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 for 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 for production of 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 the 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 either in academic environments or in industries of biotechnology and pharmacy.