978 resultados para class II


Relevância:

60.00% 60.00%

Publicador:

Resumo:

An attractive treatment of cancer consists in inducing tumor-eradicating CD8(+) CTL specific for tumor-associated Ags, such as NY-ESO-1 (ESO), a strongly immunogenic cancer germ line gene-encoded tumor-associated Ag, widely expressed on diverse tumors. To establish optimal priming of ESO-specific CTL and to define critical vaccine variables and mechanisms, we used HLA-A2/DR1 H-2(-/-) transgenic mice and sequential immunization with immunodominant DR1- and A2-restricted ESO peptides. Immunization of mice first with the DR1-restricted ESO(123-137) peptide and subsequently with mature dendritic cells (DCs) presenting this and the A2-restriced ESO(157-165) epitope generated abundant, circulating, high-avidity primary and memory CD8(+) T cells that efficiently killed A2/ESO(157-165)(+) tumor cells. This prime boost regimen was superior to other vaccine regimes and required strong Th1 cell responses, copresentation of MHC class I and MHC class II peptides by the same DC, and resulted in upregulation of sphingosine 1-phosphate receptor 1, and thus egress of freshly primed CD8(+) T cells from the draining lymph nodes into circulation. This well-defined system allowed detailed mechanistic analysis, which revealed that 1) the Th1 cytokines IFN-gamma and IL-2 played key roles in CTL priming, namely by upregulating on naive CD8(+) T cells the chemokine receptor CCR5; 2) the inflammatory chemokines CCL4 (MIP-1beta) and CCL3 (MIP-1alpha) chemoattracted primed CD4(+) T cells to mature DCs and activated, naive CD8(+) T cells to DC-CD4 conjugates, respectively; and 3) blockade of these chemokines or their common receptor CCR5 ablated priming of CD8(+) T cells and upregulation of sphingosine 1-phosphate receptor 1. These findings provide new opportunities for improving T cell cancer vaccines.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Aeromonas hydrophila AH-3 lateral flagella are not assembled when bacteria grow in liquid media; however, lateral flagellar genes are transcribed. Our results indicate that A. hydrophila lateral flagellar genes are transcribed at three levels (class I to III genes) and share some similarities with, but have many important differences from, genes of Vibrio parahaemolyticus. A. hydrophila lateral flagellum class I gene transcription is σ(70) dependent, which is consistent with the fact that lateral flagellum is constitutively transcribed, in contrast to the characteristics of V. parahaemolyticus. The fact that multiple genes are included in class I highlights that lateral flagellar genes are less hierarchically transcribed than polar flagellum genes. The A. hydrophila lafK-fliEJL gene cluster (where the subscript L distinguishes genes for lateral flagella from those for polar flagella) is exclusively from class I and is in V. parahaemolyticus class I and II. Furthermore, the A. hydrophila flgAMNL cluster is not transcribed from the σ(54)/LafK-dependent promoter and does not contain class II genes. Here, we propose a gene transcriptional hierarchy for the A. hydrophila lateral flagella.