Iranian journal of immunology
Volume:6 Issue: 2, Spring 2009

Dendritic cells (DC) are a key regulator of the immune response, and interferon-beta (IFN-β) is considered an immunomodulatory molecule for DC. The purpose of this study was to evaluate the ability of IFN-β treated DC to induce cytokinesecretion by CD4+ T cells. Dendritic cells were generated from blood monocytes with granulocyte-monocyte colony-stimulating factor and interleukin-4 withor without IFN-β. We analyzed the production of CD4+ T helper cytokines (IL-17, IFN-γ and IL-10) in the supernatant of the dendritic cell-T cell co- cultures by ELISA. Wealso studied the effects of HLA-G and costimulatory molecules on immature and matureDC. IFN-γ and IL-17 decreased significantly in the presence of HLA-GbearingDC compared to control cultures (p<0.05). Using the mixed leukocytereaction, we found that DC treated with IFN-β mediated the inhibition of T cellactivation via cytokine production. We conclude that this is important for preventingoveractivation of the immune system.

Back ground: Candida albicans is a member of the normal human microflora. C. albicanscell wall is composed of several protein and carbohydrate components which havebeen shown to play a crucial role in C. albicans interaction with the host immune system.Major components of C. albican cell wall are carbohydrates such as mannans, βglucans and chitins, and proteins that partially modulate the host immune responses.Dendritic cells (DC), as the most important antigen-presenting cells of the immune system,play a critical role in inducing immune responses against different pathogens. We investigated the effect of the cell wall protein fraction (CPF) of C. albicanson DC maturation. The CPF of C. albicans cells was extracted by a lysisbuffer containing sodium dodecyl sulphate, 2-mercaptoethanol and phosphate-bufferedsaline. The extract was dialyzed and its protein pattern was evaluated by electrophoresis.Dendritic cells were purified from Balb/c mice spleens through a three-step methodincluding mononuclear cell separation, as well as 2-h and overnight cultures. The purifiedCPF was added at different concentrations to DC. The purity and maturation statusof DC were determined by flow cytometry using monoclonal antibodies against CD11c,MHC-II, CD40 and CD86. Treatment of DC with 10 μg/ml of CPF increasedthe expression of maturation markers including MHC-II, CD86 and CD40 on DC comparedto the control group. In this study we used C. albicans CPF with themolecular weight of 40-45 kDa for pulsing and maturation of dendritic cells. Since according to our results CPF significantly increased the expression of maturation markerson DC, we suggest that CPF may act as an efficient immunomodulator, or may be usedas a potential adjuvant to boost the host immune system against infections.

Heat shock protein 70 (HSP70) is present in all organisms studied so far,and is a major immunogen in infections caused by pathogens including Leishmania spp. The aim of this study was to clone and express HSP70 from L. infantumstrain MCAN/IR/96/LON-49 and evaluate antibody response against HSP70 in visceralleishmaniasis (VL). The L. infantum HSP70 gene segment was amplified byspecific primers. It was cloned into pTZ57R vector and subcloned into pET32a (+) expressionvector. The new construct was transformed in the E.coli Rosetta strain, andHSP70 protein was expressed in the presence of 1 mM IPTG and purified using a Hi-Trap chelating column. Antibody responses against HSP70 were determined by ELISAin 37 patients with visceral leishmaniasis and 63 healthy controls. Expressionof HSP70 protein was confirmed using SDS-PAGE electrophoresis and dot blot with ananti-His tag antibody. There was no difference between the sequence of nucleotides ofthe HSP70 gene in the present study and other reported sequences. The ELISA resultsindicated that the sera of 81.1% (30/37) of the patients and 6.3% (5/63) of controls reactedto L. infantum HSP70. The conservative nature of the HSP70 moleculeis an advantage in vaccine studies, because of minor differences (6%) between thenucleotide sequences and consequently the similarity in amino acid sequences in variousstrains of L. infantum. It could therefore be used in vaccine research againstleishmaniasis and also as a tool for serodiagnosis.

The major immuno-modulating effects of Ganoderma lucidum includemitogenicity and activation of immune effector cells such as T cells, macrophages andnatural killer cells resulting in the production of cytokines. The purpose ofthis study was to evaluate the expression of CD40 and CD80 by G. lucidum-treated humanperipheral blood mononuclear cells. Monocytes were isolated and incubatedat 37°C and 5% CO2 for 24 h and 48 h in the presence or absence of different concentrationsof G. lucidum. Cells were then incubated with labelled monoclonal antibodiesagainst CD14, CD40 and B7-1(CD80) molecules utilizing standard protocols, andanalyzed by flow cytometry. The results showed that incubation of monocyteswith G. lucidum led to marked enhancement of CD40 and B7-1 expression in a doseandtime- dependent manner (p<0.001). G. lucidum was more effective in enhancing theexpression of CD80 and CD40 molecules of cells obtained from females than male donors(p<0.001). G. lucidum enhanced the expression of CD40 and CD80molecules on peripheral blood monocytic cells derived from both sexes in a dosedependentmanner, with a preferential higher effect on cells obtained from female donors.

Prostate specific antigen (PSA) has been used as a screening test for theearly detection of prostate cancer (PC) for many years. Although the introduction ofPSA test led to a considerable increase in reported prostate cancer cases, there is stillsome controversy over the sensitivity and specificity of this marker in distinguishing PCpatients from those with benign prostate hyperplasia (BPH), the most common benignprostate condition. An attempt is made to elucidate if the plasma level ofInterleukin 8 (IL-8) could be used effectively as a marker for the detection of prostatecancer. Plasma levels of IL-8 and PSA were measured in two groups of 40BPH and PC patients using enzyme-linked immunosorbent (ELISA) and radioimmunoassay(RIA) techniques, respectively. In addition IL-8 levels in PC3 and DU145 cellline supernatants were measured by ELISA technique. The concentration ofIL-8 in the plasma of PC patients was not significantly higher than the BPH subjects.Although, a correlation between plasma IL-8 concentration and the Gleason score of PCpatients was found, no indicated correlation was detected between the concentration ofIL-8 or PSA and age of the patients in both groups. DU145 and PC3 cell lines producedand secreted IL-8 in the media. Data of this investigation collectively concludeno correlation between IL-8 concentration in PC and BPH patients.

Myasthenia gravis is an autoimmune disorder of neuromuscular junctioncharacterized by skeletal muscle weakness and fatigability. Different genes may controlthe induction and clinical presentation of this disease. Various HLA alleles are reportedas predisposing or protective genetic elements in myasthenia gravis. Theaim of this study was to investigate the probable association between HLA-DQ allelesand myasthenia gravis in southern Iranian patients. HLA-DQA1 and DQB1alleles were determined in 104 sporadic patients with myasthenia gravis using polymerasechain reaction - restriction fragment length polymorphism method and the resultswere compared to 816 healthy controls. HLA-DQA1*0101/2 (39.4%) andDQB1*0502 (21.6%) were the most frequent alleles in southern Iranian patients withmyasthenia gravis. These alleles revealed positive associations with the disease withrelative risks of 1.69 and 2.41, respectively. The most common haplotype wasDQA1*0101/2-DQB1*0502 in these patients. According to the results ofthis study, DQA1*0101/2 and DQB1*0502 alleles might be considered as predisposinggenetic factors to myasthenia gravis while DQA1*0501, DQB1*0301 and *0602/3show protective roles against this disease.