885 resultados para Cellular immunity


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Aquaculture has developed to become one of the fastest growing food producing sectors in the world.Today India is one among the major shrimp producing countries in the world.There are extensive and intensive shrimp culture practices. In extensive shrimp culture, shrimps are stocked at low densities (< 25 PLs m'2)in large ponds or tidal enclosures in which little or no management is exercised or possible. Farmers depend almost entirely on natural conditions in extensive cultures. Intensive shrimp culture is carried out in high densities (>200 PLs m'2). Much of the world shrimp production still comes from extensive culture.There is a growing demand for fish and marine products for human and animal consumption. This demand has led to rapid growth of aquaculture, which some times has been accompanied by ecological impacts and economic loss due to diseases. The expansion of shrimp culture always accompanies local environmental degradation and occurrence of diseases.Disease out breaks is recognised as a significant constraint to aquaculture production. Environmental factors, water quality, pollution due to effluent discharge and pathogenic invasion due to vertical and horizontal transmission are the main causes of shrimp disease out breaks. Nutritional imbalance, toxicant and other pollutants also account for the onset of diseases. pathogens include viruses, bacteria, fungi and parasites.Viruses are the most economically significant pathogens of the cultured shrimps world wide. Disease control in shrimp aquaculture should focus first on preventive measures for eliminating disease promoting factors.ln order to design prophylactic and proactive measures against shrimp diseases, it is mandatory to understand the immune make up of the cultivable species, its optimum culture conditions and the physico chemical parameters of the rearing environment. It has been proven beyond doubt that disease is an end result of complex interaction of environment, pathogen and the host animal. The aquatic environment is abounded with infectious microbes.The transmission of disease in this environment is extremely easy, especially under dense, culture conditions. Therefore, a better understanding of the immune responses of the cultured animal in relation to its environmental alterations and microbial invasions is essential indevising strategic measures against aquaculture loss due to diseases. This study accentuate the importance of proper and regular health monitoring in shrimps employing the most appropriate haematological biomarkers for application of suitable prophylactic measures in order to avoid serious health hazards in shrimp culture systems.

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El ejercicio físico de intensidad moderada a exhaustiva genera diferentes tipos de respuestas en un individuo, dichas repuestas dependen del tipo y la duración del ejercicio y de si son agudas o crónicas. A nivel funcional afecta los diferentes sistemas corporales, pero dentro de los relativamente menos tenidos en cuenta está el hematológico. De este último la literatura refiere cambios en el volumen sanguíneo, en la actividad y poblaciones de glóbulos blancos, así como modificaciones en la inmunidad celular y humoral, y en el conteo y forma de las plaquetas. Así mismo, y como resultado de estos cambios, también se ha podido determinar cómo el ejercicio modifica desfavorablemente el tiempo de vida de los eritrocitos generando una aparente anemia, que ha sido materia de amplia discusión y que puede, dentro de múltiples factores, estar asociada a hemólisis, la cual a su vez se relaciona con diferentes factores dentro de los que se destacan mecanismos como el osmótico o el estrés oxidativo; sin embargo, lo cierto es que todos estos eventos están fuertemente relacionadas entre sí y pueden determinar y redundar en un menor rendimiento en el practicante de una determinada actividad física, y por supuesto de un deportista.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Paracoccidioidomycosis (PCM) has two main clinical presentations, a chronic form (CF) and an acute, more severe form (AF). The AF is associated with a more marked dysfunction of the patient's immune response, and a distinct anti-Paracoccidioides brasiliensis immunoglobulin (Ig)A and IgG antibody subclass expression, compared with that seen in the CF. In this study we investigated the presence of IgE antibodies against the main P. brasiliensis antigen (a 43-kDa molecule) in the serum of PCM patients using an enzyme-linked immunosorbent assay. We found that 100% of the AF patients (n = 16) produced IgE antibodies, mostly at high levels, whereas only 9 (27%) out of 33 CF patients produced this isotype. Interestingly, these nine patients presented higher serological titers on the counter-immunoelectrophoresis assays than did those who did not produce IgE; a finding that suggests that they had a relatively more severe disease. As IgE is a characteristic feature of the AF patients, and switching to a positive IgE response is dependent on interleukin-4, our results support the notion that the relatively more severe impairment of cellular immunity in the AF is probably related to a Th-2 pattern of immune response.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Cinqüenta camundongos suíços, brancos, com quatro semanas de idade, foram inoculados com 5x10(5) formas leveduriformes, viáveis de Paracoccidiodes brasiliensis (cepa 18). Dez destes animais tinham sido previamente imunizados com antígeno particulado de P. brasiliensis, durante quatro semanas, por injeção intradérmica. Os controles consistiram de 10 animais que foram somente imunizados e 10 inoculados com solução salina estéril. Os animais foram sacrificados após 2, 4, 7, 11 e 16 semanas. Estudamos: 1) resposta de hipersensibilidade retardada medida pelo teste do coxim plantar, 24 horas antes do sacrifício; 2) anticorpo- gênese específica avaliada pelo teste de imunodifusão dupla em gel de ágar; 3) histopatologia dos pulmões, fígado, baço, supra-renal e rins. Observamos: 1) os animais imunizados desenvolveram resposta imunecelular mais intensa que os infectados; 2) a infecção deprimiu a resposta imunecelular dos animais imunizados; 3) a histopatologia da infecção endovenosa revelou inflamação granulomatosa sistêmica e progressiva. Os animais infectados após imunização prévia apresentaram inflamação pulmonar menos extensa, com granulomas menores e com reduzido número de fungos. O presente modelo murino de paracoccidioidomicose mimetiza alguns achados da forma humana subaguda da micose (doença sistêmica com depressão da imunidade celular). O esquema de imunização extrapulmonar utilizado foi capaz de induzir certo grau de proteção do pulmão contra um desafio infeccioso pelo P. brasiliensis.

