A modified ex vivo skin organ culture system for functional studies

To investigate the immunological function of cells in normal and diseased s kin under conditions approximating the in vivo situation, it is necessary t o maintain the structural integrity of the tissue. To achieve this, freshly isolated skin has to be cultured ex vivo, or an in vitro-constructed compl ete skin equivalent may be used. Different skin organ culture systems have been described. Basically two systems prevail: submerged or air-exposed ski n organ cultures. The former model has been used for measuring cytokine sec retion by skin cells in the medium, and the latter to study the expression of cell membrane proteins in situ and the kinetics of epidermal Langerhans cells. Here we present a modified ex vivo skin organ culture system which a pproaches the in vivo situation by maintaining the normal skin architecture without spontaneous induction of the regenerative maturation markers. This method allowed the expression of cell membrane proteins in situ to be meas ured, and the cytokine secretion by skin cells in the culture medium to be quantitated in the same experiment. In this system, both general and specif ic stimuli (LPS and IL-1 beta) upregulated the expression of skin-derived c ytokines IL-8 and IL-6 in the medium and different markers (ICAM-1, CD40 an d CD86) on cells in the tissue in a 24-hour culture-formed. Elevation of bo th cytokine and cell marker expression could be blocked by dexamethasone an d by IL-1ra which acts specifically on IL-1 beta -mediated responses. The s ystem presented here is both quick and simple and can be used as a model to studs the behaviour of skin cells in their natural microenvironment.