RESUMEN
The presence of maternal DNA or even maternal cells within the offspring (microchimerism) has been reported for many fetal tissues, including the liver, heart, and spleen. Microchimerism is believed to be involved in the pathogenesis of autoimmune diseases; however, the cellular origin of this phenomenon remains unknown. Here, we determined whether differentiated T lymphocytes could transmigrate through the immunosuppressive environment of the placenta to reach the fetus. In vitro-differentiated effector/memory Th1 and Th17 cells from OVA323â339-specific TCR(tg) T cells of OT-II mice were adoptively transferred (i.v.) into the tail veins of pregnant Ly5.1 mice at d15 and d19 of gestation. Mice were then sacrificed 40 h after adoptive cell transfer. Using radioactive labeling of T cells with sodium chromate [Cr5¹] prior to adoptive transfer, we observed that homing of pro-inflammatory Th cells was equally efficient in both pregnant and non-pregnant mice. Transmigration of Th1- and Th17-like cells through the highly immunosuppressive environment of the placenta into the fetus was significantly enhanced in experimental mice compared to control mice (P < 0.0001). In addition, a substantial amount of effector Th cells accumulated in the placenta. Finally, we found that treatment with Pertussis Toxin resulted in a 3-fold increase in the transmigration of effector Th17 cells into the fetus (P < 0.0001). When pro-inflammatory Th1-or Th17-like cells were injected into syngeneic mothers, almost all of the fetuses analyzed exhibited radioactivity, suggesting that transmigration of effector T cells occurs frequently. Our results suggest the possibility of novel roles for these maternal effector cells in the pathogenesis or reduction of disease.
Asunto(s)
Sistema Inmunológico/embriología , Inmunidad Materno-Adquirida , Placenta/inmunología , Células TH1/inmunología , Células Th17/inmunología , Migración Transcelular de la Célula , Traslado Adoptivo , Animales , Diferenciación Celular , Movimiento Celular , Células Cultivadas , Quimerismo , Femenino , Desarrollo Fetal , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Placenta/citología , Embarazo , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/metabolismo , Organismos Libres de Patógenos Específicos , Células TH1/citología , Células Th17/citologíaRESUMEN
OBJECTIVES: The activation of T cells is closely regulated. One cell intrinsic mechanism is based on the expression of inhibitory molecules; another is mediated by regulatory T (Treg) cells. The co-regulatory molecule CTLA-4 is constitutively expressed by Treg cells and up-regulated in effector-T-cells after activation. Recently, it was described that Treg cells can display an unstable phenotype and convert into pathogenic pro-inflammatory cytokine secreting cells. Here we have analysed the role of CTLA-4 in the regulation of cytokine production by T-helper (Th) cells with a special focus on Treg cells. METHODS: Proliferation of unstimulated CTLA-4 knock-out and wild-type cells as well as their activation status and the impact of CTLA-4 blockade on proliferation of Treg and effector T cells under stimulation were analysed by flow cytometry. Furthermore, the cytokine concentrations were analysed by a multiplex suspension assay. RESULTS: CTLA-4 knock-out T cells proliferated without stimulation and displayed an activated phenotype ex vivo. Proliferation of effector but also that of Treg cells was controlled by CTLA-4. The blockade of CTLA-4 led to an increased secretion of GM-CSF, IL-1ß, IL-2, and IFN-γ by Th cells. However, the blockade of CTLA-4 in Treg cells did not cause any conversion into pathogenic pro-inflammatory T cells, since the non-cytokine secreting phenotype remained unchanged. CONCLUSIONS: These results have major implications on therapies targeting the CTLA-4-system, e.g. by CTLA4-Ig or anti-CTLA-4-antibodies, as the blockade of CTLA-4 did not unlock the stability of Treg cells.