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Responses: of vaccination and treatment to immunomodulators against rabies in mice were evaluated through macrophage inhibition factor (MIF), intra-pad inoculation (IPI) and serum neutralization (SN) tests and by the detection of gamma-interferon (IFN-gamma). Onco-BCG, Avridine and Propionibacterium acnes were administered to groups of mice. Higher survival rates were found in animals treated with P. acnes. Lower levels of IFN-gamma were observed in the groups of infected and vaccinated mice. The IPI was not effective on detecting the response of delayed-type hypersensitivity. Vaccine induced in the infected animals a more intense response to MIF reaction. (C) 1998 Elsevier B.V. Ltd. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Subcutaneous heat-coagulated egg white implants (EWI) induce chronic, intense local eosinophilia in mice, followed by asthma-like responses to airway ovalbumin challenge. Our goal was to define the mechanisms of selective eosinophil accumulation in the EWI model. EWI carriers were challenged i.p. with ovalbumin and the contributions of cellular immunity and inflammatory mediators to the resulting leukocyte accumulation were defined through cell transfer and pharmacological inhibition protocols. Eosinophil recruitment required Major Histocompatibility Complex Class It expression, and was abolished by the leukotriene B4 (LTB4) receptor antagonist CP 105.696, the 5-lipoxygenase inhibitor BWA4C and the 5-lipoxygenase activating protein inhibitor MK886. Eosinophil recruitment in EWI carriers followed transfer of: a) CD4(+) (but not CD4(-)) cells, harvested from EWI donors and restimulated ex vivo; b) their cell-free supernatants, containing LTB4. Restimulation in the presence of MK886 was ineffective. CC chemokine receptor ligand (CCL)5 and CCL2 were induced by ovalbumin challenge in vivo. mRNA for CCL17 and CCL11 was induced in ovalbumin-restimulated CD4(+) cells ex vivo. MK886 blocked induction of CCL17 Pretreatment of EWI carriers with MK886 eliminated the effectiveness of exogenously administered CCL11, CCL2 and CCL5. In conclusion, chemokine-producing, ovalburnin-restimulated CD4(+) cells initiate eosinophil recruitment which is strictly dependent on LTB4 production. (C) 2008 Elsevier B.V. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The polysaccharides beta-glucans occur as a principal component of the cellular walls. Some microorganisms, such as yeast and mushrooms, and also cereals such as oats and barley, are of economic interest because they contain large amounts of beta-glucans. These substances stimulate the immune system, modulating humoral and cellular immunity, and thereby have beneficial effect in fighting infections (bacterial, viral, fungal and parasitic). beta-Glucans also exhibit hypocholesterolemic and anticoagulant properties. Recently, they have been demonstrated to be anti-cytotoxic, antimutagenic and anti-tumorogenic, making them promising candidate as pharmacological promoters of health. (C) 2008 Elsevier B.V. All rights reserved.

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Avaliou-se a resposta imune celular e humoral de camundongos inoculados com vírus rábico de rua e submetidos aos imunomoduladores Onco-BCG, avridina e Propionibacterium acnes. Os animais submetidos ao tratamento com P.acnes apresentaram um maior percentual de sobrevivência quando comparados aos dos demais tratamentos. Foram observados menores níveis de IFN-g nos animais infectados, sugerindo imunossupressão viral. O teste do Coxim Plantar não foi eficaz para a detecção da resposta de hipersensibilidade retardada na metodologia utilizada, contrariamente ao MIF. A sobrevivência dos animais não apresentou correlação com os níveis de anticorpos soroneutralizantes, concentração de IFN-g e resposta ao MIF.

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Tick-bite naive guinea pigs were inoculated three times with Rhipicephalus sanguineus gut or salivary gland extracts and saponin as adjuvant. Dogs were inoculated three times with gut extract only as this fraction induced a more efficient resistance in guinea pigs (lower tick recovery and lower engorged female weights). Freund's adjuvant and saponin were used as adjuvants for the immunisation of dogs. Freund's adjuvant was used to enhance cellular immunity. The highest level of resistance in dogs was induced by the immunisation with gut extract and Freund's adjuvant. Many female ticks from dogs immunised this way engorged fully but died prior to oviposition. Resistant guinea pigs and dogs seemed to trigger different immune mechanisms against R. sanguineus ticks as damage to parasites also differed. A major role for cellular immunity in the resistance of dogs against R. sanguineus ticks is suggested. Resistance mechanisms against R. sanguineus ticks is discussed.

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Adult Swiss (susceptible) and BALB/c (non-susceptible) mice were inoculated by the intravenous route with 1 x 10(6) yeast cells of Paracoccidioides brasiliensis, strain 18. Immunologic parameters, histopathology and features of the bronchoalveolar lavage (BAL) were evaluated at week 2, 4, 8 and 16 post-infection. The pulmonary infection was progressive in Swiss mice and regressive in BALB/c mice. The numbers of total cells, lymphocytes and polymorphonuclear neutrophils increased in BAL, as well as the percentages of giant cells, and CD4 and CD8 positive cells. The ultrastructural study of BAL cells revealed a predominance of macrophages and a frequency of 13.2% of type II pneumocytes. As the infection progressed, the number of fungal cells and spreading macrophages, as well as the stimulated release of H2O2 by macrophages, increased. The animals exhibited an exacerbation of the humoral immune response and a depression of cellular immunity during the infection. There was a good correlation between the intensity and the pattern of the pulmonary histopathology and the cellular findings in the BAL. The present model reproduces some anatomoclinical patterns of the human disease and shows that BAL may be a useful tool in monitoring the pulmonary infection caused by P. brasiliensis.