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Deficiency of protease-activated receptor-2 (PAR2) modulates inflammation in several models of inflammatory and autoimmune disease, although the underlying mechanism(s) are not understood. PAR2 is expressed on endothelial and immune cells, and is implicated in dendritic cell (DC) differentiation. We investigated in vivo the impact of PAR2 activation on DCs and T cells in PAR2 wild-type (WT) and knockout (KO) mice using a specific PAR2 agonist peptide (AP2). PAR2 activation significantly increased the frequency of mature CD11c(high) DCs in draining lymph nodes 24 hr after AP2 administration. Furthermore, these DCs exhibited increased expression of major histocompatibility complex (MHC) class II and CD86. A significant increase in activated (CD44(+) CD62(-)) CD4(+) and CD8(+) T-cell frequencies was also observed in draining lymph nodes 48 hr after AP2 injection. No detectable change in DC or T-cell activation profiles was observed in the spleen. The influence of PAR2 signalling on antigen transport to draining lymph nodes was assessed in the context of delayed-type hypersensitivity. PAR2 WT mice that were sensitized by skin-painting with fluorescein isothiocyanate (FITC) to induce delayed-type hypersensitivity possessed elevated proportion of FITC(+) DCs in draining lymph nodes 24 hr after FITC painting when compared with PAR2 KO mice (0.95% versus 0.47% of total lymph node cells). Collectively, these results demonstrate that PAR2 signalling promotes DC trafficking to the lymph nodes and subsequent T-cell activation, and thus provides an explanation for the pro-inflammatory effect of PAR2 in animal models of inflammation.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The increase of publicly available sequencing data has allowed for rapid progress in our understanding of genome composition. As new information becomes available we should constantly be updating and reanalyzing existing and newly acquired data. In this report we focus on transposable elements (TEs) which make up a significant portion of nearly all sequenced genomes. Our ability to accurately identify and classify these sequences is critical to understanding their impact on host genomes. At the same time, as we demonstrate in this report, problems with existing classification schemes have led to significant misunderstandings of the evolution of both TE sequences and their host genomes. In a pioneering publication Finnegan (1989) proposed classifying all TE sequences into two classes based on transposition mechanisms and structural features: the retrotransposons (class I) and the DNA transposons (class II). We have retraced how ideas regarding TE classification and annotation in both prokaryotic and eukaryotic scientific communities have changed over time. This has led us to observe that: (1) a number of TEs have convergent structural features and/or transposition mechanisms that have led to misleading conclusions regarding their classification, (2) the evolution of TEs is similar to that of viruses by having several unrelated origins, (3) there might be at least 8 classes and 12 orders of TEs including 10 novel orders. In an effort to address these classification issues we propose: (1) the outline of a universal TE classification, (2) a set of methods and classification rules that could be used by all scientific communities involved in the study of TEs, and (3) a 5-year schedule for the establishment of an International Committee for Taxonomy of Transposable Elements (ICTTE).

