Effects of Oral Probiotic Feeding on Toll-Like Receptor Gene Expression of the Chicken's Cecal Tonsil.

BACKGROUND: It was proposed that probiotics may influence immune system through direct or indirect exposure. Direct exposure is mostly mediated by surface receptors. Toll-like receptors (TLRs) are conserved molecular sensors which could be triggered via some pathogen associated structures, hence, modulate the immune responses. This study was conducted to elucidate the impact of lactobacillus acidophilus as a common probiotic on the expression level of TLRs in the chicken's cecal tonsil. METHODS: Thirty one-day-old chicken were selected and separated into three groups as probiotic-fed, dairy-fed and control. In addition to commercial powder supply, each chicken in the probiotic-fed group received 109 CFU/Kg of L. acidophilus daily. While, chickens in the dairy-fed group were provided with commercial powder feed and sterile dairy milk. After 14 and 21 days of oral feeding the cecal tonsil was removed and the expression of TLR2, TLR4 and TLR5 were examined by real-time PCR. RESULTS: At the age of 14-day, there was a slight upregulation in the expression levels of TLR2 (118.9%), TLR4 (129.6%) and TLR5 (123.7%) of the cecal tonsil in the probiotic-fed group; however, these alterations were not statistically significant. At the age of 21-day, a non-significant downregulation was observed in TLR expression level of both dairy-fed (TLR2, 85%; TLR4, 79.5%; and TLR5, 86.5%) and probiotic-fed (TLR2, 88.8%; TLR4, 81%; and TLR5, 87.2%) groups in comparison to controls. CONCLUSION: The findings revealed that although the probiotic supplementation could be useful but it did not significantly affect innate immunity state through alteration of TLRs.

Current Status and Prospective Regarding the Therapeutic Potential of Natural Autoantibodies in Cancer Therapy.

The presence of natural auto-antibodies (NAbs) in normal range/activity in healthy individuals is essential for body to maintain hemostasis, which are directed to self and altered self-components, while abnormal activity of this system can be associated with several health related diseases. It has been shown that NAbs regulate immune system, and can be changed during the individual's life. In other word, the level and pattern of Nabs is among the main factors to define the state of the body, suggesting their prognostic values as markers of immune system impairment such as autoimmunity and cancer. Such NAbs have gained substantial attention because several of them, including their recombinant forms, have therapeutic potential (e.g., programmed cell death-1 [PD-1, Pdcd1], which some of its inhibitors have been approved by FDA for cancer therapy). Whereas a large number of IgM and IgG NAbs have a key role in tissue homeostasis, while others modulate cellular and enzyme properties. The aim of current review is to give an overview about some of these NAbs and how these low-titer/affinity interact with Ag in homeostasis, with particular emphasis on related diseases such as systemic inflammatory response syndrome and cancer, and their application as potential therapeutic target for cancer therapy.

Effect of Mesenchymal Stem Cells on ILT3 Expression in the Splenocytes of Skin Graft Recipient Mice.

BACKGROUND: Mesenchymal stem cells (MSCs) are considered as effective therapeutic cells in transplantation due to their immunomodulatory activities. However, precise mechanism of MSCs immunomodulatory activity is not completely understood. OBJECTIVES: To study the role of Immunoglobulin-like transcripts-3 (ILT3) immunomodulatory receptor in immune tolerance induced by MSCs in skin transplantation model and induction of tolerogenic dendritic cells (Tol-DCs) by MSCs through up-regulation of ILT3. METHODS: C57BL/6 skin grafts were transplanted to the back of BALB/c mice. Recipient mice received MSCs on days 0, 1 and 2 post transplantation. On days 2, 5 and 10 post skin transplantation, ILT3 and forkhead box P3 (FOXP3) expression in the spleens of MSCs treated mice were evaluated. Furthermore, MSCs and DCs were co-cultured in cell culture plates and transwell systems. Then, the expressions of ILT3 mRNA and protein in MSC-treated DCs were evaluated. Additionally, MSC-treated DCs were co-cultured with allogeneic T-cells and FOXP3 expression in T-cells was evaluated. RESULTS: The expression of ILT3 and FOXP3 were higher in the splenocytes of MSCs-treated mice early post-transplantation. Furthermore, we observed that MSC-treated DCs can increase FOXP3 expression in T-cells. But, we could not find any differences in ILT3 expression between MSC-treated DCs and untreated ones. CONCLUSION: One of the mechanisms underlying MSCs immunomodulatory function could be up-regulating ILT3 expression in splenocytes. But our results did not support the hypothesis that MSCs induce Tolergenic DCs by up-regulation of ILT3.

