RESUMO
Paracoccidioidomycosis (PCM) is a systemic mycosis, endemic in most Latin American countries, especially in Brazil, whose etiologic agent is the thermodimorphic fungus of the genus Paracoccidioides, comprising cryptic species of Paracoccidioides brasiliensis, S1, PS2, PS3 and Paracoccidioides lutzii. The mechanisms involved in the initial interaction of the fungus with cells of the innate immune response, as dendritic cells (DCs), deserve to be studied. Prostaglandins (PGs) are eicosanoids that play an important role in modulating functions of immune cells including DCs. Here we found that human immature DCs derived from the differentiation of monocytes cultured with GM-CSF and IL-4 release substantial concentrations of PGE2, which, however, were significantly inhibited after challenge with P. brasiliensis. In vitro blocking of pattern recognition receptors (PRRs) by monoclonal antibodies showed the involvement of mannose receptor (MR) in PGE2 inhibition by the fungus. In addition, phenotyping assays showed that after challenge with the fungus, DCs do not change their phenotype of immature cells to mature ones, as well as do not produce IL-12 p70 or adequate concentrations of TNF-α. Assays using exogenous PGE2 confirmed an association between PGE2 inhibition and failure of cells to phenotypically mature in response to P. brasiliensis. We conclude that a P. brasiliensis evasion mechanism exists associated to a dysregulation on DC maturation. These findings may provide novel information for the understanding of the complex interplay between the host and this fungus.
Assuntos
Diferenciação Celular , Células Dendríticas/microbiologia , Células Dendríticas/patologia , Dinoprostona/biossíntese , Paracoccidioides/fisiologia , Contagem de Células , Células Dendríticas/efeitos dos fármacos , Dinoprostona/farmacologia , Ensaio de Imunoadsorção Enzimática , Fluorescência , Humanos , Lipopolissacarídeos/farmacologia , Paracoccidioides/efeitos dos fármacos , Fenótipo , Receptores de Superfície Celular/metabolismo , Fator de Necrose Tumoral alfa/biossínteseRESUMO
The functions of phagocytic cells against pathogens are initiated by the interaction between membrane receptors and molecular structures which compose the cell wall of these microorganisms. Thus our study aimed to identify the neutrophil receptors involved in the recognition of different strains of Paracoccidioides brasiliensis and the consequent modulation of immune response through the production of cytokines and inflammatory mediators. Neutrophils did not produce TNF-alfa in response to both strains. However, these cells produce IL-12, mainly in response to Pb 265, with participation of TLR2 and dectin-1. These cells also produce L-10, whose levels were higher for Pb 18 with involvement of TLR2 and MR and only TLR2 for Pb 265. The production of PGE2 and LTB4 was detected similarly for the two strains. For PGE2, MR and dectin-1 were involved, while in relation to LTB4, none of them. In summary, we demonstrated that neutrophils have a dynamic role during host immune response to P. brasiliensis, since in addition to their role as effector cells of innate immunity; they have the capacity to modulate innate and adaptative immune response against this fungus by producing cytokines and lipidic mediators. This modulation may be toward a pró- or anti-inflammatory pattern in a dependence of P. brasiliensis strains and PRR involved in fungus recognition by these cells.
