RESUMO
The goal of this work is to compile and discuss molecules of marine origin reported in the scientific literature with anti-parasitic activity against Trichomonas, Giardia, and Entamoeba, parasites responsible for diseases that are major global health problems, and Microsporidial parasites as an emerging problem. The presented data correspond to metabolites with anti-parasitic activity in human beings that have been isolated by chromatographic techniques from marine sources and structurally elucidated by spectroscopic and spectrometric procedures. We also highlight some semi-synthetic derivatives that have been successful in enhancing the activity of original compounds. The biological oceanic reservoir offers the possibility to discover new biologically active molecules as lead compounds to develop new drug candidates. The molecular variety is extensive and must be correctly explored and managed. Also, it will be necessary to take some actions to preserve the source species from extinction or overharvest (e.g., by cryopreservation of coral spermatozoa, oocytes, embryos, and larvae) and coordinate appropriate exploitation to increase the chemical knowledge of the natural products generated in the oceans. Additional initiatives such as the total synthesis of complex natural products and their derivatives can help to prevent overharvest of the marine ecosystems and at the same time contribute to the discovery of new molecules.
Assuntos
Antiprotozoários , Produtos Biológicos , Parasitos , Animais , Antiprotozoários/química , Produtos Biológicos/farmacologia , Ecossistema , Giardia , HumanosRESUMO
Although no precise moment or unique event marks its birth, neuroimmunoendocrinology arguably shares a great deal of history with other medical and biologic disciplines. It originated from empirical observations and suppositions that failed to prevail upon the existing axioms. Despite the widespread resistance to embracing novel ideas, the seeming defeats inspired visionary researchers. Those pioneers managed to systematize the emerging knowledge and were able to contribute to science with real foundations. In consequence, new concepts and ideas arose in physiology, anatomy, endocrinology and early immunology. Together, they gave rise to a budding approach on the integration between the nervous, immune and endocrine systems. Then, neuroimmunoendocrinology emerged as a discipline integrating an intricate system with multidirectional functions and interactions that allow for responding to internal and external threats. Such response is mediated by cytokines, hormones and neurotransmitters, involved in different physiologic mechanisms of the organism homeostasis. Neuroimmunoendocrinology is no longer an area of scientific skepticism; on the contrary, it has cemented its position as a biomedical discipline worldwide for the past 70 years. Now, it offers a better understanding of pathologic processes.
Assuntos
Neuroimunomodulação , HomeostaseRESUMO
Background: It has been reported that sera from patients with active pulmonary tuberculosis (APT) induced nuclear changes in normal neutrophils that included pyknosis, swelling, apoptosis, and production of extracellular traps (NETs). Similar changes were observed with some sera from their household contacts but not with sera from healthy, unrelated individuals. It was suggested that those sera from household contacts that induced neutrophil nuclear changes might correspond to people with subclinical tuberculosis. Thus, our experimental approach might serve to identify individuals with early, ongoing disease. Methods: Nuclear changes in neutrophils were fully evident by 3 h of contact and beyond. Circulating mycobacterial antigens were the most likely candidates for this effect. We wanted to know whether the nuclear changes induced on neutrophils by the sera of APT patients would negatively affect the phagocytic/microbicidal ability of neutrophils exposed to APT sera for short periods. Results: We now provide evidence that short-term contact (30 min) with sera from patients with pulmonary tuberculosis increases several phagocytic parameters of normal neutrophils, including endocytosis, myeloperoxidase levels, production of free reactive oxygen species, phagolysosome fusion, and microbicidal activity on Staphylococcus aureus, with these effects not being observed with sera from healthy donors. We also give evidence that suggests that ESAT-6 and CFP-10 are involved in the phenomenon. Conclusion: We conclude that activation is a stage that precedes lethal nuclear changes in neutrophils and suggests that autologous neutrophils must circulate in an altered state in the APT patients, thus contributing to the pathology of the disease.
