Pharmacological inhibition of PDGF-C/neuropilin-1 interaction: A novel strategy to reduce melanoma metastatic potential.

Activation of neuropilin-1 (NRP-1) by platelet derived growth factor (PDGF)-C sustains melanoma invasiveness. Therefore, in the search of novel agents capable of reducing melanoma spreading, PDGF-C/NRP-1 interaction was investigated as a potential druggable target. Since the PDGF-C region involved in NRP-1 binding is not yet known, based on the sequence and structural homology between PDGF-C and vascular endothelial growth factor-A (VEGF-A), we hypothesized that the NRP-1 b1 domain region involved in the interaction with VEGF-A might also be required for PDGF-C binding. Hence, this region was selected from the protein crystal structure and used as target in the molecular docking procedure. In the following virtual screening, compounds from a DrugBank database were used as query ligands to identify agents potentially capable of disrupting NRP-1/PDGF-C interaction. Among the top 45 candidates with the highest affinity, five drugs were selected based on the safety profile, lack of hormonal effects, and current availability in the market: the antipsychotic pimozide, antidiabetic gliclazide, antiallergic cromolyn sodium, anticancer tyrosine kinase inhibitor entrectinib, and antihistamine azelastine. Analysis of drug influence on PDGF-C in vitro binding to NRP-1 and PDGF-C induced migration of human melanoma cells expressing NRP-1, indicated gliclazide and entrectinib as the most specific agents that were active at clinically achievable and non-toxic concentrations. Both drugs also reverted PDGF-C ability to stimulate extracellular matrix invasion by melanoma cells resistant to BRAF inhibitors. The inhibitory effect on tumor cell motility involved a decrease of p130Cas phosphorylation, a signal transduction pathway activated by PDGF-C-mediated stimulation of NRP-1.

Endothelial PDGF-D contributes to neurovascular protection after ischemic stroke by rescuing pericyte functions.

Ischemic stroke induces neovascularization of the injured tissue as an attempt to promote structural repair and neurological recovery. Angiogenesis is regulated by pericytes that potently react to ischemic stroke stressors, ranging from death to dysfunction. Platelet-derived growth factor (PDGF) receptor (PDGFR)ß controls pericyte survival, migration, and interaction with brain endothelial cells. PDGF-D a specific ligand of PDGFRß is expressed in the brain, yet its regulation and role in ischemic stroke pathobiology remains unexplored. Using experimental ischemic stroke mouse model, we found that PDGF-D is transiently induced in brain endothelial cells at the injury site in the subacute phase. To investigate the biological significance of PDGF-D post-ischemic stroke regulation, its subacute expression was either downregulated using siRNA or upregulated using an active recombinant form. Attenuation of PDGF-D subacute induction exacerbates neuronal loss, impairs microvascular density, alters vascular permeability, and increases microvascular stalling. Increasing PDGF-D subacute bioavailability rescues neuronal survival and improves neurological recovery. PDGF-D subacute enhanced bioavailability promotes stable neovascularization of the injured tissue and improves brain perfusion. Notably, PDGF-D enhanced bioavailability improves pericyte association with brain endothelial cells. Cell-based assays using human brain pericyte and brain endothelial cells exposed to ischemia-like conditions were applied to investigate the underlying mechanisms. PDGF-D stimulation attenuates pericyte loss and fibrotic transition, while increasing the secretion of pro-angiogenic and vascular protective factors. Moreover, PDGF-D stimulates pericyte migration required for optimal endothelial coverage and promotes angiogenesis. Our study unravels new insights into PDGF-D contribution to neurovascular protection after ischemic stroke by rescuing the functions of pericytes.

The role of THBS1 and PDGFD in the immune microenvironment of Helicobacter pylori-associated gastric cancer.

