Related Experiment Video
Updated: Mar 10, 2026
Production of Humanized Mouse via Thymic Renal Capsule Grafting, CD34+ Cells Injection, and Cytokine Delivery
Published on: September 27, 2021
A second generation of C3 humanized rats for preclinical evaluation of human C3 inhibitors
Jin Y Chen1, Maojing Yang1, Sweta Parab1
1Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH.
Abstract:
Complement component 3 (C3) is an attractive therapeutic target for several inflammatory diseases; however, the strict primate specificity of emerging C3 inhibitors mandates the use of nonhuman primates (NHPs) for preclinical evaluation, creating significant ethical and economic barriers. Although we previously developed a human C3 complementary DNA knockin rat, the model was limited by low expression levels of human C3 and an inability to support gene-targeted therapies requiring genomic architecture. To overcome these limitations, we developed a second-generation humanized rat model by introducing the full-length human C3 gene onto a rat C3-deficient background. These rats exhibited significantly increased levels of human C3 in all tissues examined while maintaining normal renal function. We validated the utility of this new model using AMY-101, a clinical-stage, primate-specific C3 inhibitor, demonstrating its suppression of complement-mediated hemolysis both in vivo and in vitro. Notably, this inhibition primarily targeted the alternative pathway while sparing the classical pathway, consistent with the reported C3-bypass phenomenon. This second-generation C3 humanized rat model represents a robust, cost-effective preclinical platform for evaluating diverse human C3-targeted therapeutics, thereby reducing reliance on NHP models.
Insights
Researchers developed a new humanized rat model for evaluating complement component 3 (C3) inhibitors. This cost-effective platform reduces the need for nonhuman primates in preclinical studies of inflammatory diseases.
Area of Science:
- Immunology
- Pharmacology
- Genetics
Background:
- Complement component 3 (C3) is a therapeutic target for inflammatory diseases.
- Existing C3 inhibitors are primate-specific, necessitating nonhuman primate (NHP) use for preclinical testing, posing ethical and economic challenges.
- Previous human C3 knockin rats had low expression and lacked genomic architecture for gene-targeted therapies.
Purpose of the Study:
- To develop an improved humanized rat model for evaluating human C3-targeted therapeutics.
- To overcome limitations of previous models, including low expression and inability to support gene-targeted therapies.
- To reduce reliance on NHP models for preclinical C3 inhibitor evaluation.
Main Methods:
- Developed a second-generation humanized rat by introducing the full-length human C3 gene onto a C3-deficient rat background.
- Assessed human C3 expression levels and renal function in the developed rat model.
- Validated the model using AMY-101, a primate-specific C3 inhibitor, to assess complement-mediated hemolysis in vivo and in vitro.
Main Results:
- The second-generation humanized rats exhibited significantly increased human C3 levels across all tissues with normal renal function.
- AMY-101 demonstrated suppression of complement-mediated hemolysis in the humanized rats, consistent with alternative pathway inhibition.
- The model effectively recapitulated C3-bypass phenomenon, showing inhibition primarily targeting the alternative pathway.
Conclusions:
- The second-generation humanized rat model provides robust and cost-effective preclinical evaluation of human C3 therapeutics.
- This model significantly reduces the ethical and economic barriers associated with NHP use.
- It serves as a valuable platform for advancing the development of novel C3-targeted therapies for inflammatory conditions.
