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Tumor-derived microvesicles induce, expand and up-regulate biological activities of human regulatory T cells (Treg).

Szajnik M, Czystowska M, Szczepanski MJ, Mandapathil M, Whiteside TL - PLoS ONE (2010)

Bottom Line: Purified Treg were resistant to TMV-mediated apoptosis relative to other T cells.Neutralizing Abs specific for TGF-beta1 and/or IL-10 significantly inhibited TMV ability to expand Treg.They induce Treg, promote Treg expansion, up-regulate Treg suppressor function and enhance Treg resistance to apoptosis.

View Article: PubMed Central - PubMed

Affiliation: University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania, United States of America.

ABSTRACT

Background: Tumor-derived microvesicles (TMV) or exosomes are present in body fluids of patients with cancer and might be involved in tumor progression. The frequency and suppressor functions of peripheral blood CD4(+)CD25(high)FOXP3(+) Treg are higher in patients with cancer than normal controls. The hypothesis is tested that TMV contribute to induction/expansion/and activation of human Treg.

Methodology/principal findings: TMV isolated from supernatants of tumor cells but not normal cells induced the generation and enhanced expansion of human Treg. TMV also mediated conversion of CD4(+)CD25(neg) T cells into CD4(+)CD25(high)FOXP3(+) Treg. Upon co-incubation with TMV, Treg showed an increased FasL, IL-10, TGF-beta1, CTLA-4, granzyme B and perforin expression (p<0.05) and mediated stronger suppression of responder cell (RC) proliferation (p<0.01). Purified Treg were resistant to TMV-mediated apoptosis relative to other T cells. TMV also increased phospho-SMAD2/3 and phospho-STAT3 expression in Treg. Neutralizing Abs specific for TGF-beta1 and/or IL-10 significantly inhibited TMV ability to expand Treg.

Conclusions/significance: This study suggests that TMV have immunoregulatory properties. They induce Treg, promote Treg expansion, up-regulate Treg suppressor function and enhance Treg resistance to apoptosis. Interactions of TMV with Treg represent a newly-defined mechanism that might be involved in regulating peripheral tolerance by tumors and in supporting immune evasion of human cancers.

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Related in: MedlinePlus

TMV Convert CD25neg T cells to Treg.(A) Flow cytometry histograms of cultured (d5) CD4+CD25neg T cells showing conversion of CD25neg T cells into CD25+ T cells ± TMV or DC-derived MV (left panel) and expression of FOXP3 in the converted CD4+CD25+ T cells (right panel) in the same cultures. (B) A phenotypic profile of CD4+CD25high T cells present in 7 day cultures of CD4+CD25+ T cells ± TMV or DC-derived MV. T cells were stained with various mAbs and evaluated by multiparameter flow cytometry. The gate is set on CD4+CD25high T cells. The data are mean percentages ± SD of positive cells from three independent experiments. (C) MFI for FasL, IL-10, TGF-β1, granzyme B and perforin expression in CD4+CD25high T cells cultured as described in (B) ± TMV. The data are representative of three independent experiments.
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pone-0011469-g004: TMV Convert CD25neg T cells to Treg.(A) Flow cytometry histograms of cultured (d5) CD4+CD25neg T cells showing conversion of CD25neg T cells into CD25+ T cells ± TMV or DC-derived MV (left panel) and expression of FOXP3 in the converted CD4+CD25+ T cells (right panel) in the same cultures. (B) A phenotypic profile of CD4+CD25high T cells present in 7 day cultures of CD4+CD25+ T cells ± TMV or DC-derived MV. T cells were stained with various mAbs and evaluated by multiparameter flow cytometry. The gate is set on CD4+CD25high T cells. The data are mean percentages ± SD of positive cells from three independent experiments. (C) MFI for FasL, IL-10, TGF-β1, granzyme B and perforin expression in CD4+CD25high T cells cultured as described in (B) ± TMV. The data are representative of three independent experiments.

Mentions: Freshly-isolated CD4+CD25neg T cells were cultured ± TMV for 5 d. The percentages of CD4+CD25+ T cells were higher (p<0.05) in the presence than in the absence of TMV (Figure 4A left panel). After 8 days of culture, the Treg frequency further increased, suggesting that TMV promoted conversion of CD4+CD25neg to CD4+CD25+ T cells (data not shown). The frequency of FOXP3+ cells was also higher in the CD4+CD25+ T cell subset cultured with TMV compared with the same cells cultured in the absence of TMV (41% vs. 25%; p<0.05) or in the presence of DC-derived MV (41% vs. 30%; p<0.05) (Figure 4A right panel).


