974 resultados para Cd4 Lymphocytes-t
Resumo:
Les cellules mylodes incluant les monocytes, les macrophages et les cellules dendritiques (DCs, dendritic cells) contribuent la pathognse de linfection VIH-1 en participant la dissmination du virus, mais galement en reprsentant des rservoirs viraux potentiels. Leurs fonctions sont exploites par le VIH-1 afin dassurer sa propagation travers lorganisme. Notamment, une infection VIH-1 est associe une altration de la prsentation antignique et la perte de lymphocytes T CD4+ spcifiques des antignes. Lautophagie est un processus catabolique universel impliqu dans la rgulation de la prsentation antignique subsquente la neutralisation/destruction du pathogne. Des tudes rcentes suggrent que le VIH-1 altre le mcanisme dautophagie afin dassurer sa survie. Le premier volet de ce projet de matrise a vis la caractrisation des effets du VIH-1 sur lautophagie dans les DCs drives de monocytes circulants (MDDC, monocyte-derived dendritic cells) et lidentification des stratgies thrapeutiques pour contrecarrer ces effets. Les objectifs spcifiques ont t de : (i) caractriser lexpression de marqueurs de maturation sur des MDDC exposes au VIH-1 in vitro, (ii) quantifier lexpression des protines lies la rgulation positive (i.e., ATG5, LC3, p62) et ngative (i.e., mTOR) de lautophagie dans les MDDC exposes au VIH, (iii) dterminer le rle de lautophagie dans la trans infection du VIH-1 aux lymphocytes T CD4+ et (iv) explorer limpact de lautophagie sur la prsentation antignique par les MDDC infectes VIH-1 in vitro. Nos rsultats dmontrent quune exposition des MDDC au VIH-1 in vitro altre dramatiquement leur maturation et leur habilet induire la prolifration des cellules T autologues en rponse Staphylococcus aureus et Cytomegalovirus (CMV) mais pas la rponse induite par Staphylococcal enterotoxin B (SEB). Nous dmontrons que lexposition des MDDC au VIH sassocie une augmentation de lexpression de la protine mTOR totale et de sa forme phosphoryle (phospho-mTOR) et de la protine p62. Le traitement des MDDC la rapamycine diminue lexpression de mTOR et rduit la capacit de trans infection du VIH-1 par les MDDC, sans toutefois restaurer leur potentiel immunogne. En effet, nous observons que la rapamycine rduit lexpression de CD83 par les MDDC et augmente lexpression de CCR7, indiquant ainsi que leffet immunosuppresseur document de la rapamycine est associ une dfaillance de maturation des MDDC. Le second volet de ce projet de recherche sest intress la contribution des cellules mylodes la persistance virale chez les sujets infects par le VIH-1 sous thrapie antirtrovirale. Les objectifs spcifiques ont t : (i) dvaluer la prsence de diffrentes formes dADN viral dans les monocytes circulants de patients infects par le VIH-1 et (ii) de mesurer lintgration et la rplication virale dans des macrophages drivs de monocytes (MDM) de patients infects sous ART. Nos rsultats indiquent que les monocytes portent des formes prcoces de transcription virale inverse (ADN du VIH RU5) et que, malgr une charge virale plasmatique indtectable sous ART, les MDM supportent la rplication virale. Ces donnes trs prliminaires apportent des vidences en faveur de la contribution des cellules mylodes la persistance virale sous ART et reprsentent une ouverture pour un projet de recherche plus complexe dans le futur. En somme, nos rsultats dmontrent que le VIH-1 altre le potentiel immunogne des MDDC et que la rapamycine peut tre employe pour limiter la trans infection des lymphocytes T CD4+ par les MDDC. Nanmoins, lincapacit de la rapamycine rtablir le potentiel immunogne des MDDC incite identifier de nouvelles stratgies manipulant lautophagie pour une restauration optimale de la comptence immunitaire chez les sujets infects VIH-1. Les cellules mylodes jouent un rle primordial dans la dissmination et la persistance virale et doivent donc tre cibles par les stratgies actuelles dradication des rservoirs du VIH sous ART.
