984 resultados para Humoral rejection


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Monitoring of the kinetics of production of serum antibodies to multiple mycobacterial antigens can be useful as a diagnostic tool for the detection of Mycobacterium bovis infection as well as for the characterization of disease progression and the efficacy of intervention strategies in several species. The humoral immune responses to multiple M. bovis antigens by white-tailed deer vaccinated with BCG orally via a lipid-formulated bait (n = 5), orally in liquid form (n = 5), and subcutaneously (n = 6) were evaluated over time after vaccination and after experimental challenge with virulent M. bovis and were compared to the responses by unvaccinated deer (n = 6). Antibody responses were evaluated by using a rapid test (RT), a multiantigen print immunoassay (MAPIA), a lipoarabinomannan enzyme-linked immunosorbent assay (LAM-ELISA), and immunoblotting to whole-cell sonicate and recombinant antigen MPB83. MAPIA and RT detected minimal to no antibody responses over those at the baseline to multiple M. bovis antigens in vaccinated white-tailed deer after challenge. This was in contrast to the presence of more readily detectable antibody responses in nonvaccinated deer with more advanced disease. The LAM-ELISA results indicated an overall decrease in the level of production of detectable antibodies against lipoarabinomannan-enriched mycobacterial antigen in vaccinated animals compared to that in nonvaccinated animals after challenge. Immunoblot data were inconsistent but did suggest the occurrence of unique antibody responses by certain vaccinated groups to Ag85 and HSP70. These findings support further research toward the improvement and potential use of antibody-based assays, such as MAPIA, RT, and LAM-ELISA, as tools for the antemortem assessment of disease progression in white-tailed deer in both experimental and field vaccine trials.

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The use of organic trace minerals is getting strength and is an alternative to increase production and improve other characteristics such as humoral immunity. The present study was conducted to evaluate the effect of different levels and sources of selenium (Se) on humoral immunity of broilers. A six-week research was conducted using 1440 one-day-old males broiler chickens. The experimental design was randomized with six experimental diets (A: 0.15mg kg(-1) inorganic (inorg.); B: 0.15mg kg(-1) organic; C: 0.15mg kg(-1) inorg. + organic; D: 0.45mg kg(-1) inorganic; E: 0.45mg kg(-1) organic; F: 0.45mg kg(-1) inorg. + organic) calculated to provide the described amount of Se. Each diet was replicated in six box with 40 birds. A 3x2 factorial arrangement was used and the data were analyzed by ANOVA. The immunity was evaluated by means of the reaction against vaccine of Newcastle disease, and a reaction against sheep red blood cells (SRBC). No significant effects were observed at 5% significance level in NewCastle antibody (P >0.05). However at 14 day-old the source factor had p value at 0.0580, that show a trend of inorganic source in prolong the maternal immunity. No effect was observed in the immune response against SRBC (P >0.05). The results showed a immunologic response against Newcastle vaccine and SRBC, but the treatments was not able to induce a significant difference. The source and the level of Se showed no effect on the response against Newcastle vaccine and SRBC.

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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.

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Human infections with EHEC such as O157:H7 have been a great concern for worldwide food-industry surveillance. This pathogen is commonly associated with bloody diarrhea that can evolve to the life-threatening hemolytic uremic syndrome. Animals are the natural reservoir where this pathogen remains asymptomatically, in steps of ingestion and colonization of the bowel. The bacterium is shed in the feces, contaminating the surroundings, including water and food that are directed for human consumption. A major player in this colonization process is intimin, an outer membrane adhesion molecule encoded by the E. coli attachment and effacement (eae) gene that has been shown to be essential for intimate bacterial attachment to eukaryotic host cells. In an attempt to reduce the colonization of animal reservoirs with EHEC O157:H7, we designed a vaccine model to induce an immune response against intimin gamma. The model is based on its recombinant expression in attenuated Salmonella, used as a suitable vaccine vector because of its recognized ability to deliver recombinant antigens and to elicit all forms of immunity: mucosal, systemic, and humoral responses. To test this model, mice were orally immunized with a S. enterica serovar Typhimurium strain carrying the pYA3137eaeA vector, and challenged with E. coli O157:H7. Here we show that immunization induced the production of high levels of specific IgG and IgA antibodies and promoted reduction in the fecal shedding of EHEC after challenge. The live recombinant vaccine reported herein may contribute to the efforts of reducing animal intestinal mucosa colonization.