Assuntos
Armadilhas Extracelulares , Mycobacterium tuberculosis , Tuberculose , Antígenos de Bactérias , Humanos , NeutrófilosRESUMO
Background: Murine leprosy is a chronic granulomatous disease caused by Mycobacterium lepraemurium (MLM) in mice and rats. The disease evolves with the development of cellular anergy that impedes the production of interferon gamma (IFNγ), tumor necrosis factor-alpha (TNFα), and nitric oxide (NO) required to kill the microorganism. In this study we investigated whether histone deacetylase inhibitors (HDACi) (valproic acid and sodium butyrate [NaB]) and the immunomodulator transfer factor in dialyzable leukocyte extracts (DLE) can prevent anergy in murine leprosy. Methods: Five groups of six Balb/c mice were intraperitoneally inoculated with 2 × 107 MLM. Thirty-days post inoculation, treatment was started; one group received no treatment, one was treated with rifampicin-clofazimine (R-C), one with sodium valproate (VPA), one with NaB, and one with DLE. The animals were monitored for the evidence of disease for 96 days. After euthanasia, their spleens were removed and processed for histologic, bacteriologic, and cytokine studies. Results: R-C completely controlled the ongoing disease. DLE and NaB significantly reduced the development of lesions, including granuloma size and the number of bacilli; VPA was less effective. DLE, NaB, and VPA reverted the anergic condition in diverse grades and allowed the expression of IFNγ, TNFα, and inducible NO synthase, also in diverse grades. Conclusion: Anergy in leprosy and murine leprosy allows disease progression. In this study, anergy was prevented, in significant degree, by DLE (an immunomodulator) and NaB (HDACi). VPA was less effective. These results suggest potential beneficial effects of DLE and NaB in the ancillary treatment of leprosy.
Assuntos
Ácido Butírico/administração & dosagem , Extratos Celulares/farmacologia , Anergia Clonal/imunologia , Inibidores de Histona Desacetilases/administração & dosagem , Hanseníase/imunologia , Ácido Valproico/administração & dosagem , Animais , Extratos Celulares/imunologia , Diálise , Feminino , Leucócitos/química , Leucócitos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Mycobacterium lepraemurium/efeitos dos fármacos , Mycobacterium lepraemurium/imunologiaRESUMO
Rheumatoid arthritis is a disabling autoimmune disease with a high global prevalence. Treatment with disease-modifying anti-arthritic drugs (DIMARDs) has been routinely used with beneficial effects but with adverse long-term consequences; novel targeted biologics and small-molecule inhibitors are promising options. In this study, we investigated whether purified omega unsaturated fatty acids (ω-UFAs) and dialysable leukocyte extracts (DLEs) prevented the development of arthritis in a model of collagen-induced arthritis (CIA) in mice. We also investigated whether the transcription factor NF-κB and the NLRP3 inflammasome were involved in the process and whether their activity was modulated by treatment. The development of arthritis was evaluated for 84 days following treatment with nothing, dexamethasone, DLEs, docosahexaenoic acid, arachidonic acid, and oleic acid. Progression of CIA was monitored by evaluating clinical manifestations, inflammatory changes, and histological alterations in the pads' articular tissues. Both DLEs and ω-UFAs led to an almost complete inhibition of the inflammatory histopathology of CIA and this was concomitant with the inhibition of NF-kB and the inhibition of the activation of NLRP3. These data suggest that ω-UFAs and DLEs might have NF-κB as a common target and that they might be used as ancillary medicines in the treatment of arthritis.
