Kinetoplastid membrane protein-11 exacerbates infection with Leishmania amazonensis in murine macrophages.

In Leishmania amazonensis, kinetoplastid membrane protein-11 (KMP-11) expression increases during meta-cyclogenesis and is higher in amastigotes than in promastigotes, suggesting a role for this protein in the infection of the mammalian host. We show that the addition of KMP-11 exacerbates L. amazonensis infection in peritoneal macrophages from BALB/c mice by increasing interleukin (IL)-10 secretion and arginase activity while reducing nitric oxide (NO) production. The doses of KMP-11, the IL-10 levels and the intracellular amastigote loads were strongly, positively and significantly correlated. The increase in parasite load induced by KMP-11 was inhibited by anti-KMP-11 or anti-IL-10 neutralising antibodies, but not by isotype controls. The neutralising antibodies, but not the isotype controls, were also able to significantly decrease the parasite load in macrophages cultured without the addition of KMP-11, demonstrating that KMP-11-induced exacerbation of the infection is not dependent on the addition of exogenous KMP-11 and that the protein naturally expressed by the parasite is able to promote it. In this study, the exacerbating effect of KMP-11 on macrophage infection with Leishmania is for the first time demonstrated, implicating it as a virulence factor in L. amazonensis. The stimulation of IL-10 production and arginase activity and the inhibition of NO synthesis are likely involved in this effect.

Different aspects of platelet evaluation in dengue: Measurement of circulating mediators, ability to interact with the virus, the degree of activation and quantification of intraplatelet protein content.

Platelets play a role in hemostasis, coagulation, angiogenesis, inflammation and immune response is one of the most affected cells in dengue. Here we describe some aspects of platelets by observing their specific circulating mediators, the ability to interact with the virus and morphological consequences of this interaction, activation markers and intraplatelet protein contents in dengue. We conducted this study using dengue-patients as well as healthy donors. Immunoenzymatic assay, flow cytometry, transmission electron microscopy and intraplatelet proteins expression assays were carried out. Briefly, we found an increase in sCD62L, NO or TBX2 ratio in platelet count, mostly in patients with the worse clinical outcome. After in vitro DENV infection or during natural infection, platelets underwent morphological alteration with increased expression of platelet activation markers, particularly in natural infections. Analysis of intraplatelet protein contents revealed different angiogenic and inflammatory profiles, maintaining or not extracellular matrix integrity between DF and DFWS patients. Thus, platelets are frequently affected by dengue, either by altering their own functionality, as "carrier" of the virus, or as an antiviral and mediator-secreting effector cell. Thus, strategies aimed at recovering platelet amounts in dengue seem to be essential for a better clinical outcome of the patients.

Pharmacokinetics comparison of two pegylated interferon alfa formulations in healthy volunteers.

BACKGROUND: Several countries have used pegylation technology to improve the pharmacokinetic properties of essential drugs. Recently, a novel interferon alfa-2b protein conjugated to four-branched 12 kDa polyethylene glycol molecules was developed jointly between Cuba and Brazil. The aim of this study was to compare the pharmacokinetic properties of BIP48 (pegylated interferon alfa-2b from Bio-Manguinhos/Fiocruz, Brazil) to those of PEGASYS® (commercially available pegylated interferon alfa-2a from Roche Pharmaceutical). METHODS: This phase I, single-centre, randomized, double-blind crossover trial enrolled 31 healthy male volunteers aged 19 to 35 who were allocated to two stages, either side of a 5-week wash-out period, with each arm lasting 14 consecutive days after subcutaneous administration of 180 µg of one formulation or the other (study or comparator). The main outcome variable was serum pegylated interferon concentrations in 15 samples collected during the course of the study and tested using an enzyme immunoassay. RESULTS: There were no differences between formulations in terms of magnitude or absorption parameters. Analysis of time parameters revealed that BIP48 remained in the body significantly longer than PEGASYS® (Tmax: 73 vs. 54 h [p = 0.0010]; MRT: 133 vs. 115 h [p = 0.0324]; ke: 0.011 vs. 0.013 h(-1) [p = 0.0153]; t1/2: 192 vs. 108 h [p = 0.0218]). CONCLUSION: BIP48 showed the expected pharmacokinetic profile for a pegylated product with a branched molecular structure. Compared to PEGASYS®, the magnitude absorption was similar, but time parameters were consistent with slower elimination. Further studies should be conducted to evaluate the clinical implications of these findings. A phase II-III repeated-dose clinical trial is ongoing to study these findings in patients with chronic hepatitis C virus infection. TRIAL REGISTRATION: This study is registered on the ClinicalTrials.gov platform (accession number NCT01889849 ). This trial was retrospectively registered in June 2013.

Kinetoplastid Membrane Protein-11 as a Vaccine Candidate and a Virulence Factor in Leishmania.

Kinetoplastid membrane protein-11 (KMP-11), a protein present in all kinetoplastid protozoa, is considered a potential candidate for a leishmaniasis vaccine. In Leishmania amazonensis, KMP-11 is expressed in promastigotes and amastigotes. In both stages, the protein was found in association with membrane structures at the cell surface, flagellar pocket, and intracellular vesicles. More importantly, its surface expression is higher in amastigotes than in promastigotes and increases during metacyclogenesis. The increased expression of KMP-11 in metacyclic promastigotes, and especially in amastigotes, indicates a role for this molecule in the parasite relationship with the mammalian host. In this connection, we have shown that addition of KMP-11 exacerbates L. amazonensis infection in peritoneal macrophages from BALB/c mice by increasing interleukin (IL)-10 secretion and arginase activity while reducing nitric oxide production. The doses of KMP-11, the IL-10 levels, and the intracellular amastigote loads were strongly, positively, and significantly correlated. The increase in parasite load induced by KMP-11 was inhibited by anti-KMP-11 or anti-IL-10-neutralizing antibodies, but not by isotype controls. The neutralizing antibodies, but not the isotype controls, were also able to significantly decrease the parasite load in macrophages cultured without the addition of KMP-11, demonstrating that KMP-11-induced exacerbation of the infection is not dependent on the addition of exogenous KMP-11 and that the protein naturally expressed by the parasite is able to promote it. All these data indicate that KMP-11 acts as a virulence factor in L. amazonensis infection.

