title: Interactions of C-reactive protein with the complement system. II. C-reactive protein-mediated consumption of complement by poly-L-lysine polymers and other polycations.
abstract: Cationic homopolymers of poly-L-lysine were found to activate complement (C) via C-reactive protein (CRP) and deplete C3 and C5 as well as early-acting C components. Maximum C consumption was obtained with polymers of 2,000-8,000 daltons; polymers of 1,700, 11,000, and 23,000 daltons were intermediate in reactivity, while L-lysine, lysyl-L-lysine, tetra-L-lysine, and polymers of 70,000-400,000 daltons lacked significant C-consuming activity. Naturally occurring polycations which consumed C in the presence of CRP included myelin basic proteins, cationic proteins of rabbit leukocytes, and both lysine- and arginine-rich histones; poly-L-arginine polymers of 17,000 but not 65,000 daltons also were C-consuming. Polycations without such reactivity included poly-L-orithine (5,000 and 165,000 daltons), egg white and human lysozymes, and Polybrene. The polycations which failed to induce C consumption via CRP, inhibited its consumption by both active polycations and by C-polysaccharide (CPS). The relative inhibitory capacity of phosphorylcholine and polycations in CPS- and polycations-CRP systems was consistent with the concept that phosphate esters and polycations react at the same or an overlapping combining site. The ability of certain polycations to activate C via CRP increases the potential for initiation of host reactions via C. The capacity of other polycations to inhibit C activation via CRP introduces a potential for physiologic or pharmacologic manipulation. These considerations would seem to expand the potential role of CRP in the initiation and modulation of the inflammatory response.
mesh_terms: D000818:Animals; D000906:Antibodies; D002097:C-Reactive Protein / Q000276:immunology / Q000378:metabolism*; D002413:Cations, Divalent / Q000378:metabolism*; D002846:Chromatography, Affinity; D003176:Complement C3 / Q000378:metabolism; D003182:Complement C5 / Q000378:metabolism; D003169:Complement Inactivator Proteins; D003165:Complement System Proteins / Q000378:metabolism*; D003429:Cross Reactions; D006168:Guinea Pigs; D006801:Humans; D005779:Immunodiffusion; D008239:Lysine / Q000378:metabolism; D008970:Molecular Weight; D011108:Polymers / Q000378:metabolism*
chemical_list: D000906:Antibodies; D002413:Cations, Divalent; D003176:Complement C3; D003182:Complement C5; D003169:Complement Inactivator Proteins; D011108:Polymers; D003165:Complement System Proteins; D002097:C-Reactive Protein; D008239:Lysine