78 resultados para cellular immunity

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Sporothrix schenckii is the etiologic agent of sporotrichosis, a mycosis of world-wide distribution more commonly occurring in tropical regions. The immunological mechanisms involved in the prevention and control of sporotrichosis are not fully understood but apparently include both the humoral and cellular responses. In the present investigation, cellular immunity was evaluated by in vivo and in vitro tests in mice infected with yeast-like forms of S. schenckii. The disease developed systemically and cellular immunity was evaluated for a period of 10 weeks. The soluble antigen utilized in the tests was prepared from yeast form of the fungus through the sonication (20 min: 10 sonications at 50 W at 2-min intervals). Delayed hypersensitivity and lymphocyte transformation tests showed that the cellular immune response was depressed between the 4th and 6th week of infection when the animals were challenged with the soluble fungal antigen. This depression frequently indicates worsening of the disease, with greater involvement of the host. This is a promising field of research for a better understanding of the pathogeny of this mycosis.

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Attempts were made to study possible effects of the periodontal disease cara inchada (CI) on the cellular immunity of cattle, using adherence-, chemotaxis- and ph-agocytosis-determinations. Adherence of Bacteroides melaninogenicus to bovine granulocytes was significantly decreased in animals with CI. Phagacytosis of B. melaninogenicus by polymorphonuclear granulocytes (PMN) was also decreased in CI-diseased animals. Chemotaxis of the granulocytes appeared to be slightly increased in animals with CI and animals without CI coming from CI-affected herds.

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This study investigated the immunotherapeutic potential of the protein aggregate magnesium-ammonium phospholinoleate-palmitoleate anhydride immuno-modulator (P-MAPA) on canine visceral leishmaniasis. Twenty mongrel dogs presenting clinical symptoms compatible with leishmaniasis and diagnosis confirmed by the detection of anti-leishmania antibodies were studied. Ten dogs received 15 doses of the immunomodulator (2.0mg/kg) intramuscularly, and 10 received saline as a placebo. Skin and peripheral blood samples were collected following administration of the immunomodulator. The groups were followed to observe for clinical signals of remission; parasite load in the skin biopsies using real-time PCR, the cytokines IL-2, IL-10 and IFN-γ in the supernatant of peripheral blood mononuclear cells stimulated in vitro with either total promastigote antigen or phytohemagglutinin measured by capture ELISA, and changes in CD4+ and CD8+ T cell subpopulations evaluated by flow cytometry. Comparison between the groups showed that treatment with the immunomodulator promoted improvement in clinical signs and a significant reduction in parasite load in the skin. In peripheral blood mononuclear cell cultures, supernatants showed a decrease in IL-10 levels and an increase in IL-2 and IFN-γ. An increase in CD8+ T cells was observed in peripheral blood. In addition, the in vitro leishmanicidal action of P-MAPA was investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and no leishmanicidal activity was detected. These findings suggest that P-MAPA has potential as an immunotherapeutic drug in canine visceral leishmaniasis, since it assists in reestablishing partial immunocompetence of infected dogs. © 2013 Elsevier B.V.

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Humoral and cell-mediated immunity was investigated in fourteen patients with non-toxic multinodular goitre and ten healthy controls by in vitro methods. These included determination of sheep erythrocyte and complement rosette-forming cells in the peripheral blood, immunoglobulin levels, titres of thyroglobulin and microsomal antibodies and migration inhibition test using thyroid extract and phytohemagglutinin. When compared with controls the patients showed high IgA levels and positive response to thyroid antigen in the leucocyte migration inhibition test. There was no correlation between the leucocyte migration results and the presence of auto-antibodies. These findings indicate a possible role of cell-mediated immunity in non-toxic multinodular goitre.

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The immunological status of five children with West syndrome consequent to previous cerebral lesions was investigated. Three children had West syndrome and two were in transition from West to Lennox-Gastaut syndrome. All of them showed cellular immunological deficiencies in the following tests: sensitization to DNCB, intracutaneous reaction to PHA, inhibition of leukocyte migration, blastic transformation of lymphocytes, T and B lymphocytes in peripheral blood and levels of serum immunoglobulins. These immunological deficiencies, of different degrees of severity, were associated with frequent infections in these children. A possible association between the immunological deficiencies and autoimmunity is discussed.