BACKGROUND AND STUDY AIMS: Immunotherapy has emerged as a hot topic in cancer treatment in recent years and has also shown potential in the treatment of Helicobacter pylori-associated gastric cancer. However, there is still a need to identify potential immunotherapy targets. MATERIAL AND METHODS: We used the GSE116312 dataset of Helicobacter pylori-associated gastric cancer to identify differentially expressed genes, which were then overlapped with immune genes from the ImmPort database. The identified immune genes were used to classify gastric cancer samples and evaluate the relationship between classification and tumor mutations, as well as immune infiltration. An immune gene-based prognostic model was constructed, and the expression levels of the genes involved in constructing the model were explored in the tumor immune microenvironment. RESULTS: We successfully identified 60 immune genes and classified gastric cancer samples into two subtypes, which showed differences in prognosis, tumor mutations, immune checkpoint expression, and immune cell infiltration. Subsequently, we constructed an immune prognostic model consisting of THBS1 and PDGFD, which showed significant associations with macrophages and fibroblasts. CONCLUSION: We identified abnormal expression of THBS1 and PDGFD in cancer-associated fibroblasts (CAFs) within the tumor immune microenvironment, suggesting their potential as therapeutic targets.

Impact of glioma peritumoral edema, tumor size, and tumor location on alternating electric fields (AEF) therapy in realistic 3D rat glioma models: a computational study.

Objective.Alternating electric fields (AEF) therapy is a treatment modality for patients with glioblastoma. Tumor characteristics such as size, location, and extent of peritumoral edema may affect the AEF strength and distribution. We evaluated the sensitivity of the AEFs in a realistic 3D rat glioma model with respect to these properties.Approach.The electric properties of the peritumoral edema were varied based on calculated and literature-reported values. Models with different tumor composition, size, and location were created. The resulting AEFs were evaluated in 3D rat glioma models.Main results.In all cases, a pair of 5 mm diameter electrodes induced an average field strength >1 V cm-1. The simulation results showed that a negative relationship between edema conductivity and field strength was found. As the tumor core size was increased, the average field strength increased while the fraction of the shell achieving >1.5 V cm-1decreased. Increasing peritumoral edema thickness decreased the shell's mean field strength. Compared to rostrally/caudally, shifting the tumor location laterally/medially and ventrally (with respect to the electrodes) caused higher deviation in field strength.Significance.This study identifies tumor properties that are key drivers influencing AEF strength and distribution. The findings might be potential preclinical implications.

Serum levels of PDGF-CC as a potential biomarker for the diagnosis of Kawasaki disease.

BACKGROUND: Kawasaki disease (KD) is an acute systemic vasculitis of unknown etiology that predominantly affects children, and no specific diagnostic biomarkers for KD are available. Platelet-derived growth factor CC (PDGF-CC) is a peptide with angiogenic properties that has been amply demonstrated to play a critical role in the cardiovascular system. This study aimed to investigate the serum expression of PDGF-CC in children with KD and to evaluate the ability of PDGF-CC to diagnose KD. METHODS: A total of 96 subjects, including 59 KD patients, 17 febrile controls (FC), and 20 healthy controls (HC), were enrolled. Serum levels of PDGF-CC were measured via enzyme-linked immunosorbent assay. The associations between PDGF-CC and clinical laboratory parameters were investigated by correlation analysis. The diagnostic performance was assessed by receiver operating characteristic (ROC) curve analysis. RESULTS: Serum PDGF-CC levels in the KD group were significantly higher than in the FC and HC groups. Serum PDGF-CC levels in the KD group were positively correlated with white blood cell counts, percentage of neutrophils, IL-2, IL-12p70, TNF-α, and IL-1ß levels, and negatively correlated with the percentage of lymphocytes. In the analysis of ROC curves, the area under the curve was 0.796 (95% confidence interval 0.688-0.880; P < 0.0001) for PDGF-CC and increased to 0.900 (95% confidence interval 0.808-0.957; P < 0.0001) in combination with white blood cell counts and C-reactive protein. CONCLUSIONS: PDGF-CC is a potential biomarker for KD diagnosis, and the combination with white blood cell counts and C-reactive protein can further improve diagnostic performance.