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The purpose of this study is to investigate the orthodontic and orthopaedic real effects of the Klammt's Elastic Open Activator (EOA) in 25 Class II Division 1 patients in growing period. We wanted to determine statistically the cephalometrics changes produced in the patients, comparing the lateral cranium teleradiographies we took for the diagnosis with the ones we took at the end of treatment. At the end of this study we confirm that by using the EOA we obtained the desired effects, especially reducing the molar relation 2.53 mm and the overjet 2.56 mm. The EOA corrected the inclination and protrusion of incisors, although we cannot avoid the use of fixed appliances to round off. The reduction of 2.48 mm of facial convexity stands out as the most important skeletal effect; the facial depth angle increases 0.8 degree, and the maxillary depth decreases 1.16 degrees. The length of the mandibular corpus also increases 6.7 mm, although this change is mainly due to the growth of the patient. The changes in the aesthetic profile do not stand out

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Despite the proven ability of immunization to reduce Helicobacter infection in mouse models, the precise mechanism of protection has remained elusive. In this study, we evaluated the role of inflammatory monocytes in the vaccine-induced reduction of Helicobacter felis infection. We first showed by using flow cytometric analysis that Ly6C(low) major histocompatibility complex class II-positive chemokine receptor type 2 (CCR2)-positive CD64(+) inflammatory monocytes accumulate in the stomach mucosa during the vaccine-induced reduction of H. felis infection. To determine whether inflammatory monocytes played a role in the protection, these cells were depleted with anti-CCR2 depleting antibodies. Indeed, depletion of inflammatory monocytes was associated with an impaired vaccine-induced reduction of H. felis infection on day 5 postinfection. To determine whether inflammatory monocytes had a direct or indirect role, we studied their antimicrobial activities. We observed that inflammatory monocytes produced tumor necrosis factor alpha and inducible nitric oxide synthase (iNOS), two major antimicrobial factors. Lastly, by using a Helicobacter in vitro killing assay, we showed that mouse inflammatory monocytes and activated human monocytes killed H. pylori in an iNOS-dependent manner. Collectively, these data show that inflammatory monocytes play a direct role in the immunization-induced reduction of H. felis infection from the gastric mucosa.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Tumor antigen-specific CD4(+) T cells generally orchestrate and regulate immune cells to provide immune surveillance against malignancy. However, activation of antigen-specific CD4(+) T cells is restricted at local tumor sites where antigen-presenting cells (APCs) are frequently dysfunctional, which can cause rapid exhaustion of anti-tumor immune responses. Herein, we characterize anti-tumor effects of a unique human CD4(+) helper T-cell subset that directly recognizes the cytoplasmic tumor antigen, NY-ESO-1, presented by MHC class II on cancer cells. Upon direct recognition of cancer cells, tumor-recognizing CD4(+) T cells (TR-CD4) potently induced IFN-γ-dependent growth arrest in cancer cells. In addition, direct recognition of cancer cells triggers TR-CD4 to provide help to NY-ESO-1-specific CD8(+) T cells by enhancing cytotoxic activity, and improving viability and proliferation in the absence of APCs. Notably, the TR-CD4 either alone or in collaboration with CD8(+) T cells significantly inhibited tumor growth in vivo in a xenograft model. Finally, retroviral gene-engineering with T cell receptor (TCR) derived from TR-CD4 produced large numbers of functional TR-CD4. These observations provide mechanistic insights into the role of TR-CD4 in tumor immunity, and suggest that approaches to utilize TR-CD4 will augment anti-tumor immune responses for durable therapeutic efficacy in cancer patients.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Acting as antigen presenting cells, mature dendritic cells (DCs) initiate both innate and adaptive alloimmune responses. However, immature DCs are weak immunostimulators and mediate tolerogenic effects under certain conditions. Tolerogenic activities of immature DCs can be enhanced by pharmacological agents. Here, we compared pharmacological DC preconditioning with rapamycin and aspirin, applied alone or in combination, on LPS-induced DC maturation and T-cell allostimulatory capacity. Preconditioning with aspirin but not rapamycin tended to reduce the number of mouse bone marrow-derived immature DCs expressing CD40 and major histocompatibility complex class II molecules upon LPS stimulation. Conversely, DC preconditioning with rapamycin, but not aspirin, reduced T-cell alloproliferative responses. A combination of rapamycin and aspirin was more effective than either drug applied alone with respect to inhibition of T-cell alloproliferation. The two agents in combination reduced numbers of CD4(+)IFN-γ(+) Th1 and CD4(+)IL-17(+) Th17 effector cells while maintaining Foxp3(+) regulatory T cells. These results suggest aspirin may moderately enhance rapamycin-mediated inhibition of DC allostimulatory capacity.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The ornamental rock industry generates huge amounts of wastes during the process of extraction and sawing of rock blocks. The ornamental rock powder waste is a non-biodegradable material, which represents the increase in environmental problem. The waste was collected from a granitic rock sawing plant located in Santo Antônio de Pádua, Rio de Janeiro. The chemical-environmental characterization and classification of the waste were done according to ABNT standards. The results showed that the granitic rock powder waste should be classified as Class II A - "No Inert", because of its high concentrations of lead, chrome, iron and manganese.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The mineral waste studied was host rock from a chromite mine located in Andorinha/Bahia, extracted and stockpiled in yards without specific application. Host rock was submitted to chemical analysis, XRD, SEM-EDS, IR and TGA and classified according to ABNT standards for solid waste classification. Analyses confirmed that this host rock, classified as ultrabasic, consists mainly of dolomite, calcite and diopside. Hazard assessment results showed this host rock should be classified as class II B - inert waste, important for its potential application in agriculture as a soil acidity correction agent.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