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Cellular immune response to specific and non-specific stimulants was investigated, both in vivo and in vitro, in 29 healthy controls and in 53 previously untreated patients with the chronic isolated organic form (CIOF), the chronic mixed form (CMF) and the acute progressive form (APF) of paracoccidioidomycosis. The study included skin tests to Paracoccidioides brasiliensis antigen (PbAg) and phytohaemagglutinin (PHA), DNCB sensitization, determination of T lymphocytes and complement rosette-forming cells, lymphocyte transformation and leucocyte migration inhibition tests using PbAg and PHA. Patients displayed staggered cutaneous response to PHA and to PbAg, with marked decrease in intensity in the APF group. DNCB sensitization test and proliferative response of lymphocytes to PHA and PbAg were severely depressed in most of the patients. Leucocyte migration inhibition indices to PbAg were highly positive, while response to PHA was slightly decreased regardless of the clinical form. The number of T lymphocytes was reduced in most of patients and in them the number of complement-rosette forming cells was normal. The distribution of patients according to a suppression index, based in the results of the tests employed, revealed a tendency towards an increased degree of cellular immunosuppression from the least severe (CIOF) to the most severe (APF) clinical form of the disease. On the whole, the present study demonstrated a gamut of immunological reactivity in paracoccidioidomycosis. © 1985.

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West syndrome is a severe epilepsy, occurring in infancy, that comprises epileptic seizures known as spasms, in clusters, and a unique EEG pattern, hypsarrhythmia, with psychomotor regression. Maturation of the brain is a crucial component. The onset is within the first year of life, before 12 months of age. Patients are classified as cryptogenic (10 to 20%), when there are no known or diagnosed previous cerebral insults, and symptomatic (80 to 90%), when associated with pre-existing cerebral damages. The time interval from a brain insult to infantile spasms onset ranged from 6 weeks to 11 months. West syndrome has a time-limited natural evolutive course, usually disappearing by 3 or 4 years of age. In 62% of patients, there are transitions to another age-related epileptic encephalopathies, the Lennox-Gastaut Syndrome and severe epilepsy with multiple independent foci. Spontaneous remission and remission after viral infections may occur. Therapy with ACTH and corticosteroids are the most effective. Reports about intravenous immunoglobulins action deserve attention. There is also immune dysfunction, characterized mainly by anergy, impaired cell-mediated immunity, presence of immature thymocytes in peripheral blood, functional impairment of T lymphocytes induced by plasma inhibitory factors, and altered levels of immunoglobulins. Changes in B lymphocytes frequencies and increased levels of activated B cells have been reported. Sensitized lymphocytes to brain extract were also described. Infectious diseases are frequent and may, sometimes, cause fatal outcomes. Increase of pro-inflamatory cytokines in serum and cerebrospinal fluid of epileptic patients were reported. Association with specific HLA antigens was described by several authors (HLA-DR7, HLA-A7, HLA-DRw52, and HLA-DR5). Auto-antibodies to brain antigens, of several natures (N-methyl-d-aspartate glutamate receptor, gangliosides, brain tissue extract, synaptic membrane, and others), were described in epileptic patients and in epileptic syndromes. Experimental epilepsy studies with anti-brain antibodies demonstrated that epileptiform discharges can be obtained, producing hyperexcitability leading to epilepsy. We speculate that in genetically prone individuals, previous cerebral lesions may sensitize immune system and trigger an autoimmune disease. Antibody to brain antigens may be responsible for impairment of T cell function, due to plasma inhibitory effect and also cause epilepsy in immature brains. © 2008 Bentham Science Publishers Ltd.

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Since little information is available regarding cellular antigen mapping and the involvement of non-neuronal cells in the pathogenesis of bovine herpesvirus type 5 (BHV-5) infection, it were determined the BHV-5 distribution, the astrocytic reactivity, the involvement of lymphocytes and the presence of matrix metalloproteinase (MMP)-9 in the brain of rabbits experimentally infected with BHV-5. Twelve New Zealand rabbits that were seronegative for BHV-5 were used for virus inoculation, and five rabbits were used as mock-infected controls. The rabbits were kept in separate areas and were inoculated intranasally with 500 μl of virus suspension (EVI 88 Brazilian isolate) into each nostril (virus titer, 107.5 TCID50). Control rabbits were inoculated with the same volume of minimum essential medium. Five days before virus inoculation, the rabbits were submitted to daily administration of dexamethasone. After virus inoculation, the rabbits were monitored clinically on a daily basis. Seven rabbits showed respiratory symptoms and four animals exhibited neurological symptoms. Tissue sections were collected for histological examination and immunohistochemistry to examine BHV-5 antigens, astrocytes, T and B lymphocytes and MMP-9. By means of immunohistochemical and PCR methods, BHV-5 was detected in the entire brain of the animals which presented with neurological symptoms, especially in the trigeminal ganglion and cerebral cortices. Furthermore, BHV-5 antigens were detected in neurons and/or other non-neural cells. In addition to the neurons, most infiltrating CD3 T lymphocytes observed in these areas were positive for MMP-9 and also for BHV-5 antigen. These infected cells might contribute to the spread of the virus to the rabbit brain along the trigeminal ganglia and olfactory nerve pathways. © 2013 Elsevier Ltd.

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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.