Acute phase response of C-reactive protein of Labeo rohita to aquatic pollutants is accompanied by the appearance of distinct molecular forms

Abstract

Different forms of C-reactive proteins have been purified to electrophoretic homogeneity by calcium dependent affinity chromatography on a phosphorylcholine (PC)-Sepharose column from the sera of Labeo rohita confined in fresh water (CRP_N) and water polluted with sublethal doses of cadmium (CRP_Cd), mercury (CRP_Hg), phenol (CRP_Ph), and hexachlorocyclohexane (CRP_Hx), which elevate serum CRP levels by three- to fivefold. On native PAGE, induced forms of CRP show remarkable differences in their electrophoteric mobility indicating differences in molecular mass, charge, and/or shape. Kinetic studies reveal the appearance of a pollutant specific molecular variant, which replaces the normal form at the peak of induction. Studies on amino acid and carbohydrate compositions, isoelectric focusing, binding to PC, C-polysaccharide (CPS) & lectins, and secondary structures of the purified CRPs, indicate, that, they differ significantly from each other, but grossly share the common properties of a CRP, including pentraxin, structure revealed by electron microscopy.