RESUMO
Acetylcholine (ACh), as a ligand of nicotinic acetylcholine receptors (nAChRs), plays a key role in the cholinergic anti-inflammatory pathway; however, its role in the immunoglobulin A (IgA) response remains unknown. Therefore, the present study aimed to investigate the role of ACh in the intestinal biomarkers involved in IgA synthesis and the polymeric immunoglobulin receptor (pIgR) involved in IgA transcytosis. Groups of mice were administered GTS-21 (an α7nAChR agonist) or mecamylamine (a non-selective nAChR antagonist) intraperitoneally for 7 days. Intestinal fluids were used for antibody concentration assessment by ELISA, cell suspensions from Peyer's patches and the lamina propria were obtained for flow cytometric analysis of plasma cells, and CD4+ T-cells expressing intracellular transforming growth factor (TGF)-ß and IgA-producing interleukin (IL)-4, -5, -6 and -10, and isolated epithelial cells to determine the levels of pIgR mRNA using reverse transcription-quantitative PCR. Regarding to the untreated control group, the concentration of IgA was reduced in the mecamylamine group and unaltered in the GTS-21 group while IgM levels exhibited no differences; the percentage of IgA+ plasma cells from Peyer's patches and the lamina propria, and the percentage of TGF-ß+/CD4+ T-cells from Peyer's patches were greater in the GTS-21-group. In both treatment groups, the percentages of IgM+ plasma cells and IL-6+/IL-10+ CD4+ T cells were greater in both compartments; pIgR mRNA expression levels decreased in epithelial cells. The percentage of IL-4 CD4+ T-cells were greater in Peyer's patches and lower in the lamina propria in the mecamylamine group, and the percentage of IL-5 CD4+ T-cells in the lamina propria were decreased in both treatment groups. These findings require further examination to address the impact of cholinergic modulation on IgA-transcytosis via pIgR. The present study may be an experimental reference for clinical trials that address the role of nicotinic system in intestinal dysfunctions as postoperative ileus.
RESUMO
Muscarinic-acetylcholine-receptors (mAChRs) modulate intestinal homeostasis, but their role in inflammation is unclear; thus, this issue was the focus of this study. BALB/c mice were treated for 7 days with muscarine (mAChR/agonist), atropine (mAChR/antagonist) or saline. Small-intestine samples were collected for histology and cytofluorometric assays in Peyer's patches (PP) and lamina propria (LP) cell-suspensions. In LP, goblet-cells/leukocytes/neutrophils/MPO+ cells and MPO/activity were increased in the muscarine group. In PP, IFN-γ+/CD4+ T or IL-6+/CD4+ T cell numbers were higher in the muscarine or atropine groups, respectively. In LP, TNF-α+/CD4+ T cell number was higher in the muscarine group and lower in the atropine.
Assuntos
Inflamação/imunologia , Mucosa Intestinal/imunologia , Receptores Muscarínicos/imunologia , Animais , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia , Mucosa Intestinal/efeitos dos fármacos , Intestino Delgado/efeitos dos fármacos , Intestino Delgado/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Agonistas Muscarínicos/farmacologia , Nódulos Linfáticos Agregados/efeitos dos fármacos , Nódulos Linfáticos Agregados/imunologiaRESUMO
Immunoglobulin (Ig) A, an antibody with a pivotal role in gut homeostasis, can be modulated by stress and bovine lactoferrin (bLf). The aim of the present study was to analyze the impact of chronic stress on the IgA response in the small intestine during bLf treatment. Male BALB/c mice (n=6 mice/group) underwent 1 h of chronic stress by immobilization for 7 consecutive days or were left unstressed, and were untreated or treated with bLf (50, 500 or 5,000 µg). Plasma corticosterone expression levels were determined by ELISA. The distal small intestine was dissected to analyze: i) total IgA, secretory IgA and IgG, as well as and specific IgA and IgG antibody levels in the intestinal liquid by ELISA; ii) αchain and polymeric immunoglobulin receptor (pIgR) protein expression in epithelial cell extracts analyzed by western blotting; iii) the mRNA expression levels of α/Jchains, pIgR, IL2, IL4, IL5 and IL6 in whole mucosal samples by reverse transcriptionquantitative PCR. Data were analyzed by oneway ANOVA, and the differences were analyzed by the HolmSidák post hoc test and were considered significant if P<0.05. Results from the present study revealed the upregulatory effects of chronic stress on the total antibody levels, protein (αchain; 78kDa pIgR) and mRNA (α and Jchains; pIgR; IL6) expression levels were restricted by bLf under stress. The effects of chronic stress on the downregulation of IL2 and IL4 mRNA expression were not changed by bLf under stress. The corticosterone response in unstressed mice treated with 5,000 µg bLf and the specificIgG levels in the unstressed and stressed groups treated with bLf at all doses were increased. The findings suggested an effect of bLf in maintaining homeostasis under stress.
