Multivalent hybrid antibody with double specificity as a tool for locating cell surface antigens by electron...

Multivalent hybrid antibody complexes with dual specificity were prepared by combining rabbit antibody with anti-mouse immunoglobulin (mIg) and anti-peroxidase (HRP) specificity using protein A of Staphylococcus aureus. The presence of two antibody molecules with anti-mIg and anti-HRP specificity in a single molecule of hybrid complex was demonstrated by their abilities to produce hemagglutination with both HRP-coated and mIg-coated sheep red cells, to give a reaction of complete identity with mIg and HRP and to allow mIg bearing lymphocytes to form rosettes with HRP-coated sheep red blood cells. Electron microscopy of mouse lymphocytes and thymocytes (previously coated with mIg anti-Thy-1 antibody) treated with hybrid antibody complex and HRP showed strong and specific staining of the cell membrane of both cell types. The hybrid antibody complex containing anti-HRP antibody is a valuable reagent for determining various antigenic markers on cell membranes by electron microscopy.