Red blood cell targeting to smooth muscle cells

Monoclonal antibody discriminating between endothelial and smooth muscle cells is suggested to be used as a vector for directed transport of drugs to injured (denuded) areas of blood vessel wall. An in vitro model system was used in the studies: vascular smooth muscle or endothelial cells grown on plastic surface were treated with specific mouse monoclonal antibody recognizing an antigen localized on the surface of smooth muscle rather than endothelial cells; then erythrocytes coated with secondary (rabbit antimouse) antibodies were added. The results were analyzed spectrophotometrically or with scanning electron microscopy. Under the experimental conditions, erythrocytes, possible 'containers' for carrying the drugs, were found to bind only to smooth muscle cells. The data show that antibody provides absolute discrimination between endothelial and smooth muscle cells and, thus, may be used as a vector for drug targeting.