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Gomez F.A.,Pontifical Catholic University of Valparaíso | Tobar J.A.,Laboratorio Centrovet | Henriquez V.,Pontifical Catholic University of Valparaíso | Sola M.,Laboratorio Centrovet | And 3 more authors.
PLoS ONE | Year: 2013

Piscirickettsia salmonis is a fish bacterial pathogen that has severely challenged the sustainability of the Chilean salmon industry since its appearance in 1989. As this Gram-negative bacterium has been poorly characterized, relevant aspects of its life cycle, virulence and pathogenesis must be identified in order to properly design prophylactic procedures. This report provides evidence of the functional presence in P. salmonis of four genes homologous to those described for Dot/Icm Type IV Secretion Systems. The Dot/Icm System, the major virulence mechanism of phylogenetically related pathogens Legionella pneumophila and Coxiella burnetii, is responsible for their intracellular survival and multiplication, conditions that may also apply to P. salmonis. Our results demonstrate that the four P. salmonis dot/icm homologues (dotB, dotA, icmK and icmE) are expressed both during in vitro tissue culture cells infection and growing in cell-free media, suggestive of their putative constitutive expression. Additionally, as it happens in other referential bacterial systems, temporal acidification of cell-free media results in over expression of all four P. salmonis genes, a well-known strategy by which SSTIV-containing bacteria inhibit phagosome-lysosome fusion to survive. These findings are very important to understand the virulence mechanisms of P. salmonis in order to design new prophylactic alternatives to control the disease. © 2013 Gómez et al.


Tobar J.A.,Laboratorio Centrovet | Jerez S.,Laboratorio Centrovet | Caruffo M.,Laboratorio Centrovet | Bravo C.,Laboratorio Centrovet | And 3 more authors.
Vaccine | Year: 2011

Effective oral immunization systems may be very helpful to the salmon industry, particularly during the seawater growth stages in which vaccination through injection is not possible. During the seawater growing stage, fish become more susceptible to several types of disease, due to the natural decay of vaccine-induced immune responses. In this study, we demonstrate the immune response and efficacy of a new salmonid rickettsial septicaemia (SRS) oral vaccine, developed using MicroMatrix™ Technology. The vaccine, which is administered together with daily feed ration, induces a specific immune response at local and systemic levels. Anti-Piscirickettsia salmonis specific antibodies were detected as soon as 300 degree-days after vaccination. Furthermore, oral vaccination was able to protect fish against a lethal pathogen challenge when administered either as a primary vaccination or as a booster for an injected vaccine. Results show that oral vaccination is an efficacious treatment for the prevention of SRS outbreaks throughout the salmon culture period. © 2010 Elsevier Ltd.


Garcia K.,University of Chile | Escobar G.,University of Chile | Mendoza P.,University of Chile | Beltran C.,University of Chile | And 7 more authors.
Mediators of Inflammation | Year: 2016

Neisseria gonorrhoeae (Ngo) has developed multiple immune evasion mechanisms involving the innate and adaptive immune responses. Recent findings have reported that Ngo reduces the IL-1β secretion of infected human monocyte-derived macrophages (MDM). Here, we investigate the role of adenosine triphosphate (ATP) in production and release of IL-1β in Ngo-infected MDM. We found that the exposure of Ngo-infected MDM to ATP increases IL-1β levels about ten times compared with unexposed Ngo-infected MDM (P<0.01). However, we did not observe any changes in inflammasome transcriptional activation of speck-like protein containing a caspase recruitment domain (CARD) (ASC, P>0.05) and caspase-1 (CASP1, P>0.05). In addition, ATP was not able to modify caspase-1 activity in Ngo-infected MDM but was able to increase pyroptosis (P>0.01). Notably ATP treatment defined an increase of positive staining for IL-1β with a distinctive intracellular pattern of distribution. Collectively, these data demonstrate that ATP induces IL-1β secretion by a mechanism not related to the NLRP3/ASC/caspase-1 axis and likely is acting at the level of vesicle trafficking or pore formation. © 2016 Killen Garciá et al.


Arancibia S.,Investigacion y Desarrollo | Arancibia S.,Laboratorio Centrovet | Barrientos A.,Laboratorio Centrovet | Torrejon J.,Laboratorio Centrovet | And 2 more authors.
Nanomedicine | Year: 2016

Aim: In the present study, we examine the effects of copper oxide nanoparticles (CuNP) on macrophage immune response and the signaling pathways involved. Materials & Methods: A peritonitis model was used to determine in vivo immune cells recruitment, while primary macrophages were used as an in vitro model for the cellular and molecular analysis. Results: In vivo, CuNP induce significant macrophages recruitment to the site of injection. In vitro, in LPS-stimulated primary macrophages, the co-treatment with CuNP inhibited the production of NO in a dose-dependent manner. The mechanism underlying NO and proinflammatory cytokines inhibition was associated with an increased arginase activity. Macrophage stimulation with CuNP did not provoke any cytokine secretion; however, arginase inhibition promoted TNFα and MIP-1β production. In addition, CuNP induced the expression of COX-2 and the production of PGE2 through arginase activation. Conclusion: Our results demonstrate that CuNP activate arginase and suppress macrophage innate immune response. © 2015 Sergio Arancibia.


PubMed | Laboratorio Centrovet
Type: Journal Article | Journal: Vaccine | Year: 2011

Effective oral immunization systems may be very helpful to the salmon industry, particularly during the seawater growth stages in which vaccination through injection is not possible. During the seawater growing stage, fish become more susceptible to several types of disease, due to the natural decay of vaccine-induced immune responses. In this study, we demonstrate the immune response and efficacy of a new salmonid rickettsial septicaemia (SRS) oral vaccine, developed using MicroMatrix Technology. The vaccine, which is administered together with daily feed ration, induces a specific immune response at local and systemic levels. Anti-Piscirickettsia salmonis specific antibodies were detected as soon as 300 degree-days after vaccination. Furthermore, oral vaccination was able to protect fish against a lethal pathogen challenge when administered either as a primary vaccination or as a booster for an injected vaccine. Results show that oral vaccination is an efficacious treatment for the prevention of SRS outbreaks throughout the salmon culture period.


PubMed | Laboratorio Centrovet, University of Chile and Investigacion y Desarrollo
Type: Journal Article | Journal: Nanomedicine (London, England) | Year: 2016

In the present study, we examine the effects of copper oxide nanoparticles (CuNP) on macrophage immune response and the signaling pathways involved.A peritonitis model was used to determine in vivo immune cells recruitment, while primary macrophages were used as an in vitro model for the cellular and molecular analysis.In vivo, CuNP induce significant macrophages recruitment to the site of injection. In vitro, in LPS-stimulated primary macrophages, the co-treatment with CuNP inhibited the production of NO in a dose-dependent manner. The mechanism underlying NO and proinflammatory cytokines inhibition was associated with an increased arginase activity. Macrophage stimulation with CuNP did not provoke any cytokine secretion; however, arginase inhibition promoted TNF and MIP-1 production. In addition, CuNP induced the expression of COX-2 and the production of PGE2 through arginase activation.Our results demonstrate that CuNP activate arginase and suppress macrophage innate immune response.

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