T cells are the key players in the development of type 1 diabetes (T1D), mediating autoimmune reactions leading to the destruction of insulin producing beta cells in the islets. We aimed to analyze the role of different T-cell subtypes in the autoimmunity and pathogenesis of T1D. The frequency of islet antigen-specific (GAD65-, proinsulin-, and insulin-specific) CD4+ T cells was investigated in vitro in T1D patients, at-risk individuals (diabetes-associated autoantibody positive), and in controls, using MHC class II tetramers. An overall higher frequency of CD4+ T-cells recognizing the GAD65 555−567 peptide was detected in at-risk individuals. In addition, increased CD4+ T-cell responses to the same GAD65 epitope displaying a memory phenotype were observed in at-risk and diabetic children, which demonstrate a previous encounter with the antigen in vivo. Avidity and phenotypic differences were also observed among CD4+ T-cell clones induced by distinct doses of GAD65 autoantigen. T-cell clones generated at the lowest peptide dose displayed the highest avidity and expressed more frequently the TCR Vβ5.1 chain than low-avidity T cells. These findings raise attention to the antigen dose when investigating the diversity of antigen-specific T cells. Furthermore, an increased regulatory response during the preclinical phase of T1D was also found in genetically at-risk children. Higher frequencies of regulatory T (Treg) cells (CD4+CD25high HLA-DR-/CD69-) and natural killer T (NKT) cells (CD161+Vbeta11+) were observed in children with multiple autoantibodies compared to autoantibody-negative controls. Taken together, these data showed increased frequency of islet-specific CD4+ T-cells, especially to the GAD65 555-567 epitope, and Treg and NKT cell upregulation in children at-risk for T1D, suggesting their importance in T1D pathogenesis

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Background: Celiac disease is a lifelong, gluten-sensitive, autoimmune-mediated chronic enteropathy, tightly associated with risk alleles at the HLA class II genes. Aims: This study was carried out as a part of the population-based Type 1 Diabetes Prediction and Prevention (DIPP) Project. The first aim was to study the natural history of celiac disease-associated antibodies before the diagnosis of celiac disease was made. The second aim was to describe when and in which order celiac disease-associated and type 1 diabetes-associated antibodies appeared in children with genetic risk for both diseases. Subjects and Methods: Antibodies against tissue transglutaminase (TGA) and other celiac disease-associated antibodies were measured in serum samples collected at 3- to 12-month intervals of children at genetic risk for celiac disease who participated in the DIPP project. Celiac disease was confirmed by duodenal biopsy. Type 1 diabetes-associated antibodies were measured in all samples that had been collected. Overt disease was diagnosed according to World Health Organization criteria. Follow-up continued until a diagnosis of type 1 diabetes or until the end of a defined follow-up period. Results: TGA appeared in children at genetic risk for celiac disease only after the first year of life, but anti-gliadin antibodies often emerged significantly earlier, at age 6 months. The data show that spontaneous disappearance of celiac disease-associated antibodies, transient or persisting, is a common phenomenon, at least in prepubertal children. In children with genetic susceptibility to type 1 diabetes and celiac disease, celiac disease-associated antibodies usually develop earlier than the type 1 diabetes-associated antibodies. Conclusions: The transient nature of celiac disease-associated antibodies emphasizes the significance of establishing seropositivity repeatedly in screening detected celiac disease before gastroscopy and duodenal biopsy are considered and emphasized the importance of duodenal biopsy for diagnosing celiac disease.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Neurofibromatosis type 1 (NF1) is an autosomal dominant cancer predisposition syndrome that affects about 1 in 3500 individuals worldwide. NF1 is caused by mutations in the NF1 gene that encodes the tumor suppressor protein neurofibromin, an inactivator of the Ras oncogene. The hallmarks of NF1 include pigmentary lesions of the skin, Lisch nodules of the iris and cutaneous neurofibromas. Cutaneous neurofibromas are benign tumors composed of all the cell types of normal peripheral nerve. The traditional view of neurofibroma development has been that cutaneous neurofibromas arise from the disruption of the small nerve tributaries of the skin and subsequent proliferation of the resident cells. The second hit mutation in the NF1 gene has been considered as a prerequisite for neurofibroma development. The second hit is detectable in a subpopulation of primary Schwann cells cultured from neurofibromas. This thesis challenges the traditional concept of neurofibroma development. The results show that cutaneous neurofibromas are intimately associated with hair follicular structures and contain multipotent precursor cells (NFPs), suggesting that neurofibromas may arise from the multipotent cells which reside in hair follicles. Furthermore, this study presents that neurofibroma-derived Schwann cells that harbor bi-allelic inactivation in the NF1 gene express HLA class II genes and may act as nonprofessional antigen presenting cells. The CD4- and FoxP3-positive cells detected in cutaneous neurofibromas suggest that these cells may represent regulatory T cells (Tregs) which interact with HLA II –positive cells and aid the tumor cells in hiding from the immune system and are thus mediators of immune tolerance. This thesis also investigated neurofibroma development in the oral cavity and the use of different biomarkers to characterize cellular differentiation in neurofibromas. The results revealed that oral neurofibromas are not rare, but they usually appear as solitary lesions contrary to multiple cutaneous neurofibromas and present high heterogeneity within and between tumors. The use of class III beta-tubulin as a marker for neuronal differentiation led to an unexpected finding showing that multiple cell types express class III beta-tubulin during mitosis. The increased understanding of the multipotency of tumor cells, cellular differentiation and ability to hide from immune system will aid in the development of future treatments. Specifically, targeting Tregs in NF1 patients could provide a novel therapeutic approach to interfere with the development of neurofibromas.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

