RESUMEN
CD4 T cell activation and differentiation mechanisms constitute a complex and intricate signaling network involving several regulatory proteins. IRF2BP2 is a transcriptional repressor that is involved in gene-expression regulation in very diverse biologic contexts. Information regarding the IRF2BP2 regulatory function in CD4 T lymphocytes is very limited and suggests a role for this protein in repressing the expression of different cytokine genes. Here, we showed that Irf2bp2 gene expression was decreased in CD4 T cells upon activation. To investigate the possible regulatory roles for IRF2BP2 in CD4 T cell functions, this protein was ectopically expressed in murine primary-activated CD4 T lymphocytes through retroviral transduction. Interestingly, ectopic expression of IRF2BP2 led to a reduction in CD25 expression and STAT5 phosphorylation, along with an impaired proliferative capacity. The CD69 expression was also diminished in IRF2BP2-overexpressing cells, whereas CD44 and CD62L levels were not altered. In vivo, transferred, IRF2BP2-overexpressing, transduced cells displayed an impaired expansion capacity compared with controls. Furthermore, overexpression of IRF2BP2 in differentiated Th cells resulted in slightly reduced IL-4 and pro-TGF-ß production in Th2 and iTregs but had no effect on IFN-γ or IL-17 expression in Th1 and Th17 cells, respectively. Taken together, our data suggest a role for IRF2BP2 in regulating CD4 T cell activation by repressing proliferation and the expression of CD25 and CD69 induced by TCR stimuli.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Activación de Linfocitos/inmunología , Receptores de Antígenos de Linfocitos T/inmunología , Factores de Transcripción/inmunología , Animales , Antígenos CD/biosíntesis , Antígenos CD/genética , Antígenos de Diferenciación de Linfocitos T/biosíntesis , Antígenos de Diferenciación de Linfocitos T/genética , Apoptosis/inmunología , Células Cultivadas , Citocinas/biosíntesis , Citocinas/genética , Femenino , Regulación de la Expresión Génica/inmunología , Humanos , Subunidad alfa del Receptor de Interleucina-2/biosíntesis , Subunidad alfa del Receptor de Interleucina-2/genética , Lectinas Tipo C/biosíntesis , Lectinas Tipo C/genética , Activación de Linfocitos/genética , Masculino , Ratones , Ratones Endogámicos C57BL , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Quimera por Radiación , Proteínas Recombinantes de Fusión/metabolismo , Factor de Transcripción STAT5/metabolismo , Transducción GenéticaRESUMEN
Stem cells from mesenchymal origin (MSC) exert a plethora of immunomodulatory effects. We created a neoplastic model based on in vitro step-wise transformation to assess whether oncogenic pathways have the capacity to mould the cross-talk of MSC and lymphocytes. Neoplastic MSC exhibit an increased inhibitory effect on T cell proliferation, either directly or mediated by myeloid derived suppressor cells. Additionally, transformation of MSC enhances T cell apoptosis without reducing either the percentage of CD25 expressing cells or the level of this protein expression. Malignant transformation drives MSC to lose dependency on nitric oxide for immunosuppression whilst increasing the constitutive production of PGE2. Our results indicate that oncogenesis tunes the interplay between MSC and immune cells, favoring cancer immune evasion.
Asunto(s)
Comunicación Celular/inmunología , Transformación Celular Neoplásica/inmunología , Células Madre Mesenquimatosas/inmunología , Linfocitos T/inmunología , Animales , Apoptosis/inmunología , Diferenciación Celular/inmunología , Proliferación Celular , Células Cultivadas , Dinoprostona/biosíntesis , Femenino , Terapia de Inmunosupresión , Subunidad alfa del Receptor de Interleucina-2/biosíntesis , Activación de Linfocitos/inmunología , Ratones , Ratones Endogámicos BALB C , Ratones Noqueados , Óxido Nítrico/inmunología , Óxido Nítrico Sintasa de Tipo II/genética , Óxido Nítrico Sintasa de Tipo II/inmunología , Escape del Tumor/inmunología , Proteína p53 Supresora de Tumor/genéticaRESUMEN
IL-10 is a regulatory cytokine that plays a major role in the homeostasis of the gut and this is illustrated by the fact that IL-10(-/-) mice develop spontaneous colitis. In this study, IL-10(-/-) mice were analyzed for immunological changes during colitis development. We found a reduced frequency of regulatory T cells CD4(+)CD25(+)Foxp3(+) and higher frequency of activated T cells in the colon that precedes the macroscopic signs of the disease. Production of IL-17 and IFN-γ was higher in the colon. Colitis progression culminates with the reduction of CD4(+)LAP(+) regulatory T cells in the intestine. Frequency of B1 cells and the secretory IgA production were both elevated. Despite these alterations, 16-week-old IL-10(-/-) mice could be rendered tolerant by a continuous feeding protocol. Our study provides detailed analysis of changes that precede colitis and it also suggests that oral tolerance could be used to design novel alternative therapies for the disease.