Assuntos
Corticosterona/sangue , Intestino Delgado/metabolismo , Lactoferrina/farmacologia , Estresse Psicológico/tratamento farmacológico , Animais , Regulação da Expressão Gênica , Imunoglobulina A/análise , Imunoglobulina A/genética , Imunoglobulina A Secretora/análise , Imunoglobulina A Secretora/genética , Imunoglobulina G/análise , Imunoglobulina G/genética , Intestino Delgado/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Estresse Psicológico/sangue , Estresse Psicológico/imunologiaRESUMO
To assess the impact of vagotomy on the IgA-response, male BALB/c mice underwent anterior vagotomy or a sham procedure were sacrificed on day 14 post-operation and the proximal and distal small-gut segments were dissected. In intestinal lavages IgA/IgM antibodies were analysed by ELISA; in Peyer's-patches and lamina-propria cell suspensions the intracellular IgA-associated interleukins (ILs) and pro-inflammatory cytokines in CD4+ T cells were analysed by cytofluorometry. Vagotomy reduced the IgA or increased the IgM antibody concentration in both segments and reduced or increased the lamina- propria CD4+ T cell pro-inflammatory cytokine responses in the distal or proximal segments, respectively. Data show the role of the vagus nerve on the IgA response.
Assuntos
Formação de Anticorpos/fisiologia , Diafragma/inervação , Imunoglobulina A/sangue , Intestino Delgado/metabolismo , Nódulos Linfáticos Agregados/metabolismo , Vagotomia/tendências , Animais , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Imunoglobulina A/imunologia , Intestino Delgado/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Nódulos Linfáticos Agregados/imunologia , Vagotomia/efeitos adversosRESUMO
Obesity is a health concern that is recognized as a critical factor for vulnerability to influenza A/pdmH1N1 virus infection, with epidemiological and clinical impacts. In humans, obesity induces disturbances in inflammatory and immune responses to the influenza virus and in some cases, this leads to severe complications, with fatal outcomes. Obesity impairs immunity by altering the response of cytokines, resulting in a decrease in the cytotoxic cell response of immunocompetent cells which have a key anti-viral role. Additionally, obesity seems to disturb the balance of endocrine hormones, such as leptin, that affect the interplay between metabolic and immune systems. This contribution focuses on reviewing the current epidemiologic data for the immune response to immunity in obese humans and animal models. In doing so, we aim to provide potential mechanisms to enhance immunity to influenza A/pdmH1N1 virus infection and protective factors in obese people.
Assuntos
Vírus da Influenza A Subtipo H1N1 , Influenza Humana/imunologia , Obesidade/imunologia , Animais , Linfócitos B/imunologia , Humanos , Imunidade Inata , Influenza Humana/complicações , Leptina/fisiologia , Camundongos , Obesidade/complicações , Infecções por Orthomyxoviridae/imunologiaRESUMO
Lactoferrin (Lf) is an iron-binding milk glycoprotein that promotes the growth of selected probiotic strains. The effect of Lf on the growth and diversification of intestinal microbiota may have an impact on several issues, including (i) strengthening the permeability of the epithelial cell monolayer, (ii) favoring the microbial antagonism that discourages the colonization and proliferation of enteric pathogens, (iii) enhancing the growth and maturation of cell-monolayer components and gut nerve fibers, and (iv) providing signals to balance the anti- and pro-inflammatory responses resulting in gut homeostasis. Given the beneficial role of probiotics, this contribution aims to review the current properties of bovine and human Lf and their derivatives in in vitro probiotic growth and Lf interplay with microbiota described in the piglet model. By using Lf as a component in pharmacological products, we may enable novel strategies that promote probiotic growth while conferring antimicrobial activity against multidrug-resistant microorganisms that cause life-threatening diseases, especially in neonates.
