Autoregulatory function of interleukin-10-producing pre-naïve B cells is defective in systemic lupus erythematosus

Introduction Pre-naïve B cells represent an intermediate stage in human B-cell development with some functions of mature cells, but their involvement in immune responses is unknown. The aim of this study was to determine the functional role of normal pre-naïve B cells during immune responses and possible abnormalities in systemic lupus erythematosus (SLE) that might contribute to disease pathogenesis. Methods Pre-naïve, naïve, and memory B cells from healthy individuals and SLE patients were stimulated through CD40 and were analyzed for interleukin-10 (IL-10) production and co-stimulatory molecule expression and their regulation of T-cell activation. Autoreactivity of antibodies produced by pre-naïve B cells was tested by measuring immunoglobulin M (IgM) autoantibodies in culture supernatants after differentiation. Results CD40-stimulated pre-naïve B cells produce larger amounts of IL-10 but did not suppress CD4+ T-cell cytokine production. Activated pre-naïve B cells demonstrated IL-10-mediated ineffective promotion of CD4+ T-cell proliferation and induction of CD4+FoxP3+ T cells and IL-10 independent impairment of co-stimulatory molecule expression and tumor necrosis factor-alpha (TNF-α) and IL-6 production. IgM antibodies produced by differentiated pre-naïve B cells were reactive to single-stranded deoxyribonucleic acid. SLE pre-naïve B cells were defective in producing IL-10, and co-stimulatory molecule expression was enhanced, resulting in promotion of robust CD4+ T-cell proliferation. Conclusions There is an inherent and IL-10-mediated mechanism that limits the capacity of normal pre-naïve B cells from participating in cellular immune response, but these cells can differentiate into autoantibody-secreting plasma cells. In SLE, defects in IL-10 secretion permit pre-naïve B cells to promote CD4+ T-cell activation and may thereby enhance the development of autoimmunity

Impacts of GFP-FoxP3+ regulatory T cells on lupus hallmarks differ by genetic background and type of GFP knock-in

FoxP3 reporter mice expressing green fluorescence protein (GFP) have been used as a very convenient tool to investigate the impact of regulatory T (Treg) cells on pathogenesis in autoimmune diseases. Here, we found that GFP-FoxP3+ knock-in (KI) mice showed alterations in the production of anti-nuclear autoantibodies (ANAs) and nephritis with different extent, depending on the presence or absence of lupus susceptibility gene locus 1 (Sle1) and KI method: contrasting with B6.Sle1.fGFP-FoxP3 mice, expressing GFP via N-terminal insertion, B6.Sle1.iGFP-FoxP3, expressing GFP via bicistronic internal ribosome entry site-driven promotion, exhibited significantly lower penetrance of serum ANA, comparing to control B6.Sle1 mice. Moreover, B6.Sle1.GFP-FoxP3+ mice reduced the Sle1-induced splenomegaly and B-cell expansion independently of the KI method employed, mainly by reducing the numbers of transitional 1 (T1) B cells and CD21–CD23– B cells, including plasmablasts and plasma cells. The absolute numbers of both splenic CD4+ T cells and Treg cells from B6.Sle1.GFP-FoxP3 KI mice were significantly reduced but their proportion was not changed, compared to B6.Sle1 mice. Although the glomerular basement membranes were thickened in both B6.Sle1 and B6.Sle1.iGFP-FoxP3 mice, they were thinner in B6.Sle1.fGFP-FoxP3 mice. The latter mice expressed more nephrophilic autoantibodies and deposited more complement component 3 in glomeruli compared to B6.iGFP-FoxP3 mice. FoxP3+ Treg cells may modulate B-cell tolerance in lupus-prone B6.Sle1 mice, presumably by modulating pathogenic, nephrophilic autoantibody production and nephritis

Indoleamine 2,3-dioxygenase-expressing CD11cdendritic cells display a phenotype consistent with the immature state

Indoleamine 2,3-dioxygenase (IDO)CD11cdendritic cells (DCs) were stained for markers of DC maturity and were analyzed using three-color flow cytometry. Mononuclear cells from Peyer's patches were stained for CD11c, IDO, and Major Histocompatibility Complex (MHC) II, or costimulatory molecule markers. All plots were first gated on IDOCD11ccells. Dotted line shows the isotype-matched controls. Data are the mean ± standard deviation of three experiments. MFI, mean fluorescence index.<p><b>Copyright information:</b></p><p>Taken from "Indoleamine 2,3-dioxygenase-expressing dendritic cells are involved in the generation of CD4CD25regulatory T cells in Peyer's patches in an orally tolerized, collagen-induced arthritis mouse model"</p><p>http://arthritis-research.com/content/10/1/R11</p><p>Arthritis Research & Therapy 2008;10(1):R11-R11.</p><p>Published online 25 Jan 2008</p><p>PMCID:PMC2374459.</p><p></p

Oral tolerance induction in indoleamine 2,3-dioxygenase-expressing CD11cdendritic cells of tolerized mice