Neutrófilos: aspectos clássicos, plasticidade e novas funções imunorregulatórias / Neutrophils: classical aspects, plasticity and new immunoregulatory functions

Os neutrófilos são o tipo leucocitário mais abundante em circulação, constituem a primeira linha de reconhecimento e defesa contra agentes infecciosos no tecido, tradicionalmente iniciam uma inflamação aguda e são responsáveis por uma resposta imune pró-inflamatória eficaz. Recentemente essas células vêm sendo descritas como complexas e com uma vasta capacidade de desempenhar funções especializadas, interagem com macrófagos, células dendríticas, e linfócitos TCD4+. É importante reconsiderar sua importância como célula efetora na imunidade adaptativa e as novas perspectivas sobre as funções imunorregulatórias nas reações imunológicas normais e patológicas. Nesta revisão, nosso foco é mostrar os aspectos clássicos e discutir o novo neutrófilo, expondo o que tem sido descrito na literatura recentemente.

Neutrophils are the most abundant leukocyte in blood and represent the first line recognition and defense against infectious agents in tissues, traditionally begin an acute inflammation and are responsible by an effective proinflammatory reaction. Recently these cells have been described with a large capacity to perform specialized functions like interaction with macrophages, dendritic cells and CD4 + T lymphocytes. It is important to reconsider its importance as effector cells in adaptive immunity and new perspectives on the immunoregulatory functions in normal and pathological immune responses. In this review, the focus is to show the classic aspects and discuss the "new neutrophils", exposing what has been described in literature recently

Practices in primary health care oriented toward the harmful consumption of drugs / Las prácticas en la atención primaria de salud relacionados con el consumo nocivo de las drogas / Práticas na Atenção Básica voltadas para o consumo prejudicial de drogas

Objective To analyze the practices of primary care focused on the harmful consumption of drugs. Method This is a qualitative study, developed with a dialectical-critical approach. Data collection was carried out through semi-structured interviews with 10 employees of a basic health unit (UBS). Results The demands are not accepted, and if they go beyond the barriers shaped by the historical absence of health care practices for drug users and moralistic and preconceived ideologies, they are not reinterpreted as health needs; practices that meet these demands and go beyond the barriers are poor; the functionalist approach, which explains drug use as a disease and considers drug users as deviants, supports the few existing practices. Conclusion primary health care is mistakenly focused on addiction; it lacks structural elements of the production process in health and internal dynamics of the working processes that would foster the development of collective practices. .

Objetivo El estudio tiene como objetivo analizar las prácticas de atención primaria dirigidos a lo consumo prejudicial de drogas. Método Se trata de un estudio cualitativo, desarrollado en la perspectiva dialéctica crítica. La recolección de datos se realizó a través de entrevistas semiestructuradas con 10 empleados de una Unidad Básica de Salud. Resultados Muestran que: las demandas no son aceptadas, y si van más allá de las barreras - formadas por la ausencia histórica de la práctica de la atención de salud para los consumidores de drogas y las ideologías morales y preconcebidas -, no son reinterpretados como necesidades de salud; las prácticas que satisfagan esas demandas son pobres; detrás de estas escasas prácticas, está la perspectiva funcionalista, que considera el uso de drogas como una enfermedad y los usuarios de drogas como desviados; los trabajadores valoran la formación clínica y culpan a los usuarios por los problemas que enfrentan. Conclusión Se pode concluir que la atención primaria: es equívoca hacia el objeto de la dependencia; carece de los elementos estructurales del proceso de producción en la salud y las dinámicas internas de los procesos de trabajo que fomenten el desarrollo de las prácticas colectivas.

