Fatores protetores e de risco envolvidos na transmissão vertical do HIV-1

Este estudo avalia os fatores maternos e fetais envolvidos na transmissão vertical do HIV-1 em 47 pares de mãe e filho. As variáveis comportamentais, demográficas e obstétricas foram obtidas mediante entrevista; os dados referentes ao parto e ao recém-nascido, dos prontuários das maternidades. Durante o terceiro trimestre de gestação foi realizada a contagem da carga viral materna e dos linfócitos T CD4+. A média de idade foi de 25 anos e 23,4% das gestantes eram primigestas, e o fator comportamental mais prevalente foi não usar preservativos. Dentre as gestantes, 48,9% tinham células CD4+ superior a 500 células/mm³ e 93,6% se enquadravam na categoria clínica A; 95,7% submeteram-se à profilaxia com zidovudina durante a gestação ou no parto, a qual foi ministrada a todos os recém-nascidos; 50,0% delas foram submetidas à cesárea eletiva. Apesar de expostas a vários fatores de risco e protetores, nenhuma criança tornou-se infectada. A transmissão vertical resulta de um desequilíbrio entre os fatores, com predomínio dos de risco sobre os protetores.

Diminished CD4+/CD25+T cell and increased IFN-gamma levels occur in dogs vaccinated with Leishmune (R) in an endemic area for visceral leishmaniasis

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

Leukotriene B(4) is essential for selective eosinophil recruitment following allergen challenge of CD4(+) cells in a model of chronic eosinophilic inflammation

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.

Immunotherapy against experimental canine visceral leishmaniasis with the saponin enriched-Leishmune((R)) vaccine

In order to assess the immunotherapeutic potential on canine visceral leishmaniasis of the Leishmune (R) vaccine, formulated with an increased adjuvant concentration (1 mg of saponin rather than 0.5 mg), 24 mongrel dogs were infected with Leishmania (L.) chagasi. The enriched-Leishmune (R) vaccine was injected on month 6, 7 and 8 after infection, when animals were seropositive and symptomatic. The control group were injected with a saline solution. Leishmune (R)-treated dogs showed significantly higher levels of anti-FML IgG antibodies (ANOVA; p < 0.0001), a higher and stable IgG2 and a decreasing IgG I response, pointing to a TH1 T cell mediated response. The vaccine had the following effects: it led to more positive delayed type hypersensitivity reactions against Leishmania lysate in vaccinated dogs (75%) than in controls (50%), to a decreased average of CD4+ Leishmania-specific lymphocytes in saline controls (32.13%) that fell outside the 95% confidence interval of the vaccinees (41.62%, CI95% 43.93-49.80) and an increased average of the clinical scores from the saline controls (17.83) that falls outside the 95% confidence interval for the Leishmune (R) immumotherapy-treated dogs (15.75, CI95% 13.97-17.53). All dogs that received the vaccine were clustered, and showed lower clinical scores and normal CD4+ counts, whereas 42% of the untreated dogs showed very diminished CD4+ and higher clinical score. The increase in clinical signs of the saline treated group was correlated with an increase in anti-FML antibodies (p < 0.0001), the parasitological evidence (p = 0.038) and a decrease in Leishinania-specific CD4+ lymphocyte proportions (p = 0.035). These results confirm the immunotherapeutic potential of the enriched-Leishmune (R) vaccine. The vaccine reduced the clinical symptoms and evidence of parasite, modulating the outcome of the infection and the dog's potential infectiosity to phlebotomines. The enriched-Leishmune (R) vaccine was subjected to a safety analysis and found to be well tolerated and safe. (c) 2007 Elsevier Ltd. All rights reserved.

