Browsing by MeSH term "Polysaccharides, Bacterial"
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Publication A Large Polysaccharide Produced by Helicobacter hepaticus Induces an Anti-inflammatory Gene Signature in Macrophages(2017-12-13) Danne, Camille; Ryzhakov, Grigory; Martinez-Lopez, Maria; Ilott, Nicholas Edward; Franchini, Fanny; Cuskin, Fiona; Lowe, Elisabeth C; Bullers, Samuel J; Arthur, J Simon C; Powrie, Fiona; Ministerio de Educación y Ciencia (España); Wellcome Trust; Kennedy Trust; Foundation Lous Jeantet; Unión Europea. Comisión Europea; Unión Europea. Comisión Europea. European Research Council (ERC)Interactions between the host and its microbiota are of mutual benefit and promote health. Complex molecular pathways underlie this dialog, but the identity of microbe-derived molecules that mediate the mutualistic state remains elusive. Helicobacter hepaticus is a member of the mouse intestinal microbiota that is tolerated by the host. In the absence of an intact IL-10 signaling, H. hepaticus induces an IL-23-driven inflammatory response in the intestine. Here we investigate the interactions between H. hepaticus and host immune cells that may promote mutualism, and the microbe-derived molecule(s) involved. Our results show that H. hepaticus triggers early IL-10 induction in intestinal macrophages and produces a large soluble polysaccharide that activates a specific MSK/CREB-dependent anti-inflammatory and repair gene signature via the receptor TLR2. These data identify a host-bacterial interaction that promotes mutualistic mechanisms at the intestinal interface. Further understanding of this pathway may provide novel prevention and treatment strategies for inflammatory bowel disease.Publication Capsule switching among C:2b:P1.2,5 meningococcal epidemic strains after mass immunization campaign, Spain(European Centre for Disease Prevention and Control (ECDC), 2002-12) Alcalá, Belén; Arreaza, Luisa; Salcedo, Celia; Uria, Maria J; De La Fuente, Laura; Vazquez-Moreno, Julio Alberto; Instituto de Salud Carlos IIIA mass immunization campaign for 18-month to 19-year-olds was undertaken in Spain in 1996-1997 because of an epidemic of serogroup C meningococcal disease associated with a C:2b:P1.2,5 strain belonging to the A4 lineage. Surveillance for the "capsule-switching" phenomenon producing B:2b:P1.2,5 isolates was undertaken. Of 2,975 meningococci characterized, B:2b:P1.2,5 and B:2b:P1.2 antigenic combinations were found in 18 isolates; 15 meningococci were defined as serogroup B belonging to the A4 lineage.Publication Eficacia de la vacuna meningocócica de polisacárido capsular del grupo C(Ministerio de Sanidad y Consumo (España), 1997-03) Gonzalez-Enriquez, Jesus; Garcia Comas, Luis; Alcaide Jimenez, Juan F; Saenz Calvo, Antonio; Conde Olasagasti, Jose LuisBACKGROUND: This report is a systematic review of the effect intensity and duration of the immune response to meningococcal serogroup C vaccine. The vaccine safety, efficacy and effectiveness are also analyzed. METHODS: MEDLINE literature search in the period 1970-1996. Meningoccocal polysaccharide vaccine clinical trials and human prospective studies were specifically searched. Quality of the retrieved studies were analyzed. Information available was integrated. RESULTS: Group C meningoccal polysaccharide vaccine is a safe product. Its efficacy is over 85% among adults and children over 5 years old. 70% (CI 95%: 5-91%) under 5 years old, and 55% among children 2-3 years old. The vaccine is not effective under 2 years. The duration of protective antibody levels decrease with age. The proportion of vaccinated children effectively protected one year after vaccination is low. Vaccination does not affect the immune response to ulterior revaccination. CONCLUSIONS: Group C meningococcal polysaccharide vaccine is indicated in adults and children over 2 years old to protect them from meningococcal disease due to group C when exposed to high risk of infection. The outbreaks control is the main indication for the use of this vaccine. Routine immunization in not outbreak situation is not recommended due to the small vaccine protection in children under 2 years old, the limited efficacy in children under 5, and the short duration of the immunity in children. Fundamento: Este trabajo consiste esencialmente en una revisión sistemática de