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Abstract Background The development of protective immunity against malaria is slow and to be maintained, it requires exposure to multiple antigenic variants of malaria parasites and age-associated maturation of the immune system. Evidence that the protective immunity is associated with different classes and subclasses of antibodies reveals the importance of considering the quality of the response. In this study, we have evaluated the humoral immune response against Plasmodium falciparum blood stages of individuals naturally exposed to malaria who live in endemic areas of Brazil in order to assess the prevalence of different specific isotypes and their association with different malaria clinical expressions. Methods Different isotypes against P. falciparum blood stages, IgG, IgG1, IgG2, IgG3, IgG4, IgM, IgE and IgA, were determined by ELISA. The results were based on the analysis of different clinical expressions of malaria (complicated, uncomplicated and asymptomatic) and factors related to prior malaria exposure such as age and the number of previous clinical malaria attacks. The occurrence of the H131 polymorphism of the FcγIIA receptor was also investigated in part of the studied population. Results The highest levels of IgG, IgG1, IgG2 and IgG3 antibodies were observed in individuals with asymptomatic and uncomplicated malaria, while highest levels of IgG4, IgE and IgM antibodies were predominant among individuals with complicated malaria. Individuals reporting more than five previous clinical malaria attacks presented a predominance of IgG1, IgG2 and IgG3 antibodies, while IgM, IgA and IgE antibodies predominated among individuals reporting five or less previous clinical malaria attacks. Among individuals with uncomplicated and asymptomatic malaria, there was a predominance of high-avidity IgG, IgG1, IgG2 antibodies and low-avidity IgG3 antibodies. The H131 polymorphism was found in 44.4% of the individuals, and the highest IgG2 levels were observed among asymptomatic individuals with this allele, suggesting the protective role of IgG2 in this population. Conclusion Together, the results suggest a differential regulation in the anti-P. falciparum antibody pattern in different clinical expressions of malaria and showed that even in unstable transmission areas, protective immunity against malaria can be observed, when the appropriated antibodies are produced.

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Abstract Background Plasmodium vivax merozoite surface protein-1 (MSP-1) is an antigen considered to be one of the leading malaria vaccine candidates. PvMSP-1 is highly immunogenic and evidences suggest that it is target for protective immunity against asexual blood stages of malaria parasites. Thus, this study aims to evaluate the acquired cellular and antibody immune responses against PvMSP-1 in individuals naturally exposed to malaria infections in a malaria-endemic area in the north-eastern Amazon region of Brazil. Methods The study was carried out in Paragominas, Pará State, in the Brazilian Amazon. Blood samples were collected from 35 individuals with uncomplicated malaria. Peripheral blood mononuclear cells were isolated and the cellular proliferation and activation was analysed in presence of 19 kDa fragment of MSP-1 (PvMSP-119) and Plasmodium falciparum PSS1 crude antigen. Antibodies IgE, IgM, IgG and IgG subclass and the levels of TNF, IFN-γ and IL-10 were measured by enzyme-linked immunosorbent assay. Results The prevalence of activated CD4+ was greater than CD8+ T cells, in both ex-vivo and in 96 h culture in presence of PvMSP-119 and PSS1 antigen. A low proliferative response against PvMSP-119 and PSS1 crude antigen after 96 h culture was observed. High plasmatic levels of IFN-γ and IL-10 as well as lower TNF levels were also detected in malaria patients. However, in the 96 h supernatant culture, the dynamics of cytokine responses differed from those depicted on plasma assays; in presence of PvMSP-119 stimulus, higher levels of TNF were noted in supernatant 96 h culture of malaria patient’s cells while low levels of IFN-γ and IL-10 were verified. High frequency of malaria patients presenting antibodies against PvMSP-119 was evidenced, regardless class or IgG subclass.PvMSP-119-induced antibodies were predominantly on non-cytophilic subclasses. Conclusions The results presented here shows that PvMSP-119 was able to induce a high cellular activation, leading to production of TNF and emphasizes the high immunogenicity of PvMSP-119 in naturally exposed individuals and, therefore, its potential as a malaria vaccine candidate.