Developmental exposure to diuron causes splenotoxicity in male Sprague-Dawley rat pups

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

Protective effects of beta-glucan extracted from Agaricus brasiliensis against chemically induced DNA damage in human lymphocytes

beta-Glucans (BGs) are polysaccharides that are found in the cell walls of organisms such as bacteria, fungi, and some cereals. The objective of the present study was to investigate the genotoxic and antigenotoxic effects of BG extracted from the mushroom Agaricus brasiliensis (=Agaricus blazei Murrill ss. Heinemann). The mutagenic activity of BG was tested in single-cell gel electrophoresis assays with human peripheral lymphocytes. In addition, the protective effects against the cooked food mutagen 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and (+/-)-anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE), which is the main metabolite of B[a]P, and against ROS (H2O2)-induced DNA damage, were studied. The results showed that the compound itself was devoid of mutagenic activity, and that a significant dose-dependent protective effect against damage induced by hydrogen peroxide and Trp-P-2 occurred in the dose range 20-80 mu g/ml. To investigate the prevention of Trp-P-2-induced DNA damage, a binding assay was carried out to determine whether BG inactivates the amine via direct binding. Since no such interactions were observed, it is likely that BG interacts with enzymes involved in the metabolism of the amine.

Frequency of Candida spp. in the Oral Cavity of Brazilian HIV-Positive Patients and Correlation with CD4 Cell Counts and Viral Load

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

Staphylococcus spp., Enterobacteriaceae and Pseudomonadaceae oral isolates from Brazilian HIV-positive patients. Correlation with CD4 cell counts and viral load

The aim was to evaluate the presence of Staphylococcus spp., Enterobacteriaceae and Pseudomonadaceae in the oral cavities of HIV-positive patients. Forty-five individuals diagnosed as HIV-positive by ELISA and Western-blot, and under anti-retroviral therapy for at least 1 year, were included in the study. The control group constituted 45 systemically healthy individuals matched to the HIV patients to gender, age and oral conditions. Oral rinses were collected and isolates were identified by API system. Counts of microorganisms from HIV and control groups were compared statistically by a Mann-Whitney test (alpha = 5%). The percentages of individuals positive for staphylococci were similar between the groups (p = 0.764), whereas for Gram-negative rods, a higher percentage was observed amongst HIV-positive (p = 0.001).There was no difference in Staphylococcus counts between HIV and control groups (p = 0.1008). Counts were lower in the oral cavities of patients with low viral load (p = 0.021), and no difference was observed in relation to CD4 counts (p = 0.929). Staphylococcus aureus was the most frequently isolated species in HIV group, and Staphylococcus epidermidis was the prevalent species in the control group. Significantly higher numbers of enteric bacteria and pseudomonas were detected in the oral cavities of the HIV group than in the control (p = 0.0001). Enterobacter cloacae was the most frequently isolated species in both groups. Counts of enteric bacteria and pseudomonas were significantly lower in patients with low CD4 counts (p = 0.011); however, there was no difference relating to viral load. It may be concluded that HIV group showed greater species diversity and a higher prevalence of Enterobacteriaceae/Pseudomonadaceae. (C) 2011 Elsevier Ltd. All rights reserved.

Apoptosis in T lymphocytes from spleen tissue and peripheral blood of L. (L.) chagasi naturally infected dogs

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

Resistance to experimental autoimmune encephalomyelitis development in Lewis rats from a conventional animal facility

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease of the brain and spinal cord that is mediated by CD4+ T lymphocytes specific to myelin components. In this study we compared development of EAE in Lewis rats from two colonies, one kept in pathogen-free conditions (CEMIB colony) and the other (Botucatu colony) kept in a conventional animal facility. Female Lewis rats were immunized with 100 µl of an emulsion containing 50 µg of myelin, associated with incomplete Freund's adjuvant plus Mycobacterium butyricum. Animals were daily evaluated for clinical score and weight. CEMIB colony presented high EAE incidence with clinical scores that varied from three to four along with significant weight losses. A variable disease incidence was observed in the Botucatu colony with clinical scores not higher than one and no weight loss. Immunological and histopathological characteristics were also compared after 20 days of immunization. Significant amounts of IFN-gamma, TNF-alpha and IL-10 were induced by myelin in cultures from CEMIB animals but not from the Botucatu colony. Significantly higher levels of anti-myelin IgG1 were detected in the CEMIB colony. Clear histopathological differences were also found. Cervical spinal cord sections from CEMIB animals showed typical perivascular inflammatory foci whereas samples from the Botucatu colony showed a scanty inflammatory infiltration. Helminths were found in animals from Botucatu colony but not, as expected, in the CEMIB pathogen-free animals. As the animals maintained in a conventional animal facility developed a very discrete clinical, and histopathological EAE in comparison to the rats kept in pathogen-free conditions, we believe that environmental factors such as intestinal parasites could underlie this resistance to EAE development, supporting the applicability of the hygiene hypothesis to EAE.

