title: Complement activation reaches maximum during equilibrium between antigen and antibody in an in vitro model for thrombolysis with streptokinase.
abstract: Treatment with streptokinase (SK) of patients with acute myocardial infarction (AMI) is known to activate the complement system. In a previous investigation we found a great variation in the degree of complement activation taking place during infusion of SK in patients with AMI (range: 0-293% increase in pretreatment complement split product 3d (C3d) levels). In this in vitro study we added SK to serum with different concentrations of SK-antibodies (SK-Ab) and found that both the relative concentrations and the total concentrations of SK and Ab determined the degree of complement activation elicited by SK. This finding was in accordance with the Kendall-Heidelberger equation of antigen-antibody equivalence. Furthermore, we found parallel rises in C3d and C4d, indicating that complement was activated via the classical pathway. A condition for maximal complement activation is antigen-antibody equivalence.
authors.affiliation: Department of Clinical Chemistry, Vejle County Hospital, Denmark.
authors.forename: E
authors.initials: E
authors.lastname: Leinøe
authors.forename: A
authors.initials: A
authors.lastname: Pachaï
authors.forename: I
authors.initials: I
authors.lastname: Brandslund
mesh_terms: D000937:Antigen-Antibody Reactions; D016022:Case-Control Studies; D003167:Complement Activation / Q000187:drug effects*; D015933:Complement C3d / Q000378:metabolism; D003181:Complement C4 / Q000378:metabolism; D015935:Complement C4b; D006801:Humans; D066298:In Vitro Techniques; D008954:Models, Biological; D009203:Myocardial Infarction / Q000188:drug therapy / Q000276:immunology; D010446:Peptide Fragments / Q000378:metabolism; D013290:Streptococcal Infections / Q000188:drug therapy / Q000276:immunology; D013300:Streptokinase / Q000009:adverse effects* / Q000276:immunology*; D015912:Thrombolytic Therapy / Q000009:adverse effects* / Q000379:methods*
chemical_list: D003181:Complement C4; D010446:Peptide Fragments; D015933:Complement C3d; D015935:Complement C4b; C032261:complement C4d; D013300:Streptokinase