Attenuation of Peripheral Regulatory T-Cell Suppression of Skin-Homing CD8+T Cells in Atopic Dermatitis

PURPOSE: Cutaneous lymphocyte-associated antigen (CLA)-expressing CD8+T cells have been known to play an important role in the pathogenesis of atopic dermatitis (AD). However, the mechanisms underlying the loss of self-tolerance remain unclear. Regulatory T cells (Tregs) play a key role in the development of homeostasis in the immune system. We, therefore, hypothesized that a reduced ability of Tregs to inhibit autologous CD8+CLA+T cells might be underlying mechanism in AD. MATERIALS AND METHODS: CD8+CLA+T cells and Tregs were obtained from the peripheral blood of AD patients and control volunteers. The frequencies of CD8+CLA+T cells were evaluated. The proliferative responses of CD8+CLA+T cells were assessed by flow cytometry, and the levels of transforming growth factor-beta1 (TGF-beta1) and interleukin-10 (IL-10) in culture supernatants were detected by enzyme-linked immunosorbent assay. RESULTS: Our results revealed higher frequency and increased expression of perforin and granzyme-B in peripheral CD8+CLA+T cells in AD, and lower inhibitory ability of Tregs on proliferation of CD8+CLA+T cells in AD. Meanwhile, the levels of TGF-beta1 produced by Tregs were significantly lower in AD, and anti-TGF-beta1 abolished such suppression. CONCLUSION: The attenuated inhibitory ability of Tregs on hyper-activated autologous CD8+CLA+T cells, mediated by TGF-beta1, plays an important role in the pathogenesis of AD.

Sclareol reduces CD4+ CD25+ FoxP3+ t-reg cells in a breast cancer model in vivo

Sclareol is a phytochemical used in people's diet in Southeast Asia. To investigate the immunotherapeutic effectiveness of Sclareol against breast cancer by direct intraperitoneal injection. Sclareol was isolated and purified from Salvia sclarea. Effect of Sclareol on cell growth inhibition was evaluated by MTT assay. Intraperitoneally injected Sclareol effects on reducing the tumor volume and shifting the cytokine profile were investigated. We also assessed if intraperitoneally injected Sclareol could improve the outcome of cancer therapy through suppressing the regulatory T cells. The results confirmed a significant decrease in the tumor size. Furthermore, a significant decrease in the level of IL-4 and an increase in the level of IFN-gamma were noticed in the intraperitoneally injected Sclareol group [p<0.05]. It was also observed that the splenocytes of treated animals significantly increase in cell proliferation assay. Moreover, measurements of splenic T regulatory cell indicated that intraperitoneally injected Sclareol significantly decreased the number of splenic T regulatory cell. Our results suggest that Sclareol, by reducing T-reg cells frequency and also tumor size can enhance the effect of cancer therapy as an immunostimulant

The imbalance between Treg and Th17 cells caused by FTY720 treatment in skin allograft rejection

OBJECTIVES: FTY720 modulates CD4+T cells by the augmentation of regulatory T cell activity, secretion of suppressive cytokines and suppression of IL-17 secretion by Th17 cells. To further understand the process of graft rejection/acceptance, we evaluated skin allograft survival and associated events after FTY720 treatment. METHODS: F1 mice (C57BL/6xBALB/c) and C57BL/6 mice were used as donors for and recipients of skin transplantation, respectively. The recipients were transplanted and either not treated or treated with FTY720 by gavage for 21 days to evaluate the allograft survival. In another set of experiments, the immunological evaluation was performed five days post-transplantation. The spleens, axillary lymph nodes and skin allografts of the recipient mice were harvested for phenotyping (flow cytometry), gene expression (real-time PCR) and cytokine (Bio-Plex) analysis. RESULTS: The FTY720 treatment significantly increased skin allograft survival, reduced the number of cells in the lymph nodes and decreased the percentage of Tregs at this site in the C57BL/6 recipients. Moreover, the treatment reduced the number of graft-infiltrating cells and the percentage of CD4+ graft-infiltrating cells. The cytokine analysis (splenocytes) showed decreased levels of IL-10, IL-6 and IL-17 in the FTY720-treated mice. We also observed a decrease in the IL-10, IL-6 and IL-23 mRNA levels, as well as an increase in the IL-27 mRNA levels, in the splenocytes of the treated group. The FTY720-treated mice exhibited increased mRNA levels of IL-10, IL-27 and IL-23 in the skin graft. CONCLUSIONS: Our results demonstrated prolonged but not indefinite skin allograft survival by FTY720 treatment. This finding indicates that the drug did not prevent the imbalance between Tr1 and Th17 cells in the graft that led to rejection.