Resumo:
PURPOSE. Interleukin (IL)-17, which is responsible for the initial influx of leukocytes into the target tissue, was recently described as the main cytokine involved in autoimmune diseases. Vogt-Koyanagi-Harada (VKH) syndrome is a significant cause of noninfectious blindness in the world. Herein the authors aimed at unraveling the involvement of IL-17 in VKH and in experimental autoimmune uveitis, focusing on the signaling pathways involved in IL-17 synthesis. METHODS. Mice were immunized with 161-180 peptide and pertussis toxin. Draining lymph node cells, harvested 21 days after immunization, were cultured in the presence or absence of p38 alpha mitogen-activated protein kinase (MAPK) inhibitor (SB203580) and assayed for cytokine production and quantification of CD4(+)IL-17(+) cells. Mice received intraocular injections of SB203580, and disease severity was evaluated by histologic examination of the enucleated eyes at day 21. CD4(+) lymphocytes from MSK-1/2-deficient mice, human CD4(+) cells silenced with MSK1 siRNA, or peripheral blood mononuclear cells (PBMCs) from VKH patients were cultured in the presence or absence of p38 alpha MAPK inhibitor and then assayed for IL-17, IFN-gamma, and IL-4 production. RESULTS. The inhibition of p38 alpha MAPK fully blocked the synthesis of IL-17 by PBMCs from VKH patients and lymphocytes from EAU mice. The absence of the msk1/2 gene resulted in failure to produce IL-17 by murine and human lymphocytes. Interestingly, intraocular injections of SB203580 in EAU mice did not suppress development of the disease. CONCLUSIONS. These data show that p38 alpha MAPK-MSK1/2 is involved in the control of IL-17 synthesis by CD4(+) T cells and that inhibition of p38 alpha MAPK in vitro suppresses IL-17 synthesis but that inhibition of this kinase in vivo did not protect from EAU. (Invest Ophthalmol Vis Sci. 2010;51:3567-3574) DOI: 10.1167/iovs.09-4393
Resumo:
Este estudo visou a determinar os valores eritroleucomtricos e quantificar as subpopulaes linfocitrias no sangue do cordo umbilical (SCU) e no sangue jugular de eqinos neonatos. Foi realizada a colheita de SCU e do sangue jugular de 20 potros ao nascimento. As amostras foram submetidas s determinaes dos valores eritroleucomtricos e quantificao de subpopulaes de linfcitos-T, pela tcnica citofluoromtrica. No foram verificadas diferenas significativas (P<0,05) entre os valores mdios de tais parmetros, entre o sangue jugular de neonatos e o SCU eqino. O valor total para neutrfilos segmentados, no SCU e na jugular dos neonatos, foi inferior ao reportado para eqinos ao nascimento. As contagens de linfcitos CD5+ e CD4+ no SCU e jugular de neonatos eqinos foram inferiores quelas admitidas para o sangue perifrico de eqinos adultos, indicando um componente imunolgico imaturo. No entanto, a contagem de linfcitos CD8+ foi semelhante descrita em sangue perifrico de eqinos adultos. A proporo CD4:CD8 obtida nesse ensaio, tanto para o SCU (2,64±0,91), como no sangue jugular de eqinos neonatos (2,41±0,81), demonstrou uma dominncia das clulas T CD4+ sobre os linfcitos T CD8+.
