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Is IutA from Escherichia coli a type 1 Thymus-independent antigen?

2013; Frontiers Media; Volume: 4; Linguagem: Inglês

10.3389/conf.fimmu.2013.02.00455

1664-3224

Landgraf Taise, Fernandes Fabr�cio, Coelho-Castelo Arlete, Panunto-Castelo Ademilson,

Protein purification and stability

Event Abstract Back to Event Is IutA from Escherichia coli a type 1 Thymus-independent antigen? Taise N. Landgraf1*, Fabrício F. Fernandes1, Arlete A. Coelho-Castelo1 and Ademilson Panunto-Castelo2 1 University of São Paulo, Biochemistry and Immunology, Brazil 2 University of São Paulo, Biology, Brazil Certain strains of Escherichia coli contain a pColV plasmid that encodes IutA, an outer membrane receptor for the iron-aerobactin complex. Preliminary results from our group suggest that IutA is a mitogen for B cells. Here we performed direct stimulation assays of CFSE-labeled B cells with recombinant IutA (rIutA) and indirect assays with B cells cocultured separately with spleen macrophages stimulated with rIutA using transwell membranes or cultured with conditioned medium from IutA-stimulated macrophages. We showed that rIutA was not able to induce directly the proliferation of B cells, but it induced macrophages to release a molecule that acted on B cells. When we used cells from mice MyD88-/-, we determined that MyD88 is crucial for signaling induced by rIutA in B cells, but not in macrophages. A similar analysis with cells from mice TLR4-/- or TLR2-/- revealed that these receptors were not required for rIutA signaling. Since IutA induced macrophages to produce IL-1 and signaling of IL-1 receptor is dependent on MyD88, we thought that IutA stimulated macrophages to produce IL-1 that, in turn, was responsible for B cell proliferation. This hypothesis was confirmed when we observed that B cells pretreated with IL-1 receptor antagonist had a significantly decrease in proliferation in response to conditioned medium from cultures of IutA-stimulated macrophages. Altogether, our results suggest that IutA induces polyclonal B-cell proliferation independently of T cells in a mechanism mediated by macrophages. These results open perspectives for studying IutA as a molecule that stimulates the mucosa-associated lymphoid tissue. 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Presentation Type: Abstract Topic: Innate immunity Citation: Landgraf TN, Fernandes FF, Coelho-Castelo AA and Panunto-Castelo A (2013). Is IutA from Escherichia coli a type 1 Thymus-independent antigen?. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00455 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 01 Apr 2013; Published Online: 22 Aug 2013. * Correspondence: Miss. Taise N Landgraf, University of São Paulo, Biochemistry and Immunology, RIBEIRAO PRETO, SP, 14049-900, Brazil, taise.landgraf@usp.br Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Taise N Landgraf Fabrício F Fernandes Arlete A Coelho-Castelo Ademilson Panunto-Castelo Google Taise N Landgraf Fabrício F Fernandes Arlete A Coelho-Castelo Ademilson Panunto-Castelo Google Scholar Taise N Landgraf Fabrício F Fernandes Arlete A Coelho-Castelo Ademilson Panunto-Castelo PubMed Taise N Landgraf Fabrício F Fernandes Arlete A Coelho-Castelo Ademilson Panunto-Castelo Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.