ABSTRACT
Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, has been detected in the thymus of multiple vertebrates. However, little is known about its distribution in the thymus of the African ostrich. In this study, we evaluated the distribution and morphological characteristics of ghrelin-producing cells in the thymus of the African ostrich. Our results revealed that the thymus consists of a capsule and a parenchyma, which comprises the cortex and medulla. Compared to the cortex, the medulla had a fewer number of thymocytes and a greater number of epithelial cells. Additionally, three thymic corpuscles were identified. Ghrelin-immunopositive (ghrelin-ip) cells were detected both in the cortex and medulla of the African ostrich thymus, specifically within epithelial cells and thymic corpuscles. On the other hand, no ghrelin-ip cells were detected within thymocytes. These results clearly demonstrate the presence of ghrelin-ip cells in the thymus of the African ostrich.
La ghrelina, un ligando endógeno para el receptor secretor de la hormona del crecimiento, se ha detectado en el timo de múltiples vertebrados. Sin embargo, poco se sabe sobre su distribución en el timo de la avestruz africana. En este estudio se evaluó la distribución y características morfológicas de las células productoras de ghrelina en el timo de la avestruz africana. Nuestros resultados revelaron que el timo consiste en una cápsula y un parénquima, que comprende la corteza y la médula. En comparación con la corteza, se observó un número menor de timocitos en la médula y un mayor número de células epiteliales. Además, se identificaron tres corpúsculos tímicos. Se detectaron células inmunopositivas a la ghrelina (ghrelin-ip) tanto en la corteza como en la médula del timo de la avestruz africana, específicamente dentro de células epiteliales y corpúsculos tímicos. Por otra parte, no se detectaron células ghrelin-ip dentro de los timocitos. Estos resultados demuestran claramente la presencia de células ghrelin-ip en el timo de la avestruz africana.
Subject(s)
Animals , Male , Female , Thymus Gland/anatomy & histology , Thymus Gland/metabolism , Struthioniformes , Ghrelin/metabolism , ImmunohistochemistryABSTRACT
BACKGROUND: Several evidences indicate that hormones and neuropeptides function as immunomodulators. Among these, growth hormone (GH) is known to act on the thymic microenvironment, supporting its role in thymocyte differentiation. The aim of this study was to evaluate the effect of GH on human thymocytes and thymic epithelial cells (TEC) in the presence of laminin. RESULTS: GH increased thymocyte adhesion on BSA-coated and further on laminin-coated surfaces. The number of migrating cells in laminin-coated membrane was higher in GH-treated thymocyte group. In both results, VLA-6 expression on thymocytes was constant. Also, treatment with GH enhanced laminin production by TEC after 24 h in culture. However, VLA-6 integrin expression on TEC remained unchanged. Finally, TEC/thymocyte co-culture model demonstrated that GH elevated absolute number of double-negative (CD4-CD8-) and single-positive CD4+ and CD8+ thymocytes. A decrease in cell number was noted in double-positive (CD4+CD8+) thymocytes. CONCLUSIONS: The results of this study demonstrate that GH is capable of enhancing the migratory capacity of human thymocytes in the presence of laminin and promotes modulation of thymocyte subsets after co-culture with TEC.
Subject(s)
Humans , Infant, Newborn , Infant , Child, Preschool , Child , Thymus Gland/cytology , Growth Hormone/pharmacology , Laminin/biosynthesis , Epithelial Cells/drug effects , Thymocytes/drug effects , Reference Values , Thymus Gland/metabolism , Time Factors , Immunohistochemistry , CD4-Positive T-Lymphocytes , Cell Adhesion/drug effects , Cell Differentiation/drug effects , Cell Movement/drug effects , Cells, Cultured , Analysis of Variance , Laminin/drug effects , CD8-Positive T-Lymphocytes , Coculture Techniques , Integrin alpha6beta1/analysis , Integrin alpha6beta1/metabolism , Flow Cytometry/methodsABSTRACT
Toll-like receptors (TLR) are a family of pattern recognition receptors identifying pathogen associated molecular patterns (PAMPs). They play a critical role in the innate immune response during the initial interaction between the infecting microorganism and phagocytic cells. Here, we verified the presence of TLR-2 in spleen, lymph node and thymus of Swiss albino mice and their modulation after infection with Staphylococcus aureus and Lipopolysaccharide (LPS) challenge. It was seen that TLR-2 gene transcribed to its respective mRNA on S. aureus infection, in thymus, spleen and lymph node of mice but their levels and mode of expression varied. When challenged with LPS no prominent changes in the expression of TLR-2 receptor was observed but its expression increased gradually with time in the thymus, spleen and lymph node of S. aureus infected mice. TLR-2 expression was also found enhanced in infected splenic macrophages. By studying the serum cytokine profile the functionality of the receptor was measured. The results indicate the presence of TLR-2 in thymus, spleen and lymph node of Swiss albino strain of mice and that they are modulated by S. aureus.