Asunto(s)
Antígenos CD/genética , Antígenos CD/inmunología , Enfermedades Autoinmunes/inmunología , Trastornos Linfoproliferativos/inmunología , Linfocitos T Reguladores/inmunología , Animales , Enfermedades Autoinmunes/terapia , Antígeno CTLA-4 , División Celular/inmunología , Células Cultivadas , Citocinas/inmunología , Inmunofenotipificación , Tejido Linfoide/inmunología , Trastornos Linfoproliferativos/terapia , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Linfocitos T Reguladores/citologíaRESUMEN
The immediate early transcription factor nuclear factor (IκBs) kappa B (NF-κB) is crucially involved in the regulation of numerous physiological or pathophysiological processes such as inflammation and tumourigenesis. Therefore, the control of NF-κB activity, which is mainly regulated by signal-induced degradation of cytoplasmic inhibitors of NF-κB (IκBs), is of high relevance. One known alternative pathway of NF-κB regulation is the stimulus-induced proteasomal degradation of RelB, a component of the NF-κB dimer. Here, we identified the serine/threonine protein kinase glycogen synthase kinase-3ß (GSK-3ß) as a critical signalling component leading to RelB degradation. In Jurkat leukaemic T cells as well as in primary human T cells, tetradecanoylphorbolacetate/ionomycin- and CD3/CD28-induced RelB degradation were impaired by a GSK-3ß-specific pharmacological inhibitor, an ectopically expressed dominant-negative GSK-3ß mutant and by small-interfering RNA-mediated silencing of GSK-3ß expression. Furthermore, a physical interaction between RelB and GSK-3ß was shown by co-immunoprecipitation, which was already notable in unstimulated cells. Most importantly, as demonstrated by in vitro kinase assays, human RelB is inducibly phosphorylated by GSK-3ß, indicating a direct substrate-enzyme relationship. The serine residue 552 is a target of GSK-3ß-mediated phosphorylation in vitro and in vivo. We conclude that GSK-3ß is a crucial regulator of RelB degradation, stressing the relevant linkage between the NF-κB system and GSK-3ß.
Asunto(s)
Glucógeno Sintasa Quinasa 3/metabolismo , Transducción de Señal , Factor de Transcripción ReIB/metabolismo , Carbazoles/farmacología , Inhibidores Enzimáticos/farmacología , Glucógeno Sintasa Quinasa 3/antagonistas & inhibidores , Glucógeno Sintasa Quinasa 3/genética , Glucógeno Sintasa Quinasa 3 beta , Humanos , Immunoblotting , Inmunoprecipitación , Indoles/farmacología , Células Jurkat , Maleimidas/farmacología , Mutación , Fosforilación/efectos de los fármacos , Unión Proteica , Proteína Quinasa C/antagonistas & inhibidores , Proteína Quinasa C/metabolismo , Pirroles/farmacología , Interferencia de ARN , Especificidad por SustratoRESUMEN
Very little is known about the effects of acute psychological stress on the production of reactive oxygen species (ROS) by human phagocytic cells and the interplay between subjectively perceived stress, mediating hormones, variations in the number of peripheral leukocytes and ROS production. We measured psychological reactions, cardiovascular parameters, plasma catecholamines, plasma prolactin and cortisol as well as peripheral lymphocyte subsets in 13 experimental subjects undergoing a brief psychological stressor, and production of ROS, as indicated by chemiluminescence (CL), in stressed subjects and in healthy controls. The stressor elevated anger (p<0.01) and cardiovascular activation (p<0.01). There were significant changes in plasma levels of cortisol (p<0.01) and prolactin (p<0.001). During psychological stress natural killer (NK) cells (p<0.01) and CD8/CD38 cells (p<0.05) increased and returned to baseline only 25 minutes later. Significant changes in the number of naive CD4+/CD45RA+ (p<0.01) and antigen-experienced CD8+/CD45RO+ T cells (p<0.05) occurred. Subjects with stronger cardiovascular reaction showed higher stress-related plasma levels of norepinephrine (p<0.05) and were mainly responsible for the increase in NK cells. We observed a significantly reduced production of ROS following the stress test (p<0.05). Our results show that psychological stress is expressed simultaneously on psychological, hormonal and immunological levels of the organism. We show the existence of a circadian rhythm leading to a pronounced increase in CL during the morning hours. This first study taking this circadian rhythm in account revealed a significant suppressive effect of stress on ROS production.