The use of biological assays for detection of polypeptide growth factors.

Polypeptide growth factors can be identified and quantified with high accuracy by the use of specific biological assays. In general these bioassays are highly sensitive for detection of growth factor activity, and enhanced specificity can be obtained by a proper choice of selective culture conditions for the target cells involved. In this paper sensitive and selective bioassays are described for growth factors acting on substrate-attached cells, in particular members of the epidermal growth factor, transforming growth factor beta, platelet-derived growth factor, insulin-like growth factor, and heparin-binding growth factor families. A cross-reactivity scheme has been worked out to identify possible contaminations in growth factor preparations.