TLR expression and NK cell activation after human yellow fever vaccination.

The yellow fever vaccine is very effective with a single injection conferring protection for at least 10 years. Recent evidence suggests that the innate immune cells activated through Toll-like receptors (TLRs), are critical determinants of the robustness of the adaptive response. Therefore, we investigated the NK cell status in eight healthy volunteers after vaccination with YF 17DD virus. Shortly after vaccination, we observed increased expression of TLR-3 and TLR-9 in NK cells and markers such as CD69, HLA-DP-DQ-DR, CD38 and CD16. The up-regulation of CD69 was positively correlated with the presence of TLRs throughout the post-vaccination period and the circulating IFN-gamma was significantly augmented. These results suggest that TLRs may play an important role in NK cell activation during the immune response to vaccination, indicating a potential role for NK cells in helping the development of long-lasting protective memory.

Kinetoplastid membrane protein-11 exacerbates infection with Leishmania amazonensis in murine macrophages

In Leishmania amazonensis, kinetoplastid membrane protein-11 (KMP-11) expression increases during metacyclogenesis and is higher in amastigotes than in promastigotes, suggesting a role for this protein in the infection of the mammalian host. We show that the addition of KMP-11 exacerbates L. amazonensis infection in peritoneal macrophages from BALB/c mice by increasing interleukin (IL)-10 secretion and arginase activity while reducing nitric oxide (NO) production. The doses of KMP-11, the IL-10 levels and the intracellular amastigote loads were strongly, positively and significantly correlated. The increase in parasite load induced by KMP-11 was inhibited by anti-KMP-11 or anti-IL-10 neutralising antibodies, but not by isotype controls. The neutralising antibodies, but not the isotype controls, were also able to significantly decrease the parasite load in macrophages cultured without the addition of KMP-11, demonstrating that KMP-11-induced exacerbation of the infection is not dependent on the addition of exogenous KMP-11 and that the protein naturally expressed by the parasite is able to promote it. In this study, the exacerbating effect of KMP-11 on macrophage infection with Leishmania is for the first time demonstrated, implicating it as a virulence factor in L. amazonensis. The stimulation of IL-10 production and arginase activity and the inhibition of NO synthesis are likely involved in this effect.

Padronização e validação de testes alternativos para avaliar a imunogenicidade das vacinas diftérica-tetânica (dT) e diftérica-tetânica-pertussis (DTP) / Standardization and validation of alternative tests to evaluate the imunogenicidade of vaccines diphtheria-tetanus (dT) and diphtheria-tetanus-pertussis (DTP)

O objetivo deste trabalho foi padronizar e validar, frente aos testes empregados atualmente, métodos alternativos capazes de avaliar a potência das vacinas bacterianas combinadas: tétano-difteria uso adulto (dT ) e tétano-difteria-pertussis (DTP) produzidas no Instituto Butantan, em São Paulo. Os seguintes testes foram padronizados: I - para o componente diftérico (toxóide diftérico): teste de citotoxicidade em células Vero, teste de inibição da ligação de toxina (ToBI toxin binding inhibition); II - para o componente tetânico (toxóide tetânico): teste ToBI; III - para o componente pertussis: método imunoenzimático (Elisa). Neste trabalho, foram analisados 20 lotes de vacinas dT, contendo 4 Lf/ml de toxóide diftérico e 15 Lf/ml de toxóide tetânico e 20 lotes de vacina DTP, contendo 15 Lf/ml de toxóide diftérico, 15 Lf/ml toxóide tetânico e 32 UO/ml de componente pertussis, ambas as vacinas adsorvidas em 0,5 mg/mL de hidróxido de alumínio. Todos os lotes de vacinas foram aprovados pelo Instituto Nacional de Controle de Qualidade em Saúde (INCQS/Fiocruz). Grupos de 6 Cobaias foram inoculados com a metade da dose total humana (0,75 ml) das vacinas. Grupos de 20 camundongos também foram inoculados com 0,5 ml do componente pertussis de referência (8,6 UI/ml) e, paralelamente, outros três grupos de camundongos foram inoculados para cada lote de vacina DTP em teste. As amostras de soros de cobaias e camundongos foram utilizados para a titulação das antitoxinas diftérica e tetânica e para a titulação de anticorpos contra a fração pertussis, respectivamente... O cálculo da potência do componente pertussis foi estimado através da análise de paralelismo... Resultados análogos foram observados na avaliação do componente tetânico. Na avaliação do componente pertussis, foi identificada uma excelente correlação entre o teste de proteção intracerebral em camundongos e o teste Elisa (r = 0,9). A utilização de testes in vitro, para avaliar a potência das vacinas dT e DTP, são tecnicamente mais simples, possuem alta especificidade, sensibilidade e reprodutibilidade. Além disso, reduzem drasticamente o número de animais usados, evitando ainda o sofrimento dos mesmos nos testes in vivo, onde a capacidade de proteção das vacinas é avaliada pela inoculação de toxinas ou de Bordetella pertussis nos animais imunizados.(AU)