After digesting the virus, the macrophage proudly displays strips of protein from the virus in the grooves of some of its MHC molecules.
The chemical that is the cause of so much woe is known as macrophage migration inhibitory factor or MIF, a protein found in the immune system that seems to help sperm cells grow .
The macrophage then secretes a protein called interleukin-1, a chemical signal that causes the T cell to begin replicating.