Assuntos
Bactérias/crescimento & desenvolvimento , Microbioma Gastrointestinal , Lactoferrina/metabolismo , Probióticos/metabolismo , Animais , Bovinos , HumanosRESUMO
The intestinal epithelium is a monolayer of cells arranged sidebyside and connected by tight junction (TJ) proteins expressed at the apical extreme of the paracellular membrane. This layer prevents stressinduced inflammatory responses, thus helping to maintain gut barrier function and gut homeostasis. The aim of the present study was to evaluate the effects of chronic immobilization stress on the colonic expression of various parameters of homeostasis. A total of two groups of female BALB/c mice (n=6) were included: A stressed group (shortterm immobilization for 2 h/day for 4 consecutive days) and an unstressed (control) group. Colon samples were obtained to detect neutrophils and goblet cells by optical microscopy, TJ protein expression (occludin, and claudin 2, 4, 7, 12 and 15) by western blotting, mRNA levels of TJ genes and proinflammatory cytokines [tumor necrosis factor (TNF)α, interleukin (IL)1ß, 6 and 8] by reverse transcriptionquantitative PCR, fecal lactoferrin by ELISA and the number of colonyforming units of aerobic bacteria. Compared with goblet cells in control mice, goblet cells were enlarged and reduced in number in stressed mice, whereas neutrophil cellularity was unaltered. Stressed mice exhibited reduced mRNA expression for all evaluated TJ mRNAs, with the exception of claudin7, which was upregulated. Protein levels of occludin and all claudins (with the exception of claudin12) were decreased in stressed mice. Fecal lactoferrin, proinflammatory cytokine mRNA levels and aerobic bacterial counts were all increased in the stressed group. These results indicated that immobilization stress induced proinflammatory and potential remodeling effects in the colon by decreasing TJ protein expression. The present study may be a useful reference for therapies aiming to regulate the effects of stress on intestinal inflammatory dysfunction.
Assuntos
Colo/patologia , Imobilização/efeitos adversos , Animais , Colo/microbiologia , Citocinas/análise , Fezes/química , Feminino , Células Caliciformes/patologia , Homeostase , Lactoferrina/análise , Camundongos Endogâmicos BALB C , Estresse Fisiológico , Proteínas de Junções Íntimas/análiseRESUMO
OBJECTIVE: The posterior vagus nerve trunk innervates the entire small intestine, and elucidating its modulatory role in the IgA response was the aim of this study. METHODS: Two groups of six male BALB/c mice underwent sham or posterior subdiaphragmatic vagotomy and were euthanized on the 14th postoperative day; then, the small intestines were dissected. The intestinal fluid was harvested for antibody analysis by ELISA, and cell suspensions from Peyer's patches and lamina propria were prepared for cytofluorometric analysis of plasma cells and T lymphocytes. The CD4+ T cells were labeled for the intracellular IgA-producing interleukins (ILs)-4, -5, -6, and -10; transforming growth factor (TGF)-ß; and the inflammatory cytokines tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and IL-12. In the intestinal tissue samples, myeloperoxidase (MPO) visualization and the enzymatic activity were assessed by immunohistochemistry and ELISA, respectively. The data were analyzed by Student's t test, and the differences were considered significant at p < 0.05. RESULTS: In the vagotomy group, the IgA levels and the CD4+ T cells labeled with mediators that promote IgA secretion, including IL-4 (only at lamina propria), TNF-α, and IFN-γ, were decreased, whereas the lamina propria IgA+ plasma cells and MPO presence/activity were increased; changes in the IgM levels, IgM+ plasma cells, and CD4+ T cells labeled with TGF-ß, which have a role in class switch recombination, were not observed. CONCLUSION: The downmodulating impact of vagotomy on IgA levels may result from defective IgA secretion without affecting class switch recombination, whereas vagotomy evoked a proinflammatory response regarding MPO. These findings may reflect the role of the vagus nerve on the control of the IgA response in the small intestine.
