Purification of equine Gc-globulin

Objectives

With the aim of producing antibodies for an equine Group specific component (Gc)-globulin assay, the protein was purified from normal equine plasma.

Methods

Equine Gc-globulin was purified from healthy horse plasma using ion exchange chromatography (Q-Sepharose, CM-Sepharose) and preparative PAGE.

Results

Equine Gc-globulin has successfully been purified from healthy horse plasma and rabbits and mice are being immunized to produce specific antibodies.

Conclusions

Purification of equine Gc-globulin and the production of specific antibodies will make it possible to develop an assay for measuring Gc-globulin in horses. Studies in rodents and humans have shown that Gc-globulin is a multifunctional acute phase plasma protein, which removes actin from the blood by binding it and facilitating its clearance from the circulation by the liver. As such, Gc-globulin prevents hyper coagulation, shock and death in human patients with massive actin release caused by severe tissue injuries like physical trauma, sepsis, endotoxemia, or liver failure. Gc-globulin is consumed in this process, and the plasma concentration of free Gc-globulin hence decreases rapidly after tissue injury and has shown to be a sensitive marker of acute tissue injury and fatal outcome in humans. Patients with a low plasma concentration of Gc-globulin due to severe tissue injury might potentially benefit from infusions with purified Gc-globulin [1]. With an equine Gc-globulin assay, future studies will investigate the concentration of Gc-globulin in colic horses with intestinal ischemia were Gc-globulin might be useful as a diagnostic and prognostic marker. Horses with intestinal ischemia often die, despite of expensive surgical treatment, because of endotoxemia and shock, therefore these horses potentially could benefit from Gc-globulin infusions.