Immunocytochemistry and Immunohistochemistry

Immunohistochemistry allows the specific histochemical localization of many diverse classes of organic substances, including inflammatory markers ranging from biogenic amines to macromolecular cytokines and their receptors. Corresponding ligands and their receptors can be demonstrated simultaneously by double-labeling protocols (1 ), since the fixation and tissue processing of the two are often compatible. One can choose between monoclonal and polyclonal antibodies raised against either the purified or at least partially purified (monoclonal antibodies) (2 ,3 ) receptors or ligands as well as against synthetic peptides (10 to 20 amino acid residues long). The latter offers the advantage of obtaining site-specific antisera for demonstrating receptor subtypes (4 ), but the amino acid sequence corresponding to the synthetic peptide may be masked in the full protein, owing to posttranslational modifications and/or folding.