Assuntos
Imunidade nas Mucosas/imunologia , Imunoglobulina A/imunologia , Mucosa Intestinal/imunologia , Intestino Delgado/imunologia , Nervo Vago/fisiologia , Animais , Linfócitos T CD4-Positivos/imunologia , Regulação para Baixo , Mucosa Intestinal/inervação , Intestino Delgado/inervação , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Plasmócitos/imunologia , VagotomiaRESUMO
Over the past 20 years, gastrointestinal infections in developing countries have been a serious health problem and are the second leading cause of morbidity among all age groups. Among pathogenic protozoans that cause diarrheal disease, the parasite Entamoeba histolytica produces amebic colitis as well as the most frequent extra-intestinal lesion, an amebic liver abscess (ALA). Usually, intestinal amebiasis and ALA are treated with synthetic chemical compounds (iodoquinol, paromomycin, diloxanide furoate, and nitroimidazoles). Metronidazole is the most common treatment for amebiasis. Although the efficacy of nitroimidazoles in killing amebas is known, the potential resistance of E. histolytica to this treatment is a concern. In addition, controversial studies have reported that metronidazole could induce mutagenic effects and cerebral toxicity. Therefore, natural and safe alternative drugs against this parasite are needed. Flavonoids are natural polyphenolic compounds. Flavonoids depend on malonyl-CoA and phenylalanine to be synthesized. Several flavonoids have anti-oxidant and anti-microbial properties. Since the 1990s, several works have focused on the identification and purification of different flavonoids with amebicidal effects, such as, -(-)epicatechin, kaempferol, and quercetin. In this review, we investigated the effects of flavonoids that have potential amebicidal activity and that can be used as complementary and/or specific therapeutic strategies against E. histolytica trophozoites. Interestingly, it was found that these natural compounds can induce morphological changes in the amebas, such as chromatin condensation and cytoskeletal protein re-organization, as well as the upregulation and downregulation of fructose-1,6-bisphosphate aldolase, glyceraldehyde-phosphate dehydrogenase, and pyruvate:ferredoxin oxidoreductase (enzymes of the glycolytic pathway). Although the specific molecular targets, bioavailability, route of administration, and doses of some of these natural compounds need to be determined, flavonoids represent a very promising and innocuous strategy that should be considered for use against E. histolytica in the era of microbial drug resistance.
Assuntos
Antiprotozoários/administração & dosagem , Antiprotozoários/farmacologia , Entamoeba histolytica/efeitos dos fármacos , Entamebíase/tratamento farmacológico , Flavonoides/administração & dosagem , Flavonoides/farmacologia , HumanosRESUMO
Lactoferrin (Lf) is a conserved cationic non-heme glycoprotein that is part of the innate immune defense system of mammals. Lf is present in colostrum, milk and mucosal sites, and it is also produced by polymorphonuclear neutrophils and secreted at infection sites. Lf and Lf N-terminus peptide-derivatives named lactoferricins (Lfcins) are molecules with microbiostatic and microbicidal action in a wide array of pathogens. In addition, they display regulatory properties on components of nonspecific immunity, including toll-like receptors, proand anti-inflammatory cytokines, and reactive oxygen species. Mechanisms explaining the ability of Lf and Lfcins to display both up- and down-modulatory properties on cells are not fully understood but result, in part, from their interactions with membrane receptors that elicit biochemical signal pathways, whereas other receptors enable the nuclear translocation of these molecules for the modulation of target genes. The dual role of Lf and Lfcins as antimicrobials and immunomodulators is of biotechnological and pharmaceutical interest. Native Lf and its peptide-derivatives from human and bovine sources, the recombinant versions of the human protein, and their synthetic peptides have potential application as adjunctive agents in therapies to combat infections caused by multi-resistant bacteria and those caused by fungi, protozoa and viruses, as well as in the prevention and reduction of several types of cancer and response to LPS-shock, among other effects. In this review, we summarize the immunomodulatory properties of the unique multifunctional protein Lf and its N-terminus peptides.
Assuntos
Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Imunidade Inata/efeitos dos fármacos , Lactoferrina/metabolismo , Anti-Infecciosos/química , Anti-Infecciosos/metabolismo , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/metabolismo , Humanos , Imunidade Inata/imunologiaRESUMO
Lactoferrin (Lf) is a glycoprotein of the primary innate immune-defense system of mammals present in milk and other mucosal secretions. This protein of the transferrin family has broad antimicrobial properties by depriving pathogens from iron, or disrupting their plasma membranes through its highly cationic charge. Noteworthy, Lf also exhibits immunomodulatory activities performing up- and down-regulation of innate and adaptive immune cells, contributing to the homeostasis in mucosal surfaces exposed to myriad of microbial agents, such as the gastrointestinal and respiratory tracts. Although the inflammatory process is essential for the control of invasive infectious agents, the development of an exacerbated or chronic inflammation results in tissue damage with life-threatening consequences. In this review, we highlight recent findings in in vitro and in vivo models of the gut, lung, oral cavity, mammary gland, and liver infections that provide experimental evidence supporting the therapeutic role of human and bovine Lf in promoting some parameters of inflammation and protecting against the deleterious effects of bacterial, viral, fungal and protozoan-associated inflammation. Thus, this new knowledge of Lf immunomodulation paves the way to more effective design of treatments that include native or synthetic Lf derivatives, which may be useful to reduce immune-mediated tissue damage in infectious diseases.
