Effects of d-allose on the endocytic activity of dendritic cells and the subsequent stimulation of T cells

We examined the effects of a rare sugar, d-allose, which is 6-carbon monosaccharide, on endocytosis and T cell stimulation by dendritic cells (DCs). The endocytosis of BCG-anti-BCG immune complexes by DCs markedly decreased in d-allose-containing medium. Co-culture with T cells (mixed leukocyte reaction, MLR) of DCs, which had been exposed to BCG in d-allose-supplemented medium, induced apoptosis of CD4+ T cells in a manner dependent on d-allose concentration. After the MLR, DCs cultured in the medium with d-allose expressed less CD40 and more Fas ligands than those cultured without d-allose. It was suggested that the functions of DCs, internalization, processing and the subsequent antigen presentation to T cells, are down-regulated via the action of d-allose.