Amorena, B. (Beatriz)

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    The extradomain A of fibronectin (EDA) combined with poly(I:C) enhances the immune response to HIV-1 p24 protein and the protection against recombinant Listeria monocytogenes-Gag infection in the mouse model
    (Elsevier, 2012) Asensio, A.C. (Aaron C.); San-Roman, B. (Beatriz); Garrido, V. (Victoria); Mansilla, C. (Cristina); Andres, D. (D.) de; Muñoz, P. (Pilar); Amorena, B. (Beatriz); Obregon, P. (Patricia); Andres, X. (Ximena) de; Arribillaga, L. (Laura); Grillo, M.J. (María Jesús); Lasarte, J.J. (Juan José)
    The development of effective vaccines against HIV-1 infection constitutes one of the major challenges in viral immunology. One of the protein candidates in vaccination against this virus is p24, since it is a conserved HIV antigen that has cytotoxic and helper T cell epitopes as well as B cell epitopes that may jointly confer enhanced protection against infection when used in immunization-challenge approaches. In this context, the adjuvant effect of EDA (used as EDAp24 fusion protein) and poly(I:C), as agonists of TLR4 and TLR3, respectively, was assessed in p24 immunizations using a recombinant Listeria monocytogenes HIV-1 Gag proteins (Lm-Gag, where p24 is the major antigen) for challenge in mice. Immunization with EDAp24 fusion protein together with poly(I:C) adjuvant induced a specific p24 IFN-γ production (Th1 profile) as well as protection against a Lm-Gag challenge, suggesting an additive or synergistic effect between both adjuvants. The combination of EDA (as a fusion protein with the antigen, which may favor antigen targeting to dendritic cells through TLR4) and poly(I:C) could thus be a good adjuvant candidate to enhance the immune response against HIV-1 proteins and its use may open new ways in vaccine investigations on this virus.
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    The enterococcal surface protein, Esp, is involved in Enterococcus faecalis biofilm formation
    (American Society for Microbiology, 2001) Cucarella, C. (Carme); Leiva, J. (José); Lasa, I. (Íñigo); Toledo-Arana, A. (Alejandro); Amorena, B. (Beatriz); Arrizubieta, M.J. (María Jesús); Penades, J.R. (José R.); Lamata, M. (M.); Solano, C. (Cristina); Valle, J. (Jaione)
    The enterococcal surface protein, Esp, is a high-molecular-weight surface protein of unknown function whose frequency is significantly increased among infection-derived Enterococcus faecalis isolates. In this work, a global structural similarity was found between Bap, a biofilm-associated protein of Staphylococcus aureus, and Esp. Analysis of the relationship between the presence of the Esp-encoding gene (esp) and the biofilm formation capacity in E. faecalis demonstrated that the presence of the esp gene is highly associated (P < 0.0001) with the capacity of E. faecalis to form a biofilm on a polystyrene surface, since 93.5% of the E. faecalis esp-positive isolates were capable of forming a biofilm. Moreover, none of the E. faecalis esp-deficient isolates were biofilm producers. Depending on the E. faecalis isolate, insertional mutagenesis of esp caused either a complete loss of the biofilm formation phenotype or no apparent phenotypic defect. Complementation studies revealed that Esp expression in an E. faecalis esp-deficient strain promoted primary attachment and biofilm formation on polystyrene and polyvinyl chloride plastic from urine collection bags. Together, these results demonstrate that (i) biofilm formation capacity is widespread among clinical E. faecalis isolates, (ii) the biofilm formation capacity is restricted to the E. faecalis strains harboring esp, and (iii) Esp promotes primary attachment and biofilm formation of E. faecalis on abiotic surfaces.
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    Protection from Staphylococcus aureus mastitis associated with poly-N-acetyl beta-1,6 glucosamine specific antibody production using biofilm-embedded bacteria
    (Elsevier, 2009) Lasa, I. (Íñigo); Maira-Litran, T. (T.); Solano, C. (C.); Penades, J. (J.); Marco, J. (J.); Andres, D. (D.) de; Amorena, B. (Beatriz); Prenafeta, A. (A.); Costa, L. (L.); Pier, G.B. (G.B.); Jimenez-Barbero, J. (J.); Irache, J.M. (Juan Manuel); Perez-Calvo, M.M. (M.M.); Rota, C. (C.); Grillo, M.J. (María Jesús); Valle, J. (Jaione)
    Staphylococcus aureus vaccines based on bacterins surrounded by slime, surface polysaccharides coupled to protein carriers and polysaccharides embedded in liposomes administered together with non-biofilm bacterins confer protection against mastitis. However, it remains unknown whether protective antibodies are directed to slime-associated known exopolysaccharides and could be produced in the absence of bacterin immunizations. Here, a sheep mastitis vaccination study was carried out using bacterins, crude bacterial extracts or a purified exopolysaccharide from biofilm
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    SarA and not sigmaB is essential for biofilm development by Staphylococcus aureus
    (Blackwell Publishing, 2003) Ghigo, J.M. (Jean Marc); Berasain, C. (Carmen); Lasa, I. (Íñigo); Toledo-Arana, A. (Alejandro); Amorena, B. (Beatriz); Penades, J.R. (José R.); Valle, J. (Jaione)
    Staphylococcus aureus biofilm formation is associated with the production of the polysaccharide intercellular adhesin (PIA/PNAG), the product of the ica operon. The staphylococcal accessory regulator, SarA, is a central regulatory element that controls the production of S. aureus virulence factors. By screening a library of Tn917 insertions in a clinical S. aureus strain, we identified SarA as being essential for biofilm development. Non-polar mutations of sarA in four genetically unrelated S. aureus strains decreased PIA/PNAG production and completely impaired biofilm development, both in steady state and flow conditions via an agr-independent mechanism. Accordingly, real-time PCR showed that the mutation in the sarA gene resulted in downregulation of the ica operon transcription. We also demonstrated that complete deletion of sigmaB did not affect PIA/PNAG production and biofilm formation, although it slightly decreased ica operon transcription. Furthermore, the sarA-sigmaB double mutant showed a significant decrease of ica expression but an increase of PIA/PNAG production and biofilm formation compared to the sarA single mutant. We propose that SarA activates S. aureus development of biofilm by both enhancing the ica operon transcription and suppressing the transcription of either a protein involved in the turnover of PIA/PNAG or a repressor of its synthesis, whose expression would be sigmaB-dependent.