Isolation and characterisation of goat C-reactive protein.

A pentraxin was isolated from acute phase goat serum by its calcium-dependent affinity for agarose, and although it did not bind to phosphorylcholine immobilised on Sepharose, its binding to agarose was reversed by exposure to fluid phase phosphorylcholine. It was identified as goat C-reactive protein on the basis of its immunochemical cross-reactivity with human and bovine C-reactive protein. The molecule was composed of five identical, glycosylated, non-covalently associated subunits, each of molecular weight approx. 24,000. Acute phase serum levels in a small number of samples were not significantly different from normal levels (means 72 and 55 micrograms/ml, respectively), suggesting that goat C-reactive protein is not a major acute phase reactant. No other pentraxin was detected in goat serum.