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Objetivo Analisar as práticas de atenção básica voltadas ao consumo prejudicial de drogas. Método Estudo qualitativo, desenvolvido na perspectiva dialético-crítica. A coleta de dados foi realizada através de entrevistas semiestruturadas com 10 trabalhadores de uma Unidade Básica de Saúde (UBS). Resultados As demandas não são acolhidas e, quando ultrapassam as barreiras - conformadas pela ausência histórica de práticas de atenção à saúde ao usuário de drogas e por ideologias moralistas e preconceituosas -, não são reinterpretadas como necessidades de saúde; as práticas que atendem essas demandas são precárias; a perspectiva funcionalista, que compreende o consumo de drogas como doença e considera usuários de drogas como desviantes, embasa as escassas práticas existentes. Conclusão A atenção básica encontra-se equivocamente voltada para a dependência; carece de elementos estruturais do processo de produção em saúde e da dinamicidade interna aos processos de trabalho, que favoreceriam o desenvolvimento de práticas coletivas. .

Emancipatory practices of nurses in primary health care: the home visit as an instrument of health needs assessment / Prácticas emancipadoras del enfermero en la atención primaria de salud: la visita domiciliaria como instrumento de reconocimiento de necesidades de la salud / Práticas emancipatórias de enfermeiros na Atenção Básica à Saúde: a visita domiciliar como instrumento de reconhecimento de necessidades de saúde

Objective Identify nurses’ emancipatory practices in primary care, to contribute to the improvement of health care. Method A case study type social research of qualitative nature, in which nurses of a primary health care service unit in São Paulo were interviewed. Results The home visit was identified as a nursing practice possible to be expanded in order to identify social determinants of health, triggering emancipatory practices in the service. This expansion occurred because the design of health care labour intended by the service team changed its focus from the traditional object of health services, the disease. Conclusion First, it is advocated that social policies lead projects with the purpose of improving health needs. On the other hand, the daily labour needs to provide opportunities for reflection and discussion of healthcare projects, leading workers to propose labour-processes targeted to both the social determinants of health and people’s illness. .

Objetivo Identificar las prácticas emancipadoras de enfermeras en Unidad de Salud Familiar fueron el objeto de este estudio. Método La investigación social cualitativa tipo estúdio de caso. Fueron entrevistados enfermeros de una Unidad de Salud Familiar en Sao Paulo. Resultados Se identificó que la Visita Domiciliaria ha ampliado su alcance y identificado determinantes del proceso salud-enfermedad, lo que provocó en la Unidad de Salud Familiar prácticas emancipadoras. Esta expansión se produjo debido a que el diseño de la atención en propósito por la USF amplió el tradicional objeto de los servicios de salud. Conclusión Se aboga que las directrices de las políticas sociales basen proyectos que tengan como fin el mejoramiento de las necesidades de salud y que el trabajo diario proporcione la reflexión y discusión de los proyectos de atención, para proponer prácticas que enfoquen en los determinantes del proceso salud-enfermedad, tanto cuanto en sus resultados - la enfermedad en el cuerpo individual. .

Objetivo Identificar as práticas emancipatórias de enfermeiros da Atenção Primária, com a finalidade de contribuir para o aprimoramento do cuidado em saúde. Método Pesquisa social de natureza qualitativa, do tipo estudo de caso. Foram entrevistados os enfermeiros de uma Unidade de Saúde da Família em São Paulo. Resultados Identificou-se que a visita domiciliária, prática protocolar, ampliou seu escopo e identificou determinantes do processo saúde-doença, desencadeando na Unidade de Saúde da Família práticas emancipatórias. Essa ampliação ocorreu porque o projeto de cuidado intencionalizado ampliou o objeto tradicional dos serviços de saúde. Conclusão Advoga-se que as diretrizes das políticas sociais ancorem projetos que tomem como finalidade o aprimoramento das necessidades de saúde e que o cotidiano do trabalho proporcione reflexão e discussão dos projetos de cuidado, para intencionalizar práticas que incidam nos determinantes do processo saúde-doença, tanto quanto nos resultados - a doença expressa no corpo individual. .

