Microscopy is an essential tool for developing strategies to use genetic therapy in the treatment of diseases. Negative staining (fig. 1) and cryo-electron microscopy are critical in understanding the structure of native and hybrid vectors to be used as transfer agents. Enzyme cytochemistry is widely used for the detection of markers that aid in determining the rate of gene transfer to cells and tissues. Immunocytochemistry is necessary to identify new gene products. Light, confocal and electron microscopy are used to evaluate pathogenesis, inflammation and cellular changes. For much of the past decade, we have been working to identify the specific gene and cell structure (chloride channel) that is compromised in Cystic Fibrosis patients. Subsequently, appropriate vectors had to be developed for treatment. A significant amount of time and effort has been expended to identify effective viral and other vectors to be used in the transfer of the normal gene construct.

In order to facilitate experimentation, we have developed a cell culture system utilizing normal and cystic fibrosis airway epithelia. These cultures are maintained at an air interface and the cells differentiate into the same types found in vivo.