Hapten-conjugated antibodies and visual markers used to label cell-surface antigens for electron microscopy: an approach to double labeling.

Haptens can be coupled to mouse immunoglobulin with retention of antibody specificity. Such hapten-coupled alloantibody, when bound to cells, can be bridged to an electron microscopic marker in two ways: (i) by a hybrid antibody, i.e., anti-hapten:anti-marker, and (ii) by untreated bivalent anti-hapten antibody if the marker is also haptenized. Through the use of immunologically non-crossreactive haptens and markers it should be possible to localize multiple, different antigens on the surface of an individual cell. Double labeling has been achieved with the first method.