Linfo-histiocitose hemofagocítica: tratamento com plasmaferese e gamaglobulina endovenosa / Haemophagocytic lymphohistiocitosis: treatment with plasmapheresis and intravenous immunoglobulin

O presente relato de caso tem como finalidade chamar a atenção de doença grave que frequentemente é confundida com septicemia, no entanto o mecanismo etiológico é decorrente de defeitos genéticos ou associados à resposta imunológica exagerada, decorrente de ação citotóxica de linfócitos T CD8 e histiócitos, acarretando proliferação clonal e ativação de células ”natural killer” (NK). Uma tempestade de linfocinas acontece e como consequência é iniciada uma incontrolável hemofagocitose de todos os elementos sanguíneos, terminando pela infecção secundária do organismo por ausência de destruição de patógenos. A maioria dos casos termina pela morte do paciente; no entanto, relatamos nesse caso a possibilidade de incluirmos a plasmaferese como forma de retirar as linfocinas circulantes, razão do estímulo à destruição celular. O tratamento concomitante com alta dose de imunoglobulina endovenosa também foi realizado

The purpose of the present case report is to call attention to a serious disease that is often mistaken with septicemia, although its etiological mechanism results from genetic defects or is associated with an immune over-reaction, resulting from cytotoxic action of CD8 T lymphocytes and histiocytes, causing clonal proliferation and activation of “natural killer” (NK) cells. There occurs a storm of lymphokines and, as a consequence, an uncontrollable hemophagocytosis of all blood elements, which leads to secondary infection of the organism because of absence of pathogens destruction. Although most of the cases end up in death, in this case we report the possibility of including plasmapheresis as a way to remove the circulating lymphokines, the reason for stimulation of cell destruction. Co-treatment with high dose of intravenous immunoglobulin was performed too

El bacilo de Calmette-Guérin como inmunomodulador en el cáncer de vejiga / The bacillus Calmette-Guérin as immunomodulator in bladder cancer

The bacillus Calmette-Guérin (BCG) is regarded as the most successful immunotherapy against superficial bladder carcinoma recurrences to date. BCG intravesical therapy for superficial bladder cancer has shown its efficacy and advantage over classical therapeutic strategies. This efficacy is based on complex and long lasting immune activation. The initial step is the binding of mycobacteria to the urothelial lining, which depends on the interaction of a fibronectin attachment protein on the bacteria surface with fibronectin in the bladder wall. Granulocytes and other immunocompetent mononuclear cells became attracted to the bladder wall and a cascade of proinflammatory cytokines sustains the immune response. In the bladder wall a largely TH1 based cytokine milieu and granuloma-like cellular foci are established. Within this scenario, the most important effector mechanisms might be the direct antitumor activity of interferons and the cytotoxic activity of NK cells. Current treatment consists of an induction phase of 6 weeks and a maintenance dose schedule of 3 weeks every three months up to 36. The majority of patients present adverse events related to dose administration due to bladder inflammatory response and on only a few ocassions, there are mayor complications like granulomatous prostatitis. Among all the neoplasms only in superficial bladder cancer the BCG is proved to be effective.