Subject(s)
Animals , Anti-Bacterial Agents/pharmacology , Cytokines/blood , Cytokines/immunology , Gene Expression/drug effects , Gene Expression/immunology , Host-Pathogen Interactions/immunology , Lipopolysaccharides/immunology , Lipopolysaccharides/pharmacology , Lymph Nodes/immunology , Lymph Nodes/metabolism , Lymph Nodes/microbiology , Macrophages/immunology , Macrophages/metabolism , Macrophages/microbiology , Male , Mice , Microbial Sensitivity Tests , Reverse Transcriptase Polymerase Chain Reaction , Spleen/immunology , Spleen/metabolism , Spleen/microbiology , Staphylococcal Infections/blood , Staphylococcal Infections/immunology , Staphylococcal Infections/microbiology , Staphylococcus aureus/drug effects , Staphylococcus aureus/immunology , Staphylococcus aureus/physiology , Thymus Gland/immunology , Thymus Gland/metabolism , Thymus Gland/microbiology , Time Factors , Toll-Like Receptor 2/genetics , Toll-Like Receptor 2/immunology , Toll-Like Receptor 2/metabolismABSTRACT
METHOD: one hundred (n=100) elderly outpatients with diabetic retinopathy taking antihypertensives and/or oral antidiabetics/insulin were interviewed. Adherence was evaluated by the adherence proportion and its association with the care taken in administrating medications and by the Morisky Scale. The National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25) was used to evaluate HRQoL. RESULTS: most (58%) reported the use of 80% or more of the prescribed dose and care in utilizing the medication. The item "stopping the drug when experiencing an adverse event", from the Morisky Scale, explained 12.8% and 13.5% of the variability of adherence proportion to antihypertensives and oral antidiabetics/insulin, respectively. CONCLUSION: there was better HRQoL in the Color Vision, Driving and Social Functioning domains of the NEI VFQ-25. Individuals with lower scores on the NEI VFQ-25 and higher scores on the Morisky Scale presented greater chance to be nonadherent to the pharmacological treatment of diabetes and hypertension. .
OBJETIVO: investigar os fatores relacionados à adesão medicamentosa e sua relação com a qualidade de vida relacionada à saúde em idosos com retinopatia diabética. MÉTODO: foram entrevistados 100 idosos, em acompanhamento ambulatorial, em uso de anti-hipertensivos e/ou antidiabéticos orais/insulina. A adesão foi avaliada pela proporção de adesão e sua associação com os cuidados no uso dos medicamentos e pela Escala de Morisky. O National Eye Institute Visual Funcioning Questionnaire foi utilizado para avaliar a qualidade de vida relacionada à saúde. RESULTADOS: A maioria (58%) relatou o uso de 80% ou mais das doses prescritas e os cuidados na tomada dos medicamentos. O item "interromper o uso dos medicamentos por se sentir pior", da Escala de Morisky, explicou 12,8 e 13,5% da variabilidade da proporção de adesão aos anti-hipertensivos e aos antidiabéticos orais/insulina, respectivamente. CONCLUSÃO: observou-se melhor qualidade de vida relacionada à saúde nos domínios visão de cores, dirigir automóvel e apectos sociais do National Eye Institute Visual Funcioning Questionnaire. Indivíduos com menor pontuação na National Eye Institute Visual Funcioning Questionnaire e maiores escores na Escala de Morisky apresentaram maiores chances de serem não aderentes aos medicamentos do diabetes e da hipertensão arterial. .
