Activins are part of the transforming growth factor-beta (TGF-β) superfamily, they function as dimers with 2 subunits connected by a disulphide bond. Mammals express 4 subunits – activin β_A, activin β_B, activin β_C and activin β_E; β_A and β_B are identical to the two β subunits of inhibin. Activins are primarily expressed in the gonads, pituitary and placenta and act as signalling proteins while inhibins act as inhibitors. Activins interact with cell surface heteromeric transmembrane receptor complexes. These transmembrane serine/kinase receptors are essential for ligand binding, signalling and phosphorylation. As an endocrine hormone activin’s role was initially characterised in the reproductive system but has since been shown to be more expansive in various development and differentiation pathways. Some of these functions are in cell proliferation, differentiation, apoptosis, metabolism, homeostasis, immune response, and wound repair.

Activins have crucial roles in cell development and progression however, it is also a well-recognised modulator of cancers across the whole body. Activin A mutations have been shown to be linked to fibrodysplasia ossificans progressiva. Dysregulation of activin levels has also been reported in polycystic ovarian syndrome (PCOS) patients while notably high levels were found in women with pre-eclampsia.  This antibody could be a useful tool to research further into the roles activin plays in the mammalian system.