Sporothrix schenckii Cell Wall Proteins-Stimulated BMDCs Are Able to Induce a Th1-Prone Cytokine Profile In Vitro.

Sporotrichosis is a subcutaneous mycosis affecting humans and other animals. The disease can be acquired by accidental inoculation of the fungus through the skin or through the respiratory system. Sporotrichosis can also be transmitted through bites or scratches by infected cats and more rarely by other animals (zoonotic transmission). Conventional antifungal therapy is especially inefficient in immunocompromised patients, who tend to develop the most severe forms of the disease, thus prompting the search for alternative therapies. Given their antigen-presenting properties, dendritic cells (DCs) have been used in both prophylactic and therapeutic vaccination strategies. Hence, this study aims to assess the use of DCs as a prophylactic tool in sporotrichosis by evaluating the immune profile induced by Sporothrix schenckii cell wall proteins (SsCWP)-stimulated, bone-marrow-derived DCs (BMDCs). Mouse BMDCs were stimulated with SsCWP for 24 h and analyzed for the surface expression of costimulatory molecules and TLR-4, as well as for the secretion of proinflammatory cytokines and IL-10. Following that, activated BMDCs were cocultured with splenocytes for 72 h and had the same cytokines measured in the supernatant. SsCWP-stimulated BMDCs showed higher expression of CD80, CD86, and CD40, but not TLR-4, and higher secretion of IL-6, IL-17A, and TNF. On the other hand, higher levels of IFN-γ, IL-10, and IL-2 were found in the supernatants of the coculture as compared with the BMDCs alone; TNF secretion was almost completely abrogated, whereas IL-6 was only partially inhibited and IL-17A was unaffected. Our results thus suggest that SsCWP-stimulated BMDCs are able to induce a Th1-prone cytokine profile which is known to be protective against other fungal diseases. This result could lead to studies which evaluate the development of prophylactic and/or therapeutic DC-based tools against sporotrichosis.

Experimental sporotrichosis in a cyclophosphamide-induced immunosuppressed mice model.

This report describes a model of host resistance for Sporothrix schenckii, an opportunistic fungi in immunosuppressed mice with cyclophosphamide (CY) to be used in studies of immunotoxicology and immunopharmacology. Two doses of CY were administered intraperitoneally: 200 mg/kg and a booster of 150 mg/kg at 9-day intervals. Three days after the first dose of CY the animals were infected subcutaneously with 1.8 × 108 yeast/ml (S. schenckii ATCC 16345). At 7 and 14 days post-infection, the animals were euthanized and analyzed the fungal load by unit forming colony count in the spleen and popliteal lymph nodes. The relative weight of thymus and spleen, splenic index, the frequency of T and B cells in spleen by flow cytometry, the hind paw inflammation index and cytokine (interleukin [IL]-17, IL-10, and interferon [IFN]-γ) profile were measured. Histopathological studies of the spleen and the hind paw were also assessed. The immunosuppression status was confirmed at the evaluated days by reduction of relative weight of thymus, reduction of the splenic white pulp, the population of B and T lymphocytes, and the cytokine profile in the treated mice with CY in comparison with nontreated groups, associated to higher fungal load in hind paw and spleen in the infected mice. The described model reveals an increasing in susceptibility to infection and severity when associated with immunosuppression. This model can serve as a reference for studies of S. schenckii host resistance in pharmaceutical and toxicological studies.

Comparative efficacy and toxicity of two vaccine candidates against Sporothrix schenckii using either Montanide™ Pet Gel A or aluminum hydroxide adjuvants in mice.

