Quantification of the C3d Split Products of Human Complement by a Sensitive Enzyme Linked Immunosorbent Assay

Publisher Website
Google Scholar
Abstract
A double-antibody biotin-avidin ELISA for quantification of the C3d split products is described. Polyethylene glycol 6000 was used to precipitate large C3 molecules, and the C3d-containing supernatant was used in the assay. C3d was measured in EDTA plasma from 40 healthy blood donors, and the normal range was defined. Twenty-two patients were tested, and 12 of these had increased levels of C3d. No correlation was observed between total C3 and C3d in these patients. There was a close correlation between the C3d measured by this method and by the double-decker rocket immunoelectrophoresis method. The C3d ELISA method is very sensitive, easy to perform, and time-saving and economical compared with most C3d methods already described. A procedure to define the lower detection limit and examine the reliability of an ELISA method in general is discussed.