c-Reactive protein levels as a biomarker of inflammation and stress in the Atlantic sharpnose shark (Rhizoprionodon terraenovae) from three southeastern USA estuaries

Circulating c-reactive protein (CRP) levels can be used as a bioindicator of the acute phase inflammatory response and as a possible biomarker of inflammation and neurogenic stress in vertebrates. Currently, there are no data describing the ranges of CRP levels in sharks living in different habitats, especially habitats of differing degrees of pollution. Developing antibodies against CRP is a first and critical step towards developing sensitive methods for quantifying CRP, and thus inflammatory and stress responses in sharks. Sharpnose shark, Rhizoprionodon terraenovae, serum C-reactive protein was purified sequentially over AH-sepharose 4B-PC and sepharose CL-4B columns and used to immunize balb/c mice for generating stocks of polyclonal anti-sera. Serum samples from 131 sharpnose sharks were collected from three different geographical regions along the coast of SC and GA, USA between June and November 2002. Total CRP concentrations were quantified by ELISA and found to be highest in the sharpnose shark population collected in the summer from Charleston, SC, compared to Beaufort, SC and Brunswick, GA. Seasonal comparisons indicated a higher CRP concentration in the summer of the Charleston, SC population compared to the fall. These data suggest that sharks living in the Charleston, SC harbor estuary may be exposed to a suite of pathogens or other stressors that are different than those found in the Beaufort, SC and Brunswick, GA estuaries. These data support the use of CRP as a bioindicator of health status in elasmobranchs.