Role of the Inflammasome, IL-1β, and IL-18 in Bacterial Infections

The inflammasome is an important innate immune pathway that regulates at least two host responses protective against infections: (1) secretion of the proinflammatory cytokines IL-1β and IL-18 and (2) induction of pyroptosis, a form of cell death. Inflammasomes, of which different types have been identified, are multiprotein complexes containing pattern recognition receptors belonging to the Nod-like receptor family or the PYHIN family and the protease caspase-1. The molecular aspects involved in the activation of different inflammasomes by various pathogens are being rapidly elucidated, and their role during infections is being characterized. Production of IL-1β and IL-18 and induction of pyroptosis of the infected cell have been shown to be protective against many infectious agents. Here, we review the recent literature concerning inflammasome activation in the context of bacterial infections and identify important questions to be answered in the future

Use of a commercial enzyme immunoassay to monitor dengue virus replication in cultured cells

Current methods for dengue virus quantitation are either time consuming, technically demanding or costly. As an alternative, the commercial enzyme immunoassay Platelia™ Dengue NS1 AG (Bio-Rad Laboratories) was used to monitor semiquantitatively dengue virus replication in cultured cells. The presence of NS1 protein was evaluated in supernatants from Vero and C6/36 HT cells infected with dengue virus. The amount of NS1 detected in the supernatants of infected cells was proportional to the initial MOI used and to the time of post infection harvest. This immunoassay was also able to detect the presence of NS1 in the supernatants of infected human macrophages. Inhibition of dengue virus replication in C6/36 HT cells treated with lysosomotropic drugs was readily monitored with the use of this assay. These results suggest that the Platelia™ Dengue NS1 AG kit can be used as a fast and reliable surrogate method for the relative quantitation of dengue virus replication in cultured cells

Intervención educativa en niños de escuelas de tiempo completo en Ciudad Mante, Tamaulipas.

Introducción: Para prevenir enfermedades relacionadas con desórdenes alimenticios, se deben implementar intervenciones que aborden educación, nutrición y actividad física en escuelas primarias de tiempo completo (EPTC) en México. Objetivo: Evaluar la efectividad de una intervención educativa sobre el estado nutricional, nivel de conocimientos, hábitos de alimentación, actividad física e implementación de menús saludables en escolares de entre 6 y 12 años. Materiales y métodos: Estudio cuasiexperimental, descriptivo longitudinal, con una muestra de 262 alumnos de 2 EPTC, (grupo intervenido y grupo control) de Ciudad Mante, Tamaulipas, México. Se realizó una encuesta de conocimiento, frecuencia alimenticia y actividad física, además de la evaluación antropométrica al inicio y al final de la intervención. En el grupo intervenido se cambiaron los menús escolares, se impartieron pláticas sobre los hábitos de alimentación y se implementó actividad física durante cuatro meses. Resultados: El sobrepeso y obesidad general al inicio y final de la intervención fue del 46% y 28% respectivamente. La intervención educativa logró disminuir el bajo peso, la obesidad y el sobrepeso. Se incrementó el tiempo de actividad física en los participantes. Conclusiones: La intervención educativa sí es funcional en EPTC con alimentación correcta, hábitos saludables y actividad física puede mejorar el estado nutricional en los escolares.

Inflammasome-dependent Pyroptosis and IL-18 Protect against Burkholderia pseudomallei Lung Infection while IL-1β Is Deleterious

Burkholderia pseudomallei is a Gram-negative bacterium that infects macrophages and other cell types and causes melioidosis. The interaction of B. pseudomallei with the inflammasome and the role of pyroptosis, IL-1β, and IL-18 during melioidosis have not been investigated in detail. Here we show that the Nod-like receptors (NLR) NLRP3 and NLRC4 differentially regulate pyroptosis and production of IL-1β and IL-18 and are critical for inflammasome-mediated resistance to melioidosis. In vitro production of IL-1β by macrophages or dendritic cells infected with B. pseudomallei was dependent on NLRC4 and NLRP3 while pyroptosis required only NLRC4. Mice deficient in the inflammasome components ASC, caspase-1, NLRC4, and NLRP3, were dramatically more susceptible to lung infection with B. pseudomallei than WT mice. The heightened susceptibility of Nlrp3-/- mice was due to decreased production of IL-18 and IL-1β. In contrast, Nlrc4-/- mice produced IL-1β and IL-18 in higher amount than WT mice and their high susceptibility was due to decreased pyroptosis and consequently higher bacterial burdens. Analyses of IL-18-deficient mice revealed that IL-18 is essential for survival primarily because of its ability to induce IFNγ production. In contrast, studies using IL-1RI-deficient mice or WT mice treated with either IL-1β or IL-1 receptor agonist revealed that IL-1β has deleterious effects during melioidosis. The detrimental role of IL-1β appeared to be due, in part, to excessive recruitment of neutrophils to the lung. Because neutrophils do not express NLRC4 and therefore fail to undergo pyroptosis, they may be permissive to B. pseudomallei intracellular growth. Administration of neutrophil-recruitment inhibitors IL-1ra or the CXCR2 neutrophil chemokine receptor antagonist antileukinate protected Nlrc4-/- mice from lethal doses of B. pseudomallei and decreased systemic dissemination of bacteria. Thus, the NLRP3 and NLRC4 inflammasomes have non-redundant protective roles in melioidosis: NLRC4 regulates pyroptosis while NLRP3 regulates production of protective IL-18 and deleterious IL-1β