El bacilo de Calmette-Guérin (BCG) es considerado como la inmunoterapia más exitosa en contra del carcinoma de vejiga superficial recidivante hasta la fecha. La terapia intravesical con el BCG para el cáncer superficial de vejiga ha mostrado su eficacia y ventaja sobre otras estrategias terapéuticas; esta eficacia está basada en una compleja y larga duración de la activación inmunológica. El paso inicial es la unión de la micobacteria al urotelio, la cual depende de la interacción con la fibronectina de la bacteria con la fibronectina del urotelio. Los granulocitos y otras células mononucleares inmunocompetentes son atraídos hacia la pared vesical, así activando una cascada inmunológica a través de secreción de diversas citocinas, quienes estimulan a las células asesinas naturales (NK) activadas por el BCG, las cuales son capaces de diferenciar células neoplásicas y del epitelio urinario normal. En la pared vesical se encuentra un medio ambiente de citocinas principalmente del tipo TH1 y se forman focos celulares similares a granulomas. Dentro de este escenario los mecanismos efectores más importantes parecen ser la actividad antitumoral directa de los interferones y la actividad citotóxicas de las células NK. El tratamiento actual consiste en la administración intravesical del bacilo en una primera fase de inducción de seis semanas y posteriormente dosis de mantenimiento cada tres meses hasta los 36 meses. La mayoría de los pacientes presentan efectos adversos locales secundarios a la reacción inflamatoria y en un porcentaje muy pequeño se presentan complicaciones mayores como prostatitis y orquiepididimitis granulomatosa. De entre todas estas neoplasias sólo en el cáncer superficial de vejiga se han demostrado resultados satisfactorios con el empleo del BCG.

Mitochondria, calcium and pro-apoptotic proteins as mediators in cell death signaling

Cellular Ca2+ signals are crucial in the control of most physiological processes, cell injury and programmed cell death through the regulation of a number of Ca2+-dependent enzymes such as phospholipases, proteases, and nucleases. Mitochondria along with the endoplasmic reticulum play pivotal roles in regulating intracellular Ca2+ content. Mitochondria are endowed with multiple Ca2+ transport mechanisms by which they take up and release Ca2+ across their inner membrane. During cellular Ca2+ overload, mitochondria take up cytosolic Ca2+, which in turn induces opening of permeability transition pores and disrupts the mitochondrial membrane potential (Dym). The collapse of Dym along with the release of cytochrome c from mitochondria is followed by the activation of caspases, nuclear fragmentation and cell death. Members of the Bcl-2 family are a group of proteins that play important roles in apoptosis regulation. Members of this family appear to differentially regulate intracellular Ca2+ level. Translocation of Bax, an apoptotic signaling protein, from the cytosol to the mitochondrial membrane is another step in this apoptosis signaling pathway

Edema cerebral em meningiomas: aspectos radiológicos e histopatológicos / Brain edema in meningiomas: radiological and histological factors

Diversos fatores têm sido associados ao desenvolvimento de edema peritumoral nos meningiomas. Foram estudados os aspectos radiológicos e anátomo-patológicos de 51 meningiomas intracranianos operados no Hospital Universitário Clementino Fraga Filho (HUCFF). Dois terços dos meningiomas apresentavam edema perilesional. O tamanho dos meningiomas correlacionou-se com a presença de edema, sendo mais frequente nos meningiomas grandes (>4cm). A localizaçäo parece, também, influenciar no desenvolvimento do edema peritumoral, sendo mais acentuado nos meningiomas da asa do esfenóide e incomum nos meningiomas do tubérculo selar. Os subtipos histológicos de meningioma näo se correlacionaram com a intensidade do edema peritumoral. Dos diversos mediadores químicos descritos na literatura recente relacionados ao desenvolvimento de edema peritumoral em tumores intracranianos, destaca-se o fator de crescimento do endotélio vascular (VEGF). A expressäo nos meningiomas do VEGF e de seu receptor flk-1 foi estudada com técnica imuno-histoquímica, demonstrando a sua expressäo nas células tumorais

Papel de mediadores solúveis na resposta imune em modelos de proteção contra o mycobacterium tuberculosis / Paper of soluble mediators in the immune reply in models of protection against mycobacterium tuberculosis