Assuntos
Lectinas Tipo C/imunologia , Lectinas de Ligação a Manose/imunologia , Neutrófilos/imunologia , Paracoccidioides/imunologia , Receptores de Superfície Celular/imunologia , Receptor 2 Toll-Like/imunologia , Células Cultivadas , Dinoprostona/biossíntese , Dinoprostona/imunologia , Humanos , Interleucina-10/biossíntese , Interleucina-10/imunologia , Interleucina-12/biossíntese , Interleucina-12/imunologia , Subunidade p35 da Interleucina-12 , Leucotrieno B4/biossíntese , Leucotrieno B4/imunologia , Receptor de Manose , Paracoccidioides/classificação , Paracoccidioidomicose/imunologia , Fator de Necrose Tumoral alfa/biossínteseRESUMO
Paracoccidioidomycosis is a human systemic mycosis caused by the fungus Paracoccidioides brasiliensis. The mechanisms involved in innate immune response to this fungus are not fully elucidated. Leukotrienes are known to be critical for the clearance of various microorganisms, mainly by mediating the microbicidal function of phagocytes. We investigated the involvement of leukotriene B4 in the early stages of experimental paracoccidioidomycosis, which was induced by intratracheal inoculation of the fungus in selected mouse lines. The mouse lines utilized were produced through bi-directional phenotypic selection, endowed with maximal or minimal acute inflammatory reactivity, and designated AIRmax and AIRmin, respectively. AIRmax mice were more resistant to the infection, which was demonstrated by reduced lung fungal loads. However, the two lines produced similar amounts of leukotriene B4, and pharmacological inhibition of this mediator provoked similar fungal load increases in the two lines. The lower fungal load in the AIRmax mice was associated with a more effective inflammatory response, which was characterized by enhanced recruitment and activation of phagocytic cells and an increased production of activator cytokines. This process resulted in an increased release of fungicidal molecules and a diminution of fungal load. In both lines, leukotriene production was associated with a protective response in the lung that was consequent to the effect of this eicosanoid on the influx and activation of phagocytes.
Assuntos
Interações Hospedeiro-Patógeno , Leucotrieno B4/imunologia , Paracoccidioides/imunologia , Paracoccidioidomicose/imunologia , Animais , Contagem de Colônia Microbiana , Modelos Animais de Doenças , Resistência à Doença , Pulmão/microbiologia , Masculino , Camundongos , FagocitoseRESUMO
Monocytes and macrophages play a central role in innate and adaptive immune response against systemic fungal infections. Imbalances in suppressor or stimulatory cytokine secretion caused by these cells may influence disease development, microorganism death, and the nature of the adaptive immune response. This study analyzed the monocyte cytokine profiles of healthy individuals challenged with high and low virulent strains of P. brasiliensis and mRNA cytokine expression kinetics by reverse transcription polymerase chain reaction (RT-PCR). Peripheral blood monocytes from healthy volunteers were cultured in vitro with and without virulent (Pb18) or low virulence (Pb265) strains from P. brasiliensis viable yeast cells. Interleukin-1 beta (IL-1beta), IL-6, IL-8, IL-10, tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-beta (TGF-beta1) were measured in culture supernatants by enzyme immunoassay (ELISA), and mRNA cytokine expression was determined by RT-PCR at 0, 4, 8, 12, 18 and 48 hr. Both P. brasiliensis strains induced monocyte production of IL-1beta, IL-6, IL-10 and TNF-alpha. Pb18 induced higher levels of IL-1beta, IL-6, and IL-10 than Pb265. IL-8 and TGF-beta1 levels were not significantly different from those cultured without stimulus. The mRNA cytokine expression was similar to supernatant cytokines measured by ELISA. In vitro monocyte challenge with virulent P. brasiliensis strain induces earlier and higher levels of pro- and anti-inflammatory cytokines than low virulence strain.
Assuntos
Citocinas/biossíntese , Imunidade Inata/imunologia , Monócitos/metabolismo , Monócitos/microbiologia , Paracoccidioides/fisiologia , Paracoccidioidomicose/imunologia , Ensaio de Imunoadsorção Enzimática , Inflamação/metabolismo , Ativação Linfocitária , RNA Mensageiro/análise , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
A aterosclerose é a doença responsável pelo maior índice de morbidade e mortalidade no mundo. A lesão aterosclerótica é a anormalidade mais comum encontrada nas artérias, decorrente inicialmente de dois processos básicos: acúmulo de colesterol e proliferação de células musculares lisas na túnica íntima o que leva à inflamação. Esse processo dará origem a uma placa fibrosa que se projeta para dentro do lúmen, modificando a túnica média, levando a uma série de complicações circulatórias decorrentes da resposta inflamatória desencadeada na parede do vaso. Assim, nesta revisão veremos o envolvimento da resposta inflamatória e do estresse oxidativo no desencadeamento e no estabelecimento da doença aterosclerótica promovido por macrófagos, uma das principais células envolvidas nesse processo, além de discutir sobre os principais marcadores bioquímicos como as citocinas, proteínas de fase aguda e moléculas de adesão.