Assuntos
Anti-Inflamatórios/farmacologia , Antirreumáticos/farmacologia , Artrite Experimental/prevenção & controle , Cartilagem Articular/efeitos dos fármacos , Extratos Celulares/farmacologia , Ácidos Graxos Insaturados/farmacologia , Leucócitos , Animais , Ácido Araquidônico/farmacologia , Artrite Experimental/induzido quimicamente , Artrite Experimental/metabolismo , Artrite Experimental/patologia , Cartilagem Articular/metabolismo , Cartilagem Articular/patologia , Colágeno Tipo II , Diálise , Ácidos Docosa-Hexaenoicos/farmacologia , Feminino , Inflamassomos/efeitos dos fármacos , Inflamassomos/metabolismo , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos DBA , NF-kappa B/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Ácido Oleico/farmacologiaRESUMO
Murine leprosy, caused by Mycobacterium lepraemurium (MLM), is a chronic disease that closely resembles human leprosy. Even though this disease does not directly involve the nervous system, we investigated a possible effect on working memory during this chronic infection in Balb/c mice. We evaluated alterations in the dorsal region of the hippocampus and measured peripheral levels of cytokines at 40, 80, and 120 days post-infection. To evaluate working memory, we used the T-maze while a morphometric analysis was conducted in the hippocampus regions CA1, CA2, CA3, and dentate gyrus (DG) to measure morphological changes. In addition, a neurochemical analysis was performed by HPLC. Our results show that, at 40 days post-infection, there was an increase in the bacillary load in the liver and spleen associated to increased levels of IL-4, working memory deterioration, and changes in hippocampal morphology, including degeneration in the four subregions analyzed. Also, we found a decrease in neurotransmitter levels at the same time of infection. Although MLM does not directly infect the nervous system, these findings suggest a possible functional link between the immune system and the central nervous system.
Assuntos
Hipocampo/fisiopatologia , Transtornos da Memória/fisiopatologia , Infecções por Mycobacterium/fisiopatologia , Animais , Doença Crônica , Giro Denteado/microbiologia , Giro Denteado/patologia , Giro Denteado/fisiopatologia , Hipocampo/microbiologia , Hipocampo/patologia , Interações Hospedeiro-Patógeno , Interleucina-4/metabolismo , Masculino , Aprendizagem em Labirinto , Transtornos da Memória/metabolismo , Transtornos da Memória/microbiologia , Memória de Curto Prazo , Camundongos Endogâmicos BALB C , Infecções por Mycobacterium/metabolismo , Infecções por Mycobacterium/microbiologia , Mycobacterium lepraemurium/fisiologia , Neurotransmissores/metabolismo , Fatores de TempoRESUMO
The dynamic regulation of NF-κB activity in the uterus maintains a favorable environment of cytokines necessary to prepare for pregnancy throughout the estrous cycle. Recently, the mechanisms that directly regulate the NF-κB transcriptional activity in different tissues are of growing interest. IκBNS and BCL-3 are negative nuclear regulators of NF-κB activity that regulate IL-6 and TNF-α transcription, respectively. Both cytokines have been described as important factors in the remodeling of uterus for blastocyst implantation. In this work we analyzed in ICR mice the mRNA expression and protein production profile of IL-6, TNF-α, and their correspondent negative transcription regulators IκBNS or BCL-3 using real-time PCR, western blot and immunochemistry. We found that the expression of TNF-α and IL-6 was oscillatory along the estrous cycle, and its low expression coincided with the presence of BCL-3 and IκBNS, and vice versa, when the presence of the regulators was subtle, the expression of TNF-α and IL-6 was exacerbated. When we compared the production of TNF-α and IL-6 in the different estrous stages relating with diestrus we found that at estrus there is an important increase of the cytokines (p<0.05) decreasing at metestrus to reach the basal expression at diestrus. In the immunochemistry analysis we found that at diestrus BCL-3 is distributed all over the tissue with a barely detected TNF-α, but on the contrary, at estrus the expression of BCL-3 is not detected with TNF-α clearly observable along the tissue; the same phenomenon occur in the analysis of IκBNS and IL-6. With that evidence we suggest that the expression of TNF-α and IL-6 might be regulated through NF-κB nuclear regulators BCL-3 and IκBNS in the uterus of mice as has been demonstrated in other systems.