Decline in Immunological Responses Mediated by Dendritic Cells in Mice Treated with 18α-Glycyrrhetinic Acid.

OBJECTIVE: 18α-Glycyrrhetinic acid (18α-GA), a bioactive component of Glycyrrhiza glabra, has been shown in vitro immunomodulatory effects on dendritic cells (DCs). The aim of the present study is to evaluate the in vivo effect of 18α-GA on DCs and T cell responses. METHODS: 18α-GA was intraperitoneally administered to mice and splenic DCs were evaluated for expression of co-stimulatory molecules using flow cytometry. Isolated DCs were added to mixed lymphocyte reaction (MLR) and the proliferation of T cells was measured using BrdU assay. The level of IFN-γ in the MLR supernatant was determined by enzyme-linked immunosorbent assay. The in vivo effect of isolated DCs on antigen-specific delayed type hypersensitivity (DTH) response, and the number of regulatory T (Treg) cells in mice spleen by flow cytometry, were investigated. RESULTS: DCs isolated from 18α-GA-treated mice expressed lower levels of CD40 (p < 0.05) and MHC II (p < 0.01) compared to those of control group. In MLR assay isolated DCs decreased T cell proliferation to 83.54% ± 4.3% of control (p < 0.05). The level of IFN-γ in the MLR supernatant was declined to 25.2% ± 6.8% of control. In DTH test, DCs isolated from 18α-GA-treated mice significantly suppressed antigen-specific cell mediated immune response (3.3 ± 1 mm in test group versus 6.5 ± 1.2 mm in control group, ρ < 0.01). The percentage of Treg cells in spleen of 18α-GA-treated mice (6.37% ± 2.3%) was lower than that of control group (13.85% ± 0.4%, ρ < 0.05). CONCLUSIONS: In vivo administration of 18α-GA resulted in inhibition of DCs maturation and T cell-mediated responses, the effects that may candidate this compound for its possible benefits in immune-mediated diseases.

Evaluation of Immunomodulatory Effects of Mesenchymal Stem Cells Soluble Factors on miR-155 and miR-23b Expression in Mice Dendritic Cells.

Mesenchymal stem cells (MSCs) can modulate dendritic cells (DCs) activation and induce tolerogenic characteristics in DCs. All mechanisms involved in MSCs-induced tolerogenic DCs are not fully understood. MicroRNAs (miRs) play important role in maturation and function of DCs. In this study, we investigated the effects of MSCs culture supernatant (C.S.) on expression of miR-155 and miR-23b in mice DCs. BALB/c mice spleens were used for DCs isolation. MSCs were isolated from the mice bone marrow and cultured in DMEM media. When MSCs expanded to sixth passage, C.S. was collected after 12, 24 and 48 h. Quantitative polymerase chain reaction (QPCR) was used to determine the expression of miR-155 and miR-23b in DCs treated with C.S. after 6 and 12 h. Secretion of IL-23 and TGF- ß were detected in DCs treated with C.S. by ELISA after 24 h. miR-23b expression was significantly increased in DCs treated with 12 h C.S. for 12 h compared to negative controls. miR-155 expression did not change in DCs treated with C.S. after 6 and 12 h. miR-23b expression was significantly increased in DCs treated with 12 h C.S. for 12 h, compared to those treated with C.S. for 6 h. Similarly, miR-23b expression was increased in DCs treated with 24 h C.S. for 12 h when compared to those treated for 6 h. Production of TGF-ß and IL-23 were not influenced by C.S. In conclusion, miR-23b is considered to be one of the mechanisms involved in tolerogenic DCs induction by C.S. in a time-dependent manner.

Effect of CD40 silenced dendritic cells by RNA interference on mice skin allograft rejection.

