FIGURE 1.

Principle of Immunohistochemistry. Target antigens are detected by the application of specific primary antibodies, followed by the addition of a biotin conjugated secondary antibody which recognizes a specific sequence on the primary antibody. Localisation of bound biotinylated secondary antibody is detected by the addition of streptavidin HRP labeled ABC solution which binds to the biotin on the secondary. Enzymatic color changes occur when DAB reacts with the HRP bound to the secondary antibody, thus resulting in the detection of the target antigen