Pathogens, sensitizing chemicals and autoimmune diseases trigger T cell-driven inflammation in the skin under control of cutaneous Dendritic Cells (DCs). No in vitro human model recapitulates the features of cutaneous immune responses. Indeed, such models frequently lack an epidermal barrier, necessary to investigate topically applied compounds, and fail to acknowledge the influence of non-immune cells which modulate the activation of DCs and T cells. This represents a major shortcoming and prevents accurate pre-clinical evaluation of anti-inflammatory drugs, vaccine adjuvants or potentially allergenic chemicals (sensitizers). To resolve this, we developed a novel Innervated and Vascularized immunocompetent Tissue- Engineered Skin Tissue-Engineered Skin (IV-iTES) combining all structural and functional elements of the healthy skin. The IV-iTES model integrates human keratinocytes, fibroblasts, dendritic cells and pseudo-capillaries, as well as a sensory nerve network derived from either murine embryos or human induced pluripotent stem (iPS) cells. Our  culture conditions were adjusted to guarantee a stable phenotype for all cell populations, thereby mimicking steady-state human skin. The structure of the resulting co-culture and cell-specific markers were thoroughly characterized. Sensory nerves could be triggered in situ by agonists of their specific receptors and subsequently released neuropeptides substance P and CGRP.  When exposed to known sensitizers and control molecules, cytokines were released in the supernatant with a pattern that reflected the properties of the chemicals. Altogether, the IV-iTES should allow in-depth investigations and predictions on cutaneous toxicity, angiogenesis and inflammation.

An innervated, vascularized and immunocompetent human skin model to evaluate the properties of chemical substances.