Immunohistochemical (IHC) staining is the technique of using antibodies against a specific antigen (such as amyloid, CD68, ubiquitin, or GFAP) to label a tissue.  This technique is extremely versatile, since it can be applied to virtually any epitope to which a specific antibody can be created.  It can be very specific for the target antigen, and can also be quite sensitive.  Once learned, the same technique can be applied with a wide array of antibodies.

Some examples are shown below.