Resumo:
Objective: HIV infection is exacerbated through additional pro-atherogenic mechanisms related to the processes of immune activation, inflammation, coagulation, and the modification of lipoproteins (e.g., particles of high density lipoprotein), contributing to increased cardiovascular risk. The aim of this study was to analyze the serum concentrations of myeloperoxidase (MPO) and other laboratory parameters in HIV-infected patients treated or not with antiretroviral drugs compared to non-infected individuals.Materials/Methods: The study included 154 volunteers: 47 non-infected individuals (control group - CON), 27 infected and untreated individuals (NTARv group) and 80 treated individuals (TARV group). We analyzed the counts of CD4+ lymphocytes and the viral load of the infected patients, along with the blood count, fasting glucose, total serum cholesterol (CHOL), HDL cholesterol, LDL cholesterol, triglycerides, MPO and high-sensitivity C-reactive protein (CRP) of all study participants.Results: There were significant increases in glucose, CHOL, LDL cholesterol, and triglycerides in the TARV group and significant reductions in the levels of HDL cholesterol for the TARV and NTARV groups. Significantly elevated levels of Hs-CRP were observed only in the TARV group, while levels of MPO were significantly higher in the TARV and NTARV groups compared to the control group. A correlation of MPO with Hs-CRP (r = 0.21, p = 0.032) was observed for HIV-infected patients, but MPO did not correlate significantly with the other analyzed parameters.Conclusions: The investigation of early biomarkers for cardiovascular risk evaluation, such as MPO, contributes to the clinical monitoring of HIV-infected individuals. The serum levels of MPO correlated with Hs-CRP and were high in HIV-infected individuals, indicating a possible predictor of cardiovascular events in these patients. (c) 2012 Elsevier B.V. All rights reserved.
Resumo:
HIV infection is associated with disturbances in lipid metabolism due to a host's response mechanism and the current antiretroviral therapy. The pathological appearance and progression of atherosclerosis is dependent on the presence of injurious agents in the vascular endothelium and variations in different subsets of candidate genes. Therefore, the Hha I polymorphism in the apolipoprotein E gene was evaluated in addition to triglycerides, total cholesterol, very low-density lipoprotein (VLDL), LDL, high-density lipoprotein (HDL), and apolipoprotein (apo) Al, B and E levels in 86 Brazilian HIV-infected patients and 29 healthy controls. The allele frequency for apoE in the HIV-infected group and controls was in agreement with data on the Brazilian population. Dyslipidemia was observed in the HIV group and verified by increased levels of triglycerides, VLDL and apoE, and decreased levels of HDL and apoAl. The greatest abnormalities in these biochemical variables were shown in the HIV-infected individuals whose immune function was more compromised. The effect of the genetic variation at the APOE gene on biochemical variables was more pronounced in the HIV-infected individuals who carried the apoE2/3 genotype. The highly active antiretroviral therapy (HAART)-receiving group presented increased levels of total cholesterol and apoE. Dyslipidemia was a predictable consequence of HIV infection and the protease inhibitors intensified the increase in apoE values.
Resumo:
From the beginning of the AIDS epidemic, pneumocystis pneumonia ( PCP) has been distinguished as one of the most frequent opportunistic diseases with high morbid-mortality. As from 1996, the advent of the highly active antiretroviral therapy ( HAART) has changed the characteristics of such epidemic by reducing its related diseases and, as a result, AIDS-related mortality. With the purpose to estimate PCP occurrence and HAART interference, 376 HIV-infected or AIDS patients were studied from January 1992 to December 2002. Among them, 58 ( 15.5%) PCP cases were found. There was a higher occurrence of PCP in the group of patients in which HAART was not used, with 40 ( 69.0%) of the episodes. As regards the studied period, a tendency to a linear reduction in annual PCP incidence was observed. The mean of T CD4+ lymphocytes in the patients with PCP ( 117 cells/mm(3)) was significantly lower when compared to that of the other individuals ( 325 cells/mm(3)). Therefore, this study suggests a temporal reduction in PCP occurrence related to HAART use with higher T CD4+ lymphocyte counts. Nevertheless, this opportunistic infection still shows significant incidence in AIDS patients. ( NCT00516581).
