There is a range of brands of bioreactors such as CellMax and Technomouse which are hollow fibre systems, as well as the MiniPerm which is the system that Dr Howard Petrie who spoke at our seminar uses most successfully. He is the Director of the Monoclonal Antibody Core Facility at the Memorial Sloan-Kettering Cancer Centre in New York. He also uses a serum-free nutrient to culture the cells...usually the nutrient fluid contains foetal calf serum! He is extremely happy with the MiniPerm system as the quality and quantity of antibody produced by the system is better than that produced in mice. Some mice are still killed to produce the initial cells but alternatives are being worked on. I think that Howard must use an alternative as he said they use no mice in the production of monoclonal antibodies.