Circulating human C-reactive protein binds very low density lipoproteins.

Native human CRP in solution formed complexes with the abnormal lipoprotein beta-VLDL in serum of patients with type III hyperlipoproteinaemia. CRP also formed complexes in sera from individuals with type IV and type V hyperlipoproteinaemia. The binding was calcium-dependent and inhibitable by free phosphoryl choline. No complexes were demonstrable in sera containing high LDL levels from cases of type IIa hyperlipoproteinaemia. Addition of isolated beta-VLDL, but not of isolated LDL, to acute phase normolipoproteinaemic serum caused the appearance of soluble CRP-lipoprotein complexes. In contrast, addition of an excess of isolated normal VLDL to acute phase serum or to isolated CRP was followed by agglutination (creaming) of the lipoprotein particles. Rabbit CRP, on the other hand, formed soluble complexes both with normal human apoB containing lipoproteins and with the abnormal beta-VLDL. Human CRP complexed with rabbit beta-VLDL but not with normal rabbit serum lipoproteins. These interactions may be important for the role of CRP in health and disease.