Andrew Wakefield used immunohistochemistry to detect measles virus in gut tissue samples.

“he would use for example a technology called um well immunohistochemistry it's it's a it's a chemical essentially a chemical staining a microscopic staining technique and so you take bits of tissue out the gut and you uh you prepare it and you stain it and with certain things use certain antibodies and what have you and you look down a microscope and if the thing that you're looking for in this case it would be measles you'll see it you'll see a stain a color a change in the a color in the stains usually Brown”