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Functional Characterization of the Avian Inflammatory Mediators Nod1, MIF and IL-22

Inflammation can be initiated by an innate immune sensor, followed by activation of a signal mediator, resulting in control of immune response by a signal regulator. Mammalian nucleotide-binding oligomerization domain protein 1 (Nod1) and Nod2 initiate host innate immune response by recognition of specific bacterial molecules, resulting in the production of pro-inflammatory cytokines, chemokines, and anti-microbial peptides. A candidate sequence of chicken Nod1 (ChNod1) was identified with no current evidence of ChNod2. Stimulation of transiently overexpressed ChNod1 and its mutants with mammalian Nod-specific ligands was not conclusive of the function of ChNod1 most likely due to self-activation of ChNod1. In vitro studies showed no significant difference in expression of Nod1, its signaling molecules and pro-inflammatory cytokines in stimulated chicken mononuclear cells with synthetic ligands for mammalian Nod1 or Nod2.

A signal mediator, macrophage migration inhibitory factor (MIF) inhibits the random migration of macrophages. Chemotaxis assay using recombinant ChMIF (rChMIF) revealed a substantial decrease in migration of macrophages. qRT-PCR analysis revealed that the presence of rChMIF enhanced levels of IL-1β and iNOS during monocytes stimulation with LPS. Additionally, Con A-stimulated lymphocytes exhibited enhanced IFN-γ and IL-2 transcripts in the presence of rChMIF.

IL-22, which may act as a signal regulator, is an important effector of activated Th1 and Th17 as well as natural killer cells during inflammation. Recombinant ChIL-22 alone did not have an impact on chicken embryo kidney epithelial cells (CKECs); however, co-stimulation of CKECs with LPS and rChIL-22 enhanced the production of pro-inflammatory cytokines and anti-microbial peptides. Furthermore, rChIL-22 alone stimulated acute phase reactants in chicken embryo liver cells. These effects of rChIL-22 were abolished by addition of rChIL22 binding protein. Taken together, these results indicate an important role of ChIL-22 on epithelial cells and hepatocytes during inflammation.

In this project, we identified and characterized the avian inflammatory mediators ChNod1, ChMIF, and ChIL-22. Studying each of their biological function in avian inflammation, especially under pathogenic challenges in epithelial tissues will provide a foundation for understanding the role of these inflammatory mediators in mucosal immunity. / Ph. D.

Identiferoai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/77232
Date31 October 2011
CreatorsKim, Sungwon
ContributorsAnimal and Poultry Sciences, Dalloul, Rami A., McElroy, Audrey P., Miska, Kate B., Wong, Eric A., Li, Liwu, Keeler, Calvin L.
PublisherVirginia Tech
Source SetsVirginia Tech Theses and Dissertation
Languageen_US
Detected LanguageEnglish
TypeDissertation, Text
Formatapplication/pdf
RightsIn Copyright, http://rightsstatements.org/vocab/InC/1.0/

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