Assuntos
Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Lactoferrina/metabolismo , Lactoferrina/farmacologia , Animais , Anti-Infecciosos/química , Anti-Inflamatórios/química , Anti-Inflamatórios/metabolismo , Anti-Inflamatórios/farmacologia , Doenças Transmissíveis/tratamento farmacológico , Doenças Transmissíveis/etiologia , Doenças Transmissíveis/imunologia , Doenças Transmissíveis/metabolismo , Humanos , Imunidade Inata/efeitos dos fármacos , Fatores Imunológicos/metabolismo , Fatores Imunológicos/farmacologia , Imunomodulação/efeitos dos fármacos , Inflamação/tratamento farmacológico , Inflamação/etiologia , Inflamação/imunologia , Inflamação/metabolismo , Lactoferrina/químicaRESUMO
Extracellular matrix metalloproteases and the fibrinolytic system are important protease systems interacting with each other in charge of remodeling and recycling of tissues. Their role in tumor invasion and metastasis is often discussed. In this study several metalloproteases such as MMP-1, MMP-3, MMP-9, and TIMP-1 together with molecules from the fibrinolytic system like uPA, its receptor uPAR, and its inhibitor, PAI-1, were studied by immune-histochemistry to establish a comparison with and without metastasis. From the (118) primary tumors of Mexican patients with ductal breast cancer studied, 56% were grade II and 69% were size T2; the group with metastatic ganglia included 64 samples (54.3%). In patients with metastasis the estimated expression of MMP-3 and uPA (resp., 28% and 45%) was higher than that from no metastatic tumors; it means there is higher expression of both markers in metastatic tumors (p < 0.05). At the same time, metastatic tumors showed statistically significant lower signal of PAI-1 (24%) than tumors without metastasis (p < 0.05). We concluded that overexpression of MMP-3 and uPA, altogether with diminished expression of PAI-1 from metastatic tumors, might be a crucial step towards metastasis in ductal breast cancer. Nevertheless, additional studies in different populations are necessary to establish a pattern.
Assuntos
Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/genética , Carcinoma Ductal de Mama/patologia , Metaloproteinase 3 da Matriz/genética , Inibidor 1 de Ativador de Plasminogênio/genética , Ativador de Plasminogênio Tipo Uroquinase/genética , Adulto , Idoso , Biomarcadores Tumorais , Neoplasias da Mama/epidemiologia , Carcinoma Ductal de Mama/epidemiologia , Feminino , Expressão Gênica , Hospitalização , Humanos , Metaloproteinases da Matriz/genética , Metaloproteinases da Matriz/metabolismo , México/epidemiologia , Pessoa de Meia-Idade , Gradação de Tumores , Metástase Neoplásica , Estadiamento de Neoplasias , Fenótipo , Vigilância da População , Estudos Retrospectivos , Carga TumoralRESUMO
Bovine lactoferrin (bLf) up-modulates intestinal IgA that is essential for homeostasis and which might confer protection to the distal small intestine that is vulnerable to inflammation. This study analyzed the effects of bLf administered orally on the IgA response at inductive (Peyer's patches) and effector (lamina propria) sites of the distal small intestine in mice. Groups of five healthy male BALB/c mice were orally treated with 5 mg of bLf for 7, 14, 21, or 28 days. Then, mice were killed and the distal small intestine was dissected. Intestinal fluid samples were analyzed to determine IgA and IgM levels by enzyme-immuno assay. Peyer's patches and lamina propria were analyzed for IgA(+) or IgM(+) plasma cells, B, CD4(+) T and CD8(+) T cells as well as CD4(+) T cells positive for either pro-inflammatory cytokines [tumor necrosis factor (TNF)-α, interferon-γ and interleukin (IL)-12] or for IgA-producing ILs (IL-4, -5, -10 and -6) by cytofluorometry. Antibodies, antibody-secreting cells, and B and T responses in both Peyer's patches and lamina propria were higher in bLf-treated than bLf-untreated mice. The generation of IL-10 and IL-6 CD4(+) T cells in Peyer's patches or TNF-α and IL-12 CD4(+) T cells in lamina propria showed similar response patterns. On days 14 and 28, cytokine/IL CD4(+) T cell responses were increased in Peyer's patches or decreased in lamina propria. The effect of bLf on the elicitation of IgA indicates a potential application of bLf as a nutraceutical to control inflammation in the distal small intestine.
