Different Profiles of Cytokines, Chemokines and Coagulation Mediators Associated with Severity in Brazilian Patients Infected with Dengue Virus.

The incidence of dengue in Latin America has increased dramatically during the last decade. Understanding the pathogenic mechanisms in dengue is crucial for the identification of biomarkers for the triage of patients. We aimed to characterize the profile of cytokines (IFN-γ, TNF-α, IL-1β, IL-6, IL-18 and IL-10), chemokines (CXCL8/IL-8, CCL2/MCP-1 and CXCL10/IP-10) and coagulation mediators (Fibrinogen, D-dimer, Tissue factor-TF, Tissue factor pathway inhibitor-TFPI and Thrombomodulin) during the dengue-4 epidemic in Brazil.

Dengue Virus Induces NK Cell Activation through TRAIL Expression during Infection.

Dengue is an acute febrile illness with a wide spectrum of signs and symptoms ranging from mild to severe forms characterized by plasma leakage that can be fatal. NK cells are one of the main effectors in early infection and may play an important role in dengue pathogenesis. We investigated NK cell involvement during dengue infection.

Inflammatory early events associated to the role of P2X7 receptor in acute murine toxoplasmosis.

Activation of the purinergic P2X7 receptor by extracellular ATP (eATP) potentiates proinflammatory responses during infections by intracellular pathogens. Extracellular ATP triggers an antimicrobial response in macrophages infected with Toxoplasma gondii in vitro, suggesting that purinergic signaling may stimulate host defense mechanisms against toxoplasmosis. Here, we provide in vivo evidence in support of this hypothesis, by showing that P2X7 mice are more susceptible than P2X7 mice to acute infection by the RH strain of T.

The purinergic receptor P2X7 role in control of Dengue virus-2 infection and cytokine/chemokine production in infected human monocytes.

Purinergic signaling has a crucial role in intracellular pathogen elimination. The P2X7 purinergic receptor (P2X7R), once activated by ATP, leads to pro-inflammatory responses including reactive oxygen species production. ATP can be released by injured cells, as endogenous danger signals.

Pyrimidinergic Receptor Activation Controls Toxoplasma gondii Infection in Macrophages.

Infection by the protozoan parasite Toxoplasma gondii is highly prevalent worldwide and may have serious clinical manifestations in immunocompromised patients. T. gondii is an obligate intracellular parasite that infects almost any cell type in mammalian hosts, including immune cells.

Circulating cytokines and chemokines associated with plasma leakage and hepatic dysfunction in Brazilian children with dengue fever.

Dengue fever is usually a benign acute viral infection transmitted by arthropods but may evolve to severe clinical manifestations such as coagulation and/or hemodynamic disorders, caused mainly by an increase of vascular permeability. Deregulated circulating immunological factors have been associated with severity. In Brazil severe cases appeared in children only recently and we evaluated the profile of cytokine/chemokine kinetics in 134 hospitalized young patients during the epidemic in Rio de Janeiro in 2008.

Characterizing the presence and sensitivity of the P2X7 receptor in different compartments of the gut.

Purinergic signaling has been established as an important feature of inflammation and homeostasis. The expression of a number of P2 receptor subtypes in the gut has been reported. In this study, using a well-known permeabilization method that is assessed by flow cytometry, we show that lymphocytes and macrophages from the mesenteric lymph nodes (MLN) and the peritoneal cavity exhibit different sensitivities to extracellular ATP.

Host-cell lipid rafts: a safe door for micro-organisms?

The lipid raft hypothesis proposed that these microdomains are small (10-200 nM), highly dynamic and enriched in cholesterol, glycosphingolipids and signalling phospholipids, which compartmentalize cellular processes. These membrane regions play crucial roles in signal transduction, phagocytosis and secretion, as well as pathogen adhesion/interaction. Throughout evolution, many pathogens have developed mechanisms to escape from the host immune system, some of which are based on the host membrane microdomain machinery.

Activation of the P2X(7) receptor triggers the elimination of Toxoplasma gondii tachyzoites from infected macrophages.

Toxoplasmosis is caused by the protozoan parasite Toxoplasma gondii, which is widespread throughout the world. After active penetration, the parasite is enclosed within a parasitophorous vacuole and survives in the host cell by avoiding, among other mechanisms, lysosomal degradation. A large number of studies have demonstrated the importance of ATP signalling via the P2X(7) receptor, as a component of the inflammatory response against intracellular pathogens.

Cell death induction in Giardia lamblia: effect of beta-lapachone and starvation.

Giardia lamblia is a protozoan that parasitizes the small intestine of vertebrates. It is a cause of intestinal infection and diarrhea and infects millions of people worldwide. This protozoan presents many characteristics common to eukaryotic cells but it lacks organelles found in most eukaryotes (e.

The P2X(7) receptor and intracellular pathogens: a continuing struggle.

The purinergic receptor, P2X(7), has recently emerged as an important component of the innate immune response against microbial infections. Ligation of P2X(7) by ATP can stimulate inflammasome activation and secretion of proinflammatory cytokines, but it can also lead directly to killing of intracellular pathogens in infected macrophages and epithelial cells. Thus, while some intracellular pathogens evade host defense responses by modulating with membrane trafficking or cell signaling in the infected cells, the host cells have also developed mechanisms for inhibiting infection.

Giardia lamblia behavior under cytochalasins treatment.

Giardia lamblia, a flagellated protist, is the parasite most commonly found in the intestinal tract of humans and other mammals causing a disease known as giardiasis. This parasite presents several cytoskeletal structures whose major components are microtubules, namely: the ventral adhesive disk, eight flagella axonemes, the median body, and funis. However, the cytoskeletal filamentous structures are poorly understood, and therefore, less studied.

Centrin in Giardia lamblia - ultrastructural localization.

Giardia lamblia is a multiflagellar parasite and one of the earliest diverging eukaryotic cells. It possesses a complex cytoskeleton based on different groups of microtubular structures - a ventral adhesive disc, four pairs of flagella, a median body and funis. Centrin is an important member of the EF-hand family of calcium-binding proteins, and it is known to show calcium-sensitive contractile behaviour.