Asunto(s)
Subgrupos de Linfocitos B/metabolismo , Colitis/inmunología , Inflamación/inmunología , Interleucina-10/inmunología , Mucosa Intestinal/inmunología , Linfocitos T Reguladores/metabolismo , Animales , Subgrupos de Linfocitos B/inmunología , Colitis/complicaciones , Colitis/patología , Colon/inmunología , Colon/patología , Factores de Transcripción Forkhead/biosíntesis , Factores de Transcripción Forkhead/inmunología , Tolerancia Inmunológica , Inmunoglobulina A/biosíntesis , Inmunoglobulina A/inmunología , Inflamación/complicaciones , Inflamación/patología , Interferón gamma/biosíntesis , Interferón gamma/inmunología , Interleucina-10/deficiencia , Interleucina-10/genética , Interleucina-17/biosíntesis , Interleucina-17/inmunología , Subunidad alfa del Receptor de Interleucina-2/biosíntesis , Subunidad alfa del Receptor de Interleucina-2/inmunología , Mucosa Intestinal/patología , Ratones , Ratones Noqueados , Linfocitos T Reguladores/inmunologíaRESUMEN
BACKGROUND: Heat shock proteins (Hsps) are stress induced proteins with immunomodulatory properties. The Hsp70 of Mycobacterium tuberculosis (TBHsp70) has been shown to have an anti-inflammatory role on rodent autoimmune arthritis models, and the protective effects were demonstrated to be dependent on interleukin-10 (IL-10). We have previously observed that TBHsp70 inhibited maturation of dendritic cells (DCs) and induced IL-10 production by these cells, as well as in synovial fluid cells. METHODOLOGY/PRINCIPAL FINDINGS: We investigated if TBHsp70 could inhibit allograft rejection in two murine allograft systems, a transplanted allogeneic melanoma and a regular skin allograft. In both systems, treatment with TBHsp70 significantly inhibited rejection of the graft, and correlated with regulatory T cells (Tregs) recruitment. This effect was not tumor mediated because injection of TBHsp70 in tumor-free mice induced an increase of Tregs in the draining lymph nodes as well as inhibition of proliferation of lymph node T cells and an increase in IL-10 production. Finally, TBHsp70 inhibited skin allograft acute rejection, and depletion of Tregs using a monoclonal antibody completely abolished this effect. CONCLUSIONS/SIGNIFICANCE: We present the first evidence for an immunosuppressive role for this protein in a graft rejection system, using an innovative approach--immersion of the graft tissue in TBHsp70 solution instead of protein injection. Also, this is the first study that demonstrates dependence on Treg cells for the immunosuppressive role of TBHsp70. This finding is relevant for the elucidation of the immunomodulatory mechanism of TBHsp70. We propose that this protein can be used not only for chronic inflammatory diseases, but is also useful for organ transplantation management.