Sporotrichosis is an important zoonosis in Brazil and the most frequent subcutaneous mycosis in Latin America, caused by different Sporothrix species. Currently, there is no effective vaccine available to prevent this disease. In this study, the efficacy and toxicity of the adjuvant Montanide™ Pet Gel A (PGA) formulated with S. schenckii cell wall proteins (ssCWP) was evaluated and compared with that of aluminum hydroxide (AH). Balb/c mice received two subcutaneous doses (1st and 14th days) of either the unadjuvanted or adjuvanted vaccine candidates. On the 21st day, anti-ssCWP antibody levels (ELISA), the phagocytic index, as well as the ex vivo release of IFN-γ, IL-4, and IL-17 by splenocytes and IL-12 by peritoneal macrophages were assessed. Cytotoxicity of the vaccine formulations was evaluated in vitro and by histopathological analysis of the inoculation site. Both adjuvanted vaccine formulations increased anti-ssCWP IgG, IgG1, IgG2a, and IgG3 levels, although IgG2a levels were higher in response to PGA+CWP100, probably contributing to the increase in S. schenckii yeast phagocytosis by macrophages in the opsonophagocytosis assay when using serum from PGA+CWP100-immunized mice. Immunization with AH+CWP100 led to a mixed Th1/Th2/Th17 ex vivo cytokine release profile, while PGA+CWP100 stimulated a preferential Th1/Th2 profile. Moreover, PGA+CWP100 was less cytotoxic in vitro, caused less local toxicity and led to a similar reduction in fungal load in the liver and spleen of S. schenckii- or S. brasiliensis-challenged mice as compared with AH+CWP100. These results suggest that PGA may be an effective and safe adjuvant for a future sporotrichosis vaccine.

TLR expression, phagocytosis and oxidative burst in healthy and septic newborns in response to Gram-negative and Gram-positive rods.

The objective was to investigate whether phagocytes from healthy and septic newborns have a developmental deficiency in their capacity to recognize, phagocytize and generate hydrogen peroxide (H2O2) in response to Escherichia coli and Staphylococcus aureus. TLR expression and phagocytic ability of neutrophils and monocytes from 44 healthy preterm and term neonates, from 13 newborns with late-onset sepsis and from 24 healthy adults were determined using flow cytometry, and H2O2 production was measured by dihydrorhodamine test. TLR-2 and TLR-4 expressions were similar among the groups. The phagocytic ability of monocytes and neutrophils exposed to E. coli and S. aureus in healthy and septic neonates was significantly reduced compared to that of adults. Monocytes from septic newborns exposed to E. coli had higher H2O2 production than those of the other groups. The oxidative burst of monocytes exposed to S. aureus was reduced in preterm newborns compared with term ones and those with sepsis, and no differences were found in the oxidative burst of neutrophils. Even with the ability to recognize bacteria, a decreased clearance of pathogens can cause an imbalance in the immune response, which could lead to a predisposition to sepsis. Once established, the increased production of cytokines and ROS in an attempt to control the infection as well as the lack of full phagocytic activity leads to persistence of the pathogen and a state of constant inflammation.

Hydrophobicity and antioxidant activity acting together for the beneficial health properties of nordihydroguaiaretic acid.

Nordihydroguaiaretic acid (NDGA) and rosmarinic acid (RA), phenolic compounds found in various plants and functional foods, have known antioxidant and anti-inflammatory properties. In the present study, we comparatively investigated the importance of hydrophobicity and oxidisability of NDGA and RA, regarding their antioxidant and pharmacological activities. Using a panel of cell-free antioxidant protocols, including electrochemical measurements, we demonstrated that the anti-radical capacities of RA and NDGA were similar. However, the relative capacity of NDGA as an inhibitor of NADPH oxidase (ex vivo assays) was significantly higher compared to RA. The inhibitory effect on NADPH oxidase was not related to simple scavengers of superoxide anions, as confirmed by oxygen consumption by the activated neutrophils. The higher hydrophobicity of NDGA was also a determinant for the higher efficacy of NDGA regarding the inhibition of the release of hypochlorous acid by PMA-activated neutrophil and cytokine (TNF-α and IL-10) production by Staphylococcus aureus-stimulated peripheral blood mononuclear cells. In conclusion, although there have been extensive studies about the pharmacological properties of NDGA, our study showed, for the first time, the importance not only of its antioxidant activity, but also its hydrophobicity as a crucial factor for pharmacological action.

Caffeic Acid phenethyl ester: consequences of its hydrophobicity in the oxidative functions and cytokine release by leukocytes.

