RESUMO
Cerebral malaria (CM) is a neurological complication derived from the Plasmodium falciparum infection in humans. The mechanisms involved in the disease progression are still not fully understood, but both the sequestration of infected red blood cells (iRBC) and leukocytes and an exacerbated host inflammatory immune response are significant factors. In this study, we investigated the effect of Monocyte Locomotion Inhibitory Factor (MLIF), an anti-inflammatory peptide, in a well-characterized murine model of CM. Our data showed that the administration of MLIF increased the survival and avoided the neurological signs of CM in Plasmodium berghei ANKA (PbA) infected C57BL/6 mice. MLIF administration down-regulated systemic inflammatory mediators such as IFN-γ, TNF-α, IL-6, CXCL2, and CCL2, as well as the in situ expression of TNF-α in the brain. In the same way, MLIF reduced the expression of CD31, CD36, CD54, and CD106 in the cerebral endothelium of infected animals and prevented the sequestration of iRBC and leucocytes in the brain microvasculature. Furthermore, MLIF inhibited the activation of astrocytes and microglia and preserved the integrity of the blood-brain barrier (BBB). In conclusion, our results demonstrated that the administration of MLIF increased survival and conferred neuroprotection by decreasing neuroinflammation in murine CM.
Assuntos
Anti-Inflamatórios/administração & dosagem , Malária Cerebral/prevenção & controle , Fármacos Neuroprotetores/administração & dosagem , Oligopeptídeos/administração & dosagem , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/imunologia , Encéfalo/efeitos dos fármacos , Encéfalo/imunologia , Encéfalo/patologia , Modelos Animais de Doenças , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/imunologia , Feminino , Humanos , Mediadores da Inflamação/antagonistas & inibidores , Mediadores da Inflamação/metabolismo , Malária Cerebral/imunologia , Malária Cerebral/parasitologia , Malária Cerebral/patologia , Camundongos , Microglia/efeitos dos fármacos , Microglia/imunologia , Plasmodium berghei/imunologiaRESUMO
Allergic asthma is a chronic inflammatory disease characterized by the accumulation of eosinophils, Th2 cells and mononuclear cells in the airways, leading to changes in lung architecture and subsequently reduced respiratory function. We have previously demonstrated that CDIP-2, a chemokine derived peptide, reduced in vitro chemotaxis and decreased cellular infiltration in a murine model of allergic airway inflammation. However, the mechanisms involved in this process have not been identified yet. Now, we found that CDIP-2 reduces chemokine-mediated functions via interactions with CCR1, CCR2 and CCR3. Moreover, using bone marrow-derived eosinophils, we demonstrated that CDIP-2 modifies the calcium fluxes induced by CCL11 and down-modulated CCR3 expression. Finally, CDIP-2 treatment in a murine model of OVA-induced allergic airway inflammation reduced leukocyte recruitment and decreases production of cytokines. These data suggest that chemokine-derived peptides represent new therapeutic tools to generate more effective antiinflammatory drugs.
Assuntos
Anti-Inflamatórios/farmacologia , Peptídeos/farmacologia , Receptores CCR1/metabolismo , Receptores CCR2/metabolismo , Receptores CCR3/metabolismo , Alérgenos , Animais , Anti-Inflamatórios/uso terapêutico , Células CHO , Cálcio/metabolismo , Linhagem Celular Tumoral , Quimiotaxia/efeitos dos fármacos , Cricetulus , Citocinas/metabolismo , Eosinófilos/efeitos dos fármacos , Eosinófilos/fisiologia , Feminino , Humanos , Pulmão/efeitos dos fármacos , Pulmão/patologia , Linfonodos/citologia , Camundongos Endogâmicos BALB C , Ovalbumina , Peptídeos/uso terapêutico , Pneumonia/tratamento farmacológico , Pneumonia/patologia , Receptores CCR1/genética , Receptores CCR2/genética , Receptores CCR3/genética , Hipersensibilidade Respiratória/tratamento farmacológico , Hipersensibilidade Respiratória/patologiaRESUMO