Asunto(s)
Linfocitos T CD4-Positivos/citología , Células Dendríticas/citología , Proteínas HSP70 de Choque Térmico/metabolismo , Subunidad alfa del Receptor de Interleucina-2/biosíntesis , Linfocitos T Reguladores/citología , Animales , Linfocitos T CD4-Positivos/metabolismo , Línea Celular Tumoral , Enfermedad Crónica , Femenino , Inmunosupresores/metabolismo , Interleucina-10/metabolismo , Melanoma Experimental , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Líquido Sinovial/metabolismo , Linfocitos T/citología , Trasplante HomólogoRESUMEN
We have previously demonstrated that PAS-1, a 200 kDa protein from Ascaris suum, has a potent immunomodulatory effect on humoral and cell-mediated responses induced by APAS-3 (an allergenic protein from A. suum) or unrelated antigens. In this study, we investigated the mechanisms by which PAS-1 is able to induce this effect on an allergic airway inflammation induced by OVA in mice. C57BL/6 mice were adoptively transferred on day 0 with seven different PAS-1-primed cell populations: PAS-1-primed CD19(+) or B220(+) or CD3(+) or CD4(+) or CD8(+) or CD4(+) CD25â» or CD4(+) CD25(+) lymphocytes. These mice were immunized twice with OVA and alum by intraperitoneal route (days 0 and 7) and challenged twice by intranasal route (days 14 and 21). Two days after the last challenge, the airway inflammation was evaluated by antibody levels, cellular migration, eosinophil peroxidase levels, cytokine and eotaxin production, and pulmonary mechanical parameters. Among the adoptively transferred primed lymphocytes, only CD4(+) CD25(+) , CD8(+) or the combination of both T cells impaired the production of total IgE and OVA-specific IgE and IgG1 antibodies, eosinophilic airway inflammation, Th2-type cytokines (IL-4, IL-5 and IL-13), eotaxin release and airway hyperreactivity. Moreover, airway recruited cells from CD4(+) CD25(+) and CD8(+) T-cell recipient secreted more IL-10/TGF-ß and IFN-γ, respectively. Moreover, we found that PAS-1 expands significantly the number of CD4(+) CD25(+) FoxP3(+) and CD8(+) γδTCR(+) cells. In conclusion, these findings demonstrate that the immunomodulatory effect of PAS-1 is mediated by these T-cell subsets.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Proteínas del Helminto/inmunología , Inmunomodulación , Receptores de Antígenos de Linfocitos T gamma-delta/fisiología , Hipersensibilidad Respiratoria/inmunología , Traslado Adoptivo , Animales , Linfocitos T CD4-Positivos/patología , Linfocitos T CD8-positivos/patología , Factores de Transcripción Forkhead/biosíntesis , Inflamación/inmunología , Subunidad alfa del Receptor de Interleucina-2/biosíntesis , Masculino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratas , Ratas Wistar , Hipersensibilidad Respiratoria/patologíaRESUMEN
Circulation CD4(+)CD25(+)FoxP3(+) regulatory T cells (Tregs) have been associated with the delicate balancing between control of overwhelming acute malaria infection and prevention of immune pathology due to disproportionate inflammatory responses to erythrocytic stage of the parasite. While the role of Tregs has been well-documented in murine models and P. falciparum infection, the phenotype and function of Tregs in P. vivax infection is still poorly characterized. In the current study, we demonstrated that patients with acute P. vivax infection presented a significant augmentation of circulating Tregs producing anti-inflammatory (IL-10 and TGF-beta) as well as pro-inflammatory (IFN-gamma, IL-17) cytokines, which was further positively correlated with parasite burden. Surface expression of GITR molecule and intracellular expression of CTLA-4 were significantly upregulated in Tregs from infected donors, presenting also a positive association between either absolute numbers of CD4(+)CD25(+)FoxP3(+)GITR(+) or CD4(+)CD25(+)FoxP3(+)CTLA-4(+) and parasite load. Finally, we demonstrate a suppressive effect of Treg cells in specific T cell proliferative responses of P. vivax infected subjects after antigen stimulation with Pv-AMA-1. Our findings indicate that malaria vivax infection lead to an increased number of activated Treg cells that are highly associated with parasite load, which probably exert an important contribution to the modulation of immune responses during P. vivax infection.
