An important objective of this project will be isolation and characterization of the growth factor (PGF) produced by plerocercoids of the tapeworm, Spirometra mansonoides. Procedures for initial steps of purification have been established and attempts will be made to sensitize appropriate animals to make specific antibodies directed against PGF. With specific antibodies against PGF, a specific radioimmunoassay will be established. Single step isolation of PGF from crude incubation media should also be possible using affinity chromatography. More efficient methods for collection of PGF are being developed including attempts to maintain plerocercoid cells in prolonged tissue culture. Once PGF is purified in sufficient quantities, the amino acid sequence and the primary structure of the molecule will be determined. A second objective will be to determine the effects of PGF in subhuman primates in short-term as well as extended studies. If PGF stimulates growth in monkeys, it is highly conceivable that it will be active in humans. A third objective will be to determine the effects of PGF on metabolism and how these effects relate to other growth factors, such as growth hormone, somatomedin, and insulin. A fourth objective will be to determine what direct effects PGF has in isolated tissue preparations such as hepatocytes, adipocytes, and skeletal muscle and to compare these effects to those of growth hormone and insulin. The effects of PGF on the immune system will be investigated.
