Animal cell technology is a growing discipline of cell biology which aims not only to understand structures, functions and behaviors of differentiated animal cells but also to ascertain their abilities to be used in industrial and medical purposes. The goal of animal cell technology includes accomplishments of clonal expansion of differentiated cells with useful ability, optimization of their culture conditions, modulation of their ability to produce medically and pharmaceutically, important proteins, and the application of animal cells to gene therapy and artificial organs. This volume gives the readers a complete review of present state of the art in Japan. The Proceedings will be useful for cell biologists, biochemists, molecular biologists, immunologists, biochemical engineers and other disciplines related to animal cell culture, working in either academic environments or in biotechnology and pharmaceutical industries.