From in vitro to in vivo. Progress in the use of cultured cells for human therapy.

The use of cultured cells with the ultimate goal of using the cells or their products for human therapy has experienced an exponential growth during the last decade. Stable cell cultures have been established and genetically modified to obtain high quality products for protein replacement therapy or vaccines. Cells have also been directly isolated from the human organism and, after their expansion in vitro, been retransferred as skin grafts for treatment of burns or for cancer therapy by activated lymphocytes. With the explosive development of molecular biology techniques, it is now possible to genetically modify ex vivo, cells derived from the human body. These modifications should allow targeted expression of therapeutic genes into specific cells which will, upon retransfer to the body, exert their therapeutic action in a diseased organism.