ALTERED PERMEABILITY AND DISORDERED CUTANEOUS IMMUNOREGULATORY FUNCTION IN MICE WITH ACUTE BARRIER DISRUPTION

In vivo and in vitro T-cell-activating ability of murine epidermal cel ls (EC) was investigated in acutely barrier-disrupted skin by extracti on of epidermal lipids with acetone or removal of corneocytes by tape stripping, Contact sensitivity (CS) to 2,4-dinitrofluorobenzene (DNFB) and picryl chloride (PCI) and contact photosensitivity (CPS) to tetra chlorosalicylanilide (TCSA) were significantly augmented when challeng ed or sensitized at sites treated with acetone 24 h before, compared w ith the intact skin, CS to DNFB was also enhanced by tape stripping, b ut not by water rubbing, suggesting that physical stress or a toxic ef fect of acetone was not responsible for the augmentation. Semi-quantif ication of TCSA-EC photoadducts showed markedly increased permeability of hapten in the epidermis 24 h after acetone treatment. Bioactive IL -1 alpha was more pronounced in barrier-disrupted than in intact skin. Lymph node T cells from PCl-sensitized mice proliferated significantl y more in a hapten-specific and co-stimulatory molecule-dependent mann er in response to trinitrophenylated (TNP) EC from acetone-treated ski n than to those from untreated skin. Immunofluorescence staining of ep idermal sheets and how cytometric analysis of dispersed EC showed that subpopulations of Langerhans cells (LC) in acetone-rubbed or tape-str ipped skin expressed major histocompatibility complex class II CD54 an d CD86 molecules at levels higher than the rest of LC and LC from wate r-treated or untreated epidermis, Therefore, not only increased permea bility of hapten through the epidermis but also altered immune functio ns of EC potentiate T-cell activation in acute barrier disruption. Suc h augmentation of immune reactivity may be critical to elimination of environmental noxious agents that penetrate easily into the barrier-di srupted epidermis.