OBJETIVO: investigar los factores relacionados a la adhesión a la medicación y su relación con la Calidad de Vida Relacionada a la Salud (CVRS) de ancianos con retinopatía diabética. MÉTODO: fueron entrevistados cien (n=100) pacientes ancianos de ambulatorio con retinopatía diabética que toman medicamentos antihipertensivos y/o antidiabéticos orales/insulina. La adhesión fue evaluada mediante la proporción de adhesión y su asociación con el cuidado tomado en la administración de medicamentos y mediante la Escala de Morisky. El National Eye Institute Visual Functioning Questionnaire (NEI VFQ-25) fue usado para evaluar la CVRS. RESULTADOS: la mayoría (58%) relató el uso de 80% o más de la dosis prescrita y cuidado con el uso de la medicación. El ítem "suspender la droga cuando vivencia un evento adverso", de la Escala de Morisky, explicó 12.8% y 13.5% de la variabilidad en la proporción de adhesión a los antihipertensivos y antidiabéticos orales/insulina, respectivamente. CONCUSIÓN: fue encontrada mejor CVRS en los dominios de Visión Cromática, Dirección y Funcionamiento Social del NEI VFQ-25. Individuos con puntuaciones menores en el NEI VFQ-25 y puntuaciones mayores en la Escala de Morisky revelaron mayor chance de no adhesión al tratamiento farmacológico de la diabetes y hipertensión. .
Subject(s)
Animals , Cattle , Arsenites , DNA , DNA-Binding Proteins/physiology , Receptors, Glucocorticoid/metabolism , Sodium Compounds , Thymus Gland/metabolism , Arsenic/pharmacology , Chemical Phenomena , Chemistry , Chromatography, Gel , Cytosol/metabolism , Dextrans , Methyl Methanesulfonate/analogs & derivatives , Methyl Methanesulfonate/pharmacology , Molybdenum/pharmacologyABSTRACT
OBJECTIVE: to identify the perceptions of professionals working in a facility connected with the Brazilian Unified Health System - SUS in regard to what they know, think and talk about public health policy. METHOD: this exploratory-descriptive study with a qualitative nature was conducted with 28 professionals working in a facility connected with the SUS. Data were collected through interviews with guiding questions and analyzed through the thematic content analysis technique. RESULTS: coded and interpreted data resulted in three thematic axes: The SUS - perfect web that does not work in practice; The recurrent habit of complaining about the SUS; The need to rethink the way of thinking about, acting in and managing the SUS. CONCLUSION: the professionals working for the SUS are aware of the principles and guidelines that govern the Brazilian health system, however, they reproduce a dichotomous and linear model of conception and practice strongly linked to the thinking of society in general. .
OBJETIVO: conhecer a percepção de profissionais que atuam em uma instituição conveniada com o Sistema Único de Saúde sobre o que sabem, pensam e falam dessa política pública de saúde. MÉTODO: trata-se de estudo exploratório-descritivo, de caráter qualitativo, realizado com 28 profissionais que atuam em uma instituição conveniada com o Sistema Único de Saúde. Os dados foram coletados por meio de entrevistas com questões norteadoras e analisados pela técnica de análise de conteúdo temática. RESULTADOS: os dados codificados e interpretados resultaram em três eixos temáticos: Sistema Único de Saúde - teia perfeita que não funciona na prática; o recorrente hábito de reclamar do Sistema Único de Saúde; a necessidade de repensar o modo de pensar, atuar e gerir o Sistema Único de Saúde. CONCLUSÃO: os profissionais que atuam no Sistema Único de Saúde têm conhecimento dos princípios e diretrizes que regem o sistema de saúde nacional, no entanto, reproduzem um modelo de concepção e atuação dicotômico, pontual e linear ainda fortemente vigente no pensar da sociedade em geral. .
OBJETIVO: conocer la percepción de profesionales que actúan en una institución que tiene convenio con el Sistema Único de Salud - SUS sobre lo que saben, piensan y hablan de esta política pública de salud. MÉTODO: se trata de un estudio exploratorio descriptivo, de carácter cualitativo, realizado con 28 profesionales que actúan en una institución que tiene convenio con el SUS. Los datos fueron recolectados por medio de entrevistas con preguntas orientadoras y analizados con la técnica de análisis de contenido temático. RESULTADOS: los datos codificados y interpretados resultaron en tres ejes temáticos: SUS - red perfecta que no funciona en la práctica; el recurrente hábito de reclamar del SUS; y la necesidad de repensar el modo de pensar, actuar y administrar el SUS. CONCLUSIÓN: los profesionales que actúan en el SUS tienen conocimiento de los principios y directrices que gobiernan el sistema de salud nacional, sin embargo, reproducen un modelo de concepción y actuación dicotómico, puntual, linear y además fuertemente vigente en el pensar de la sociedad en general. .
