Isolation and characterization of acute phase protein C-reactive protein in shark serum: a potential biomarker for assessing health in wild sharks

Abstract

Abstract The acute phase protein, C-reactive protein (CRP), has become an established clinical biomarker in both animal and human health, where it is used to assess the degree of acute and/or chronic inflammation. CRP has also been proposed as a potential biomarker for measuring health in sharks by indicating when a shark is experiencing an inflammatory state or is under a chronic state of stress that may have significant physiological impact. Despite the promise in using increased levels of CRP as well as other acute phase proteins as indicators of compromised health, there has not to date been a developed shark-specific assay to accurately measure CRP. An initial step in the development of a specific bioassay for CRP is isolation and characterization of the protein. The purpose of the present study is to use both field and laboratory techniques to obtain serum samples and isolate CRP from nurse sharks, Ginglymostoma cirratum. A secondary aim is to characterize the molecule and produce shark CRP specific antisera. A two step isolation procedure is now being refined to positively identify the pentraxins present and characterize them further. Protein affinity chromatography was used to identify serum amyloid P component (SAP) in addition to CRP given that they are both pentraxin proteins displaying similar binding properties. Isolated protein bands resulting from concentrated chromatographic peaks were analyzed by LC-MS/MS. Results thus far include the isolation of a pentraxin domain-containing protein within shark serum.