The induction of oral tolerance increases the proportion of indoleamine 2,3-dioxygenase (IDO)-expressing CD11cdendritic cells (DCs) in Peyer's patches of tolerized mice. Flow cytometric analysis of IDO in CD11cDCs isolated from Peyer's patches. Mononuclear cells obtained from Peyer's patches of tolerized mice and of CIA mice were probed with Fluorescein isothiocyanate-labeled anti-CD11c mAb and were fixed with CytoPerm/CytoFix for 20 minutes. Cells were probed for intracellular IDO using anti-mouse IDO antibody and were analyzed by flow cytometry. The histograms were gated on CD11cDCs. Dotted histogram lines represent cells stained with isotype-matched control monoclonal antibodies. Results are the mean ± standard deviation of replicate samples from seven independent experiments. SSC. Analysis of IDO transcription in tolerized mice and CIA mice. CD11cDCs were isolated from Peyer's patch mononuclear cells using the magnetic-activated cell sorting system. The expression of IDO mRNA was analyzed using RT-PCR. β-Actin was used as an internal control. Each value is the mean ± standard deviation of replicate determinations in one of four experiments. *< 0.05. Immunofluorescent confocal microscopic examination of IDO expression by CD11cDCs. Mononuclear cells obtained from Peyer's patches of tolerized and CIA mice were stained with Fluorescein isothiocyanate-labeled anti-CD11c (green) and anti-IDO (red), fixed, and were examined using confocal microscopy. Isotype-matched control antibody staining was negative (data not shown). Data are representative of three independent experiments.<p><b>Copyright information:</b></p><p>Taken from "Indoleamine 2,3-dioxygenase-expressing dendritic cells are involved in the generation of CD4CD25regulatory T cells in Peyer's patches in an orally tolerized, collagen-induced arthritis mouse model"</p><p>http://arthritis-research.com/content/10/1/R11</p><p>Arthritis Research & Therapy 2008;10(1):R11-R11.</p><p>Published online 25 Jan 2008</p><p>PMCID:PMC2374459.</p><p></p

Indoleamine 2,3-dioxygenase-expressing CD11cdendritic cells essential for antigen-specific CD4CD25regulatory T-cell induction in tolerized mice

Increased CD4CD25T-cell proportion through an indoleamine 2,3-dioxygenase (IDO)-dependent mechanism. For regulatory T-cell induction, isolated CD4CD25T cells (1 × 10/well) were cultured with CD11cdendritic cells (DCs) (2 × 10/well) from tolerized mice or collagen-induced arthritis (CIA) mice in the absence or presence of type II collagen (CII) (40 μg/ml) for 3 days. 1-Methyl tryptophan (1-MT) was added to selected cultures. The proportion of CD4CD25T cells was determined using flow cytometry. Numbers represent the percentage of double-positive cells. Summary of the percentages of CD4CD25T cells from the coculture experiments in (a). Values are the mean from four independent experiments; individual symbols are the mean in individual animals, and bars show the group means. *< 0.02. Analysis of Foxp3 expression by converted CD4CD25T cells. Plots were gated on CD4CD25DCs. Dotted histogram lines represent cells stained with isotype-matched control monoclonal antibodies. Data represent the mean ± standard deviation and are representative of four independent experiments. Foxp3 mRNA expression in the same conditions as (a). β Actin was used as an internal control. Results are representative of four independent experiments. Regulatory function of the CII-induced CD4CD25T cells. CD4CD25T cells were expanded by exposure to CD11cDCs from Peyer's patches from tolerized mice in the presence of CII antigen stimulation. Varying numbers of CD4CD25T cells were cultured for 3 days with CII-reactive CD4T cells (1 × 10) and irradiated antigen-presenting cells (1 × 10) from mice with CIA in the presence of CII (40 μg/ml). Values are the mean ± standard deviation from three independent experiments. *< 0.05, **< 0.001. cpm, counts per minute.<p><b>Copyright information:</b></p><p>Taken from "Indoleamine 2,3-dioxygenase-expressing dendritic cells are involved in the generation of CD4CD25regulatory T cells in Peyer's patches in an orally tolerized, collagen-induced arthritis mouse model"</p><p>http://arthritis-research.com/content/10/1/R11</p><p>Arthritis Research & Therapy 2008;10(1):R11-R11.</p><p>Published online 25 Jan 2008</p><p>PMCID:PMC2374459.</p><p></p

Tolerized mice CD11cdendritic cells induce indoleamine 2,3-dioxygenase-dependent inhibition of type II collagen-specific T-cell proliferation

Type II collagen (CII)-reactive CD4T cells (1 × 10/well) and irradiated antigen-presenting cells (APCs) (1 × 10/well) isolated from Peyer's patches of collagen-induced arthritis (CIA) mice were cultured with CD11cdendritic cells (DCs) (1 × 10/well) from tolerized mice or CIA mice in the presence or absence of CII (40 μg/ml) in 96-well, U-bottomed plates for 3 days. Some DCs were pretreated with 1-methyl tryptophan (1-MT) (200 μM) for 2 hours before coculture. Data presented as the mean counts per minute (cpm) of triplicate cultures. Values are the mean ± standard deviation from three independent experiments. *< 0.05. Cytokine concentrations in the coculture supernatants. Concentrations of IL-17, IL-10, and transforming growth factor beta (TGFβ) in the culture supernatants were measured by ELISA. Values are the mean ± standard deviation from three independent experiments. *< 0.05, **< 0.001.<p><b>Copyright information:</b></p><p>Taken from "Indoleamine 2,3-dioxygenase-expressing dendritic cells are involved in the generation of CD4CD25regulatory T cells in Peyer's patches in an orally tolerized, collagen-induced arthritis mouse model"</p><p>http://arthritis-research.com/content/10/1/R11</p><p>Arthritis Research & Therapy 2008;10(1):R11-R11.</p><p>Published online 25 Jan 2008</p><p>PMCID:PMC2374459.</p><p></p