Immunologic aspects of West syndrome and evidence of plasma inhibitory effects on T cell function

OBJETIVO: O objetivo deste estudo foi determinar o perfil da deficiência imune em um grupo bem definido de epilepsia: crianças com síndrome de West (SW) e seus padrões EEG de evolução, idade-dependentes, como os complexos onda-aguda- onda lenta generalizadas da síndrome de Lenox-Gastaut (SLG) e as pontas multifocais independentes (PMI). MÉTODO: Um grupo de 50 crianças, 33 com SW, 10 com SLG, 7 com PMI e 20 crianças sadias (controle) foram avaliadas em relação aos seguintes parâmetros:determinação de subpopulações de linfócitos T (CD1, CD3, CD4 e CD8), relação CD4/CD8 e resposta proliferativa de linfócitos frente a fitohemaglutinina (PHA), na presença de plasma autólogo ou de plasma AB (homólogo). A prova cutânea de sensibilização ao Dinitroclorobenzeno (DNCB) foi realizada apenas nos pacientes. Os níveis séricos de IgG, IgA e IgM foram comparados aos valores normais em crianças Brasileiras, em diferentes faixas etárias. RESULTADOS: A resposta ao DNCB foi ausente ou fracamente reativa em 76% dos pacientes. Níveis séricos elevados de IgG (45,7%) e de IgM (61,4%) e baixos de IgA (23,9%) foram detectados nos pacientes. A determinação das subpopulações de linfócitos T em sangue periférico mostrou: deficiência nas proporções de células CD3+ (p<0,05) e de CD4+ (p<0,05), aumento de CD8+ (p<0,01) e diminuição da relação CD4 / CD8 (p<0,001). A proporção de células CD1+ no grupo controle manteve-se menor que 3%, enquanto que em 18% dos pacientes esses níveis variaram entre 3 e 11%. A resposta proliferativa de linfócitos frente a PHA revelou índices blastogênicos significativamente mais baixos apenas quando células dos pacientes foram cultivadas na presença do próprio plasma (plasma autólogo). Quando estas células foram cultivadas na presença de plasma AB, não se evidenciou diferença significativa em relação ao grupo controle. CONCLUSÃO: A imunodeficiência na SW caracterizou-se por: anergia, alteração de imunidade mediada por células e dos níveis de imunoglobulinas, presença de timócitos imaturos na circulação periférica e deficiência funcional de linfócitos T induzida por fatores plasmáticos inibidores. Discutem-se as principais evidências de disfunção imune como imunodeficiência e autoimunidade.

Study of pulmonary experimental paracoccidioidomycosis by analysis of bronchoalveolar lavage cells: Resistant vs. susceptible mice

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.

EFFECT OF PRETREATMENT WITH VENOM OF APIS-MELLIFERA BEES ON THE YIELD OF GAMMA-RAY INDUCED CHROMOSOME-ABERRATIONS IN HUMAN BLOOD-LYMPHOCYTES

Venom of the honey bee Apis mellifera induced a protective effect against the induction of dicentric chromosomes by gamma radiation (2.0 Gy) in human peripheral blood lymphocytes which the cultures were treated with 0.00015 mul venom/1 ml medium 6 h before irradiation. In cultures to which the venom was added immediately before irradiation with 0.25, 1.0 and 2.0 Gy, no significant differences in number of dicentric chromosomes induced was observed when compared to cultures submitted to irradiation only. The venom did not induce clastogenic effects nor did it increase the frequency of sister chromatid exchanges.