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Objective To compare autoantibody features in patients with primary biliary cirrhosis (PBC) and individuals presenting antimitochondria antibodies (AMAs) but no clinical or biochemical evidence of disease. Methods A total of 212 AMA-positive serum samples were classified into four groups: PBC (definite PBC, n = 93); PBC/autoimmune disease (AID; PBC plus other AID, n = 37); biochemically normal (BN) individuals (n = 61); and BN/AID (BN plus other AID, n = 21). Samples were tested by indirect immunofluorescence (IIF) on rat kidney (IIF-AMA) and ELISA [antibodies to pyruvate dehydrogenase E2-complex (PDC-E2), gp-210, Sp-100, and CENP-A/B]. AMA isotype was determined by IIF-AMA. Affinity of anti-PDC-E2 IgG was determined by 8 M urea-modified ELISA. Results High-titer IIF-AMA was more frequent in PBC and PBC/AID (57 and 70 %) than in BN and BN/AID samples (23 and 19 %) (p < 0.001). Triple isotype IIF-AMA (IgA/IgM/IgG) was more frequent in PBC and PBC/AID samples (35 and 43 %) than in BN sample (18 %; p = 0.008; p = 0.013, respectively). Anti-PDC-E2 levels were higher in PBC (mean 3.82; 95 % CI 3.36–4.29) and PBC/AID samples (3.89; 3.15–4.63) than in BN (2.43; 1.92–2.94) and BN/AID samples (2.52; 1.54–3.50) (p < 0.001). Anti-PDC-E2 avidity was higher in PBC (mean 64.5 %; 95 % CI 57.5–71.5 %) and PBC/AID samples (66.1 %; 54.4–77.8 %) than in BN samples (39.2 %; 30.9–37.5 %) (p < 0.001). PBC and PBC/AID recognized more cell domains (mitochondria, nuclear envelope, PML/sp-100 bodies, centromere) than BN (p = 0.008) and BN/AID samples (p = 0.002). Three variables were independently associated with established PBC: high-avidity anti-PDC-E2 (OR 4.121; 95 % CI 2.118–8.019); high-titer IIF-AMA (OR 4.890; 2.319–10.314); antibodies to three or more antigenic cell domains (OR 9.414; 1.924–46.060). Conclusion The autoantibody profile was quantitatively and qualitatively more robust in definite PBC as compared with AMA-positive biochemically normal individuals.

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The humoral immune response is dependent on the formation of antibodies. Antibodies are produced by terminally differentiated B cells, plasma cells. Plasma cells are generated either directly from antigen challenged B cells, memory cells or from cells that have undergone the germinal center (GC) reaction. The GC is the main site for class switch, somatic hypermutation and generation of memory cells. Different factors, both internal and external, shape the outcome of the immune response. In this thesis, we have studied a few factors that influence the maturation of the humoral response. We have studied how age affects the response, and we show that responses against thymus dependent antigens (TD) are more affected than responses to thymus independent (TI) antigens, in concordance with the view that the T cell compartment is more affected by age than the B cell compartment. Furthermore, we demonstrate that priming early in life have a big influence on the immune response in the aged individual. Priming with a TI form of the carbohydrate dextran B512 (Dx) induces a reduction of IgG levels in later TD responses against Dx. We have evaluated possible mechanisms for this reduction. The reduction does not seem to be caused by clonal exhaustion or antibody mediated mechanisms. We also showed that the reduced TD response after TI priming can be induced against another molecule than Dx. With the hypothesis that TI antigens induce a plasma cell biased maturation of the responding B cells, we examined the presence of Blimp-1, a master regulator of plasma cell differentiation, in GCs induced by TD and TI antigen. Blimp-1 was found earlier in GCs induced by TI antigen and the staining intensity in these GCs was stronger than in TD antigen induced GCs, indicating that plasma cells might be continuously recruited from these GCs. B cells undergoing the GC reaction are thought to be under a strict selection pressure that removes cells with low affinity for the antigen and also cells that have acquired self-reactivity. We investigated the effect of apoptotic deficiencies on the accumulation of somatic mutations in GC B cells. In mice lacking the death receptor Fas, lpr mice, the frequency of mutations was increased but the pattern of the mutations did not differ from wild type mice. In contrast, mice over-expressing the anti-apoptotic protein Bcl-2, had a lowered frequency of mutations and the mutations introduced had other characteristics.

