Description (Adapted from the application): The goals of the cell culture/transfection core are to provide proven cell culture and transfection methodology and stocks of well-characterized WIF-B and MDCK lines to PPG users. There are several advantages to making these services part of a central core that is available to multiple users. Stocks of valuable epithelial cell clones can be characterized, maintained and stored for use by all PPG labs and distribution to those outside the PPG. This insures a uniform starting point for all PPG projects using a particular line and fosters interactions among the projects and sharing of expertise. Development of efficient and effective gene delivery systems for expression of foreign proteins in polarized epithelial cells can be optimized in one facility through the cooperation of investigators with different backgrounds. Development time for new cell manipulation techniques that will be used in multiple projects is minimized through reciprocal interactions of the PPG labs with Core B.