The role of metabolism on regulatory T cell development and its impact in tumor and transplantation immunity.

Regulatory CD4+ T (Treg) cells play a key role in the induction of immune tolerance and in the prevention of autoimmune diseases. Treg cells are defined by the expression of transcription factor FOXP3, which ensures proliferation and induction of the suppressor activity of this cell population. In a tumor microenvironment, after transplantation or during autoimmune diseases, Treg cells can respond to various signals from their environment and this property ensures their suppressor function. Recent studies showed that a metabolic signaling pathway of Treg cells are essential in the control of Treg cell proliferation processes. This review presents the latest research highlights on how the influence of extracellular factors (e.g. nutrients, vitamins and metabolites) as well as intracellular metabolic signaling pathways regulate tissue specificity of Treg cells and heterogeneity of this cell population. Understanding the metabolic regulation of Treg cells should provide new insights into immune homeostasis and disorders along with important therapeutic implications for autoimmune diseases, cancer and other immune-system-mediated disorders.

Maturation and cytokine production potential of dendritic cells isolated from rheumatoid arthritis patients peripheral blood and induced in vitro.

BACKGROUND: Since dendritic cells (DC) are involved in the development of autoimmune inflammation, researchers consider DC both as target cells for specific therapy of rheumatoid arthritis (RA) and as candidate cells for the development of cell-based methods to treat autoimmune diseases. The development of treatment strategies requires comprehensive research into the quantitative and qualitative characteristics of DC subtypes both ex vivo from RA patients and in vitro, to determine the possibility of inducing functionally mature DC in RA. OBJECTIVE: To study the phenotypic and functional properties of myeloid (mDC) and plasmacytoid (pDC) DC isolated from the peripheral blood of patients with RA and induced in vitro. MATERIALS AND METHODS: Blood samples were obtained from RA patients and healthy donors. Immature DC in the whole blood and in vitro induced DC were characterized by the positive expression of CD80, CD83, CCR7, IL-10, IL-4, IL-12 and IFN-α. R848 and lipopolysaccharide were used to determine DC maturation ability. From PBMCs of RA patients and health donors DCs with myeloid (imDC) and plasmacytoid (ipDC) phenotype were induced. RESULTS: The relative count of mDC in the peripheral blood between studied groups did not differ. pDC count was significantly lower for RA patients. DC from RA patients were characterized by low expression levels of CD80 and CD83 on both populations cells and high expression of CCR7 only on pDC. An increase in pDC producing IL-12 and IFN-α and a decrease in mDC and pDC producing IL-4 and IL-10 were shown in RA. imDC and ipDC obtained from RA patients according to their phenotype and cytokine profile did not differ from those obtained from healthy donors. CONCLUSIONS: There is an imbalance between subpopulations of DC in the peripheral blood of RA patients. DC of RA patients are less mature. The data suggest the involvement of DC in RA pathogenesis and confirm DC participation in balance shift towards Th1-type immune responses. At the same time, in vitro induced RA DC are phenotypically and functionally competent.

Differences of IL-1ß Receptors Expression by Immunocompetent Cells Subsets in Rheumatoid Arthritis.

IL-1ß is involved in the induction and maintenance of chronic inflammation in rheumatoid arthritis (RA). Its activity is regulated and induced by soluble and membrane-bound receptors, respectively. The effectiveness of the cytokine depends not only on the percentage of receptor-positive cells in an immunocompetent subset but also on the density of receptor expression. The objective of this study was to investigate the expression of IL-1ß membrane-bound receptors (IL-1R1 and IL-1R2) in terms of the percentage of receptor-positive cells and the number of receptors per cell in different subsets of immune cells in RA patients before and after a course of basic (excluding anticytokine) therapy and in healthy individuals. The resulting data indicate differences in the expression of IL-1ß receptors among T cells, B cells, and monocytes in healthy volunteers and in rheumatoid arthritis patients. The importance of determining both the relative percentage of cells expressing receptors to immunomodulatory cytokines and the number of membrane-bound receptors per cell is highlighted by evidence of unidirectional or multidirectional changing of these parameters according to cell subset and health status.

Expression of TNFα membrane-bound receptors in the peripheral blood mononuclear cells (PMBC) in rheumatoid arthritis patients.

OBJECTIVE: To investigate the expression of TNFα membrane-bound receptors: the percentage of cells expressing these receptors and the number of molecules expressed on different immune cell subsets, and to evaluate serum concentrations of soluble TNFα and its receptors (sTNFRI and sTNFRII) in patients with rheumatoid arthritis in acute stage and after response to treatment compared to healthy donors. METHODS: The objects of the study are peripheral blood mononuclear cells (PBMC) of healthy donors (n=150) and RA patients (n=40) subjected to hospital treatment with either biological agents (Rituximab) or glucocorticosteroids (methylprednisolone). To determine PBMC phenotype antibodies anti-hCD3-APC, anti-hCD19 PECy7, anti-hCD14 FITC (eBioscience), as well as anti-hTNFRI-PE and anti-hTNFRII-PE (R&D Systems) were used. To determine receptor number on the cells Quantibrite PE Beads (BD) were used. RESULTS: Cells obtained from patients who responded to therapy and achieved disease remission exhibited either an increase in the percentage of TNFRI+ cells or elevated expression density of this receptor type. CONCLUSION: Subsets of immunocompetent cells from RA patients show variation in the percentage of membrane-bound receptor positive cells and receptor expression density, which influences the development and progression of the pathological processes in RA. Response to therapy and achievement of disease remission are associated with an increase of TNFRI expression.

Polymorphisms in the tumor necrosis factor receptor genes affect the expression levels of membrane-bound type I and type II receptors.

The level of TNF receptors on various cells of immune system and its association with the gene polymorphism were investigated. Determining the levels of membrane-bound TNFα receptors on peripheral blood mononuclear cells (PBMCs) was performed by flow cytometry using BD QuantiBRITE calibration particles. Soluble TNF α receptor (sTNFRs) levels were determined by ELISA and genotyping was determined by PCR-RFLP. Homozygous TT individuals at SNP -609G/T TNFRI (rs4149570) showed lower levels of sTNFRI compared to GG genotype carriers. Homozygous carriers of CC genotype at SNP -1207G/C TNFRI (rs4149569) had lower expression densities of membrane-bound TNFRI on intact CD14(+) monocytes compared to individuals with the GC genotype. The frequency differences in the CD3(+) and CD19(+) cells expressing TNFRII in relation to SNP -1709A/T TNFRII (rs652625) in healthy individuals were also determined. The genotype CC in SNP -3609C/T TNFRII (rs590368) was associated with a lower percentage of CD14(+) cells expressing TNFRII compared to individuals with the CT genotype. Patients with rheumatoid arthritis had no significant changes in the frequencies of genotypes. Reduced frequency was identified for the combination TNFRI -609GT + TNFRII -3609CC only. The polymorphisms in genes represent one of cell type-specific mechanisms affecting the expression levels of membrane-bound TNF α receptors and TNF α -mediated signaling.