Assuntos
Linfócitos B/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Imunomodulação , Inflamação/imunologia , Intestino Delgado/efeitos dos fármacos , Lactoferrina/administração & dosagem , Administração Oral , Animais , Bovinos , Citocinas/metabolismo , Suplementos Nutricionais , Humanos , Imunidade Humoral/efeitos dos fármacos , Imunoglobulina A/metabolismo , Inflamação/tratamento farmacológico , Mediadores da Inflamação/metabolismo , Intestino Delgado/imunologia , Lactoferrina/efeitos adversos , Masculino , Camundongos Endogâmicos BALB CRESUMO
Intermittent fasting prolongs the lifespan and unlike intense stress provides health benefits. Given the role of the immunoglobulin A (IgA) in the intestinal homeostasis, the aim of this study was to assess the impact of intermittent fasting plus intense stress on secretory IgA (SIgA) production and other mucosal parameters in the duodenum and ileum. Two groups of six mice, with intermittent fasting or fed ad libitum for 12weeks, were submitted to a session of intense stress by a bout of forced swimming. Unstressed ad libitum fed or intermittently fasted groups were included as controls. After sacrifice, we evaluated intestinal SIgA and plasma adrenal hormones, lamina propria IgA+ plasma-cells, mRNA expression of polymeric immunoglobulin receptor, α- and J-chains in the liver and intestinal mucosa, as well as pro- (tumor necrosis factor-α, interleukin-6 and Interferon-γ) and anti- (interleukin-2, -4, -10 and transforming growth factor-ß) inflammatory cytokines in mucosal samples. Under intense stress, intermittent fasting down- or up-modulated the levels of most parameters in the duodenum and ileum, respectively while up-regulated corticosterone levels without affecting epinephrine. Our data suggest intermittent fasting plus intense stress elicited neuroendocrine pathways that differentially controlled IgA and pIgR expression in duodenum and ileum. These findings provide experimental foundations for a presumable impact of intermittent fasting under intense stress on the intestinal homeostasis or inflammation by triggering or reducing the IgA production in ileum or duodenum respectively.
Assuntos
Modelos Animais de Doenças , Duodeno/metabolismo , Jejum/metabolismo , Íleo/metabolismo , Imunoglobulina A/biossíntese , Estresse Psicológico/metabolismo , Animais , Jejum/psicologia , Intestino Delgado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Estresse Psicológico/psicologia , Fatores de TempoRESUMO
Computational identification of potential epitopes with an immunogenic capacity challenges immunological research. Several methods show considerable success, and together with experimental studies, the efficiency of the algorithms to identify potential peptides with biological activity has improved. Herein, an epitope was designed by combining bioinformatics, docking, and molecular dynamics simulations. The hemagglutinin protein of the H1N1 influenza pandemic strain served as a template, owing to the interest of obtaining a scheme of immunization. Afterward, we performed enzyme-linked immunosorbent assay (ELISA) using the epitope to analyze if any antibodies in human sera before and after the influenza outbreak in 2009 recognize this peptide. Also, a plaque reduction neutralization test induced by virus-neutralizing antibodies and the IgG determination showed the biological activity of this computationally designed peptide. The results of the ELISAs demonstrated that the serum of both prepandemic and pandemic recognized the epitope. Moreover, the plaque reduction neutralization test evidenced the capacity of the designed peptide to neutralize influenza virus in Madin-Darby canine cells.
