Mouse Anti-Bovine Fibrillin monoclonal antibody for IHC. The fibrillins are extracellular matrix glycoproteins which occur as a major component of a subset of connective tissue microfibrils. These microfibrils have a beaded appearance and a cross-sectional diameter of 10-12 nm. In elastic tissues, these structures are thought to provide the scaffold onto which elastin is assembled to form elastic fibers, although their function in non-elastic tissues is unclear.1 In immunohistochemical staining of paraformaldehyde-fixed human skin, mAb 12D2.4 labels the elastic framework and more specifically the oxytalantic network close to the epidermis.