Flavonoids, nobiletin, heptamethoxyflavone, and genistein enhance antigen-presenting cell function in vitro

Abstract

Aim: Antigen (Ag) presentation by Ag-presenting cells (APCs) is the first step in the generation of adaptive humoral and cellular immune responses. However, there have been few studies on the effects of flavonoids on APC function. In this study, we examined the effects of five polymethoxyflavones, two isoflavones, and one flavanol on CD11c+ dendritic cell function. Methods: CD11c+ dendritic cells were differentiated from bone marrow cells by culturing with granulocyte macrophage-colony stimulating factor. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The Ag-presenting ability was determined by a mixed lymphocyte reaction assay. Expressions of MHC class II, CD40, CD80, and CD86 molecules on CD11c+ cells were determined by flow cytometric analysis. Lipopolysaccharide-induced inflammatory cytokines productions were determined by enzyme-linked immunosorbent assay. Results: The flavonoids used in the study did not show strong toxicity to CD11c+ cells. Nobiletin, heptamethoxyflavone, and genistein enhance Ag-presenting function. Nobiletin and heptamethoxyflavone increased the expression of MHC class II and CD80 molecules. A direct correlation between APC function and lipopolysaccharide-induced cytokine production was not found. Conclusions: The results of the in vitro study indicate that flavonoids, nobiletin, heptamethoxyflavone, and genistein regulate innate dendritic cell function.

Keywords

• antigen-presenting cells
• citrus flavonoids
• nobiletin
• heptamethoxyflavone
• genistein