title: Granulocyte aggregometry: a sensitive technique for the detection of C5a and complement activation.
abstract: We have previously shown that complement (C) activated plasma causes granulocyte (PMN) aggregation in vitro and that C5a is responsible. The C-induced aggregation of PMNs treated with cytochalasin-B (CB) is markedly enhanced and irreversible, and the magnitude of the response is proportional to the log (concentration of activated plasma), allowing use of this technique to detect C5a and hence C-activation. To compare the sensitivity of granulocyte aggregometry to that of more standard methods of detecting C-activation, we produced graded C-activation in vitro by treating fresh serum with varying amounts of zymosan. Aggregometry was the most sensitive index of C-activation, detecting C-activation, produced by 0.02 mg zymosan/ml of serum--1/10 that required to produce C-activation detectable by C3 immunoelectrophoresis (the next most sensitive technique). Granulocyte aggregometry may also be used to detect in vivo C-activation. We have found aggregating activity in plasmas from patients with systemic lupus erythematosus, immune vasculitis, transfusion reactions, and other conditions associated with in vivo C-activation, but not in the plasmas of normal subjects.
mesh_terms: D002449:Cell Aggregation / Q000187:drug effects; D002634:Chemotaxis, Leukocyte; D003167:Complement Activation; D003176:Complement C3; D003182:Complement C5; D003170:Complement Pathway, Alternative; D003571:Cytochalasin B / Q000494:pharmacology; D006098:Granulocytes / Q000276:immunology*; D006801:Humans; D007122:Immunoelectrophoresis; D007158:Immunologic Techniques; D015054:Zymosan / Q000494:pharmacology
chemical_list: D003176:Complement C3; D003182:Complement C5; D003571:Cytochalasin B; D015054:Zymosan