# Development of an anti-rat complement C2 antibody that improves renal outcome in a rat kidney transplant model

**Authors:** Laura Bracke, Jolien Delaere, Eline Haspeslagh, Karen De Winter, Yasmine Driege, Raphael Bilgraer, Tim Delahaye, C. Erik Hack, Inge Van de Walle

PMC · DOI: 10.3389/fimmu.2025.1668376 · 2026-01-15

## TL;DR

Researchers developed a new antibody targeting rat complement C2, which improved kidney function in a rat transplant model.

## Contribution

A high-affinity anti-rat C2 antibody was developed and shown to improve renal outcomes in a preclinical kidney transplant model.

## Key findings

- The anti-rat C2 antibody improved kidney function in rats after transplantation.
- The antibody demonstrated favorable pharmacokinetics and pharmacodynamics in Sprague Dawley rats.
- C2-blocking shows potential as a therapeutic strategy to prevent delayed graft function.

## Abstract

Previously we reported on the therapeutic monoclonal anti-human C2 antibody empasiprubart that inhibits activation of the classical and lectin pathways of complement. Preclinical studies with this antibody are hampered by its low affinity for C2 of animal species other than primates.

We developed a high affinity, Ca2+-dependent anti-rat C2 antibody using the sequences and structural data of empasiprubart. Pharmacokinetics and pharmacodynamics of the resulting antibody in Sprague Dawley rats were assessed and used for an intervention study in a rat model of delayed graft function following kidney transplantation. The anti-rat C2 antibody improved kidney function and health in the rats within the first 2 weeks post-transplantation.

Our study shows the successful development of an analogue of empasiprubart that can be used in preclinical in vivo disease models and highlights the potential of C2-blocking as a therapeutic strategy for preventing delayed graft function following kidney transplantation.

## Linked entities

- **Proteins:** C2 (complement C2)
- **Species:** Rattus norvegicus (taxon 10116)

## Full-text entities

- **Genes:** C2 (complement C2) [NCBI Gene 24231]
- **Chemicals:** Ca2+ (-)
- **Species:** Homo sapiens (human, species) [taxon 9606], Rattus norvegicus (brown rat, species) [taxon 10116]

## Figures

4 figures with captions in the complete paper: https://tomesphere.com/paper/PMC12852032/full.md

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Source: https://tomesphere.com/paper/PMC12852032