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Updated: Mar 30, 2026
In Vitro Methods for Comparing Target Binding and CDC Induction Between Therapeutic Antibodies: Applications in Biosimilarity Analysis
Published on: May 4, 2017
Using an in vitro xenoantibody-mediated complement-dependent cytotoxicity model to evaluate the complement inhibitory
Junxiang Wang1, Lu Wang1, Ying Xiang2
1Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Abstract:
Simple and reliable methods for evaluating the inhibitory effects of drug candidates on complement activation are essential for preclinical development. Here, using an immortalized porcine aortic endothelial cell line (iPEC) as target, we evaluated the feasibility and effectiveness of an in vitro xenoantibody-mediated complement-dependent cytotoxicity (CDC) model for evaluating the complement inhibitory activity of Cp40, a potent analog of the peptidic C3 inhibitor compstatin. The binding of human xenoantibodies to iPECs led to serum dilution-dependent cell death. Pretreatment of the human serum with Cp40 almost completely inhibited the deposition of C3 fragments and C5b-9 on the cells, resulting in a dose-dependent inhibition of CDC against the iPECs. Using the same method to compare the effects of Cp40 on complement activation in humans, rhesus and cynomolgus monkeys, we found that the inhibitory patterns were similar overall. Thus, the in vitro xenoantibody-mediated CDC assay may have considerable potential for future clinical use.
Insights
A novel in vitro assay using porcine cells effectively evaluates drug inhibition of complement activation. This method shows promise for preclinical drug development and potential clinical applications.
Area of Science:
- Immunology
- Pharmacology
- Biotechnology
Background:
- Evaluating drug effects on complement activation is crucial for preclinical development.
- Existing methods may lack simplicity or reliability for assessing complement inhibition.
Purpose of the Study:
- To assess the feasibility and effectiveness of an in vitro xenoantibody-mediated complement-dependent cytotoxicity (CDC) model.
- To evaluate the complement inhibitory activity of Cp40, a compstatin analog, using this model.
Main Methods:
- Utilized an immortalized porcine aortic endothelial cell line (iPEC) as the target.
- Employed human xenoantibodies to induce complement activation and CDC.
- Measured C3 fragment and C5b-9 deposition and cell death inhibition by Cp40.
Main Results:
- Xenoantibody binding to iPECs induced serum dilution-dependent cell death.
- Cp40 significantly inhibited C3 fragment and C5b-9 deposition and CDC.
- Cp40 demonstrated similar inhibitory patterns across human, rhesus, and cynomolgus monkey serum.
Conclusions:
- The in vitro xenoantibody-mediated CDC assay is a feasible and effective model for evaluating complement inhibitors.
- This assay shows potential for preclinical drug development and future clinical applications.
