Calcitonin Gene-Related Peptide Effects on Phenotype and IL-12 Production of Monocyte-Derived Dendritic Cells in Rheumatoid Arthritis Patients

Objective(s)Recent studies on human indicate that the introduction of therapeutic use of tolerogenic dendritic cell (DC) for chronic inflammatory conditions is imminent. For the purpose of defining CGRP potency in tolerogenic DC production, we investigated the phenotype and IL-12 production of DCs generated from the monocytes of rheumatoid arthritis (RA) patients in the presence of the calcitonin gene-related peptide (CGRP), as a multifunctional neuropeptide.Materials and MethodsDCs were generated from isolated monocytes from four resistant and two early female RA patients using IL-4, GM-CSF, and CGRP at concentrations of 0, 1, and 100 nM. Then, the phenotype of neuropeptide-treated or untreated DCs was determined using flow cytometry and the IL-12 production was measured by ELISA.ResultsOur study showed that, on the last day of the culture, at a concentration of 1 nM CGRP, the mean fluorescence intensity (MFI) for CD80 increased (14.13%) and the MFIs for CD83, CD86, and HLA-DR decreased (14.57%, 5.28%, and 6.88% respectively). Moreover, at 100 nM CGRP concentration, the MFI for CD80 increased (11.10%) and the MFIs for CD83, CD86, and HLA-DR decreased (4.27%, 18.60%, and 19.75% respectively). In addition, our results indicated that the mean concentrations of IL-12 produced at 0, 1, and 100 nm CGRP concentrations measured 13.72±2.41, 11.01±1.61, and 7±1.34 pg/ml respectively. ConclusionDecreased CD83, CD86, and HLA-DR expression and reduced IL-12 production by CGRP were found in the RA patients' monocyte-derived DCs. CD83 is a well-defined DC activation marker. HLA-DR and CD86 are appropriate molecules for inducing an immune response. IL-12 promotes cell-mediated immunity. Therefore we suggest that CGRP may be used as an inducer in the production of tolerogenic DCs

Tolerance Induction by CD40 Blocking through Specific Antibody in Dendritic Cells

Blocking antibodies are valuable tools for inhibiting the specific receptor- ligand interactions. The interaction of co-stimulatory molecules on the antigen presenting cells with their ligands on T cells is an essential step for T cell activation. In the present study, the effect of blocking antibody against CD40 on its T cell stimulatory potential is investigated. The DCs (dendritic cells) were collected from the mice spleens and then cultured in vitro. We used purified rat anti-mice CD40 (Clone HM40-3) (BD USA) as a blocking antibody and the appropriate titer of the blocking antibody was determined by flow cytometry. The DCs were then treated by antibody and used in MLR assay. The results of these experiments showed that CD40 blockade were associated with the increase in the of IL-4 secretion, shifting the DCs to stimulate Th2 cytokine production by the allogenic T cells, while the secretion of IL-12 by DCs decreased. Similarly, the DCs with reduced CD40 expression poorly responded to alloantigen stimulation in the MLR. Collectively, these results emphasize the importance of CD40 pathway in tolerogenic DCs generation and also support the idea that downregulation of CD40 is effective in inhibiting the allostimulatory function

Expression of Activation-Induced Cytidine Deaminase Gene in B Lymphocytes of Patients with Common Variable Immunodeficiency

Objective: Common variable immunodeficiency (CVID) is a heterogeneous disorder characterized by reduced serum level of IgG, IgA or IgM and recurrent bacterial infections. Class switch recombination (CSR) as a critical process in immunoglobulin production is defective in a group of CVID patients. Activation-induced cytidine deaminase (AID) protein is an important molecule involving CSR process. The aim of this study was to investigate the AID gene mRNA production in a group of CVID patients indicating possible role of this molecule in this disorder. Methods: Peripheral blood mononuclear cells (PBMC) of 29 CVID patients and 21 healthy controls were isolated and stimulated by CD40L and IL-4 to induce AID gene expression. After 5 days AID gene mRNA production was investigated by real time polymerase chain reaction. Findings: AID gene was expressed in all of the studied patients. However the mean density of extracted AID mRNA showed higher level in CVID patients (230.95±103.04 ng/ml) rather than controls (210.00±44.72 ng/ml; P=0.5). CVID cases with lower level of AID had decreased total level of IgE (P=0.04) and stimulated IgE production (P=0.02); while cases with increased level of AID presented higher level of IgA (P=0.04) and numbers of B cells (P=0.02) and autoimmune disease (P=0.02). Conclusion: Different levels of AID gene expression may have important roles in dysregulation of immune system and final clinical presentation in CVID patients. Therefore investigating the expression of AID gene can help in classifying CVID patients