Assuntos
Interleucina-6/imunologia , NF-kappa B/imunologia , Proteínas/imunologia , Proteínas Proto-Oncogênicas/imunologia , Fatores de Transcrição/imunologia , Fator de Necrose Tumoral alfa/imunologia , Útero/metabolismo , Animais , Proteína 3 do Linfoma de Células B , Ciclo Estral/genética , Ciclo Estral/imunologia , Feminino , Regulação da Expressão Gênica , Interleucina-6/genética , Peptídeos e Proteínas de Sinalização Intracelular , Camundongos , Camundongos Endogâmicos ICR , NF-kappa B/genética , Gravidez , Proteínas/genética , Proteínas Proto-Oncogênicas/genética , Transdução de Sinais , Fatores de Transcrição/genética , Transcrição Gênica , Fator de Necrose Tumoral alfa/genética , Útero/imunologiaRESUMO
OBJECTIVES: Neutrophils play an important role in the control of pathogens through several mechanisms, including phagocytosis and the formation of neutrophil extracellular traps (NETs). The latter consists of DNA as a backbone with embedded antimicrobial peptides, histones, and proteases, providing a matrix to entrap and in some cases to kill microbes. Some metabolic requirements for NET formation have recently been described. The virus-induced formation of NETs and the role of these traps in viral infections remain scarcely reported. Here, we analyzed whether dengue virus serotype-2 (DENV-2) induces NET formation and the DENV-2 effect on phorbol myristate acetate (PMA)-induced NETs. METHODS: Peripheral blood-derived neutrophils were exposed in vitro to DENV-2 or exposed to DENV-2 and then stimulated with PMA. NET formation was assessed by fluorescence microscopy. Cell membrane Glut-1, glucose uptake, and reactive oxygen species (ROS) production were assessed. RESULTS: DENV-2 does not induce the formation of NETs. Moreover, DENV-2 inhibits PMA-induced formation of NETs by about 80%. This effect is not related to the production of ROS. The mechanism seemingly accountable for this inhibitory effect is the DENV-2-mediated inhibition of PMA-induced glucose uptake by neutrophils. CONCLUSION: Our results suggest that DENV-2 inhibits glucose uptake as a metabolism-based way to avoid the formation of NETs.
Assuntos
Vírus da Dengue/metabolismo , Armadilhas Extracelulares/virologia , Neutrófilos/virologia , Vírus da Dengue/imunologia , Armadilhas Extracelulares/imunologia , Glucose/metabolismo , Transportador de Glucose Tipo 1/genética , Microscopia de Fluorescência , Neutrófilos/efeitos dos fármacos , Neutrófilos/imunologia , Neutrófilos/ultraestrutura , Espécies Reativas de Oxigênio/metabolismo , Sorogrupo , Acetato de Tetradecanoilforbol/farmacologiaRESUMO
BACKGROUND: The phagocytic function in pulmonary tuberculosis (PTB) and Type 2 diabetes (T2D) has been explored mainly in macrophages but not in polymorphonuclears (PMN). The purpose of this study was to determine the functional status of PMN leukocytes in patients with pulmonary tuberculosis (PTB), Type 2 diabetes (T2D), and in patients with both diseases. METHODS: An observational, prospective, and comparative study was carried out. 30 ambulatory patients with T2D, 10 with PTB undergoing treatment and 10 patients with PTB and T2D, and 44 healthy subjects were studied. PMN leukocytes were separated, the capacity of these cells to produce hydrogen peroxide and to reduce nitroblue tetrazolium (NBT) in response to stimulus with the phorbolic ester of myristic acid (PMA) was measured; and the capacity of PMN leukocytes to adhere to surfaces was determined. RESULTS: Concerning the test for adherence, on comparing healthy subjects with patients with T2D+PTB, we observed a clear decrease in cellular adherence in the group of patients with both diseases; it was statistically significant (p = 0.007).With regard to phagocytic function, we observed that in NBT reduction as well as in hydrogen peroxide production, statistically significant differences were not obtained on comparing healthy subjects with any of the three groups of patients. CONCLUSIONS: We observed a clear decrease in cellular adherence when both diseases co-exist. These results could indicate the need for the co-existence of T2D and TB to cause deterioration in the cells' adherence activity. The microtechniques employed permit the evaluation in a practical manner of certain phagocytic-activity expressions.
