title: Activation of complement C3 by different calcium phosphate powders.
abstract: The ability of different calcium phosphate to activate the complement system is studied by crossed immunoelectrophoresis demonstrating conversion of C3 to C3b. Complement consumption is determined by a haemolytic assay CH50. Hydroxyapatite powders after sintering induce a significant conversion of C3 and reduction of CH50 value. However the complement system is not activated by sintered tricalciumphosphate (beta-whitlockite). This is not related to the adsorption behaviour; it depends neither on chemical composition nor on crystal lattice. It is argued that C3 conversion is not triggered by the convertase of the classical pathway.
mesh_terms: D002130:Calcium Phosphates / Q000494:pharmacology*; D002516:Ceramics / Q000009:adverse effects; D003167:Complement Activation / Q000187:drug effects*; D003176:Complement C3 / Q000378:metabolism*; D003179:Complement C3b / Q000096:biosynthesis; D006801:Humans; D006882:Hydroxyapatites / Q000494:pharmacology; D066298:In Vitro Techniques; D011208:Powders
chemical_list: D002130:Calcium Phosphates; D003176:Complement C3; D006882:Hydroxyapatites; D011208:Powders; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; D003179:Complement C3b; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous; C494366:calcium phosphate, dibasic, dihydrate