Combined use of immunoferritin and immunocolloidal gold for the simultaneous demonstration of two antigens by immuno-electron microscopy.

In this report we describe a double-label bridging technique for the simultaneous visualization of two cell surface antigens by immuno-electron microscopy. Mouse IgG-labeled horse spleen ferritin and rabbit IgG-labeled gold sols served as the electron dense marker-conjugates. The technique was found to discriminate reproducibly two cell surface antigens simultaneously in two separate murine systems, one an in vivo cell line and the other an in vitro cell line. The technique described in this report differs from other double-labeling procedures in two notable ways: (1) the electron dense markers are easily distinguished from one another, and (2) the primary and link antibodies are not modified.