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TLR4/MyD88-induced CD11b+Gr-1 int F4/80+ non-migratory myeloid cells suppress Th2 effector function in the lung.

Arora M, Poe SL, Oriss TB, Krishnamoorthy N, Yarlagadda M, Wenzel SE, Billiar TR, Ray A, Ray P - Mucosal Immunol (2010)

Bottom Line: LPS promoted the development of a CD11b(+)Gr1(int)F4/80(+) lung-resident cell resembling myeloid-derived suppressor cells in a Toll-like receptor 4 and myeloid differentiation factor 88 (MyD88)-dependent manner that suppressed lung dendritic cell (DC)-mediated reactivation of primed Th2 cells.Suppression of Th2 effector function was reversed by anti-interleukin-10 (IL-10) or inhibition of arginase 1.These data suggest that CD11b(+)Gr1(int)F4/80(+) cells contribute to the protective effects of LPS in allergic asthma by tempering Th2 effector function in the tissue.

View Article: PubMed Central - PubMed

Affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Pittsburgh, Pennsylvania, USA.

ABSTRACT
In humans, environmental exposure to a high dose of lipopolysaccharide (LPS) protects from allergic asthma, the immunological underpinnings of which are not well understood. In mice, exposure to a high LPS dose blunted house dust mite-induced airway eosinophilia and T-helper 2 (Th2) cytokine production. Although adoptively transferred Th2 cells induced allergic airway inflammation in control mice, they were unable to do so in LPS-exposed mice. LPS promoted the development of a CD11b(+)Gr1(int)F4/80(+) lung-resident cell resembling myeloid-derived suppressor cells in a Toll-like receptor 4 and myeloid differentiation factor 88 (MyD88)-dependent manner that suppressed lung dendritic cell (DC)-mediated reactivation of primed Th2 cells. LPS effects switched from suppressive to stimulatory in MyD88(-/-) mice. Suppression of Th2 effector function was reversed by anti-interleukin-10 (IL-10) or inhibition of arginase 1. Lineage(neg) bone marrow progenitor cells could be induced by LPS to develop into CD11b(+)Gr1(int)F4/80(+)cells both in vivo and in vitro that when adoptively transferred suppressed allergen-induced airway inflammation in recipient mice. These data suggest that CD11b(+)Gr1(int)F4/80(+) cells contribute to the protective effects of LPS in allergic asthma by tempering Th2 effector function in the tissue.

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CD11b+Gr1intF4/80+ cells induced by LPS administration are distinct from conventional lung DCs. (a) CD11c+ cells were purified from the lung cells obtained from LPS-treated mice. Conventional DCs were identified as CD11c+ cells with a relatively low level of autofluorescence and side scatter and were used as APCs in experiments where needed. The purity of these cells was more than 95%. (b) 2×105 cells (cDCs or CD11b+Gr1intF4/80+ cells) were plated for 20 h and culture supernatants were analyzed for cytokine production. Values shown are mean ± SEM, *, P<0.01, **, P< 0.001. (c) Expression of co-stimulatory molecules detected by flow cytometry on the cDC and CD11b+Gr1int F4/80+ populations. Dark lines represent expression of the indicated molecules, the light lines being background fluorescence determined by staining with appropriate isotype control antibodies. (d) Levels of NO in the supernatants of cell cultures. DC and Gr1int/F4/80+ were isolated from the same LPS-treated mice as described before. Data shown are representative of two independent experiments and depict mean ± SD *, P<0.05.
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Figure 2: CD11b+Gr1intF4/80+ cells induced by LPS administration are distinct from conventional lung DCs. (a) CD11c+ cells were purified from the lung cells obtained from LPS-treated mice. Conventional DCs were identified as CD11c+ cells with a relatively low level of autofluorescence and side scatter and were used as APCs in experiments where needed. The purity of these cells was more than 95%. (b) 2×105 cells (cDCs or CD11b+Gr1intF4/80+ cells) were plated for 20 h and culture supernatants were analyzed for cytokine production. Values shown are mean ± SEM, *, P<0.01, **, P< 0.001. (c) Expression of co-stimulatory molecules detected by flow cytometry on the cDC and CD11b+Gr1int F4/80+ populations. Dark lines represent expression of the indicated molecules, the light lines being background fluorescence determined by staining with appropriate isotype control antibodies. (d) Levels of NO in the supernatants of cell cultures. DC and Gr1int/F4/80+ were isolated from the same LPS-treated mice as described before. Data shown are representative of two independent experiments and depict mean ± SD *, P<0.05.

Mentions: We next compared the Gr1int cells with conventional dendritic cells (cDCs) isolated side-by-side from the lungs of the same LPS-treated mice, the DCs being identified based on CD11c expression and low autofluorescence (Figure 2a). The cells were cultured briefly to identify the cytokines they produce. The CD11b+Gr1intF4/80+ cells produced higher levels of IL-6 and GM-CSF as compared to equal numbers of cultured cDCs (Figure 2b). The cDCs, however, secreted more IL-12p40 (Fig. 2b). The cDCs expressed higher levels of cell surface markers such as MHC class II, CD86 and CD40 and the reverse was true for CD80 (Figure 2c). High level of CD80 expression is a characteristic of MDSCs and is important for their suppressive function 16. The CD11b+Gr1int cells have considerable similarity to MDSCs including the expression of CD80. Given that the Gr1int cells resembled MDSCs, we also examined nitric oxide production by the cells and as shown in Figure 2d, the cells produced NO which was more than that produced by cDCs. For convenience, from here on we have referred to the LPS-induced myeloid cells as CD11b+Gr1int to distinguish them from neutrophils that are CD11b+Gr1hi and lung cDCs in which this phenotype has not been encountered.


