Soybean isoflavones regulate dendritic cell function: implications in food allergy (79.16)

Abstract

Abstract Peanuts and tree nuts are the most allergenic foods in children and adults in the U.S. Several allergens in peanut and soy share amino acid similarity by as much as 60%, yet soy allergy is less common and less severe compared to peanut allergy. Unlike peanuts, soybeans are rich in isoflavones such as genistein, daidzein and glycitein and are the most common source of isoflavones in the human food supply. Isoflavones are known to have anti-inflammatory and anti-oxidant properties. The maximum bioavailability of isoflavones is from the gut since they are quickly converted to inactive forms before entering the circulation. Therefore, we hypothesize that the active-isoflavones in the gut milieu are capable of modulating the initiation of immune responses to dietary-antigens by regulating DC function. In vitro, isoflavones inhibited lipopolysachharide (LPS) or cholera toxin (CT)-induced cell-surface expression of CD83, CD80 and CD86 in a dose dependent manner in human monocyte derived dendritic cells (MDDC). Isoflavone treatment augmented CT induced up-regulation of CXCR4 and CCR7. Isoflavone treated MDDC inhibited T cell proliferation in a mixed lymphocyte reaction and inhibited the secretion of Th2 cytokines. We hypothesize that these changes in DC function could induce tolerance to food allergens. Studies are underway to test this hypothesis in a peanut allergic mouse model.