With the advent of genetic engineering technology, it has become clear that there is a growing need to produce cloned cell products in larger quantities for the treatment of various cardiovascular, immunologic, infectious and neoplastic diseases. Verax Corporation has developed a novel system for the mass culture of hybridoma cells as well as anchorage-preferred and anchorage-dependent genetically engineered mammalian cells. We have successfully grown murine hybridoma cells in serum-free media containing a total protein content of 1 Mug/ml. We now propose to extend our development work to studies of genetically- engineered mammalian cells. Of particular interest is an analysis of the feasibility of growing several mammalian cell lines in a well defined, serum-free medium in continuous cultures that utilize our proprietary cell immobilizing matrix material. Our goal is to develop minimal culture medium for the continuous growth and enhanced productivity of these cells when they are immobilized in the collagen matrix. Our preliminary studies with genetically-engineered cells derived from Chinese hamster ovary, human embryonic kidney or murine mammary cell lines in T-flask cultures suggest that very significant differences exist between those cell lines in terms of their growth and therapeutic product production potential. We plan to define the conditions that are necessary for the efficient production of bioactive molecules.