lmmunocytochemical Methods for Regulatory Peptides

Immunocytochemistry employs antibodies to detect peptides or proteins in tissue preparations (1 ). However, this in itself is not a visible reaction. Several methods, employing secondary antibodies labeled in some way to render them visible, generally with fluorescent compounds or enzymes fed with suitable chromogenic substrates, are in current use (2 ). The method chosen depends on a number of factors. The greater sensitivity of enzyme methods is rarely an advantage in the immunocytochemical demonstration of regulatory peptides, as these substances tend to occur at relatively high concentrations in tissues. Advantages of enzyme methods are that the preparations are permanent and the underlying tissue morphology is available for study along with the labeled antigen. This is of particular importance in diagnostic histopathology.