Subject(s)
Animals , Male , Rats , Dexamethasone/analogs & derivatives , Body Weight/drug effects , Corticosterone/blood , Cytosol/metabolism , Cytosol/ultrastructure , Dexamethasone/pharmacology , Liver/metabolism , Liver/ultrastructure , Molybdenum/pharmacology , Rats, Inbred Strains , Receptors, Glucocorticoid/metabolism , Thymus Gland/metabolism , Thymus Gland/ultrastructure , TritiumABSTRACT
Argentinian native plants Aspidosperma quebracho-blanco, Lantana grisebachii and Ilex paraguariensis are known to have antiinflammatory and antioxidant properties. We demonstrated it in vivo by the redox changes in murine hemolymphatic tissues after infusive extract intake of these plants as revealed in organic trophism, tissue phenolics, hydroperoxides, superoxide, nitrites and γ-glutamyltranspeptidase in thymus, blood and spleen. A. quebracho-blanco reduced hydroperoxidation in blood and spleen of both sexes, with γ-glutamyltranspeptidase negativization in lymphatic organs and thymic nitrosative up-regulation. Males have shown increased phenolic content in blood after treatment. L. grisebachii and I. paraguariensis treatment exhibited incomplete antioxidation and oxidative induction in the studied tissues. Different results according to sex were found in redox response to phenolics and their kinetics, with males showing antioxidant effects, whereas females showed oxidative susceptibility. A. quebracho-blanco exhibited protection of murine tissues against oxidation in both sexes and modulation of their trophism, supporting its therapeutic uses in inflammatory diseases. Also, gender had significant influence in phenolic biodistribution and redox response.
Subject(s)
Animals , Anti-Inflammatory Agents/chemistry , Anti-Inflammatory Agents/pharmacology , Antioxidants/chemistry , Antioxidants/pharmacology , Aspidosperma/chemistry , Female , Ilex paraguariensis/chemistry , Lantana/chemistry , Male , Mice , Mice, Inbred BALB C , Oxidative Stress/drug effects , Plant Extracts/chemistry , Plant Extracts/pharmacology , Spleen/chemistry , Spleen/drug effects , Spleen/metabolism , Thymus Gland/chemistry , Thymus Gland/drug effects , Thymus Gland/metabolismABSTRACT
Developing thymocytes interact with thymic epithelial cells (TECs) through cell-cell interactions, TEC-derived secretory moieties and extracellular matrix (ECM)-mediated interactions. These physiological interactions are crucial for normal thymocyte differentiation, but can be disrupted in pathological situations. Indeed, there is severe thymic atrophy in animals acutely infected with Trypanosoma cruzi due to CD4+CD8+ thymocyte depletion secondary to caspase-mediated apoptosis, together with changes in ECM deposition and thymocyte migration. We studied an in vitro model of TEC infection by T. cruzi and found that infected TEC cultures show a reduced number of cells, which was likely associated with decreased proliferative capacity, but not with increased cell death, as demonstrated by bromodeoxyuridine and annexin-V labelling. The infected TEC cultures exhibited increased expression of fibronectin (FN), laminin (LM) and type IV collagen. Importantly, treatment with FN increased the relative number of infected cells, whereas treatment with anti-FN or anti-LM antibodies resulted in lower infection rates. Consistent with these data, we observed increased thymocyte adhesion to infected TEC cultures. Overall, these results suggest that ECM molecules, particularly FN, facilitate infection of the thymic epithelium and that the consequent enhancement of ECM expression might be associated with changes in TEC-thymocyte interactions.
