What is the difference between HLA-DR and Iba1?

HLA-DR and Iba1, which both serve as markers for human microglia, are not expressed evenly in all microglial tissue. HLA-DR, which is an MHC II cell surface receptor, serves mostly as a marker for active microglia. On the other hand, Iba1, or the ionized calcium binding molecule-1, is expressed in all microglia and plays a role in actin-binding and microglial membrane ruffling, rendering it better as a structural marker.