Resumo:
The study of the in-situ cellular immune response is very important for the understanding of different liver infections. In the present study, 53 liver samples obtained by viscerotomy from patients who died during the course of jungle yellow fever were analyzed. The diagnosis was confirmed by serology, viral isolation and virus-specific immunohistochemistry. The specimens were analyzed by immunohistochemistry using specific antibodies for apoptosis, CD45RO, CD4, CD8, CD20, S100, CD57 and CD68. Quantitative analysis of the labeling pattern showed a clear predominance of the different phenotypes in the portal tract and midzone region of the acini. There was a predominance of T CD4+ lymphocytes, accompanied by the presence of T CD8+ lymphocytes, natural killer cells (CD57), macrophages and antigen-presenting cells (S100). The disproportion between the intensity of inflammation and the degree of hepatic injury was probably due to the intense apoptotic component, which classically does not induce an inflammatory response. The present study demonstrates that, despite the disproportion between injury and inflammation, the cellular immune response plays an important role in the pathogenesis of the hepatocytic injury observed in yellow fever, probably as a result of cytolytic actions through mechanisms involving MHC II and the activation of Fas receptors and granzymes/perforins. (C) 2006 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.
Resumo:
A infeco pelo Vrus da imunodeficincia humana 1 (HIV -1) em associao com a do Vrus da hepatite C (HCV) representa, atualmente, uma comorbidade que pode interferir principalmente na histria natural da hepatite C. Este trabalho tem como objetivo descrever aspectos demogrfico, clnico e laboratorial, incluindo exame histopatolgico de pacientes coinfectados HIV/RCV. No perodo de agosto de 2004 a dezembro de 2006, 36 pacientes coinfectados, foram selecionados para o estudo. Noventa e dois por cento desses pacientes eram procedentes de Belm, com mdia de idade de 42 anos. Entre as principais informaes demogrficas da populao estudada, foram identificados 72,52% solteiros, 83,5% do sexo masculino e 61,1% relataram ser heterossexuais. Entre os fatores de risco para o HCV o uso de drogas ilcitas injetveis foi identificado em 41,7% dos casos, o uso de cocana intranasal foi relatado por 38,9% dos pacientes, e o compartilhamento de seringas e material pessoal, em 38,9% dos casos. A histria de etilismo em 77,8% e o uso de TARV foram os possveis fatores agravantes mais frequentes para a doena heptica. Apenas um paciente apresentou sinais clnicos de insuficincia heptica crnica. Entre os testes bioqumicos hepticos, a mediana de ALT e AST foi de 68UI/L e 61UI/L, respectivamente. Os nveis de linfcitos T CD4+ apresentaram mediana de 327 clulas/mm, a carga viral do HIV com mediana de 2,53 logl0 cpias/mL (ep=0,34), carga viral do HCV com mediana de 5,9 log10UI/mL. O gentipo 1 do HCV foi o mais frequente (58,82%). Cinqenta e sete por cento dos pacientes submetidos bipsia heptica apresentavam fibrose de moderada a severa, e 11% no apresentaram fibrose pela classificao MET AVIR. Houve associao entre nveis de linfcitos T CD4+ e nveis de ALT e de AST (p=0,0009 e p=0,0002, respectivamente), assim como associao entre gentipo 1 do HCV e HCV-RNA maior ou igual a 6 log10 UI/mL (p=0.0039). Foi observada tambm associao entre HCV-RNA e HIV-RNA (p=0,039). Os pacientes apresentam estado geral bom, imunologicamente estveis, sem sinais de descompensao heptica, mas com alteraes estruturais hepticas importantes, sendo portanto bons candidatos terapia antiviral para o HCV. Futuros estudos, talvez de caso controle, com casustica maior so necessrios para melhor entendimento da co-infeco HIV/HCV.
