation without Treg cells)]×100 (B). Representative histograms illustrate CFSElo dividing cells within the non-Treg CD4+ T cell gate (C). The experiment was performed with PBMCs of multiple donors, and data from a single donor is presented as representative data.

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