la literatura científica sobre los efectos, intensidad y duración de la respuesta serológica, así como sobre la eficacia, efectividad y seguridad de la vacuna meningocócica de polisacárido capsular del grupo C. Métodos: Búsqueda en repertorio MEDLINE en el periodo 1970-1996. Búsqueda específica de ensayos clínicos aleatorizados y estudios de intervención prospectivos en humanos con vacunas de polisacáridos capsulares de meningococo en el mismo repertorio y periodo. Análisis crítico de literatura científica y síntesis de evidencia. Resultados: La vacuna de polisacárido capsular del serogrupo C es considerada segura y ha mostrado una eficacia superior al 85% en adultos y niños mayores, 70% (IC95%: 5-91%) en niños menores de 5 años y 55% (IC90%: 14-76%) en niños de 2-3 años. La vacuna no se ha mostrado eficaz en niños menores de 2 años. La duración de niveles de anticuerpos protectores disminuye con la edad. La proporción de niños menores de 6 años efectivamente protegidos al año de la vacunación es baja. La vacunación no limita la respuesta serológica de vacunaciones ulteriores. Conclusiones: La vacuna meningocócica de polisacárido capsular del serogrupo C está indicada en adultos y niños mayores de 2 años como protección contra la enfermedad meningocócica causada por este serogrupo en situaciones de alto riesgo de enfermedad. La escasa protección que ofrece la vacuna en los menores de 2 años, la limitada eficacia en menores de 5 años y la corta duración de la inmunidad que confiere a estas edades, hace que la vacunación rutinaria no esté recomendada y que la vacuna se use fundamentalmente en el control de brotes epidémicos causados por serogrupo C.Publication Emerging, Non-PCV13 Serotypes 11A and 35B of Streptococcus pneumoniae Show High Potential for Biofilm Formation In Vitro(Public Library of Science (PLOS), 2015-04-30) Domenech Lucas, Mirian; Damián, Diana; Ardanuy, Carmen; Liñares, Josefina; Fenoll, Asuncion; García, Ernesto; Ministerio de Economía y Competitividad (España); Instituto de Salud Carlos IIIBACKGROUND: Since the use of pneumococcal conjugate vaccines PCV7 and PCV13 in children became widespread, invasive pneumococcal disease (IPD) has dramatically decreased. Nevertheless, there has been a rise in incidence of Streptococcus pneumoniae non-vaccine serotypes (NVT) colonising the human nasopharynx. Nasopharyngeal colonisation, an essential step in the development of S. pneumoniae-induced IPD, is associated with biofilm formation. Although the capsule is the main pneumococcal virulence factor, the formation of pneumococcal biofilms might, in fact, be limited by the presence of capsular polysaccharide (CPS). METHODOLOGY/PRINCIPAL FINDINGS: We used clinical isolates of 16 emerging, non-PCV13 serotypes as well as isogenic transformants of the same serotypes. The biofilm formation capacity of isogenic transformants expressing CPSs from NVT was evaluated in vitro to ascertain whether this trait can be used to predict the emergence of NVT. Fourteen out of 16 NVT analysed were not good biofilm formers, presumably because of the presence of CPS. In contrast, serotypes 11A and 35B formed ≥45% of the biofilm produced by the non-encapsulated M11 strain. CONCLUSIONS/SIGNIFICANCE: This study suggest that emerging, NVT serotypes 11A and 35B deserve a close surveillance.Publication Interpretación de los resultados de laboratorio de estudios de protección tras la vacuna.(1998-09) Berron-Morato, Sonsoles; Sanz-Moreno, Juan Carlos; Martin Garcia, E; Salcedo Peláez, C; Bermúdez Saugar, MP; Vazquez-Moreno, Julio AlbertoTras la vacunación con vacuna polisacaroidea frente a Neisseria meningitis A+C, se obtiene una respuesta de anticuerpos polisacárido específicos hacia las dos semanas después, alcanzándose los niveles máximos de anticuerpos inducidos al mes de la vacunación1. En el momento actual, los dos métodos más ampliamente aceptados para conocer in vitro los niveles de seroconversión y "traducir" de ellos la protección adquirida son: medida de actividad bactericida del suero y medida de anticuerpos totales polisacárido-específicos.Publication Pleiotropic effects of cell wall amidase LytA on Streptococcus pneumoniae sensitivity to the host immune response(American Society for Microbiology (ASM), 2015-02) Ramos-Sevillano, Elisa; Urzainqui, Ana; Campuzano, Susana; Moscoso, Miriam; Gonzalez-Camacho, Fernando; Domenech