Effect of thymosin alpha-1 on subpopulations of Th1, Th2, Th17, and regulatory T cells (Tregs) in vitro

Thymosin alpha 1 (Tα1) has been shown to have beneficial effects on numerous immune system parameters, but little is known about the effects of Tα1 on patients with gastric carcinoma. The objective of this study was to determine the effect of Tα1 on subpopulations of Th1, Th2, Th17, and regulatory T cells (Tregs) in vitro, and to evaluate its efficacy as an immunoregulatory factor in patients with gastric carcinoma. We compared the effect of Tα1 on the frequency of CD4+ and CD8+ T cells, especially the CD4+CD25+Foxp3+ Tregs in peripheral blood mononuclear cells (PBMCs) from gastric carcinoma patients (N = 35) and healthy donors (N = 22). We also analyzed the changes in the proliferation of PBMCs in response to treatment with Tα1, and examined the production of Th1, Th2, and Th17 cytokines by PBMCs and tumor-infiltrating lymphocytes. The treatment of PBMCs from gastric cancer patients, with Tα1 (50 µg/mL) alone increased the percentage of CD4+CD25+Foxp3+ (suppressive antitumor-specific Tregs) from 1.68 ± 0.697 to 2.19 ± 0.795 percent (P < 0.05). Our results indicate that Tα1 increases the percentage of Tregs and IL-1β, TNF-α, and IL-6 in vitro.

Cyclosporin A-treated Dendritic Cells may affect the outcome of organ transplantation by decreasing CD4+CD25+ regulatory T cell proliferation

One of the mechanisms for generation of tolerance involves immature dendritic cells (DCs) and a subpopulation of regulatory CD4+ CD25+ T lymphocytes (T REG). The purpose of this work was to analyze how Cyclosporine A (CsA), a widely used immunosuppressive drug, may affect T REG proliferation. Purified and activated murine DCs obtained from bone marrow precursors differentiated with rGMCSF were co-cultured with purified CFSE-labeled T REG from OTII mice, and their phenotype and proliferation analyzed by flow cytometry. Our data indicate that DCs differentiated in the presence of CsA show an altered phenotype, with a lower expression of MHC-II and a lower activating capacity. Additionally, these CsA-treated DCs show decreased production of IL-2 and IL-12 and increased IL-10 secretion when stimulated with LPS, indicating an effect on the polarization of the immune response. Interestingly, CsA-treated DCs show an anti-tolerogenic effect since they reduce the proliferation of T REG cells from 72 to 47 percent. Further inhibition to a 24 percent of T REG proliferation was obtained as a direct effect of CsA on T REG. In conclusion, the anti-tolerogenic effect of CsA should be considered in the planning of immunosuppression in the context of clinical transplantation.

Immunomodulatory effect of cimetidine on the proliferative responses of splenocytes from T. cruzi-infected rats

O efeito imunomodulatorio da Cimetidine (CIM), um antagonista do receptor de histamina-tipo 2, foi avaliado na resposta blastogenica a Con A em celulas de ratos Wistar Furth (WF) infectados pela cepa Y de Trypanosoma cruzi (T.cruzi). Foi observado que apenas na concentracao de "10 POT. -3"M de Cimetidine houve amplificacao da resposta blastogenica de esplenocitos normais a Con A. Entretanto, a capacidade mitogenica de esplenocitos de animais infectados foi restaurada na presenca de molaridades da droga que variaram entre "10 POT. -8" a "10 POT. -3". Os resultados demonstraram que a CIM tem o potencial de modular a resposta mitogenica de celulas de animais infectados pelo T.cruzi, sugerindo um papel imunoregulatorio da histamina e/ou celulas que expressam receptores H2 nesta infeccao.

Effect of high dose intravenous pulse dexamethasone on lymphocyte phenotypes.

The lymphocyte phenotypes were enumerated in 10 patients with collagen diseases at 0 h, 4 h, 24 h and 7 days after a megadose (100 mg) iv pulse dexamethasone. A significant decrease in CD3 (from a mean of 2324.3/mm3 to 705.9/mm3) and CD4 (from a mean of 1642.6 to 317.6/mm3) cells was observed at 4 h, which recovered partially by 24 h (186.7 and 1226.3/mm3 respectively) and completely at 7 days (2496.1 and 1838.4/mm3). A transient decrease in CD8 cells at 4 h was also observed. There was no significant effect on B cells.