Assuntos
Adesão Celular/fisiologia , Diabetes Mellitus Tipo 2/imunologia , Granulócitos/imunologia , Fagocitose , Tuberculose Pulmonar/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Diabetes Mellitus Tipo 2/complicações , Feminino , Granulócitos/metabolismo , Humanos , Peróxido de Hidrogênio/metabolismo , Masculino , Pessoa de Meia-Idade , Nitroazul de Tetrazólio/metabolismo , Estudos Prospectivos , Acetato de Tetradecanoilforbol/metabolismo , Tuberculose Pulmonar/complicaçõesRESUMO
Although murine leprosy is no longer a common illness, our understanding of the biology of this disease is incomplete. One particular example of this concerns the etiologic agent Mycobacterium lepraemurium (MLM). MLM is a fastidious microorganism that is difficult to grow in axenic media; in a way, this has hampered attempts to thoroughly study its physiological and metabolic characteristics. MLM is an obligate intracellular bacillus that invades macrophages and replicates profusely with a generation time that oscillates between 0.5 and 11 days. In the present study, we have successfully maintained MLM alive for more than 12 days in vitro, providing us with an opportunity to study its susceptibility to several anti-leprosy agents and other drugs. To achieve this, we used a fluorescence reduction assay of alamar blue (a resazurin) in a microplate format (microplate-alamar-blue-assay; MABA), which is a highly sensitive, practical, and inexpensive method for assaying cell viability. We found that MLM was highly susceptible to clofazimine and rifampicin and was less susceptible to streptomycin, thiacetazone, kanamycin, dapsone, and ethionamide, in that order. MLM was not susceptible to four plant triterpenoids (oleanolic acid, neolignan-c, sitosterol, and ursolic acid) for which bactericidal activity has been reported in M. tuberculosis. Because the MABA has high sensitivity, it can be used to monitor the activity of microorganisms that are difficult to cultivate (such as M. lepraemurium), in response to various drugs, thus offering a method to complement the study of murine leprosy, about which many questions remain unanswered.
Assuntos
Hansenostáticos/farmacologia , Testes de Sensibilidade Microbiana/métodos , Mycobacterium lepraemurium/efeitos dos fármacos , Oxazinas/química , Xantenos/química , Análise de Variância , Animais , Modelos Animais de Doenças , Feminino , Histocitoquímica , Indicadores e Reagentes/química , Fígado/química , Fígado/microbiologia , Fígado/patologia , Camundongos , Camundongos Endogâmicos BALB C , Viabilidade Microbiana/efeitos dos fármacos , Infecções por Mycobacterium/microbiologia , Mycobacterium lepraemurium/patogenicidade , Extratos Vegetais/farmacologiaRESUMO
Mycobacterium lepraemurium (MLM) is a successful parasite of murine macrophages; in vitro, this microorganism infects macrophages without triggering these cells' ability to produce either the reactive oxygen intermediaries (ROI) or the reactive nitrogen intermediaries (RNI), and ends up lodging within these cells, that, in addition, do not contain myeloperoxidase (MPO). In this study, we analyzed the effect of exogenous peroxidase on the evolution of murine leprosy. Bacilli were intraperitoneally injected, either alone (MLM) or precoated with horseradish peroxidase (MLM-PO), into two different groups of mice. At two-week intervals, the groups were blood-sampled to measure the levels of antibodies to protein- or lipid-MLM antigens. The extent of the disease was also assessed by looking at the histopathologic changes that occurred both in the liver and the spleen of the infected animals. We found that the animals injected with MLM-PO developed a disease that evolved at a slower pace than the disease that occurred in the animals injected with intact MLM. The difference between groups, both in terms of antibody levels and histological changes, was clearly evident at the intermediate stages of the disease (2 to 2.5 months), but was not so obvious at the more advanced stage of 3 months. Several possibilities to explain how the PO-coated bacilli might have regained their infectiousness are discussed. Lowering the infective dose of MLM and MLM-PO from 5 x 10(7) bacilli to 5 x 10(6) bacilli would, probably, have resulted in a different outcome of the disease: more extended in the MLM-group than in the MLM-PO group.