TLR4/MyD88-induced CD11b+Gr-1 int F4/80+ non-migratory myeloid cells suppress Th2 effector function in the lung.

Arora M, Poe SL, Oriss TB, Krishnamoorthy N, Yarlagadda M, Wenzel SE, Billiar TR, Ray A, Ray P - Mucosal Immunol (2010)

CD11b+Gr1intF4/80+ cells induced by LPS administration are distinct from conventional lung DCs. (a) CD11c+ cells were purified from the lung cells obtained from LPS-treated mice. Conventional DCs were identified as CD11c+ cells with a relatively low level of autofluorescence and side scatter and were used as APCs in experiments where needed. The purity of these cells was more than 95%. (b) 2×105 cells (cDCs or CD11b+Gr1intF4/80+ cells) were plated for 20 h and culture supernatants were analyzed for cytokine production. Values shown are mean ± SEM, *, P<0.01, **, P< 0.001. (c) Expression of co-stimulatory molecules detected by flow cytometry on the cDC and CD11b+Gr1int F4/80+ populations. Dark lines represent expression of the indicated molecules, the light lines being background fluorescence determined by staining with appropriate isotype control antibodies. (d) Levels of NO in the supernatants of cell cultures. DC and Gr1int/F4/80+ were isolated from the same LPS-treated mice as described before. Data shown are representative of two independent experiments and depict mean ± SD *, P<0.05.
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Related In: Results  -  Collection

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Figure 2: CD11b+Gr1intF4/80+ cells induced by LPS administration are distinct from conventional lung DCs. (a) CD11c+ cells were purified from the lung cells obtained from LPS-treated mice. Conventional DCs were identified as CD11c+ cells with a relatively low level of autofluorescence and side scatter and were used as APCs in experiments where needed. The purity of these cells was more than 95%. (b) 2×105 cells (cDCs or CD11b+Gr1intF4/80+ cells) were plated for 20 h and culture supernatants were analyzed for cytokine production. Values shown are mean ± SEM, *, P<0.01, **, P< 0.001. (c) Expression of co-stimulatory molecules detected by flow cytometry on the cDC and CD11b+Gr1int F4/80+ populations. Dark lines represent expression of the indicated molecules, the light lines being background fluorescence determined by staining with appropriate isotype control antibodies. (d) Levels of NO in the supernatants of cell cultures. DC and Gr1int/F4/80+ were isolated from the same LPS-treated mice as described before. Data shown are representative of two independent experiments and depict mean ± SD *, P<0.05.
Mentions: We next compared the Gr1int cells with conventional dendritic cells (cDCs) isolated side-by-side from the lungs of the same LPS-treated mice, the DCs being identified based on CD11c expression and low autofluorescence (Figure 2a). The cells were cultured briefly to identify the cytokines they produce. The CD11b+Gr1intF4/80+ cells produced higher levels of IL-6 and GM-CSF as compared to equal numbers of cultured cDCs (Figure 2b). The cDCs, however, secreted more IL-12p40 (Fig. 2b). The cDCs expressed higher levels of cell surface markers such as MHC class II, CD86 and CD40 and the reverse was true for CD80 (Figure 2c). High level of CD80 expression is a characteristic of MDSCs and is important for their suppressive function 16. The CD11b+Gr1int cells have considerable similarity to MDSCs including the expression of CD80. Given that the Gr1int cells resembled MDSCs, we also examined nitric oxide production by the cells and as shown in Figure 2d, the cells produced NO which was more than that produced by cDCs. For convenience, from here on we have referred to the LPS-induced myeloid cells as CD11b+Gr1int to distinguish them from neutrophils that are CD11b+Gr1hi and lung cDCs in which this phenotype has not been encountered.

Bottom Line: LPS promoted the development of a CD11b(+)Gr1(int)F4/80(+) lung-resident cell resembling myeloid-derived suppressor cells in a Toll-like receptor 4 and myeloid differentiation factor 88 (MyD88)-dependent manner that suppressed lung dendritic cell (DC)-mediated reactivation of primed Th2 cells.Suppression of Th2 effector function was reversed by anti-interleukin-10 (IL-10) or inhibition of arginase 1.These data suggest that CD11b(+)Gr1(int)F4/80(+) cells contribute to the protective effects of LPS in allergic asthma by tempering Th2 effector function in the tissue.

View Article: PubMed Central - PubMed

Affiliation: Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, Pittsburgh, Pennsylvania, USA.

ABSTRACT
In humans, environmental exposure to a high dose of lipopolysaccharide (LPS) protects from allergic asthma, the immunological underpinnings of which are not well understood. In mice, exposure to a high LPS dose blunted house dust mite-induced airway eosinophilia and T-helper 2 (Th2) cytokine production. Although adoptively transferred Th2 cells induced allergic airway inflammation in control mice, they were unable to do so in LPS-exposed mice. LPS promoted the development of a CD11b(+)Gr1(int)F4/80(+) lung-resident cell resembling myeloid-derived suppressor cells in a Toll-like receptor 4 and myeloid differentiation factor 88 (MyD88)-dependent manner that suppressed lung dendritic cell (DC)-mediated reactivation of primed Th2 cells. LPS effects switched from suppressive to stimulatory in MyD88(-/-) mice. Suppression of Th2 effector function was reversed by anti-interleukin-10 (IL-10) or inhibition of arginase 1. Lineage(neg) bone marrow progenitor cells could be induced by LPS to develop into CD11b(+)Gr1(int)F4/80(+)cells both in vivo and in vitro that when adoptively transferred suppressed allergen-induced airway inflammation in recipient mice. These data suggest that CD11b(+)Gr1(int)F4/80(+) cells contribute to the protective effects of LPS in allergic asthma by tempering Th2 effector function in the tissue.

Show MeSH
Related in: MedlinePlus