Numerous anti-inflammatory properties have been attributed to caffeic acid phenethyl ester (CAPE), an active component of propolis. NADPH oxidases are multienzymatic complexes involved in many inflammatory diseases. Here, we studied the importance of the CAPE hydrophobicity on cell-free antioxidant capacity, inhibition of the NADPH oxidase and hypochlorous acid production, and release of TNF-α and IL-10 by activated leukocytes. The comparison was made with the related, but less hydrophobic, caffeic and chlorogenic acids. Cell-free studies such as superoxide anion scavenging assay, triene degradation, and anodic peak potential (E pa) measurements showed that the alterations in the hydrophobicity did not provoke significant changes in the oxidation potential and antiradical potency of the tested compounds. However, only CAPE was able to inhibit the production of superoxide anion by activated leukocytes. The inhibition of the NADPH oxidase resulted in the blockage of production of hypochlorous acid. Similarly, CAPE was the more effective inhibitor of the release of TNF-α and IL-10 by Staphylococcus aureus stimulated cells. In conclusion, the presence of the catechol moiety and the higher hydrophobicity were essential for the biological effects. Considering the involvement of NADPH oxidases in the genesis and progression of inflammatory diseases, CAPE should be considered as a promising anti-inflammatory drug.

TLR-2 and TLR-4 expression in monocytes of newborns with late-onset sepsis, / Expressão do TLR-2 e do TLR-4 em monócitos de recém-nascidos a termo com sepse tardia

Objective: To analyze toll-like receptor (TLR)-2 and TLR-4 expression in monocytes of newborns with late-onset sepsis. Methods: This prospective study included 27 full-term newborns aged 8 to 29 days, with clinical and laboratory diagnosis of late-onset sepsis. Ten newborns (37%) had positive cultures. Cytokines were measured by cytometric bead array in peripheral blood, while TLR-2, TLR-4 expression, and median fluorescence intensity (MFI) were determined by immunophenotyping peripheral whole blood monocytes, and were analyzed with a BD FACSDiva flow cytometer (Becton, Dickinson and Company, USA). A comparison was performed with healthy adults. Results: Microorganisms were identified in 37% of these septic newborns, and all of them had high levels of pro-inflammatory cytokines (IL-8, IL-6, IL-1β) and anti-inflammatory cytokine (IL-10) corroborating the inflammatory/septic process. In monocytes, the frequency of TLR-4 expression was higher in infected newborns (p = 0.01). Conclusion: This study investigated the innate immune response in septic newborns. Septic newborns that relied almost exclusively on the innate immune system showed little in vivo response at monocyte activation, suggesting impaired immune response and increased susceptibility to infection. .

Objetivos: Analisar a expressão dos TLR-2 e TLR-4 em monócitos de recém-nascidos com sepse tardia. Métodos: Trata-se de um estudo prospectivo com 27 recém-nascidos a termo entre 8 e 29 dias de vida com diagnóstico clínico e laboratorial de sepse tardia dos quais dez (37%) apresentaram cultura positiva. As citocinas foram determinadas por teste de CBA em sangue periférico enquanto que a expressão e MFI (mediana de intensidade de fluorescência) dos TLR-2 e TLR-4 foi determinado por imunofenotipagem em monócitos de sangue periférico total através de análise pelo citômetro de fluxo BD FACSDiva. O grupo usado para comparação foi de adultos saudáveis. Resultados: Microrganismos foram identificados em 37% dos pacientes e estes juntamente com os pacientes com sepse clínica tiveram níveis elevados de citocinas pró-inflamatórias (IL-8, IL-6, IL-1β) e de citocina anti-inflamatória (IL-10) corroborando o processo inflamatório/infeccioso. No monócito, a frequência de expressão do TLR-4 foi mais elevada (p = 0,01). Conclusões: Este estudo analisou a resposta imune inata no recém-nascido com sepse. Recémnascidos sépticos que dependem quase exclusivamente do sistema imune inato apresentaram pouca resposta in vivo na ativação de monócitos o que sugere uma resposta imune deficiente e maior susceptibilidade à infecção. .

TLR-2 and TLR-4 expression in monocytes of newborns with late-onset sepsis.

