Changes in gene expression in gamma delta T cells induced by Yamoa

Yamoa is marketed and sold as a dietary supplement with anecdotal positive effects in asthma and hay fever. We determined that Yamoa (ground bark of Funtumia elastica tree) stimulated innate immunity in part by affecting gamma delta T cells. Yamoa had distinct priming effects, very similar to, but more robust than, that of lipopolysaccharide (LPS), on bovine, mouse and human gamma delta T cells. However, the optimal effect was dependent on the presence of accessory cells. Gene expression patterns in bovine gamma delta T cells and monocytes induced by Yamoa were very similar to those induced by ultrapure LPS, but the agonists in Yamoa did not signal entirely through TLR4. Yamoa stimulated human cells to produce cytokines involved innate protection. The bioactive component of Yamoa was delineated to a complex polysaccharide fraction (Yam-I). Intraperitoneal injection of Yamoa and very low doses of Yam-I in mice induced rapid increases peritoneal neutrophils directed by changes chemokine expression. Yamoa and Yam-I were effective as therapeutic treatments in mice with Salmonella enterica serotype Typhimurium (ST) induced enterocolitis that resulted in decreased bacterial counts in feces. This initial characterization of the immune stimulatory properties of polysaccharides derived from Yamoa suggests potential mechanisms for positive effects in asthma and that they have potential for application in infectious disease settings. .

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Graff JC, Kimmel EM, Freedman B, Schepetkin IA, Holderness J, Quinn MT, Jutila MA, Hedges JF