Resumo:
Ps-graduao em Medicina Veterinria - FCAV
Resumo:
The aim of the present trial was to determine the frequencies and absolute number of B and T lymphocytes subpopulations in bovine leukemia virus (BLV)-infected dairy cows with distinct lymphocyte profile known as non-leukemic (AL) and persistent lymphocytosis (PL). Thus, 15 animals were selected and divided uniformly in three groups (negative, AL, PL). The BLV infection was detected by agar gel immunodiffusion and enzyme-linked immunosorbent-assay. The lymphocytes subsets were evaluated using monoclonal antibodies by flow cytometry. The results of the present study pointed out to an increase in B lymphocytes, and also an augment in CD5(+) and CD11b(+) cells in animals showing PL. Consequently, it can be observed a decrease in the percentage of T cells subsets in these animals. Conversely, no significant alterations in the absolute number of the T lymphocytes, T CD4(+) cells and T CD8(+) lymphocytes were found in BLV-infected dairy cows with PL. Therefore, the correlation between the absolute numbers of B- and T cell subsets in the peripheral blood applied to each group showed a significant and positive strong correlation between numbers of B cells and T cells or T CD8(+) cells in the PL animals, although the same cannot be predicted for T CD4(+) lymphocytes. No such correlation was encountered for the AL and negative-control animals.
Resumo:
Mucosal-associated invariant T (MAIT) cells are an abundant antibacterial innate-like lymphocyte population. There are conflicting reports as to their fate in HIV infection. The objective of this study was to determine whether MAIT cells are truly depleted in HIV infection.In this case-control study of HIV-positive patients and healthy controls, quantitative real-time polymerase chain reaction was used to assess the abundance of messenger RNA (mRNA) and genomic DNA (gDNA) encoding the canonical MAIT cell T cell receptor (V7.2-J33). Comparison was made with flow cytometry.Significant depletion of both V7.2-J33 mRNA and gDNA was seen in HIV infection. Depletion of V7.2+CD161++ T cells was confirmed by flow cytometry. In HIV infection, the abundance of V7.2-J33 mRNA correlated most strongly with the frequency of V7.2+CD161++ cells. No increase was observed in the frequency of V7.2+CD161- cells among CD3+CD4- lymphocytes.MAIT cells are depleted from blood in HIV infection as confirmed by independent assays. Significant accumulation of a CD161- MAIT cell population is unlikely. Molecular approaches represent a suitable alternative to flow cytometry-based assays for tracking of MAIT cells in HIV and other settings.
Resumo:
Disseminated MAC (dMAC) is the third most prevalent opportunistic infection in AIDS patients. In order to understand the role MAC infection plays in affecting survival of AIDS patients, a cohort of 203 suspected dMAC veterans seen at the Houston Veterans Affairs Medical Center between August 14, 1987 and December 31, 1991 were analyzed. The criteria for suspected dMAC infection was HIV+ men having a CD4+ level $\le$200 cells/mm$\sp3,$ on zidovudine treatment $\ge$1 month and who had any of the following: (a) a confirmed respiratory MAC infection, (b) fever $\ge$101$\sp\circ\rm F$ for $\ge$48 hours, (c) unexplained weight loss of 10 lbs or $\ge$10% BW over 3 months or (d) Hgb $\le$7.5 g/dl or decrease in Hgb $\ge$3.0 g/dl, while on 500-600 mg/day AZT. The study was conducted before the commencement of an effective MAC anti-mycobacterial therapy, so the true course of MAC infection was seen without the confounder of a therapeutic regimen. Kaplan-Meier and Cox regression survival analysis was used to compare 45 MAC culture positive and 118 MAC culture negative veterans. The 1 year survival rate of veterans with documented dMAC infection was 0.37 compared to 0.50 for veterans not acquiring dMAC infection. Significant differences between subgroups were also seen with the variables: PCP prophylaxis, the AIDS indicator disease Candida esophagitis, CD4+ lymphocyte level, CD4 percent lymphocyte level, WBC level, Hgb and Hct levels. Using multivariate modeling, it was determined that PCP prophylaxis (RR = 6.12, CI 2.24-16.68) was a predictor of survival and both CD4% lymphocytes $\le$6.0% (RR = 0.33, CI 0.17-0.68) and WBC level $\le$3000 cells/mm$\sp3$ (RR = 0.60, CI 0.39-0.93) were predictors of mortality. CD4+ level $\le$50 cells/mm$\sp3$ was not a significant predictor of mortality. Although MAC culture status was a significant predictor of mortality in the univariate model, a positive dMAC culture was not a significant predictor of AIDS mortality in the multivariate model. A positive dMAC culture, however, did affect mortality in a stratified analysis when baseline laboratory values were: CD8+ lymphocytes $>$600 cells/mm$\sp3,$ Hgb $>$11.0 g/dl, Hct $>$31.0% and WBC level $>$3000 cells/mm$\sp3.$ ^