A imunoprofilaxia permanece como uma importante ferramenta para o controle da pandemia tuberculosa. Neste contexto, assume especial importância o estudo de marcadores que possam ser correlacionados à proteção contra a doença, tornando mais viável em termos de custo-benefício a avaliação de novas vacinas e imunoterápicos. A detecção de mediadores solúveis implicados na resposta contra a micobactéria pode revelar potenciais marcadores de proteção, além de constituir um método suficientemente simples para aplicação em grandes grupos populacionais. Escolheu-se avaliar a modulação de mediadores solúveis em duas situações-modelo identificadas com o desenvolvimento de uma resposta eficaz contra o bacilo na infecção humana: a tuberculose pleural, por ser uma forma que apresenta regressão espontânea dos sintomas, e a vacinação com o bacilo de Calmette-Guérin (BCG), que pode ser relacionada a altos índices de proteção pelo menos contra as formas mais graves da doença. Partindo dos pressupostos de que (1) os mecanismos de contenção do bacilo estimulados nestas duas situações estarão também implicados na resposta à infecção primária e (2) mediadores que apresentem uma variação significativa em ambos os estudos poderão ser úteis para estimar a eficácia de novas estratégias vacinais, nós avaliamos a evolução do perfil de mediadores solúveis nestes dois modelos de proteção contra o M. tuberculosis. Nos dois estudos foi possível identificar correlações entre os níveis de citocinas do tipo Th1. Em pacientes com tuberculose pleural, níveis diminuídos de IFN-y e TNF-a foram associados à regressão espontânea dos sintomas e à resolução da reação granulomatosa, sugerindo um papel da modulação negativa da resposta anti-micobacteriana na proteção contra a doença. Também foi evidenciada nos dois estudos a correlação entre os níveis de TNF-a e IL-10, sugerindo um papel para a IL-10 na modulação da resposta imune celular e provavelmente na limitação do dano tecidual associado a esta resposta. O trabalho reforça a aplicabilidade da investigação de mediadores solúveis para a estimativa da eficácia de novas estratégias vacinais, apontando como candidatos de interesse as citocinas IFN-y, TNF-a e IL-10, mediadores implicados em nossos estudos na proteção contra a infecção pelo M. tuberculosis.

The low efficiency of dendritic cells and macrophages from mice susceptible to Paracoccidioides brasiliensis in inducing a Th1 response

In the present study we evaluated T cell proliferation and Th lymphokine patterns in response to gp43 from Paracoccidioides brasiliensis presented by isolated dendritic cells from susceptible and resistant mice. T cell proliferation assays showed that dendritic cells from susceptible mice were less efficient than those from resistant mice. The pattern of T cell lymphokines stimulated by dendritic cells was always Th1, although the levels of IL-2 and IFN-gamma were lower in T cell cultures from susceptible mice. To determie whether different antigen-presenting cells such as macrophages and dendritic cells stimulated different concentrations of Th1 lymphokines, the production of IFN-gamma and IL-2 was measured. It was observed that dendritic cells were more efficient than macrophages in stimulating lymphoproliferation in resistant mice. However, no significant difference was observed for IFN-gamma or IL-2 production. When cells from susceptible mice were used, macrophages were more efficient in stimulating lymphoproliferation than dendritic cells, but no difference was observed in the production of Th1 cytokine. Taken together, these results suggest the lower efficiency of dendritic cells and macrophages from B10.A mice in stimulating T cells that secrete Th1 lymphokines in vitro, an effect that may be involved in the progression of the disease in vivo

Glicoproteína P en leucocitos de sangre periférica de individuos sanos / Glycoprotein P in peripheral blood leukocytes of healthy individual

