anti-Haptoglobin, mAb (26E11)

Haptoglobin (abbreviated as Hp) is a protein in the blood plasma that binds free hemoglobin released from erythrocytes with high affinity and thereby inhibits its oxidative activity. Hp in its simplest form consists of two α- and two β-chains, connected by disulfide bridges. The chains originate from a common precursor protein which is proteolytically cleaved during protein synthesis. Hp exists in two allelic forms in the human population, so called Hp1 and Hp2; the latter one having arisen due to the partial duplication of Hp1 gene. Three phenotypes of Hp are found in humans: Hp1-1, Hp2-1, and Hp2-2. Hp phenotypes are associated with pathogenesis of a number of human disorders, such as diabetes, cardiovascular disease, etc. Hp plays a role in the host defence responses to infection and inflammation, acting as a natural antagonist for receptor-ligand activation of the immune system, also. Haptoglobin combines with free plasma hemoglobin, preventing loss of iron through the kidneys and protecting the kidneys from damage by hemoglobin, while making the hemoglobin accessible to degradative enzymes.