Resumo:
The Nef protein is an important virulence factor of primate lentiviruses, yet the mechanisms by which it exerts this influence are imperfectly understood. Here, using an inducible system, we demonstrate that Nef increases IL-2 secretion from T cells stimulated via CD3 or CD28. This effect requires the conservation of the Nef myristoylation signal and SH3-binding proline-based motif. Together with several proteins involved in the initiation and propagation of T cell signaling, Nef associates with membrane microdomains known as rafts. The Nef-mediated superinduction of IL-2 reflects the activation of both NFAT and NFB. Accordingly, Nef also enhances HIV-1 transcription in response to CD3 or CD28 stimulation. Nef-induced IL-2 hyperresponsiveness is also observed in primary CD4 lymphocytes. Overall, these data suggest that Nef acts at the level of rafts to prime T cells for activation. Likely consequences of this effect are the promotion of HIV-1 replication and the facilitation of virus spread.
Resumo:
To identify the physiological functions of the retinoid-related orphan receptor (ROR), a member of the nuclear receptor superfamily, mice deficient in ROR function were generated by targeted disruption. ROR/ mice lack peripheral and mesenteric lymph nodes and Peyer's patches, indicating that ROR expression is indispensable for lymph node organogenesis. Although the spleen is enlarged, its architecture is normal. The number of peripheral blood CD3+ and CD4+ lymphocytes is reduced 6- and 10-fold, respectively, whereas the number of circulating B cells is normal. The thymus of ROR/ mice contains 74.4% 8.9% fewer thymocytes than that of wild-type mice. Flow cytometric analysis showed a decrease in the CD4+CD8+ subpopulation. Terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) staining demonstrated a 4-fold increase in apoptotic cells in the cortex of the thymus of ROR/ mice. The latter was supported by the observed increase in annexin V-positive cells. ROR/ thymocytes placed in culture exhibit a dramatic increase in the rate of spontaneous apoptosis. This increase is largely associated with CD4+CD8+ thymocytes and may, at least in part, be related to the greatly reduced level of expression of the anti-apoptotic gene Bcl-XL. Flow cytometric analysis demonstrated a 6-fold rise in the percentage of cells in the S phase of the cell cycle among thymocytes from ROR/ mice. Our observations indicate that ROR is essential for lymphoid organogenesis and plays an important regulatory role in thymopoiesis. Our findings support a model in which ROR negatively controls apoptosis in thymocytes.
Resumo:
The association between human immunodeficiency virus type I (HIV-1) RNA load changes and the emergence of resistant virus variants was investigated in 24 HIV-1-infected asymptomatic persons during 2 years of treatment with zidovudine by sequentially measuring serum HIV-1 RNA load and the relative amounts of HIV-1 RNA containing mutations at reverse transcriptase (RT) codons 70 (K-->R), 41 (M-->L), and 215 (T-->Y/F). A mean maximum decline in RNA load occurred during the first month, followed by a resurgence between 1 and 3 months, which appeared independent of drug-resistance. Mathematical modeling suggests that this resurgence is caused by host-parasite dynamics, and thus reflects infection of the transiently increased numbers of CD4+ lymphocytes. Between 3 and 6 months of treatment, the RNA load returned to baseline values, which was associated with the emergence of virus containing a single lysine to arginine amino acid change at RT codon 70, only conferring an 8-fold reduction in susceptibility. Despite the relative loss of RNA load suppression, selection toward mutations at RT codons 215 and 41 continued. Identical patterns were observed in the mathematical model. While host-parasite dynamics and outgrowth of low-level resistant virus thus appear responsible for the loss of HIV-1 RNA load suppression, zidovudine continues to select for alternative mutations, conferring increasing levels of resistance.
