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.