Application of magnetic microspheres in labelling and separation of cells

POLYMERIC microspheres conjugated to antibodies and lectins have been used previously as cell surface markers for the detection and localisation of antigens and lectin receptors using scanning electron microscopy (SEM) (refs 1–4). In this report we describe a new, more versatile cell surface probe consisting of iron-containing polymeric microspheres tagged with fluorescent dyes and chemically coupled to antibodies or lectins. The magnetic and fluorescent properties of these microspheres have been utilised in the magnetic separation of red blood cells (RBC) and lymphoid cells and in the detection of immunoglobulin (Ig) receptors and wheat germ agglutinin (WGA) receptors on lymphocytes and Hela cells by SEM and fluorescent microscopy.