OBJECTIVE: To analyze toll-like receptor (TLR)-2 and TLR-4 expression in monocytes of newborns with late-onset sepsis. METHODS: This prospective study included 27 full-term newborns aged 8 to 29 days, with clinical and laboratory diagnosis of late-onset sepsis. Ten newborns (37%) had positive cultures. Cytokines were measured by cytometric bead array in peripheral blood, while TLR-2, TLR-4 expression, and median fluorescence intensity (MFI) were determined by immunophenotyping peripheral whole blood monocytes, and were analyzed with a BD FACSDiva flow cytometer (Becton, Dickinson and Company, USA). A comparison was performed with healthy adults. RESULTS: Microorganisms were identified in 37% of these septic newborns, and all of them had high levels of pro-inflammatory cytokines (IL-8, IL-6, IL-1ß) and anti-inflammatory cytokine (IL-10) corroborating the inflammatory/septic process. In monocytes, the frequency of TLR-4 expression was higher in infected newborns (p = 0.01). CONCLUSION: This study investigated the innate immune response in septic newborns. Septic newborns that relied almost exclusively on the innate immune system showed little in vivo response at monocyte activation, suggesting impaired immune response and increased susceptibility to infection.

IgG placental transfer in healthy and pathological pregnancies.

Placental transfer of maternal IgG antibodies to the fetus is an important mechanism that provides protection to the infant while his/her humoral response is inefficient. IgG is the only antibody class that significantly crosses the human placenta. This crossing is mediated by FcRn expressed on syncytiotrophoblast cells. There is evidence that IgG transfer depends on the following: (i) maternal levels of total IgG and specific antibodies, (ii) gestational age, (iii) placental integrity, (iv) IgG subclass, and (v) nature of antigen, being more intense for thymus-dependent ones. These features represent the basis for maternal immunization strategies aimed at protecting newborns against neonatal and infantile infectious diseases. In some situations, such as mothers with primary immunodeficiencies, exogenous IgG acquired by intravenous immunoglobulin therapy crosses the placenta in similar patterns to endogenous immunoglobulins and may also protect the offspring from infections in early life. Inversely, harmful autoantibodies may cross the placenta and cause transitory autoimmune disease in the neonate.

Uso de fatores de crescimento epidérmico e estimulador de colônias de granulócitos na prevenção e tratamento da enterocolite necrosante no recém-nascido / Use of epidermic and granulocyte-colony stimulating growth factors in the prevention and treatment of necrotizing enterocolitis of the newborn

OBJETIVO: Revisar os conhecimentos existentes em relação ao uso de fatores de crescimento epidérmico e estimulador de colônias de granulócitos na prevenção e/ou no tratamento da enterocolite necrosante (ECN) durante o período neonatal. FONTES DE DADOS: Revisão da literatura, nas bases de dados Medline, Lilacs, SciELO e PubMed, utilizando os unitermos "recém-nascidos", "enterocolite" e "fatores de crescimento", no período de 2003 a 2007. Nesta busca, 49 artigos foram encontrados, sendo 17 pertinentes ao tema. Também foram utilizados outros artigos, independente do ano de publicação, relacionados a aspectos definidores da ECN no recém-nascido. SÍNTESE DOS DADOS: A ECN continua sendo responsável por uma elevada morbimortalidade neonatal. Os mecanismos fisiopatológicos vêm sendo elucidados e, a partir deles, são discutidas novas terapias, como o uso de fatores de crescimento, destacando-se o fator de crescimento epidérmico e o fator estimulador de colônias de granulócitos. CONCLUSÕES: O uso de fatores de crescimento no tratamento e prevenção da ECN neonatal parece promissor. É necessário maior número de ensaios clínicos para comprovar sua eficácia e segurança. Enquanto isso, a melhor prática médica continua sendo a prevenção da doença.

OBJECTIVE: To review the literature regarding the use of hematopoietic and epidermic growth factors for prevention or treatment of neonatal necrotizing enterocolitis (NEC). DATA SOURCES: Literature review of Medline, Lilacs, SciELO and Pubmed databases, using the key-words "newborn", "enterocolitis" and "growth factors", from 2003 to 2007. Fourty-nine papers were retrieved, but only 17 related to the subject. Other studies that described some clinical aspects of enterocolitis were also included, regardless of the year of publication. DATA SYNTHESIS: Necrotizing and enterocolitis has been an important cause of morbidity and mortality in the neonatal period. As the knowledge about the pathophysiology of this disease improves, new therapies, such as the administration of epidermal growth factor and granulocyte colony-stimulating factor, are being discussed. CONCLUSIONS: The use of growth factors for treatment and prevention of NEC seems promising. However, further clinics assays are needed to evaluate the effectiveness and the safety of these growth factors. At this moment, the best clinical practice is the prevention of the disease.