Immunogenic Subviral Particles Displaying Domain III of Dengue 2 Envelope Protein Vectored by Measles Virus

Vaccines against dengue virus (DV) are commercially nonexistent. A subunit vaccination strategy may be of value, especially if a safe viral vector acts as biologically active adjuvant. In this paper, we focus on an immunoglobulin-like, independently folded domain III (DIII) from DV 2 envelope protein (E), which contains epitopes that elicits highly specific neutralizing antibodies. We modified the hepatitis B small surface antigen (HBsAg, S) in order to display DV 2 DIII on a virus-like particle (VLP), thus generating the hybrid antigen DIII-S. Two varieties of measles virus (MV) vectors were developed to express DIII-S. The first expresses the hybrid antigen from an additional transcription unit (ATU) and the second additionally expresses HBsAg from a separate ATU. We found that this second MV vectoring the hybrid VLPs displaying DIII-S on an unmodified HBsAg scaffold were immunogenic in MV-susceptible mice (HuCD46Ge-IFNarko), eliciting robust neutralizing responses (averages) against MV (1:1280 NT90), hepatitis B virus (787 mIU/mL), and DV2 (1:160 NT50) in all of the tested animals. Conversely, the MV vector expressing only DIII-S induced immunity against MV alone. In summary, DV2 neutralizing responses can be generated by displaying E DIII on a scaffold of HBsAg-based VLPs, vectored by MV

Use of a commercial enzyme immunoassay to monitor dengue virus replication in cultured cells-1

Ere collected and used for: measurement of NS1 protein levels with Platelia™ Dengue NS1 Ag kit (open symbols) and for focus forming units (FFU) calculation (solid symbols). Points are mean values of three independent experiments.<p><b>Copyright information:</b></p><p>Taken from "Use of a commercial enzyme immunoassay to monitor dengue virus replication in cultured cells"</p><p>http://www.virologyj.com/content/5/1/51</p><p>Virology Journal 2008;5():51-51.</p><p>Published online 25 Apr 2008</p><p>PMCID:PMC2386455.</p><p></p

Use of a commercial enzyme immunoassay to monitor dengue virus replication in cultured cells-0

Ent times post-infection, the media were collected and tested for the presence of NS1 protein with Platelia™ Dengue NS1 Ag kit. (C) Ten micro liters of the supernatant media collected from the experiments shown in (A) were mixed with 40 μl of diluent buffer provided with the kit and used to measure NS1 protein levels with Platelia™ Dengue NS1 Ag kit. Points in (A) and (B) are mean values ± SD of three independent experiments.<p><b>Copyright information:</b></p><p>Taken from "Use of a commercial enzyme immunoassay to monitor dengue virus replication in cultured cells"</p><p>http://www.virologyj.com/content/5/1/51</p><p>Virology Journal 2008;5():51-51.</p><p>Published online 25 Apr 2008</p><p>PMCID:PMC2386455.</p><p></p

Use of a commercial enzyme immunoassay to monitor dengue virus replication in cultured cells-4

Ere collected and used for: measurement of NS1 protein levels with Platelia™ Dengue NS1 Ag kit (open symbols) and for focus forming units (FFU) calculation (solid symbols). Points are mean values of three independent experiments.<p><b>Copyright information:</b></p><p>Taken from "Use of a commercial enzyme immunoassay to monitor dengue virus replication in cultured cells"</p><p>http://www.virologyj.com/content/5/1/51</p><p>Virology Journal 2008;5():51-51.</p><p>Published online 25 Apr 2008</p><p>PMCID:PMC2386455.</p><p></p