Assuntos
Infecções por Mycobacterium/tratamento farmacológico , Mycobacterium lepraemurium/crescimento & desenvolvimento , Peroxidase/farmacologia , Animais , Anticorpos Antibacterianos/sangue , Antígenos de Bactérias/isolamento & purificação , Feminino , Granuloma/enzimologia , Granuloma/patologia , Fígado/microbiologia , Fígado/patologia , Camundongos , Infecções por Mycobacterium/enzimologia , Infecções por Mycobacterium/patologia , Mycobacterium lepraemurium/metabolismo , Organismos Livres de Patógenos Específicos , Baço/microbiologia , Baço/patologiaRESUMO
Pathogenic mycobacteria must possess efficient survival mechanisms to resist the harsh conditions of the intraphagosomal milieu. In this sense, Mycobacterium lepraemurium (MLM) is one of the most evolved intracellular parasites of murine macrophages; this microorganism has developed a series of properties that allows it not only to resist, but also to multiply within the inhospitable environment of the phagolysosome. Inside the macrophages, MLM appears surrounded by a thick lipid-envelope that protects the microorganism from the digestive effect of the phagosomal hydrolases and the acid pH. MLM produces a disease in which the loss of specific cell-mediated immunity ensues, thus preventing activation of macrophages. In vitro, and possibly also in vivo, MLM infects macrophages without triggering the oxidative (respiratory burst) response of these cells, thus preventing the production of the toxic reactive oxygen intermediaries (ROI). Supporting the idea that MLM is within the most evolved pathogenic microorganisms, in the present study we found, that contrary to BCG, M. lepraemurium infects macrophages without stimulating these cells to produce meaningful levels of tumor necrosis factor alpha (TNF alpha) or nitric oxide (NO). Thus, the ability of the microorganisms to stimulate in their cellular hosts, the production of ROI and RNI (reactive nitrogen intermediates), seems to be an inverse correlate of their pathogenicity; the lesser their ability, the greater their pathogenicity.
Assuntos
Macrófagos Peritoneais/microbiologia , Mycobacterium bovis/imunologia , Mycobacterium lepraemurium/imunologia , Óxido Nítrico/biossíntese , Fator de Necrose Tumoral alfa/biossíntese , Animais , Células Cultivadas , Feminino , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Infecções por Mycobacterium/microbiologia , Mycobacterium bovis/patogenicidade , Mycobacterium lepraemurium/patogenicidadeRESUMO
Mycobacterium lepraemurium (MLM) is a successful parasite of murine macrophages; in vitro, this microorganism infects macrophages without triggering these cells' ability to produce either the reactive oxygen intermediaries (ROI) or the reactive nitrogen intermediaries (RNI), and ends up lodging within these cells, that, in addition, do not contain myeloperoxidase (MPO). In this study, we analyzed the effect of exogenous peroxidase on the evolution of murine leprosy. Bacilli were intraperitoneally injected, either alone (MLM) or precoated with horseradish peroxidase (MLM-PO), into two different groups of mice. At two-week intervals, the groups were blood-sampled to measure the levels of antibodies to protein- or lipid-MLM antigens. The extent of the disease was also assessed by looking at the histopathologic changes that occurred both in the liver and the spleen of the infected animals. We found that the animals injected with MLM-PO developed a disease that evolved at a slower pace than the disease that occurred in the animals injected with intact MLM. The difference between groups, both in terms of antibody levels and histological changes, was clearly evident at the intermediate stages of the disease (2 to 2.5 months), but was not so obvious at the more advanced stage of 3 months. Several possibilities to explain how the PO-coated bacilli might have regained their infectiousness are discussed. Lowering the infective dose of MLM and MLM-PO from 5 x 10(7) bacilli to 5 x 10(6) bacilli would, probably, have resulted in a different outcome of the disease: more extended in the MLM-group than in the MLM-PO group.