Assuntos
Epitopos/metabolismo , Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Influenza Humana/metabolismo , Peptídeos/metabolismo , Animais , Anticorpos/imunologia , Linhagem Celular , Biologia Computacional , Cães , Glicoproteínas de Hemaglutininação de Vírus da Influenza/química , Humanos , Influenza Humana/imunologia , Simulação de Dinâmica Molecular , Peptídeos/química , CoelhosRESUMO
The toxicity of the curcin on cancer cells allows to consider this protein as the toxic component of an immunotoxin directed to Her2, which is associated with cancer. Reductive amination was proposed to conjugate curcin and an anti-Her2; the binding was tested using Polyacrylamide gel electrophoresis, western blot, and immunocytochemistry. The in vitro cytotoxicity of curcin and the immunotoxin was assessed on breast cancer cell lines SK-BR-3 (Her2(+)) and MDA-MB-231 (Her2(-)). IC50 values for curcin were 15.5 ± 8.3 and 18.6 ± 2.4 µg/mL, respectively, statistically equivalent (p < 0.05). While to the immunotoxin was 2.2 ± 0.08 for SK-BR-3 and 147.6 ± 2.5 µg/mL for MDA-MB-231. These values showed that the immunotoxin was seven times more toxic to the SK-BR-3 than curcin and eight times less toxic to the MDA-MB-231. The immunotoxin composed of curcin and an antibody against Her2 and constructed by reductive amination could be a therapeutic candidate against Her2(+) cancer.
Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/metabolismo , Imunotoxinas/metabolismo , Receptor ErbB-2/imunologia , Proteínas Inativadoras de Ribossomos Tipo 1/metabolismo , Aminação , Linhagem Celular Tumoral , Fenômenos Químicos , Simulação por Computador , Humanos , Imunotoxinas/química , Imunotoxinas/imunologia , Modelos Moleculares , Oxirredução , Conformação Proteica , Proteínas Inativadoras de Ribossomos Tipo 1/químicaRESUMO
BACKGROUND: The parasympathetic nervous system modulates the immune response in the abdominal-pelvic gut through the vagus nerve, which releases acetylcholine. This endogenous ligand acts on α7 nicotinic receptors expressed on immune cells. OBJECTIVE: To study the mechanism of the production and regulation of cytokines in parasympathectomized and control hamsters during the development of amoebic liver abscesses (ALA) caused by Entamoeba histolytica. METHODOLOGY: Six- to 8-week-old male hamsters with and without vagotomy were used in a model of ALA. The animals were infected with trophozoites (350,000; HM1:IMSS strain) via the intrahepatic route and sacrificed at 6, 12, and 24 h and at 2, 4, and 7 days postinfection. Immune parameters were recorded at each time point using morphometric techniques including immunofluorescence and immunohistochemistry assays. These parameters included signal transducer and activator of transcription 3 (STAT3) levels, pro- and anti-inflammatory cytokine levels, and nuclear factor-κB (NFκB) activation in neutrophils and macrophages. RESULTS: Compared to the control groups, the vagotomized (VAG) hamsters showed a significant increase in NFκB activation in neutrophils and macrophages, and higher levels of interleukin (IL)-1ß, IL-6, interferon-γ, and tumor necrosis factor-α. VAG hamsters showed an increase in the expression of IL-8 and phosphorylated STAT3 during the first 24 h postinfection as well as slightly increased levels of transforming growth factor-ß on days 2-7 postinfection. No significant differences were demonstrated in the levels of IL-10. CONCLUSIONS: These results suggest that the vagus nerve plays an important role in the regulation of inflammation during ALA formation.
Assuntos
Citocinas/metabolismo , Abscesso Hepático Amebiano/patologia , Abscesso Hepático Amebiano/cirurgia , Vagotomia/métodos , Análise de Variância , Animais , Cricetinae , Citocinas/genética , Modelos Animais de Doenças , Entamoeba histolytica/patogenicidade , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/fisiologia , Abscesso Hepático Amebiano/microbiologia , Macrófagos/imunologia , Macrófagos/patologia , Masculino , Neutrófilos/imunologia , Neutrófilos/patologia , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Fatores de TempoRESUMO
BACKGROUND: Pterygium is a disorder of the ocular surface induced by chronic exposure to UV-light. Abundant data is available from patients with primary pterygium, but scarce from those with recurrent pterygium. The present study aimed to explore the oxidant/antioxidant status in tissue of primary and recurrent pterigium in men and women. METHODS: Pathological tissue samples were taken during surgery on patients with primary and recurrent pterygium. Healthy conjunctive tissue samples were taken during cataract surgery. After homogenization of 77 tissue samples, evaluation was made of thiobarbituric reactive substances (TBARS), nitric oxide (NO), total antioxidant status (TAS) and the activity of the three main antioxidant enzymes: glutathione peroxidase, superoxide dismutase and catalase. Gender differences were evaluated. RESULTS: Compared to the control group, in the primary pterygium group there was an increase in NO and TAS, and a tendency to a decrease of all antioxidant enzymes, indicating an increase in non-enzymatic antioxidant activity. Compared to the control group, in the recurrent pterygium group there was a significant decrease in the level of TAS and antioxidant enzymes. A high positive correlation was found between most of measured parameters within the control group and the recurrent pterygium group, but not within the primary pterygium group. Compared to men, a significant difference was observed in the elevated NO level and low TAS level of women in the prymary pterygium group. CONCLUSIONS: The diminished antioxidant defense in the recurrent pterygium group, possibly determined mainly by decreased non-enzymatic activity, supports the idea that oxidative stress plays an important role in the recurrence of this disorder.