Asunto(s)
Linfocitos T CD4-Positivos/citología , Factores de Transcripción Forkhead/biosíntesis , Subunidad alfa del Receptor de Interleucina-2/biosíntesis , Malaria/parasitología , Plasmodium vivax/genética , Adulto , Antígenos CD/metabolismo , Antígeno CTLA-4 , Proliferación Celular , Humanos , Interferón gamma/metabolismo , Interleucina-10/metabolismo , Interleucina-17/metabolismo , Malaria/sangre , Persona de Mediana Edad , Fenotipo , Factor de Crecimiento Transformador beta/metabolismoRESUMEN
PURPOSE: Interleukin-12 (IL-12) is an immunostimulatory cytokine with potent antitumor effects in several animal models. However, serious toxicity has been associated with its systemic application in humans. Gene transfer has emerged as a tool to specifically express therapeutic genes into the tumor/peritumoral milieu, thus avoiding systemic toxicity. The aim of this study was to analyze whether subtherapeutic doses of an adenovirus encoding IL-12 (AdIL-12) might synergize with low immunopotentiating doses of cyclophosphamide in the treatment of colorectal carcinoma. EXPERIMENTAL DESIGN: The antitumor effect of combining a single low dose of cyclophosphamide with an intratumoral injection of AdIL-12 was evaluated in an in vivo murine colorectal carcinoma model. The immune responses achieved with different treatments were monitored, comparing the effect of combining both therapies with individual treatments. RESULTS: The combined therapy induced a complete tumor regression in >50% of mice in a synergistic fashion, and it significantly prolonged their survival. This strategy was superior to each single treatment in reducing both peripheral and splenic CD4+CD25+Foxp3+ regulatory T cells, increasing the number of activated dendritic cells, and inducing IFN-gamma-secreting CD4-positive T lymphocytes. Importantly, the combined treatment generated a powerful tumor-specific CTL response. Consistently, a significant reduction in IL-10 levels was found. Our data suggest that the combination of nontoxic doses of cyclophosphamide with AdIL-12 allows the generation of good antitumoral responses, thus avoiding undesired side effects of both agents. CONCLUSIONS: Our data strongly support the use of a combination of cyclophosphamide and AdIL-12 as a novel therapeutic strategy against colorectal carcinoma.
Asunto(s)
Antineoplásicos Alquilantes/farmacología , Carcinoma/tratamiento farmacológico , Neoplasias Colorrectales/tratamiento farmacológico , Ciclofosfamida/farmacología , Técnicas de Transferencia de Gen , Terapia Genética/métodos , Interleucina-12/metabolismo , Animales , Linfocitos T CD4-Positivos/citología , Factores de Transcripción Forkhead/biosíntesis , Interferón gamma/metabolismo , Interleucina-10/metabolismo , Subunidad alfa del Receptor de Interleucina-2/biosíntesis , Masculino , Ratones , Ratones Endogámicos BALB CRESUMEN
BACKGROUND: Atmospheric pollutants may cause alterations on health of persons exposed to urban environment. OBJECTIVE: To evaluate in vitro immunological response in young population exposed to different levels of atmospheric pollution. PARTICIPANTS AND METHODS: The study was performed in two groups of young men, one from Guadalajara, and the other from Tlajomulco. The volunteers had to be healthy and without precedents of atopia. The immunological responses studied on PBMC were: stimulation index by timidin incorporation, CD25 expression by flow citometry, and production of citokines IL-2 and IL-4 by ELISAtest. Atmospheric parameters monitored were: NO2, O3, SO2, CO and PM10. RESULTS: In Guadalajara the concentrations of NO2 and PM10 exceeded in 30% and 40%, respectively, the index established by WHO. Stimulation index of PBMC of the young men to Guadalajara was 18 +/- 4, whereas that of the volunteers from Tlajomulco was 23 +/- 3. Expression of CD25 did not show a significant difference between studied groups. IL-2 and IL-4 levels were similar between the young men of the city and those from the rural area. CONCLUSION: The environmental pollution in Guadalajara did not modify in a significant way proliferation, CD25 expression, nor secretion of IL-2 and IL-4 on PBMC. This demonstrates that healthy young men are less susceptible than other groups to the alterations caused by exposure to moderate levels of atmospheric pollutants.