Analysis of the mechanisms underlying the inflammatory response in amoebiasis is important to understand the immunopathology of the disease. Mucosal associated effector and regulatory T cells may play a role in regulating the inflammatory immune response associated to Entamoeba histolytica infection in the colon. A subpopulation of regulatory T cells has recently been identified and is characterized by the expression of the chemokine receptor CCR9. In this report, we used CCR9 deficient (CCR9(-/-)) mice to investigate the role of the CCR9(+) T cells in a murine model of E. histolytica intestinal infection. Intracecal infection of CCR9(+/+), CCR9(+/-) and CCR9(-/-) mice with E. histolytica trophozoites, revealed striking differences in the development and nature of the intestinal inflammatory response observed between these strains. While CCR9(+/+) and CCR9(+/-) mice were resistant to the infection and resolved the pathogen-induced inflammatory response, CCR9(-/-) mice developed a chronic inflammatory response, which was associated with over-expression of the cytokines IFN-γ, TNF-α, IL-4, IL-6 and IL-17, while IL-10 was not present. In addition, increased levels of CCL11, CCL20 and CCL28 chemokines were detected by qRT-PCR in CCR9(-/-) mice. E. histolytica trophozoites were identified in the lumen of the cecum of CCR9(-/-) mice at seven days post infection (pi), whereas in CCR9(+/+) mice trophozoites disappeared by day 1 pi. Interestingly, the inflammation observed in CCR9(-/-) mice, was associated with a delayed recruitment of CD4(+)CD25(+)FoxP3(+) T cells to the cecal epithelium and lamina propria, suggesting that this population may play a role in the early regulation of the inflammatory response against E. histolytica, likely through IL-10 production. In support of these data, CCR9(+) T cells were also identified in colon tissue sections obtained from patients with amoebic colitis. Our data suggest that a population of CCR9(+)CD4(+)CD25(+)FoxP3(+) T cells may participate in the control and resolution of the inflammatory immune response to E. histolytica infection.
Assuntos
Modelos Animais de Doenças , Disenteria Amebiana/imunologia , Entamoeba histolytica/imunologia , Receptores CCR/imunologia , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Quimiocina CCL11/genética , Quimiocina CCL11/imunologia , Quimiocina CCL11/metabolismo , Quimiocina CCL20/genética , Quimiocina CCL20/imunologia , Quimiocina CCL20/metabolismo , Quimiocinas CC/genética , Quimiocinas CC/imunologia , Quimiocinas CC/metabolismo , Disenteria Amebiana/metabolismo , Disenteria Amebiana/parasitologia , Entamoeba histolytica/fisiologia , Citometria de Fluxo , Fatores de Transcrição Forkhead/imunologia , Fatores de Transcrição Forkhead/metabolismo , Expressão Gênica , Humanos , Mediadores da Inflamação/imunologia , Mediadores da Inflamação/metabolismo , Interferon gama/imunologia , Interferon gama/metabolismo , Interleucina-17/imunologia , Interleucina-17/metabolismo , Subunidade alfa de Receptor de Interleucina-2/imunologia , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Interleucina-4/imunologia , Interleucina-4/metabolismo , Interleucina-6/imunologia , Interleucina-6/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores CCR/genética , Receptores CCR/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Trofozoítos/imunologia , Trofozoítos/fisiologia , Fator de Necrose Tumoral alfa/imunologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
To ascertain the in vivo role of mycobacterial lipids phthiocerol dimycocerosates (PDIM) in experimental murine tuberculosis (Tb), airways infection was used to compare the parental virulent clinical isolate MT103 with its mutant fadD26, lacking PDIM. Lungs were assessed as the Tb-target organ and mediastinal lymph nodes as the corresponding lymphoid tissue, in order to quantify: the major T-cell subsets (CD4+/CD8+/gammadelta+) and their activation kinetics, bacillary burden, and in vivo cytotoxicity against inoculated target cells loaded with mycobacterial Ags. After 4 weeks, infection augmented total and activated CD4+ and CD8+ T cells in lungs and nodes mainly with MT103, while gammadelta+ T cells increased earlier in nodes. MT103 bacillary burden was bigger and appeared earlier than the mutant fadD26, especially in the lung than in mediastinal nodes. At day 14 of MT103 infection, there was no cytotoxicity in lungs and nodes; while with fadD26 there was some in the nodes. At day 21 of MT103 infection, important cytotoxicity was detected only in lungs; while with fadD26 both tissues showed important activity. Interestingly, unlike the infection with fadD26, cytotoxicity under MT103 fell considerably in the target organ (lung) from days 21 to 60, the advanced phase. Although upon airways infection both mycobacteria behaved similarly regarding T cell (CD4/CD8/gammadelta) stimulation kinetics; they differed in the magnitude of these responses, in the bacterial load within tissues, and to trigger in vivo cytotoxicity in lungs and regional lymph nodes. This highlights the relevance of certain mycobacterial lipids to modify crucial effector branches of immunity.
