It may be difficult to provide sufficient donor skin for autografting when extensive areas of skin are wounded by burn, disease, or other forms of trauma. Consideration of this problem has led to the hypothesis that human skin epithelial cells can be grown in culture and the greatly increased number of progeny cells can be used as autografts. This hypothesis has been tested successfully in rabbits. The objective of the project now is to define the optimal conditions for propagating human skin epithelial cells in vitro, and subsequently the optimal conditions for using these cells as autografts. These studies will be carried out by placing small explants of human skin on the dermal collagen bed of pigskin and monitoring the outgrowth of epithelial cells under varying conditions. The autograft-xenograft will then be applied as autografts under varying conditions, and the degree of epithelialization and success rate will be monitored by gross and histologic evaluation.