Asunto(s)
Contaminantes Atmosféricos/efectos adversos , Leucocitos Mononucleares/inmunología , Salud Urbana , Adolescente , Contaminantes Atmosféricos/análisis , Monóxido de Carbono/efectos adversos , Monóxido de Carbono/análisis , Células Cultivadas/inmunología , Replicación del ADN , Ensayo de Inmunoadsorción Enzimática , Citometría de Flujo , Humanos , Interleucina-2/biosíntesis , Subunidad alfa del Receptor de Interleucina-2/biosíntesis , Interleucina-4/biosíntesis , Recuento de Leucocitos , Masculino , México , Dióxido de Nitrógeno/efectos adversos , Dióxido de Nitrógeno/análisis , Ozono/efectos adversos , Ozono/análisis , Material Particulado/efectos adversos , Material Particulado/análisis , Población Rural , Dióxido de Azufre/efectos adversos , Dióxido de Azufre/análisis , Población Urbana , Adulto JovenRESUMEN
Delayed development of virus-specific immune response has been observed in pigs infected with the porcine reproductive and respiratory syndrome virus (PRRSV). Several studies support the hypothesis that the PRRSV is capable of modulating porcine immune system, but the mechanisms involved are yet to be defined. In this study, we evaluated the induction of T regulatory cells by PRRSV-infected dendritic cells (DCs). Our results showed that PRRSV-infected DCs significantly increased Foxp3(+)CD25(+) T cells, an effect that was reversible by IFN-alpha treatment, and this outcome was reproducible using two distinct PRRSV strains. Analysis of the expressed cytokines suggested that the induction of Foxp3(+)CD25(+) T cells is dependent on TGF-beta but not IL-10. In addition, a significant up-regulation of Foxp3 mRNA, but not TBX21 or GATA3, was detected. Importantly, our results showed that the induced Foxp3(+)CD25(+) T cells were able to suppress the proliferation of PHA-stimulated PBMCs. The T cells induced by the PRRSV-infected DCs fit the Foxp3(+)CD25(+) T helper 3 (Th3) regulatory cell phenotype described in the literature. The induction of this cell phenotype depended, at least in part, on PRRSV viability because IFN-alpha treatment or virus inactivation reversed these effects. In conclusion, this data supports the hypothesis that the PRRSV succeeds to establish and replicate in porcine cells early post-infection, in part, by inducing Th3 regulatory cells as a mechanism of modulating the porcine immune system.
Asunto(s)
Células Dendríticas/inmunología , Síndrome Respiratorio y de la Reproducción Porcina/inmunología , Virus del Síndrome Respiratorio y Reproductivo Porcino/inmunología , Porcinos/inmunología , Linfocitos T Colaboradores-Inductores/inmunología , Linfocitos T Reguladores/inmunología , Animales , Células Dendríticas/virología , Factores de Transcripción Forkhead/biosíntesis , Subunidad alfa del Receptor de Interleucina-2/biosíntesis , Activación de Linfocitos , Porcinos/virologíaRESUMEN
Docosahexaenoic (DHA; C22:6 n-3), eicosapentaenoic (EPA; C20:5 n-3), palmitic (PA; C16:0), and stearic (SA; C18:0) acids decrease lymphocyte proliferation in concentrations of >50 muM, as observed in our previous study. However, oleic acid (OA; C18:1 n-9) and linoleic acid (LA; C18:2 n-6) increase lymphocyte proliferation at 25 muM. In this study, the effect of these FAs on the interleukin-2 (IL-2) signaling pathway in human lymphocytes was investigated. Cells were isolated from heparinized venous blood of healthy human donors by density-gradient sedimentation. Cells were stimulated with 5 mug/ml concanavalin A and treated with FAs in the absence or presence of IL-2 for 1 hour. CD25-alpha externalization was analyzed by flow cytometry, and Janus kinase 1 (JAK1), JAK3, signal transducer and activator of transcription (STAT) 5, extracellular signal-regulated kinases (ERKs) 1 and 2, Akt, and protein kinase C (PKC)-zeta phosphorylation were analyzed by Western blotting. The expression of CD25-alpha at the cell surface was increased by DHA, SA, and PA but was unaffected by EPA, OA, and LA. PA, SA, DHA, and EPA decreased JAK1, JAK3, STAT5, and Akt phosphorylation induced by IL-2, but OA and LA did not cause any effect. OA and LA increased ERK1/2 phosphorylation, whereas the other FAs caused a marked decrease. PKC-zeta phosphorylation was decreased by OA and LA and was not altered by the remaining FAs. In conclusion, the inhibitory effect of PA, SA, DHA, and EPA on lymphocyte proliferation observed in our previous study was attributable to a decrease in JAK/STAT, ERK, and Akt pathways activated by IL-2. Probably, OA and LA stimulated lymphocyte proliferation by increasing ERK1/2 phosphorylation through PKC-zeta activation. The inhibition of JAK1, JAK3, STAT5, ERK1/2, and Akt phosphorylation caused by DHA, SA, and PA is associated with an alteration of CD25 expression at the cell surface.