Assuntos
Hanseníase/fisiopatologia , Hanseníase/imunologia , Peroxidase/imunologia , Peroxidase/síntese químicaRESUMO
Pathogenic mycobacteria must possess efficient survival mechanisms to resist the harsh conditions of the intraphagosomal milieu. In this sense, Mycobacterium lepraemurium (MLM) is one of the most evolved intracellular parasites of murine macrophages; this microorganism has developed a series of properties that allows it not only to resist, but also to multiply within the inhospitable environment of the phagolysosome. Inside the macrophages, MLM appears surrounded by a thick lipid-envelope that protects the microorganism from the digestive effect of the phagosomal hydrolases and the acid pH. MLM produces a disease in which the loss of specific cell-mediated immunity ensues, thus preventing activation of macrophages. In vitro, and possibly also in vivo, MLM infects macrophages without triggering the oxidative (respiratory burst) response of these cells, thus preventing the production of the toxic reactive oxygen intermediaries (ROI). Supporting the idea that MLM is within the most evolved pathogenic microorganisms, in the present study we found, that contrary to BCG, M. lepraemurium infects macrophages without stimulating these cells to produce meaningful levels of tumor necrosis factor alpha (TNF alpha) or nitric oxide (NO). Thus, the ability of the microorganisms to stimulate in their cellular hosts, the production of ROI and RNI (reactive nitrogen intermediates), seems to be an inverse correlate of their pathogenicity; the lesser their ability, the greater their pathogenicity.
Assuntos
Hanseníase/genética , Hanseníase/imunologia , Receptores do Fator de Necrose Tumoral/imunologia , Vacina BCG/imunologia , Vacina BCG/uso terapêuticoRESUMO
In order to know whether antibodies to phospholipids and other host lipids play a role in the pathology of murine leprosy, we looked for the presence of antibodies to cardiolipin, cerebroside sulfatide, and to lipids extracted from normal murine spleen, liver and brain in the sera of mice bearing a 6-month infection with Mycobacterium lepraemurium. We also looked for the presence of antibodies to lipids isolated from M. lepraemurium. We found that all of the 16 animals examined contained high levels of antibodies to the mycobacterial lipids of intermediate polarity (mostly glycolipids) but none of them had antibodies to the other lipids tested, including those isolated from mouse liver, spleen and brain, bovine cardiolipin and sulfatide, nor any significant levels of antibodies to mycobacterial lipids of high or low polarity. The infected animals also had high levels of antibodies to antigens sonically extracted from the microorganism. Antibodies to the socially extracted antigens (mostly proteins) were mainly IgG, while antibodies to the lipid antigens were predominantly IgM. Despite the low but significant percentage (1%-3%) of infected animals developing bilateral paralysis of the rear limbs, autoimmunity (due to antibodies to phospholipids and other host lipids) does not seem to be a feature of murine leprosy.
Assuntos
Hanseníase/fisiopatologia , Hanseníase/imunologiaRESUMO
Background. This study was carried out with the aim of detecting possible differences between proteins secreted by fresh wild isolates of Mycrobacterium tuberculosis and from a reference strain of this microorganism, H37Rv TMCC 102. Materials and Methods. This reference strain of M tuberculosis has been in our laboratory for over 10 years, where it has been maintained by serial subcultures in PBY and Lo-wenstein-Jensen media. Patterns of protein secretion and recognition by sera derive from both tuberculosis patients and normal individuals were analysed by electrophoresis and Western blotting. Results. No major qualitative differences were observed among the several strains studied with respect to protein patterns or recognition of these proteins by test sera. Normal sera were found to react with almost all antigens recognized by tuberculosis sera, but with less intensity. However, a small protein of 14.5 kDa, secreted by both the wild and reference strain of M. tuberculosis, was recognized by 32 of the 40 tuberculous patient sera tested (80 percent), and was not recognized by any of the 40 serum samples derived from healthy individuals. Conclusions. This small protein seems to be a potentially important antigen for the serological diagnosis of tuberculosis and/or for use in the follow-up patients who received treatment
Assuntos
Humanos , Antígenos de Bactérias/fisiologia , Mycobacterium tuberculosis/imunologia , Proteínas de Bactérias , Estudos de Casos e Controles , Padrões de ReferênciaRESUMO
We have studied the susceptibility to infection by Mycobacterium lepraemurium (MLM) of a nude, hypothymic, CD1-derived, spontaneous mouse mutant called [quot ]et[quot ] because of its extraterrestrial appearance. We found that despite their hypothymia, et/et mice were not more susceptible to infection by MLM than their euthymic et/+ counterparts. Infection of both et/et and et/+ mice with 50 x 10(6) bacilli by the intraperitoneal route led only to a mild infection with low levels of antimycobacterial antibodies and a small number of lesions. These lesions were indicative of reactive hepatitis and hyaline perisplenitis with lymphoid hyperplasia. Some small bacilliferous granulomas were also observed at the end of the experiment (5 months of infection). CD1 mice behave in a rather [quot ]resistant[quot ] manner to the infection by MLM. It is clear that the nu gene is not necessarily linked to the thymus defect, and it is also clear that the hypothymia of et/et mice does not obviously affect their general cell-mediated immune competence.