De Hahnemann a la inmunologia actual / From Hahnemann to the actual immunology

Los conocimientos actuales sobre inmunologia, han llegado a las mismas conclusiones que el Dr. Samuel Hahnemann en 1813 expreso sobre la dermatitis por contacto y el Rhus toxicodendron. Los inmunologos, al estudiar los efectos de diferentes haptenos capaces de producir dermatitis por contacto, entre los que esta el Rhus toxicodendron, pudieron constatar que la inmunidad celular es la directamente responsable de la patologia manifiestal; asimismo, han demonstrado que los haptenos administrados por via oral a pequenas dosis provocan la proliferacion de linfocitos T supresores que limitan y regulan la respuesta celular. Es importante hacer notar que el Dr. Hahnemann desarrollo dentro de su terapeutica el uso del Rhus toxicodendron y que este medicamento se emplea en terapia homeopatica actual para curar padecimientos en los que la inmunidad celular es la responsable de las lesiones tisulares como son algunos cuadros de dermatitis por contacto, tuberculosis, enfermedades virales y artritis reumatoide. Los inmunologos han concluido conceptos que los llevan a la terapia homeopatica en lo que se refiere a la dermatitis por contacto; quedando por comprobar experimentalmente si en los otros padecimientos en donde se usa el Rhus toxicodendron tambien intervienen los linfocitos T supresores para impedir el dano a los tejidos

Effect of suppressor cells on antibody producing cells in mice infected with Mycobacterium leprae.

Swiss albino mice were transfused with suppressor cells obtained after in vivo stimulation of mice with Con A (NS group). Some of the animals were infected with Mycobacterium leprae (NSI-group). Half of these animals were treated with dapsone (NSIT group). Adequate normal (NC) and infected (NI) controls were included. A plaque assay was carried out at different time periods to elucidate the effect of suppressor cells on antibody producing cells. No significant difference was seen in the number of plaque forming cells (PFC) in infected and dapsone treated animals (NSIT) when these were compared with controls. However significant increase seen in the number of IgM plaque forming cells at 6 months in NI and NSI groups and IgG PFC in NI group could be due to the peak footpad infection during this period. The significant decrease in the number of IgG PFC in NS and NSIT group compared to NC at 0 month is probably due to the suppressor cell activity in these groups.

Efecto de la ciclosfosfamida sobre el crecimiento de un sarcoma transplantable de rata S-E 100 / Effect of cyclophosphamide on a transplantable rat sarcoma S-E 100

La ciclosfosfamida (Cy) se utiliza en el tratamiento del cáncer como droga citotóxica, produciendo grados variables de inmunodepresión. En trabajos experimentales se ha observado que al administrarse en dosis bajas aumenta la respuesta inmune, preferentemente la mediada por células. Este efecto se debería a una acción selectiva sobre los linfocitos T supresores. Con el objeto de investigar la Cy como moduladora de la respuesta inmune antitumoral se estudió el efecto de una dosis única (20 mg/Kg de peso) sobre el crecimiento de un sarcoma transplantable de rata (S-E100). La droga se administró a distintos días del desafío tumoral. Previamente, se evaluó el efecto de la droga sobre el peso del bazo, el número de células esplénicas y la viabilidad de las células S-E100 in vivo ]cámaras de difusión) con el objeto de determinar una dosis que no ejerciera una acción citotóxica inmediata sobre las células esplénicas ni sobre las células tumorales. Los resultados mostraron que una dosis única de 20mg/Kg de peso no modificó el peso del bazo, el número de células esplénicas ni la viabilidad de las células neoplásicas. Esta misma dosis produjó, en cambio, distintos efectos sobre el crcimiento del S-E100 dependidendo del día de su administración. Cuando se administró la Cy a los 7, 14 o 21 días del crcimiento tumoral se obtuvo la regresión del 100% de los tumores. la histopatología de los tumoes en regresión mostró alteraciones compatibles con un rechazo mediado por células

T-cell subpopulations in tuberculosis and the effects of rifampicin.

T-cell subpopulations were evaluated by several recent methods in 38 tuberculosis patients (24 active and 10 quiescent cases of pulmonary tuberculosis; two of miliary and two of active extra-pulmonary tuberculosis) before and during rifampicin (RMP) treatment. There was a significant reduction in the total number of T cells (E-RFC and OKT3+ cells) and of helper T cells (OKT4+) coinciding with an increase in the number of suppressor T cells when the 38 tuberculosis patients were compared with 21 healthy control subjects. When the changes of T-cell subpopulations in groups of subjects and patients with different clinical forms of the disease were analysed, these changes could be clearly shown with both sets of assays (receptor assays and monoclonal antibody assays) among those with the active pulmonary form of tuberculosis while similar changes could be demonstrated only by one or the other assay among those with the other forms of the disease. The effects of one month of RMP treatment on these parameters were much more obvious among the clinically active patients than the quiescent patients, i.e. a recovery of total T cells from a low pre-treatment to a near normal level accompanied by a significant reduction in the number of suppressor cells (OKT8+). In fact, among quiescent patients the number of suppressor cells (as TG) appeared to rise further with RMP treatment.