AIM: Tolerogenic dendritic cells (DCs) play a critical role in inducing and maintaining tolerance. CD40 is a member of tumor necrosis factor receptor super family and is a potent T-cell costimulatory molecule. Therefore, in this study we evaluated the effect of CD40 silenced DCs by RNA interference on mice skin allograft rejection. MATERIALS & METHODS: Skin transplantation was performed from C57BL/6 to BALB/c mouse. Skin allograft recipients were assigned to four groups (n = 5). CD40 downregulated DCs were injected to the BALB/c mice intravenously 7 days before transplantation. Then, graft survival time, Treg generation, CD4(+) and CD8(+) T cells infiltration and cytokine levels in serum of this group were compared with those of untreated and cyclosporine groups. RESULTS: In comparison with untreated group, BALB/c mice injected with CD40 siRNA transfected DCs showed an increased graft survival time, Treg cells, IL-4 and IL-10 cytokine levels as well as decreased number of intragraft CD4(+) and CD8(+) T cells. IFN-γ and IL-12 secretion were diminished, too. CONCLUSION: Taken together, these data demonstrate that downregulation of CD40 in DCs can expand Treg cells and increase skin allograft survival.

Immunostimulatory effects of Leishmania infantum HSP70 recombinant protein on dendritic cells in vitro and in vivo.

BACKGROUND: Activation of dendritic cells (DCs) has an important role in immunity against Leishmania. AIM: We investigated the effect of Leishmania infantum (L. infantum) heat shock protein 70 recombinant protein (rHSP70) as a vaccine on DC maturation and function. MATERIALS & METHODS: BALB/c mouse splenic DCs were isolated and treated with different concentrations of rHSP70. Maturation markers, cytokine production and capability of DCs to proliferate allogeneic T cells were evaluated. Furthermore, this recombinant protein was injected into BALB/c mice, and expression of CD86, CD40 and MHC class II molecules by their splenic DCs were evaluated. RESULTS: rHSP70 significantly increases the production of IL-12p70 by DCs. It had no effect on allogeneic T-cell proliferation in mixed lymphocyte reaction. It increased IFN-γ and decreased IL-4 cytokine level in mixed lymphocyte reaction supernatant. The in vitro study showed that rHSP70 had no significant effect neither on the percentage of CD40(+), CD86(+) and MHC class II(+) DCs nor on the mean fluorescent intensity. However, in vivo results showed that rHSP70 increases the percentage of CD86-, CD40- and MHC class II-expressing cells as well as mean fluorescent intensity of CD40 and MHC class II. CONCLUSION: This study demonstrated the capability of L. infantum-derived rHSP70 in maturating BALB/c mice splenic DCs and in vivo polarization of immunity to a Th1 response.

The effects of cichorium intybus extract on the maturation and activity of dendritic cells.

BACKGROUND: Cichorium intybus is a medicinal plant commonly used in traditional medicine for its benefits in immune-madiated disorders. There are several evidences showing that C. intybus can modulate immune responses. In the present study we have investigated the effects of the ethanolic root extract of this plant on the immune system by targeting dendritic cells (DCs). For this purpose, phenotypic and functional maturity of murine DCs after treatment with the extract was analyzed by flow cytometry and mixed lymphocyte reaction (MLR) assay. RESULTS: C. intybus did not change the expression of CD40, CD86 and MHC-II molecules as important co-stimulatory markers on DCs compared to the control, indicating that it could not promote DCs phenotypic maturation. Treatment of DCs with lower concentrations of the extract resulted in an increased production of IL-12 by these cells with no change in IL-10 release. The capacity of treated DCs to stimulate allogenic T cells proliferation and cytokines secretion was examined in the co-cuture of these cells with T cells in MLR. C. intybus at higher concentrations inhibited proliferation of allogenic T cells and in lower concentrations changed the level of cytokines such that IL-4 decreased and IFN-γ increased. CONCLUSIONS: These results indicated that C. intybus extract at higher concentrations can inhibit T cell stimulating activity of DCs, whereas at lower concentrations can modulate cytokine secretion toward a Th1 pattern. These data may in part explain the traditional use of this plant in treatment of immune-mediated disorders.