Subject(s)
Animals , Male , Chagas Disease/metabolism , Epithelial Cells/metabolism , Extracellular Matrix/metabolism , Fibronectins/metabolism , Thymocytes/metabolism , Thymus Gland/metabolism , Cell Adhesion/physiology , Cell Communication/physiology , Cell Movement/physiology , Disease Models, Animal , Epithelial Cells/parasitology , Mice, Inbred BALB C , Thymocytes/parasitology , Thymus Gland/cytologyABSTRACT
OBJECTIVES: The purpose of this study was to investigate the association between T cell receptor excision circle levels in peripheral blood mononuclear cells and regulatory T cells that co-express CD25 and Foxp3 in healthy children and adolescents of different ages. MATERIALS AND METHODS: The quantification of signal-joint T-cell receptor excision circle levels in the genomic DNA of peripheral blood mononuclear cells was performed using real-time quantitative PCR. The analysis of CD4, CD8, CD25, and Foxp3 expression was performed using flow cytometry. RESULTS: Ninety-five healthy controls (46 females and 49 males) ranging in age from 1 to 18 years were analyzed. The mean T-cell receptor excision circle count in all individuals was 89.095¡36.790 T-cell receptor excision circles per microgram of DNA. There was an inverse correlation between T-cell receptor excision circles counts and age (r = -0.846; p<0.001) as well as between the proportion of CD4+CD25+Foxp3+ T cells and age (r = -0.467; p = 0.04). In addition, we observed a positive correlation between the amount of CD4+CD25+Foxp3+ T cells and the amount of Tcell receptor excision circles per microgram of DNA in individuals of all ages (r = -0.529; p = 0.02). CONCLUSIONS: In this study, we observed a decrease in the thymic function with age based on the fact that the level of T-cell receptor excision circles in the peripheral blood positively correlated with the proportion of regulatory T cells in healthy children and adolescents. These findings indicate that although T-cell receptor excision circles and regulatory T cells levels decrease with age, homeostasis of the immune system and relative regulatory T cells population levels are maintained in the peripheral blood.
Subject(s)
Adolescent , Child , Child, Preschool , Female , Humans , Infant , Autoimmune Diseases/immunology , Forkhead Transcription Factors/analysis , /analysis , T-Lymphocytes, Regulatory/immunology , Thymus Gland/immunology , Age Factors , /analysis , /analysis , Receptors, Antigen, T-Cell/metabolism , T-Lymphocytes, Regulatory/metabolism , Thymus Gland/metabolismABSTRACT
The radioactive iodine has been used with great value as a diagnostic and therapeutic method in patients with differentiated thyroid carcinoma previously submitted to total thyroidectomy. False-positive whole-body scans may occur due to misinterpretation of the physiologic distribution of the radioisotope or lack of knowledge on the existence of other pathologies that could eventually present radioiodine uptake. Thymic uptake is an uncommon cause of false-positive whole-body scan, and the mechanism through which it occurs is not completely understood. The present paper reports five cases of patients with differentiated thyroid cancer who presented a mediastinum uptake of radioiodine in a whole-body scan during follow-up. The patients had either histological or radiological confirmation of the presence of residual thymus gland. It is very important to know about the possibility of iodine uptake by the thymus in order to avoid unnecessary treatment, such as surgery or radioiodine therapy.
O iodo radioativo tem sido utilizado com grande valia como método diagnóstico e terapêutico em pacientes com carcinoma diferenciado de tireoide previamente submetidos à tireoidectomia total. Resultados falso-positivos na pesquisa de corpo inteiro (PCI) podem ocorrer por má interpretação da distribuição fisiológica do radioisótopo ou por não conhecimento da existência de outras patologias que podem eventualmente captar o radioiodo. Captação pelo timo é uma causa incomum de resultado falso-positivo e o mecanismo pelo qual ocorre não é totalmente esclarecido. O presente trabalho relata cinco casos que apresentaram PCI positiva em mediastino durante o seguimento, com comprovação histológica ou tomográfica sugestiva de timo. Ressalta-se a importância do conhecimento dessa possível causa de falso-positivo a fim de se evitar tratamentos desnecessários.