OBJECTIVE: to assess alcohol intake in the bariatric surgery pre and postoperative periods. METHODS: Patients were interviewed atSurgery Clinic of the Hospital das Clínicas da Universidade Federal de Pernambuco - HC/UFPE (Brazil) from July 2011 to March 2012. We analyzed socioeconomic, anthropometric and clinical variables. We used the Alcohol Use Disorders Identification Test (AUDIT C). RESULTS: One hundred nineteen patients were enrolled (mean age: 41.23+11.30 years), with a predominance of the female gender (83.2%), non-Caucasian race (55%), married individuals or in a stable union (65.5%), with a high school education (40.3%)and active in the job market (37%). Weight and body mass index (BMI) were 128.77+25.28Kg and 49.09+9.26Kg/m2,respectively in the preoperative period (class II obesity) and 87.19+19.16Kg and 33.04+6.21Kg/m2, respectively in the postoperative period (class I obesity) (p<0.001). Hypertension was the most frequent disease in the pre (66.6%) and postoperative (36.5%) periods. The prevalence of alcohol use was 26.6% in the preoperative period, of which 2.2% of high risk, and 35.1% in the postoperative period, of which 1.4% of probable dependence; this difference did not achieve statistical significance (p=0.337). CONCLUSION: The prevalence of abusive alcohol intake and/or probable dependence was low in both the pre and postoperative periods, with little evidence of risky consumption among the patients submitted to bariatric surgery.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Cellular immune responses are a critical part of the host's defense against intracellular bacterial infections. Immunity to Brucella abortus crucially depends on antigen-specific T cell-mediated activation of macrophages, which are the major effectors of cell-mediated killing of this organism. T lymphocytes that proliferate in response to B. abortus were characterized for phenotype and cytokine activity. Human, murine, and bovine T lymphocytes exhibited a type 1 cytokine profile, suggesting an analogous immune response in these different hosts. In vivo protection afforded by a particular cell type is dependent on the antigen presented and the mechanism of antigen presentation. Studies using MHC class I and class II knockout mice infected with B. abortus have demonstrated that protective immunity to brucellosis is especially dependent on CD8+ T cells. To target MHC class I presentation we transfected ex vivo a murine macrophage cell line with B. abortus genes and adoptively transferred them to BALB/c mice. These transgenic macrophage clones induced partial protection in mice against experimental brucellosis. Knowing the cells required for protection, vaccines can be designed to activate the protective T cell subset. Lastly, as a new strategy for priming a specific class I-restricted T cell response in vivo, we used genetic immunization by particle bombardment-mediated gene transfer