Abstract: The invention relates to the purification and characterization of growth stimulatory and inhibitory protein factors produced by various organs which appear to play a role in the successful formation of metastatic colonies of tumor cells. In particular, it has been found that syngeneic organs secrete protein growth stimulatory and inhibitory factors which can, at low concentrations, affect metastatic tumor cells. The ability of a malignant cell to respond to these factors is believed to be related to tumor cell metastasis to specific body organs. In particular a lung growth stimulatory glycoprotein having a molecular weight of approximately 66,000 daltons has been found to stimulate growth of lung-metastatic rat and human mammary tumor cells in serum deprived medium.

Abstract: Processes are provided for producing purified, hepatitis B surface antigen particles in mammalian cells which comprise culturing mammalian cells which produce the particles in a culture medium supplemented with a serum free of high molecular weight contaminant proteins and recovering the purified, hepatitis B surface antigen particles.Removal of molecules having a molecular weight greater than about 3.times.10.sup.5 daltons by prefractionation, for example, allows cells to be grown in culture media containing high levels of fetal calf serum, removes high molecular weight contaminant proteins which may be inhibitory to cell growth and simplifies purification of HBsAg since high molecular weight contaminant proteins are the major contaminants removed by purification processes.

Abstract: This invention relates to polypeptides that are human somatomedin carrier protein subunits and to processes for producing them. The carrier protein subunits bind to human somatomedin-like polypeptides also known as insulin-like growth factors. The process involves preparation from a human serum fraction, Cohn IV-1, by a molecule of various chromatographic steps.This invention also relates to DNA molecules encoding human somatomedin carrier protein-like polypeptides, recombinant DNA molecules, hosts, processes for producing carrier protein-like polypeptides, human somatomedin carrier protein-like polypeptides produced using those molecules, hosts and processes. The invention relates to DNA molecules and their expression in appropriate hosts. The recombinant DNA molecules contain DNA molecules that code for polypeptides which have a biological activity of the human carrier protein or a human carrier protein subunit capable of binding somatomedins.