Subject(s)
Adult , Aged , Female , Humans , Middle Aged , Carcinoma , Iodine Radioisotopes/pharmacokinetics , Mediastinal Neoplasms , Thymus Gland/metabolism , Thyroid Neoplasms/metabolism , Carcinoma/metabolism , Carcinoma/radiotherapy , False Positive Reactions , Iodine Radioisotopes , Iodine Radioisotopes/therapeutic use , Mediastinal Neoplasms/secondary , Thymus Gland , Thyroid Neoplasms , Thyroid Neoplasms/radiotherapy , Whole Body ImagingABSTRACT
A non-toxic dose of abrin, (1.25 microg/kg body wt) consecutively for five days in normal mice stimulated specific humoral responses. A noticeable increase was observed in total leucocyte count, lymphocytosis, weights of spleen and thymus, circulating antibody titre, antibody forming cells, bone marrow cellularity and alpha-esterase positive bone marrow cells. The results suggest that abrin can potentiate the humoral immune response of the host.
Subject(s)
Abrin/pharmacology , Abrus/chemistry , Adjuvants, Immunologic/pharmacology , Animals , Antibody Formation/drug effects , Bone Marrow Cells/drug effects , Esterases/metabolism , Female , Immunity, Cellular/drug effects , Leukocyte Count , Lymphocytosis/chemically induced , Mice , Mice, Inbred BALB C , Organ Size/drug effects , Seeds/chemistry , Spleen/metabolism , Stem Cells/drug effects , Thymus Gland/metabolismABSTRACT
El objetivo de este trabajo fue analizar los efectos provocados por la administración de una dieta con un desequilibrio en el perfil de aminoácidos indispensables sobre el contenido de DNA y la actividad de ADA y PNP en timo de ratas con desnutrición precoz al destete y durante 18 días y la posterior realimentación. Ratas de la cepa Wistar (14-16 crías por madre) recibieron a partir del destete 18 días, luego fueron alimentadas con dieta conteniendo caseína (20 por ciento) de protéina durante 20 días (R). Como control se utilizaron ratas de igual edad que recibierondesde el destete dieta stock de vivero (C). Al finalizar la experiencia se extrajo y pesó el timo, determinándose el contenido de DNA y la actividad de las enzimas ADA y PNP. La administración de proteína de harina de maíz provocó una disminución en el contenido de DNA y aumento en la actividad de ADA y PNP. La realimentación con una dieta que aportaba de proteína de alta calidad y en alta concentración, revirtió dicho efecto
Subject(s)
Animals , Rats , Nutrition Disorders/complications , Rats, Wistar , Thymus Gland/metabolism , Adenosine Deaminase/analysis , Nutrition Rehabilitation , Dietary Proteins/metabolism , Purine-Nucleoside Phosphorylase/analysisABSTRACT
Thiobarbituric acid reactant substances (TBARs) content, and the activities of glucose-6-phosphate dehydrogenase (G6PDh), citrate synthase (CS), Cu/Zn- and Mn-superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPX) were measured in the lymphoid organs (thymus, spleen, and mesenteric lymph nodes (MLN)) and skeletal muscles (gastrocnemius and soleus) of adrenodemedullated (ADM) rats. The results were compared with those obtained for sham-operated rats. TBARs content was reduced by adrenodemedullation in the lymphoid organs (MLN (28 percent), thymus (40 percent) and spleen (42 percent)) and gastrocnemius muscle (67 percent). G6PDh activity was enhanced in the MLN (69 percent) and reduced in the spleen (28 percent) and soleus muscle (75 percent). CS activity was reduced in all tissues (MLN (75 percent), spleen (71 percent), gastrocnemius (61 percent) and soleus (43 percent)), except in the thymus which displayed an increment of 56 percent. Cu/Zn-SOD activity was increased in the MLN (126 percent), thymus (223 percent), spleen (80 percent) and gastrocnemius muscle (360 percent) and was reduced in the soleus muscle (31 percent). Mn-SOD activity was decreased in the MLN (67 percent) and spleen (26 percent) and increased in the thymus (142 percent), whereas catalase activity was reduced in the MLN (76 percent), thymus (54 percent) and soleus muscle (47 percent). It is particularly noteworthy that in ADM rats the activity of glutathione peroxidase was not detectable by the method used. These data are consistent with the possibility that epinephrine might play a role in the oxidative stress of the lymphoid organs. Whether this fact represents an important mechanism for the establishment of impaired immune function during stress remains to be elucidated
Subject(s)
Animals , Rats , Male , Adrenal Medulla/surgery , Catalase/metabolism , Glutathione Peroxidase/metabolism , Lymphoid Tissue/metabolism , Muscle, Skeletal/metabolism , Superoxide Dismutase/metabolism , Thiobarbituric Acid Reactive Substances/metabolism , Catalase/analysis , Glutathione Peroxidase/analysis , Lymph Nodes/metabolism , Mesentery/metabolism , Rats, Wistar , Spleen/metabolism , Superoxide Dismutase/analysis , Thiobarbituric Acid Reactive Substances/analysis , Thymus Gland/metabolismABSTRACT
Mouse spleen cells activated in a mixed lymphocyte reaction release a soluble factor, which induces a significant proliferative response in fresh mouse spleen cells. This proliferation inducing factor (PIF) was found to be heat stable (90 degrees C for 45 min) and also resistant to trypsin or chymotrypsin treatment. By using a sizing HPLC column, the molecular weight of PIF appears to be 25 kDa. Mouse spleen cells treated with anti-thy-1 + complement lost Con-A induced proliferative responses but responded well to PIF. B cell depleted spleen cells obtained by negative selection panning, did not respond to PIF. These results indicate that B cells proliferated in response to PIF. Polymixin-B, which blocks the B cell proliferative response to LPS, did not inhibit PIF induced proliferation.
