Research in practice: Different dendritic cell types in skin with various functions - important implications for...

It was long believed that epidermal Langerhans cells (LC) are responsible for the initiation of cellular immunity. Only recently it has been shown that in skin alone 5 different subtypes of dendritic cells (DC) can be identified. Among these, LC, but also two Langerin-expressing dermal DC populations and two more Langerin-negative DC subtypes exist. Novel findings in the model disease leishmaniasis, as well as evidence from research in contact hypersensitivity, have revealed that activation of LC in skin leads to induction of regulatory, immunosuppressive T cells, whereas the other skin DC subtypes stimulate effector T cells. Thus, when producing vaccines designed for intradermal use, it would seem advisable to attempt to activate dermal DC subtypes while avoiding activation of epidermal LC.