Assuntos
Citotoxicidade Imunológica , Lipídeos/fisiologia , Pulmão/imunologia , Linfonodos/imunologia , Linfócitos T/imunologia , Tuberculose/imunologia , Animais , Hipersensibilidade Tardia , Ativação Linfocitária , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Tuberculose/microbiologiaRESUMO
A three-dimensional model of the alphaX I-domain of the horse integrin CD11c from dendritic cells provided information for selecting two segments of the primary structure for peptide synthesis. Peptide 1 contains 20 amino acids and peptide 2 has 17 amino acid residues. The first spans from position Thr229 to Arg248 of an alpha-helix segment of the structure, whereas peptide 2 goes from Asp158 to Phe174 and corresponds to an exposed segment of the loop considered to be the metal ion-dependent adhesion site. Murine polyclonal antisera against both peptides were generated and assayed in peripheral blood cell suspensions and in cryosections of horse lymph nodes. Only the serum against peptide 2 was capable of identifying cells in suspension and in situ by immunohistochemistry, some with evident dendritic morphology. Using this approach, an immunogenic epitope exposed in CD11c was identified in cells from horse lymph node in situ.
Assuntos
Antígeno CD11c/imunologia , Células Dendríticas/imunologia , Cavalos/imunologia , Sequência de Aminoácidos , Animais , Formação de Anticorpos , Antígeno CD11c/química , Antígeno CD11c/genética , Reações Cruzadas , Epitopos/química , Epitopos/genética , Feminino , Cavalos/genética , Humanos , Imuno-Histoquímica , Linfonodos/citologia , Linfonodos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Dados de Sequência Molecular , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Engenharia de Proteínas , Dobramento de Proteína , Estrutura Terciária de Proteína , Homologia de Sequência de AminoácidosRESUMO
Atherosclerosis is a complex disease involved in major fatal events such as myocardial infarction and stroke. It is the result of interactions between metabolic, dietetic and environmental risk factors acting on a genetic background that could result in endothelial susceptibility. Our aim was to determine the patterns of expression of adhesion molecules and whether phosphatidylserine is translocated to the cell surface of human umbilical vein endothelial cells (HUVECs) isolated from healthy newborns born to parents with a strong family history of myocardial infarction under TNF-alpha or oxLDL stimulated conditions. Compared to control HUVECs, experimental cords showed: (a) a four-fold increase in VCAM-1 expression under basal conditions, which showed no change after stimulation with the pro-atherogenic factors; (b) a two-fold increase in basal P-selectin expression that reached a 10-fold increase with any of the pro-atherogenic factors; (c) a basal ICAM-1 expression similar to P-selectin that was not modified by the pro-atherogenic molecules; (d) a similar PECAM-1 expression. Unexpectedly, phospathidylserine expression in experimental cord HUVECs was significantly increased (211 817 versus 3354 TFU) but was not associated to apoptotic death as the percentage of dead cells induced by TNF-alpha treatment was very low (0.55 versus 9.87% in control HUVECs). The latter result was corroborated by TUNEL staining. T cell adherence to HUVECs was highly up-regulated in the genetically predisposed samples. The analysis of nonpooled HUVECs, from newborns to family predisposed myocardial-infarction individuals, might represent a useful strategy to identify phenotypical and functional alterations, and hopefully, to take early preventive actions.
Assuntos
Moléculas de Adesão Celular/sangue , Células Endoteliais/química , Endotélio Vascular/citologia , Sangue Fetal/citologia , Infarto do Miocárdio/sangue , Estudos de Casos e Controles , Adesão Celular , Células Cultivadas , Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Predisposição Genética para Doença , Humanos , Recém-Nascido , Molécula 1 de Adesão Intercelular/sangue , Células Jurkat , Lipoproteínas LDL/farmacologia , Infarto do Miocárdio/genética , Selectina-P/sangue , Molécula-1 de Adesão Celular Endotelial a Plaquetas/sangue , Estimulação Química , Linfócitos T/fisiologia , Fator de Necrose Tumoral alfa/farmacologia , Células U937 , Molécula 1 de Adesão de Célula Vascular/sangueRESUMO
It has been shown recently that different genotypes of Mycobacterium tuberculosis induce distinct immune responses in the host, as reflected by variations in cytokine and iNOS expression. Because these molecules are probably regulated by multiple factors in vivo this complex phenomenon was partially analysed by assessing cytokine and iNOS expression by real-time polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) in an in vitro model of bone marrow-derived macrophages infected with three different M. tuberculosis genotypes: Canetti, H37 Rv and Beijing. Although the three genotypes induced production of iNOS and the different cytokines tested at 24 h post-infection, macrophages infected with the Beijing isolate expressed the highest levels of mRNA for iNOS, interleukin (IL)-1beta, tumour necrosis factor (TNF)-alpha, IL-12 cytokines and lower levels of IL-10 compared with cells infected with other genotypes. This expression pattern has been associated with infection control, but during infection in vivo with the Beijing genotype it is lost upon progression to chronic phase. The failure to control infection is likely to be influenced by cytokines produced by other cell types and bacterial molecules expressed during the course of disease. Results presented in this work show that each genotype has the ability to induce different levels of cytokine expression that could be related to its pathogenesis during infection.