Lucas, Mirian; Rodríguez de Córdoba, Santiago; Sánchez Madrid, Francisco; Brown, Jeremy S; García, Ernesto; Yuste, Jose Enrique; Ministerio de Economía y Competitividad (España); Instituto de Salud Carlos IIIThe complement system is a key component of the host immune response for the recognition and clearance of Streptococcus pneumoniae. In this study, we demonstrate that the amidase LytA, the main pneumococcal autolysin, inhibits complement-mediated immunity independently of effects on pneumolysin by a complex process of impaired complement activation, increased binding of complement regulators, and direct degradation of complement C3. The use of human sera depleted of either C1q or factor B confirmed that LytA prevented activation of both the classical and alternative pathways, whereas pneumolysin inhibited only the classical pathway. LytA prevented binding of C1q and the acute-phase protein C-reactive protein to S. pneumoniae, thereby reducing activation of the classical pathway on the bacterial surface. In addition, LytA increased recruitment of the complement downregulators C4BP and factor H to the pneumococcal cell wall and directly cleaved C3b and iC3b to generate degradation products. As a consequence, C3b deposition and phagocytosis increased in the absence of LytA and were markedly enhanced for the lytA ply double mutant, confirming that a combination of LytA and Ply is essential for the establishment of pneumococcal pneumonia and sepsis in a murine model of infection. These data demonstrate that LytA has pleiotropic effects on complement activation, a finding which, in combination with the effects of pneumolysin on complement to assist with pneumococcal complement evasion, confirms a major role of both proteins for the full virulence of the microorganism during septicemia.Publication Two genomic regions encoding exopolysaccharide production systems have complementary functions in B. cereus multicellularity and host interaction(Springer, 2020-01-22) Caro-Astorga, Joaquin; Álvarez-Mena, Ana; Hierrezuelo, Jesús; Guadix, Juan Antonio; Heredia-Ponce, Zahira; Arboleda-Estudillo, Yohanna; González-Munoz, Elena; de Vicente, Antonio; Romero, Diego; [Caro-Astorga,J; Álvarez-Mena,A; Hierrezuelo,J; Heredia-Ponce,Z; de Vicente,A; Romero,D] Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora” –Departamento de Microbiología, Universidad de Málaga, Málaga, Spain. [Guadix,JA] Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga - IBIMA, Málaga, Spain. [Guadix,JA] Centro Andaluz de Nanomedicina y Biotecnología (BIONAND), Junta de Andalucía, Universidad de Málaga, Campanillas (Málaga), Spain. [Arboleda-Estudillo,Y; González-Munoz,E] LARCEL, Andalusian Laboratory of Cell Reprogramming, Andalusian Center for Nanomedicine and Biotechnology-BIONAND, Málaga, Spain.Bacterial physiology and adaptation are influenced by the exopolysaccharides (EPS) they produce. These polymers are indispensable for the assembly of the biofilm extracellular matrix in multiple bacterial species. In a previous study, we described the profound gene expression changes leading to biofilm assembly in B. cereus ATCC14579 (CECT148). We found that a genomic region putatively dedicated to the synthesis of a capsular polysaccharide (eps2) was overexpressed in a biofilm cell population compared to in a planktonic population, while we detected no change in the transcript abundance from another genomic region (eps1) also likely to be involved in polysaccharide production. Preliminary biofilm assays suggested a mild role for the products of the eps2 region in biofilm formation and no function for the products of the eps1 region. The aim of this work was to better define the roles of these two regions in B. cereus multicellularity. We demonstrate that the eps2 region is indeed involved in bacterial adhesion to surfaces, cell-to-cell interaction, cellular aggregation and biofilm formation, while the eps1 region appears to be involved in a kind of social bacterial motility. Consistent with these results, we further demonstrate using bacterial-host cell interaction experiments that the eps2 region is more relevant to the adhesion to human epithelial cells and the zebrafish intestine, suggesting that this region encodes a bacterial factor that may potentiate gut colonization and enhance pathogenicity against humans.