Histology Look-a-like #142
Macrophages (ED2 Immunoreactive) v Cat and Mouse
If you have ever tried to look for macrophages in tissues like the liver you will know just how tricky they can be to see in regular H&E stained sections.
So to make them easier to identify, scientists may choose to use an antibody that identifies a macrophage specific surface antigen. In this case the CD163 antigen which is located on the surface of certain types of macrophages. The antibody is commonly referred to as the ED2 antibody.
Kupffer cells are those elusive, special macrophages that are located in the sinusoids of the liver and so dang impossible to see. However, add the ED2 and, Aparecium!, as if by magic…they will appear. The cells are referred to as being ED2 immunoreactive or ED2 positive.
There are other ED2 positive macrophages in the body. For example researchers can use the ED2 antibody to differentiate between two populations of macrophages located in the thymus: cortical macrophages are ED2 positive but macrophages located in the thymic medulla are ED2 negative and do not stain.
The fact that this macrophage looks like a cat chasing its mousey prey is a coincidental but highly appropriate histological analogy - reflecting the role of the macrophage in stalking, capturing and ultimately devouring its biological victim.
Histology by P. McMenamin