Mycobacterium avium subsp. paratuberculosis is an intracellular pathogen that has been implicated in Johne’s disease in cattle and possibly Crohn’s disease in humans. Cells expressing the NK cell activating receptor NKp46 have been shown to play an important role in mycobaterial infections in cattle by producing IFNγ and lysing infected monocytes. Therefore, compounds that enhance the activity of these cells may be useful in the treatment of these types of pathogens. Oenothein B is an immunomodulatory tannin isolated from Epilobium angustifolium plants and shown to have antitumor properties. This compound is known to activate myeloid cells, as well as NK cells, NKT cells, and γδ T cells. Previous work from our laboratory has shown that certain tannins have the ability to enhance the response of innate lymphocytes to secondary stimuli. Here, we report that oenothein B is capable of priming bovine peripheral blood mononuclear cells to produce increased levels of IFNγ in response to the IFNγ-inducing cytokine IL-18. This enhanced response is dependent upon the presence of cells expressing NKp46. Our preliminary results also suggest that oenothein B is able to enhance IFNγ production in response to M. avium subsp. paratuberculosis infected monocytes. This demonstrates that priming of innate lymphocytes by supplementation with specific polyphenols may be a useful strategy to enhance immunity to certain intracellular pathogens.
- Copyright © 2011 by The American Association of Immunologists, Inc.