Assuntos
Citocinas/imunologia , Macrófagos/imunologia , Tuberculose/imunologia , Animais , Células da Medula Óssea/imunologia , Células Cultivadas , Genótipo , Interleucina-1/imunologia , Interleucina-10/imunologia , Interleucinas/imunologia , Camundongos , Mycobacterium tuberculosis/genética , Óxido Nítrico Sintase/imunologia , Óxido Nítrico Sintase Tipo II , Fagocitose/imunologia , RNA Mensageiro/imunologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Fator de Crescimento Transformador beta/imunologia , Tuberculose/genéticaRESUMO
CD40, a glycoprotein expressed on B lymphocytes plays an important role in B cell development, growth and differentiation. The ligand for the CD40 is a 39-kDa glycoprotein (CD154) expressed on the surface of activated T lymphocytes and is essential for thymus-dependent humoral immunity. The expression of CD154 is tightly regulated and its transient expression reduces the chances of potentially deleterious bystander activation of B cells. Stimulation through CD40 has been studied in vitro by using antibodies against CD40, by membranes of activated T cells or lately, by CD154 transfected cells. In this work we have evaluated the outcome of CD40-CD40 ligand interaction in vitro and in vivo by using CD154-transfected L929 cells. In vitro assays showed that CD154-L929 cells can induce on B cells: IL-4-dependent proliferation, up-regulation of CD23, CD54 and class II molecules and can also rescue WEHI-231 B cell lymphoma from anti-IgM-induced apoptosis. Interestingly, in vivo assays revealed that when CD154-L929 cells were inoculated into the spleen, mice developed a strong but transient production of anti-erythrocyte autoantibodies. Through B lymphocyte activation with CD154-transfected L929 cells both in vitro and in vivo, our data reveal that enforced and prolonged expression of CD40 ligand overcomes the tightly regulated mechanisms of B cell activation, triggering the production of autoantibodies. This system might be used to evaluate the early steps of an autoimmune response and the role of CD40-CD154 in the induction of primary responses in vivo.
Assuntos
Autoanticorpos/biossíntese , Linfócitos B/imunologia , Ligante de CD40/fisiologia , Ativação Linfocitária , Animais , Apoptose , Antígenos CD40/fisiologia , Células Cultivadas , Feminino , Antígenos de Histocompatibilidade Classe II/análise , Imunoglobulina M/imunologia , Lipopolissacarídeos/farmacologia , Masculino , Camundongos , Camundongos Endogâmicos C3H , Receptores de IgE/análiseRESUMO
Intraperitoneal inoculation of axenically cultured Entamoeba histolytica trophozoites constitutes an easy to perform, highly reproducible procedure for inducing amebic liver abscesses in hamsters. Efficiency in abscess production (95% of infected animals after 1 week) was similar to data reported using direct intrahepatic or intraportal inoculation. The morphological sequence of infection shows that amebas in the peritoneal cavity initially produce a large exudate constituted mainly of acute inflammatory cells. These cells form a rim of polymorphonuclear leukocytes surrounding the amebas, which adhere to the trophozoite and can sometimes be observed polarized to one end of the parasite, suggesting capping of surface receptors. Early stages are also characterized by the production of distant inflammatory reactions in the hepatic portal spaces. At 6 h postintraperitoneal inoculation, larger foci of inflammatory reactions surrounding amebas are developed in the peritoneum, extending to and damaging the liver surface membranes as well as the serosa of other internal organs. Thereafter, tissue damage progresses deeper into the liver parenchyma, and a few days later, coalescing granulomas and large necrotic areas are observed in the liver tissue. Based on the present morphological time-sequence study, we suggest that inflammatory cells associated with E. histolytica trophozoites play an important role in commencing the damage of liver sheaths and producing the subsequent parenchymal lesions. The simplicity and reliability of this model are important factors to consider when large numbers of experimentally induced amebic liver abscesses are needed.