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BACTERIOLOGY * EPIDEMIOLOGY * IMMUNOLOGY * PARASITOLOGY * TOXINOLOGY * VIROLOGY * PHILOSOPHY OF SCIENCE * FUNDRAISING |
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Publications are dated since 1995 and are written by (or in participation with) Central American Investigators. |
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2007 * BIBLIOGRAPHY |
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Brucella abortus uses a stealthy strategy to avoid
activation of the innate Immune system during the onset of infection Barquero-Calvo et al., PloSOne : DOI number 10.1371/journal.pone.0000631 This work presents experimental evidence to understand the natural course of brucellosis, a zoonosis of worldwide importance. Brucella abortus was first described as an intracellular parasite in 1919 (Smith, J. Exp. Med., 29:451) and, since then, the basis of this behavior has attracted most of the research carried out in the field. A type IV secretion system and some atypical virulence factors relevant to intracellular survival (a non canonical lipopolysaccharide and periplasmic cyclic glucans) have been described for Brucella. Although these findings have improved the understanding of this pathogen, they do not provide a general hypothesis encompassing of the clinical effects and pathogenesis that we observe in animals and human beings. In these hosts, brucellosis is a stealthy disease in which infection runs ahead of overt symptoms, with incubation periods that can be exceedingly long, without pathognomic signs and without the characteristics of acute infection. Hosts can be asymptomatic and congenital transmission in this situation is not rare. As consequence those characteristics, the disease is often misdiagnosed or not diagnosed in humans, and very difficult to eradicate from animals. In this compressive and systematic work, the authors have demonstrated for the first time, that B. abortus evades innate immunity, thus hampering the support that this innate system provides to adaptive immunity. The participating experimental teams have contrasted the innate immune responses and proinflammatory profiles in wild type and knock out animals during the first stages of Brucella and Salmonella infections, the latter considered as one of the paradigms of gram-negative intracellular parasites. By using for the first time this comparative approach, it was possible to show (1) the distinct strategy followed by Brucella; and (2) to connect it to previous fragmentary evidence, supporting the notion that the lack of macromolecules with conspicuous pathogen associated molecular patterns is decisive in Brucella virulence. These results explain the course of brucellosis in the natural hosts and provide a conceptual framework to understand the disease and the clinical development of this malady. Moreover, this model can be extended to other intracellular parasites that are phylogenetically related or structurally similar to Brucella, which also cause long lasting infections. |
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