Subject(s)
Mice , Animals , B-Lymphocytes/physiology , B-Lymphocytes/drug effects , Bone Marrow/metabolism , Cell Division/physiology , Chromatography, High Pressure Liquid , Chymotrypsin/pharmacology , Dose-Response Relationship, Drug , Growth Substances/pharmacology , Growth Substances/chemistry , Hot Temperature , Mice, Inbred BALB C , Mice, Inbred C57BL , Molecular Weight , Polymyxin B/pharmacology , Protein Denaturation , Spleen/metabolism , Thymus Gland/metabolism , Trypsin/pharmacologyABSTRACT
A growing number of investigators consider extracellular matrix (ECM) proteins to be determinant factors in lymphocyte positioning and activation. One major ECM component is laminin, which is constitutively expressed in the thymus as well as in thymus-dependent areas of peripheral lymphoid organs. In the thymus, laminin is produced by epithelial and dendritic cells, and appears to mediate interactions with thymocytes through specific laminin receptors, in particular the integrin VLA-6. This receptor is also expressed by peripheral T cells, and is apparently involved in effector T cell migration and activation. We showed that CD4+ T lymphocytes from chronic chagasic mice exhibited an increase in the absolute and relative number of cells with high VLA-6 expression. Additionally, it is likely that VLA-6/laminin interactions are required for the development of the CD4+ T cell-dependent anti-myocardial autoreactive process that occurs in these animals. Lastly, laminin can bind to some cytokines, a fact that may represent an additional mechanism by which this extracellular matrix component modulates the behavior of T lymphocytes. Taken together, the present data strongly indicate that interactions involving laminin and VLA-6 are functionally linked to relevant events in T cell physiology, comprising entrance of pro-thymocytes into the thymus, intrathymic T cell migration and differentiation, as well as the functioning of mature T lymphocytes, including effector cells.
Subject(s)
Mice , Humans , Animals , Autoimmunity/physiology , Cytokines/immunology , In Vitro Techniques , Laminin/immunology , Lymphoid Tissue/metabolism , Receptors, Laminin/immunology , T-Lymphocytes/immunology , Chagas Disease/immunology , Laminin/analogs & derivatives , Thymus Gland/metabolism , Trypanosoma cruzi/immunologyABSTRACT
Trabajos previos han demostrado que la deficiencia proteica leve o severa al destete provoca el franado de la proliferación y maduración celular del timo de ratas en crecimiento. El objetivo de este trabajo fue estudiar el efecto de la administración, durante período corto o largo, de dieta al 7,5% de proteína de maíz sobre el timo de ratas Wistar con deficiencia proteica leve o severa al destete. Como control se utilizaron ratas deplecionadas que recibieron dieta a base de caseína a igual concentración y tiempo. Se observó que la ingesta proteica completa, el peso corporal y el peso y número total de células del timo de los grupos experimentales fueron significativamente inferiores que sus respectivos controles, alcanzando valores semejantes a sus respectivos grupos deplecionados. Esto indica que la administración de dieta de baja calidad proteica ejerce un efecto que perpetúa el daño provocado por la depleción proteica leve o severa sobre el timo de ratas al destete