Gum Arabic (GA), a nonabsorbable nutrient manufactured from the exudate of Acacia senegal, is composed of a complex polysaccharide. GA is used by the pharmaceutical and food industry as an emulsifier but may, at an appropriate dosage, modify intestinal transport. Dendritic cells (DCs) can protrude between epithelial cells and sense the composition of the lumen. As DCs are stimulated by bacterial polysaccharides, we hypothesized that GA may similarly stimulate DCs. To test that hypothesis, mouse DCs were treated with either LPS or GA and expression of maturation markers, phagocytotic activity, cytokine production and ability to stimulate CD4+ T cells in allogenic mixed leukocyte reaction (allo-MLR) was analyzed. As a result both LPS and GA increased the percentage of CD11c+CD86+, CD11c+MHCII+, CD11c+CD40+, CD54-expressing DCs and decreased their phagocytic activity. Both LPS and GA stimulated the production of IL-6, IL-10, IL12p70 and TNFΑ in a p38- and/or ERK-dependent manner. GA treatment led to an enhanced IL-10 secretion, whereas LPS was more effective on IL-6 and IL-12p70 production. Both LPS- and GA-stimulated DCs enhanced CD4+ T cell proliferation but the profile of cytokines produced in allo-MLR was different. High levels of IL-10 and IL-6 were observed in the presence of GA-treated DCs, whereas IFN-Γ and IL-12p70 production was similar with LPS- or GA-treated DCs. LPS upregulated p38 and transiently ERK1/2, while GA led to more sustained activation of ERK1/2, only. In conclusion, the observations reveal a powerful immunomodulatory effect of GA.

Keywords:
Interferon γ, Interleukin 6, Interleukin 12, TNFα, Phagocytosis, MAPK, Erk
This content is only available via PDF.
© 2010 S. Karger AG, Basel
2010
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.