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INTRODUCTION. Late chronic allograft disfunction (CAD) is one of the more concerning issues in the management of patients (pts) with renal transplant (tx). Humoral immune response seems to play an important role in CAD pathogenesis. AIM OF THE STUDY. To identify the causes of late chronic allograft disfunction. METHODS. This study (march 2004-august 2011) enrolled pts who underwent renal biopsy (BR) because of CAD (increase of creatininemia (s-Cr) >30% and/or proteinuria >1g/day at least one year after tx). BR were classified according to 1997/2005 Banff classification. Histological evaluation of C4d (positive if >25%), glomerulitis, tubulitis, intimal arteritis, atrophy/fibrosis and arteriolar-hyalinosis were performed. Ab anti-HLA research at BR was an inclusion criteria. Pts were divided into two groups: with or without transplant glomerulopathy (CTG). RESULTS. Evaluated BR: 93/109. BR indication: impaired s-Cr (52/93), proteinuria (23/93), both (18/93). Time Tx-BR: 7.4±6.3 yrs; s-Cr at BR: 2.7±1.4 mg/dl. CTG group(n=49) not-CTG group(n=44) p Time tx-BR (yrs) 9.3±6.7 5.3±5.2 0.002 Follow-up post-BR (yrs) 2.7±1.8 4.1±1.4 0.0001 s-Cr at BR (mg/dl) 2.9±1.3 2.4±1.5 NS Rate (%) of pts: Proteinuria at BR 61% 25% 0.0004 C4d+ 84% 25% <0.0001 Ab anti-HLA+ 71% 30% 0.0001 C4d+ and/or Ab antiHLA 92% 43% 0.0001 Glomerulitis 76% 16% <0.0001 Tubulitis 6% 32% 0.0014 Intimal arteritis 18% 0% 0.002 Arteriolar hyalinosis 65% 50% NS Atrophy/fibrosis 80% 77% NS Graft survival 45% 86% 0.00005 Histological Diagnosis: CTG group (n=49:Chronic rejection 94%;IgA recurrence + humoral activity 4%;IIA acute rejection + humoral activity 2%. Not-CTG group (n=44: GN recurrence 27%;IF/TA 23%; acute rejection 23%;BKV nephritis 9%; mild not specific alterations 18%. CONCLUSIONS: CTG is the morphological lesion mainly related to CAD. In the 92% of the cases it is associated with markers of immunological activity. It causes graft failure within five years after diagnosis in 55% of pts.

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A new control scheme has been presented in this thesis. Based on the NonLinear Geometric Approach, the proposed Active Control System represents a new way to see the reconfigurable controllers for aerospace applications. The presence of the Diagnosis module (providing the estimation of generic signals which, based on the case, can be faults, disturbances or system parameters), mean feature of the depicted Active Control System, is a characteristic shared by three well known control systems: the Active Fault Tolerant Controls, the Indirect Adaptive Controls and the Active Disturbance Rejection Controls. The standard NonLinear Geometric Approach (NLGA) has been accurately investigated and than improved to extend its applicability to more complex models. The standard NLGA procedure has been modified to take account of feasible and estimable sets of unknown signals. Furthermore the application of the Singular Perturbations approximation has led to the solution of Detection and Isolation problems in scenarios too complex to be solved by the standard NLGA. Also the estimation process has been improved, where multiple redundant measuremtent are available, by the introduction of a new algorithm, here called "Least Squares - Sliding Mode". It guarantees optimality, in the sense of the least squares, and finite estimation time, in the sense of the sliding mode. The Active Control System concept has been formalized in two controller: a nonlinear backstepping controller and a nonlinear composite controller. Particularly interesting is the integration, in the controller design, of the estimations coming from the Diagnosis module. Stability proofs are provided for both the control schemes. Finally, different applications in aerospace have been provided to show the applicability and the effectiveness of the proposed NLGA-based Active Control System.

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Definition of acute renal allograft rejection (AR) markers remains clinically relevant. Features of T-cell-mediated AR are tubulointerstitial and vascular inflammation associated with excessive extracellular matrix (ECM) remodeling, regulated by metzincins, including matrix metalloproteases (MMP). Our study focused on expression of metzincins (METS), and metzincins and related genes (MARGS) in renal allograft biopsies using four independent microarray data sets. Our own cases included normal histology (N, n = 20), borderline changes (BL, n = 4), AR (n = 10) and AR + IF/TA (n = 7). MARGS enriched in all data sets were further examined on mRNA and/or protein level in additional patients. METS and MARGS differentiated AR from BL, AR + IF/TA and N in a principal component analysis. Their expression changes correlated to Banff t- and i-scores. Two AR classifiers, based on METS (including MMP7, TIMP1), or on MARGS were established in our own and validated in the three additional data sets. Thirteen MARGS were significantly enriched in AR patients of all data sets comprising MMP7, -9, TIMP1, -2, thrombospondin2 (THBS2) and fibrillin1. RT-PCR using microdissected glomeruli/tubuli confirmed MMP7, -9 and THBS2 microarray results; immunohistochemistry showed augmentation of MMP2, -9 and TIMP1 in AR. TIMP1 and THBS2 were enriched in AR patient serum. Therefore, differentially expressed METS and MARGS especially TIMP1, MMP7/-9 represent potential molecular AR markers.