Introducing a new method to detect bound C3d on erythrocytes during complement activation

Abstract

Background: Measurement of complement activation products has recently been the popular means of assessing the complement activation. Objective: To introduce a new method to detect bound C3d on erythrocytes during complement activation and to compare it with free C3d levels. Methods: An indirect ELISA used in routine measurement of free C3d levels was developed together with the modified ELISA. To capture bound C3d on erythrocytes, ELISA plate were coated with anti-C3d and after incubation, blood samples were added for two hours. Bound erythrocytes were lysed with 100µl water perwell and the OD were read at 405nm. Findings: The levels of free C3d and bound C3d on the erythrocytes during complement activation was significantly increased compared to the control (800% and 500% respectively). Conclusion: Both free C3d and bound C3d as final dogradation product of C3d reflect the ongoing complement activation.