Assuntos
Antioxidantes/metabolismo , Óxido Nítrico/metabolismo , Oxidantes/metabolismo , Pterígio/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo , Adulto , Idoso , Catalase/metabolismo , Túnica Conjuntiva/metabolismo , Feminino , Glutationa Peroxidase/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Estresse Oxidativo , Recidiva , Fatores Sexuais , Superóxido Dismutase/metabolismoRESUMO
The molecular mechanisms by which Entamoeba histolytica causes amebic liver abscess (ALA) are still not fully understood. Amebic mechanisms of adherence and cytotoxic activity are pivotal for amebic survival but apparently do not directly cause liver abscess. Abundant evidence indicates that chronic inflammation (resulting from an inadequate immune response) is probably the main cause of ALA. Reports referring to inflammatory mechanisms of liver damage mention a repertoire of toxic molecules by the immune response (especially nitric oxide and reactive oxygen intermediates) and cytotoxic substances released by neutrophils and macrophages after being lysed by amoebas (e.g., defensins, complement, and proteases). Nevertheless, recent evidence downplays these mechanisms in abscess formation and emphasizes the importance of peroxynitrite (ONOO(-)). It seems that the defense mechanism of amoebas against ONOO(-), namely, the amebic thioredoxin system (including peroxiredoxin), is superior to that of mammals. The aim of the present text is to define the importance of ONOO(-) as the main agent of liver abscess formation during amebic invasion, and to explain the superior capacity of amoebas to defend themselves against this toxic agent through the peroxiredoxin and thioredoxin system.
Assuntos
Interações Hospedeiro-Parasita , Abscesso Hepático Amebiano , Modelos Biológicos , Peroxirredoxinas , Ácido Peroxinitroso , Animais , Linhagem Celular , Cricetinae , Humanos , Inflamação , Camundongos , RatosRESUMO
The nasal mucosa is the first contact with antigens to induce IgA response. The role of this site has rarely been studied. We have shown than intranasal administration with Naegleria fowleri lysates plus Cholera toxin (CT) increased the protection (survival up to 100%) against N. fowleri infection in mice and apparently antibodies IgA and IgG together with polymorphonuclear (PMN) cells avoid the attachment of N. fowleri to apical side of the nasal epithelium. We also observed that nasal immunization resulted in the induction of antigen-specific IgG subclasses (IgG1 and IgG2a) in nasal washes at days 3 and 9 after the challenge and IgA and IgG in the nasal cavity, compared to healthy and infected mice. We found that immunization with both treatments, N. fowleri lysates plus CT or CT alone, increased the expression of the genes for alpha chain, its receptor (pIgR), and it also increased the expression of the corresponding proteins evidenced by the â¼65 and â¼74kDa bands, respectively. Since the production of pIgR, IgA and IgG antibodies, is up-regulated by some factors, we analyzed the expression of genes for IL-10, IL-6, IFN-γ, TNF-α and IL-1ß by using RT-PCR of nasal passages. Immunization resulted in an increased expression of IL-10, IL-6, and IFN-γ cytokines. We also aimed to examine the possible influences of immunization and challenge on the production of inflammatory cytokines (TNF-α and IL-1ß). We observed that the stimulus of immunization inhibits the production of TNF-α compared to the infected group where the infection without immunization causes an increase in it. Thus, it is possible that the coexistence of selected cytokines produced by our immunization model may provide a highly effective immunological environment for the production of IgA, IgG and pIgR as well as a strong activation of the PMN in mucosal effector tissue such as nasal passages.