Immunocytochemistry

=Immunocytochemistry=

**Immunocytochemistry** is a technique used to detect proteins within cells; **immunohistochemistry** is the equivalent process in tissues.

First the cells are fixed using formaldehyde to preserve structures and cross-link any proteins. Then the cells are permeabilised, to allow antibody access, using a membrane-disrupting detergent such as Triton X-100, memanol or acetone. Antibodies complementary to any proteins of interest are added and then visualised, either directly or indirectly by the addition of an enzyme- or fluorophore-conjugated secondary antibody. If using an enzyme, then it must produce an insoluble product.

This technique allows the determination of which cells express a particular protein, and where in the cell the protein is localised; however, it does not allow this study //in vivo// since the cell has to be killed. Fluorescent protein tagging has become more common in recent years for the study of //living// interactions between proteins.