TLR-3 and TLR-7/8 ligands indirectly activate Langerhans cells when intradermally injected by triggering the recruitment of inflammatory cells

Background TLR-3 and TLR-7/8 agonists are promising vaccine adjuvants but their effects on immune cells remain to be define in vivo. We analysed the modifications in the Langerhans cell (LC) network after intradermal injection of these TLR ligands in non-human primates used as a model for assessing human vaccines. LCs, which are the only antigen-presenting cells in the epidermis, are endowed with great ability to induce immune responses.