Apple polyphenols suppress antigen presentation of ovalbumin by THP-1-derived dendritic cells

► We develop in vitro-generated human dendritic cells. ► We examine the effects of apple procyanidins on human dendritic cells. ► Apple procyanidins show the suppressive effect on antigen presentation of ovalbumin. ► The mechanism relies on the activation of ubiquitin-proteasome pathway.