Atherosclerosis and the direct outcomes of ischemia are the major causes of morbidity and mortality worldwide.Dysfunction of the vascular endothelium can produce atherosclerotic disease processes with consequentinflammation, which is a significant component of atherosclerosis lesions. Atherosclerosis is characterizedby chronic inflammation and enrichment of inflammatory cells in the vessel wall. This review besides focusingon both the inflammatory response and the oxidative stress that play a major role in the atherogenesis and inthe development of cardiovascular disease stimulated by macrophages, the key cell involved in this process,will in addition discuss the several biochemical markers such as cytokines, acute phase proteins, and cellularadhesion molecules.
Assuntos
Aterosclerose/imunologia , LDL-Colesterol , Citocinas/imunologia , Macrófagos , Receptores de LDL OxidadoRESUMO
Patients with paracoccidioidomycosis (PCM) present marked involvement of the lungs during the course of the mycosis. The purpose of this work was to obtain bronchoalveolar lavage (BAL) fluid from these patients to study the cytopathology, TNF levels and the oxidative and fungicidal response of alveolar macrophages (AMs) to in vitro incubation with recombinant IFN-gamma. To compare the lung and blood compartments, these determinations were also made in plasma and blood monocytes (BMs) obtained from the same patients. The cytopathology of BAL fluid revealed a predominance of macrophages, but with the presence of neutrophil exudation, and rare lymphocytes and epithelioid and giant cells. Comparison of the oxidative status and fungicidal activity of AMs and circulating BMs demonstrated that both cell types are highly activated for these two functions when compared to control cells. However, TNF levels were higher in BAL fluid than in plasma. The possible mechanisms involved in the hyperresponsiveness of cells from PCM patients are discussed.
Assuntos
Líquido da Lavagem Broncoalveolar/imunologia , Interferon gama/farmacologia , Macrófagos Alveolares/efeitos dos fármacos , Monócitos/efeitos dos fármacos , Paracoccidioidomicose/patologia , Fator de Necrose Tumoral alfa/metabolismo , Humanos , Macrófagos Alveolares/imunologia , Monócitos/imunologia , Paracoccidioides/imunologia , Paracoccidioidomicose/imunologia , Paracoccidioidomicose/microbiologia , Proteínas RecombinantesRESUMO
STUDY OBJECTIVE: The purpose of this study was to assess the extent of immune dysfunction in a well-defined group of epileptic patients: children with diagnosis of West syndrome (WS) or with transitions to another age-related EEG patterns, the multifocal independent spikes (MIS), and the slow spike-wave complexes (Lennox-Gastaut syndrome - LGS). Thus, WS was studied at different points of the natural evolutive history of the disease. METHOD: A group of 50 patients (33 with WS, 10 with LGS and 7 with MIS) and 20 age-matched healthy controls were submitted to enumeration of T lymphocyte subsets: CD1, CD3, CD4, CD8, CD4/CD8 ratio and lymphocyte proliferation assay to phytohaemagglutinin (PHA), in the presence of autologous and AB, homologous plasma. Dinitrochlorobenzene (DNCB) skin test sensitization was performed only in patients. Determinations of IgG, IgA, and IgM serum levels were compared to standard values for Brazilian population in different age ranges. RESULTS: Sensitization to DNCB showed absent or low skin reactions in 76% of the patients. High levels of IgG (45.7%) and IgM (61.4%), and lower levels of IgA (23.9%) were detected in the serum of the patients. Enumeration of lymphocyte subsets in peripheral blood showed: low CD3+ (p<0.05), low CD4+ (p<0.05), high CD8+ (p<0.01) and low CD4+ / CD8+ ratio (p<0.001). The proportion of CD1+ cells in the control group was less than 3%, while ranged between 6 and 11 % in 18% of the patients. The in vitro PHA-induced T cell proliferation showed significantly low blastogenic indices only when patients, cells were cultured in presence of their own plasma. No differences in blastogenic indices were observed when the cells of patients and controls were cultured with human AB plasma. CONCLUSION: The immunodeficiency in WS was mainly characterized by anergy, impaired cell-mediated immunity, altered levels of immunoglobulins, presence of immature thymocytes in peripheral blood and functional impairment of T lymphocytes induced by plasma inhibitory factors.