El objetivo de este trabajo fue estudiar la distribución de la expresión de la Gp-P y su ARNm en sangre periférica de una amplia población de sujetos sanos para identificar probables diferencias individuales. Para ello se estudiaron un total de 126 muestras sanguíneas mediantes inmunofluorescencia directa, por citometría de flujo, con el anticuerpo monoclonal JSB1 conjugado con FITC. Los parámetros a evaluar fueron el número de células positivas (por ciento POS) e incorporación media de fluorescencia específica (IMFE). Posteriormente, se estudió el ARNm del gen MDR1 por RT-PCR. Los resultados mostraron que en aproximadamente el 82 por ciento de los individuos estudiados, la IMFE presentó valores entre 10 y 25 en las tres subpoblaciones celulares de sangre periférica; en los linfocitos y monocitos, se observó además que un grupo de donantes, no superior al 10 por ciento, presentaron valores de IMFE menores de 10 y mayores de 25. Entre los subpoblaciones celulares, el por ciento POS más elevado correspondió a los linfocitos (t de student; p<0.001). Los resultados del estudio de ARNm del gen MDR1 por TR-PCR mostró correlación con los valores obtenidos por citometría del flujo. Se concluye que el estudio de la Glicoproteína P en el leucocitos de sangre periférica en una población de individuos sanos, pone de manifiesto la existencia de variabilidad individual en los niveles de expresión, lo que hace suponer un condicionamiento genético de control de los niveles de expresión basal de la Gp-P

Inmunoprofilaxis contra la infección por Salmonella enteritidis en pollos de engorda mediante el uso de linfocinas / Immunoprophylaxis againts Salmonella enteritidis infection by lymphokines in broiler chicks

Se investigó el efecto del tratamiento profiláctico de pollos de engorda con productos solubles de linfocitos T estimulados con concanavalina-A, procedentes de aves inmunizadas con Eimeria tenella, sobre la invasión de órganos por Salmonella enteritidis. Los pollos fueron asignados de manera aleatoria en tres grupos: a) Grupo experimental (tratado, infectado con S. enteritidis); las aves fueron inyectadas intraperitonealmente al día de edad con linfocinas procedentes de aves inmunizadas con Eimeria tenella. Treinta minutos después de la inyección de linfocinas, las aves fueron desafiadas vía oral con 105 unidades formadoras de colonia de S. enteritidis; b) grupo testigo positivo (no tratado, infectado con S. enteritidis); y c) grupo testigo negativo (no tratado, no infectado con S. enteritidis). Todas las aves fueron sacrificadas 24 horas después del desafío y se realizó cultivo bacteriológico a partir de hígado, bazo y tonsilas cecales. La administración de linfocinas redujo significativamente (P<0.05) el crecimiento bacteriano en medio de cultivo a partir de muestras de hígado y bazo, pero no de tonsilas cecales (P>0.05). Estos resultados demuestran que el tratamiento profiláctico con linfocinas procedentes de aves inmunizadas con Eimeria tenella reduce la invasión a órganos por S. enteritidis, pero no impide la colonización intestinal en pollitos de engorda.

Os superantígenos e as doenças humanas / The superantigens and the human diseases

Os superantigenos são proteinas que exercem potente efeito no sistema imune. Como moléculas bifuncionais, eles permitem uma interação entre as moléculas MHC de classe II das células apresentadoras de antígeno e a região VB do receptor TCR de linfócitos, levando a uma intensa ativação destas células. Tal ativação pode ter diferentes consequencias, como proliferação, deleção ou indução de anergia celular. Os superantigenos podem ser expressos por uma grande variedade de microorganismos, como bactérias, vírus e algumas espécies de micoplasmas. Os superantígenos bacterianos mais bem caracterizados são as exotoxinas pirogênicas produzidas por Staphylococcus aureus e Streptococcus pyogenes, as quais estão envolvidas em muitas doenças, tais como a síndrome do choque tóxico, intoxicação alimentar, síndrome de Kawasaki e síndrome da pele escaldada estafilocócica. O tratamento dessas patologias pode ser feito com o uso de antibióticos, quando o diagnóstico for precoce. Em estágios mais avançados, tratamentos direcionados em bloquear o sistema imune são mais recomendados. Aplicações terapêuticas para as moléculas de superantígenos no tratamento do câncer e doenças infecciosas têm sido investigadas.