Tumor-derived microvesicles induce, expand and up-regulate biological activities of human regulatory T cells (Treg).

Szajnik M, Czystowska M, Szczepanski MJ, Mandapathil M, Whiteside TL - PLoS ONE (2010)

TMV Convert CD25neg T cells to Treg.(A) Flow cytometry histograms of cultured (d5) CD4+CD25neg T cells showing conversion of CD25neg T cells into CD25+ T cells ± TMV or DC-derived MV (left panel) and expression of FOXP3 in the converted CD4+CD25+ T cells (right panel) in the same cultures. (B) A phenotypic profile of CD4+CD25high T cells present in 7 day cultures of CD4+CD25+ T cells ± TMV or DC-derived MV. T cells were stained with various mAbs and evaluated by multiparameter flow cytometry. The gate is set on CD4+CD25high T cells. The data are mean percentages ± SD of positive cells from three independent experiments. (C) MFI for FasL, IL-10, TGF-β1, granzyme B and perforin expression in CD4+CD25high T cells cultured as described in (B) ± TMV. The data are representative of three independent experiments.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2908536&req=5

pone-0011469-g004: TMV Convert CD25neg T cells to Treg.(A) Flow cytometry histograms of cultured (d5) CD4+CD25neg T cells showing conversion of CD25neg T cells into CD25+ T cells ± TMV or DC-derived MV (left panel) and expression of FOXP3 in the converted CD4+CD25+ T cells (right panel) in the same cultures. (B) A phenotypic profile of CD4+CD25high T cells present in 7 day cultures of CD4+CD25+ T cells ± TMV or DC-derived MV. T cells were stained with various mAbs and evaluated by multiparameter flow cytometry. The gate is set on CD4+CD25high T cells. The data are mean percentages ± SD of positive cells from three independent experiments. (C) MFI for FasL, IL-10, TGF-β1, granzyme B and perforin expression in CD4+CD25high T cells cultured as described in (B) ± TMV. The data are representative of three independent experiments.
Mentions: Freshly-isolated CD4+CD25neg T cells were cultured ± TMV for 5 d. The percentages of CD4+CD25+ T cells were higher (p<0.05) in the presence than in the absence of TMV (Figure 4A left panel). After 8 days of culture, the Treg frequency further increased, suggesting that TMV promoted conversion of CD4+CD25neg to CD4+CD25+ T cells (data not shown). The frequency of FOXP3+ cells was also higher in the CD4+CD25+ T cell subset cultured with TMV compared with the same cells cultured in the absence of TMV (41% vs. 25%; p<0.05) or in the presence of DC-derived MV (41% vs. 30%; p<0.05) (Figure 4A right panel).

Bottom Line: Purified Treg were resistant to TMV-mediated apoptosis relative to other T cells.Neutralizing Abs specific for TGF-beta1 and/or IL-10 significantly inhibited TMV ability to expand Treg.They induce Treg, promote Treg expansion, up-regulate Treg suppressor function and enhance Treg resistance to apoptosis.

View Article: PubMed Central - PubMed

Affiliation: University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania, United States of America.

ABSTRACT

Background: Tumor-derived microvesicles (TMV) or exosomes are present in body fluids of patients with cancer and might be involved in tumor progression. The frequency and suppressor functions of peripheral blood CD4(+)CD25(high)FOXP3(+) Treg are higher in patients with cancer than normal controls. The hypothesis is tested that TMV contribute to induction/expansion/and activation of human Treg.

Methodology/principal findings: TMV isolated from supernatants of tumor cells but not normal cells induced the generation and enhanced expansion of human Treg. TMV also mediated conversion of CD4(+)CD25(neg) T cells into CD4(+)CD25(high)FOXP3(+) Treg. Upon co-incubation with TMV, Treg showed an increased FasL, IL-10, TGF-beta1, CTLA-4, granzyme B and perforin expression (p<0.05) and mediated stronger suppression of responder cell (RC) proliferation (p<0.01). Purified Treg were resistant to TMV-mediated apoptosis relative to other T cells. TMV also increased phospho-SMAD2/3 and phospho-STAT3 expression in Treg. Neutralizing Abs specific for TGF-beta1 and/or IL-10 significantly inhibited TMV ability to expand Treg.

Conclusions/significance: This study suggests that TMV have immunoregulatory properties. They induce Treg, promote Treg expansion, up-regulate Treg suppressor function and enhance Treg resistance to apoptosis. Interactions of TMV with Treg represent a newly-defined mechanism that might be involved in regulating peripheral tolerance by tumors and in supporting immune evasion of human cancers.

Show MeSH
Related in: MedlinePlus