Assuntos
Antígenos CD1/fisiologia , Mycobacterium lepraemurium/fisiologia , Mycobacterium lepraemurium/imunologiaRESUMO
We measured the release of reactive oxygen intermediaries [ROI (hydrogen peroxide and superoxide anion)] by murine peritoneal macrophages challenged in vitro with Mycobacterium lepraemurium (MLM), complement-opsonized yeast, M. bovis BCG, M. phlei, or phorbol myristate acetate (PMA). We found that except for MLM, all of the other materials provoked the release of significant amounts of hydrogen peroxide and superoxide. MLM entered the macrophages without triggering their oxidative metabolism. Pre-infection of macrophages with MLM did not alter these cells' capacity to release the normal amounts of ROI in response to other microorganisms or PMA. Killing of MLM did not revert the macrophages' failure to release ROI upon ingestion of the microorganism, nor were macrophages able to produce these toxic metabolites when pre-incubated in the presence of murine gamma interferon (IFN-gamma). MLM has several attributes that allow it to survive within macrophages: a) it is a nontoxigenic microorganism (it does not harm its host), b) it resists the harsh conditions of the intraphagolysosomal milieu (a property perhaps dependent on its thick lipidic envelope), and c) it penetrates the macrophages without triggering their oxidative response (thus avoiding the generation of the toxic intermediaries of oxygen). For these attributes (and others discussed in this paper), we recognize MLM as a highly evolved, well-adapted parasite of macrophages. In addition, the results of the present study prompted the analysis of the biochemical pathways used by MLM and M. bovis BCG to penetrate into their cellular hosts, a subject now under investigation in our laboratory.
Assuntos
Macrófagos Peritoneais , Macrófagos Peritoneais/metabolismo , Macrófagos Peritoneais/microbiologia , Mycobacterium lepraemurium/fisiologiaRESUMO
Lipids extracted from mouse tissues infected with Mycobacterium lepraemurium (MLM) were analyzed by thin-layer chromatography. Although the extracted lipids were heterogeneous in polarity, the lipids of intermediate polarity were the ones that predominated. All of the lipids of intermediate polarity were glycosylated species. There were also lipids of low and high polarity, the latter being glycolipids. Compared to lipids extracted from normal tissue (mostly to lipids of high and low polarity), all of the additional lipids extracted from the infected tissue corresponded to lipids present in the purified bacteria. Enzyme-linked immunoassays (ELISAs) were then performed with the whole lipids extracted from purified bacilli, the lipids of high, intermediate and low polarity, and the sera from 20 normal and 20 MLM-infected mice. Lipids of intermediate polarity were specifically recognized by MLM-infected mice. Neither sera (diluted 1:500) from normal mice nor infected mice reacted with the lipids of high or low polarity, but a higher concentration (sera diluted 1:100) of some sera from mice in both groups reacted significantly with these lipids. In the ELISAs the whole-lipid extract and the lipids of intermediate polarity were similarly recognized by the sera of the infected mice. Thus, as observed in human leprosy, the mycobacterial disease in the mouse (murine leprosy) is also accompanied by the development of antibodies to the glycolipids of the infecting microorganism.