Assuntos
Antígenos CD/sangue , Epilepsia/imunologia , Espasmos Infantis/imunologia , Subpopulações de Linfócitos T/imunologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Dinitroclorobenzeno , Epilepsia/fisiopatologia , Feminino , Humanos , Imunoglobulina A/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Lactente , Contagem de Linfócitos , Masculino , Fito-Hemaglutininas/farmacologia , Plasma/imunologia , Testes Cutâneos , Espasmos Infantis/fisiopatologia , Estatísticas não Paramétricas , Subpopulações de Linfócitos T/efeitos dos fármacosRESUMO
STUDY OBJECTIVE: The purpose of this study was to assess the extent of immune dysfunction in a well-defined group of epileptic patients: children with diagnosis of West syndrome (WS) or with transitions to another age-related EEG patterns, the multifocal independent spikes (MIS), and the slow spike-wave complexes (Lennox-Gastaut syndrome - LGS). Thus, WS was studied at different points of the natural evolutive history of the disease. METHOD: A group of 50 patients (33 with WS, 10 with LGS and 7 with MIS) and 20 age-matched healthy controls were submitted to enumeration of T lymphocyte subsets: CD1, CD3, CD4, CD8, CD4/CD8 ratio and lymphocyte proliferation assay to phytohaemagglutinin (PHA), in the presence of autologous and AB, homologous plasma. Dinitrochlorobenzene (DNCB) skin test sensitization was performed only in patients. Determinations of IgG, IgA, and IgM serum levels were compared to standard values for Brazilian population in different age ranges. RESULTS: Sensitization to DNCB showed absent or low skin reactions in 76 percent of the patients. High levels of IgG (45.7 percent) and IgM (61.4 percent), and lower levels of IgA (23.9 percent) were detected in the serum of the patients. Enumeration of lymphocyte subsets in peripheral blood showed: low CD3+ (p<0.05), low CD4+ (p<0.05), high CD8+ (p<0.01) and low CD4+ / CD8+ ratio (p<0.001). The proportion of CD1+ cells in the control group was less than 3 percent, while ranged between 6 and 11 percent in 18 percent of the patients. The in vitro PHA-induced T cell proliferation showed significantly low blastogenic indices only when patients, cells were cultured in presence of their own plasma. No differences in blastogenic indices were observed when the cells of patients and controls were cultured with human AB plasma. CONCLUSION: The immunodeficiency in WS was mainly characterized by anergy, impaired cell-mediated immunity, altered levels of immunoglobulins, presence of immature thymocytes in peripheral blood and functional impairment of T lymphocytes induced by plasma inhibitory factors
Assuntos
Humanos , Masculino , Feminino , Lactente , Pré-Escolar , Criança , Antígenos CD , Epilepsia , Estudos de Casos e Controles , Dinitroclorobenzeno , Epilepsia , Imunoglobulina A , Imunoglobulina G , Imunoglobulina M , Contagem de Linfócitos , Fito-Hemaglutininas , Plasma , Testes CutâneosRESUMO
Monocytes and macrophages can produce a large repertoire of cytokines and participate in the pathogenesis of granulomatous diseases. We investigated the production of pro- and anti-inflammatory cytokines by monocytes from patients with active paracoccidioidomycosis. Peripheral blood monocytes from 37 patients and 29 healthy controls were cultivated with or without 10 microg/ml of lipopolysaccharide (LPS) for 18 h at 37 degrees C, and the cytokine levels were determined in the culture supernatants by enzyme immunoassay. The results showed that the endogenous levels of tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6, IL-8, IL-10 and transforming growth factor beta detected in the supernatant of patient monocytes cultivated without stimulus were significantly higher than those produced by healthy controls. These data demonstrated that monocytes from patients with active paracoccidioidomycosis produce high levels of cytokines with both inflammatory and anti-inflammatory activities. However, patient monocytes produced significantly lower TNF-alpha and IL-6 levels in response to LPS when compared to normal subjects, suggesting an impairment in their capacity to produce these cytokines after LPS stimulation. Concentrations of IL-1beta, IL-8 and IL-10 in cultures stimulated with LPS were higher in patients than in controls. These results suggest that an imbalance in the production of pro- and anti-inflammatory cytokines might be associated with the pathogenesis of paracoccidioidomycosis.