High blood levels of cholesterol of which low density lipoprotein (LDL) is the principal carrier is an established cause for atherosclerosis and coronary heart disease. For selected patients, extracorporeal LDL removal is the most effective therapy. The goal of this project is to develop a monoclonal antibody-based immunoadsorption device capable of removing LDL from hypercholesterolemic patients. Phase I studies demonstrated safety and efficacy of goat polyclonal antibody-based immunosorbents for removal of LDL from whole blood experimental animals. In addition, murine anti-LDL monoclonal antibodies were shown to be suitable in an LDL-immunosorbent device. Phase II studies will include production and purification of a monoclonal anti-LDL antibody (C3D1) and limited clinical trials of an immunosorbent device incorporating this monoclonal antibody and, if appropriate, continued clinical trials of the goat polyclonal immunosorbent. During Phase III, extended clinical trials will begin when the monoclonal-based research, new technology will be developed in two areas: (1) design of whole blood immunosorbents; and (2) application of monoclonal antibodies to clinical immunosorbents.