Immunocytochemistry with internally labeled monoclonal antibodies.

Abstract

One of the advantages of the production of monoclonal antibodies by tissue culture methods is that they can be internally labeled by using appropriate radioactive amino acid in the culture fluid. Thus, radioactive immunological probes of high specific activity can be prepared. Such internally labeled monoclonal antibodies were used for the direct localization of immunoreactive sites in the CNS of the rat by both light microscopy and EM (radiommunocytochemistry). The combined use of radioimmunocytochemistry with immunoenzymatic methods for the simultaneous detection of 2 antigenic sites, substance P and serotonin or substance P and enkephalin, was explored. In neurobiology this procedure could help to clarify certain aspects of transmitter-specific synaptic interactions and the coexistence of neuroactive substances in single neuronal cell bodies or nerve terminals. The application of radioimmunocytochemistry with internally labeled monoclonal antibodies was used to quantify the immunoreactions in discrete microscopic areas.