Activation of complement C3 by different calcium phosphate powders.
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.
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
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