Targeted complement inhibition by C3d recognition ameliorates tissue injury without apparent increase in...

Area of Science:

• Immunology
• Gastroenterology
• Translational Medicine

Background:

• Complement system activation exacerbates local and remote organ injury following intestinal ischemia and reperfusion (I/R).
• Targeting complement inhibition specifically to sites of complement activation may offer a more effective therapeutic strategy.

Purpose of the Study:

• To investigate the efficacy of a novel fusion protein, CR2-Crry, which targets complement inhibition to sites of complement activation.
• To compare the therapeutic effects and safety profile of CR2-Crry with a systemically administered complement inhibitor (Crry-Ig).

Main Methods:

• A mouse model of intestinal I/R injury was utilized.
• CR2-Crry fusion protein was designed to target complement activation sites via a complement receptor 2 (CR2) fragment.
• Efficacy was assessed by measuring local and remote injury, serum complement activity, and susceptibility to infection.

Main Results:

• CR2-Crry effectively targeted complement activation sites in both local intestinal and remote lung tissues following I/R.
• CR2-Crry demonstrated equivalent protection at a 10-fold lower dose compared to Crry-Ig.
• Unlike Crry-Ig, CR2-Crry did not significantly affect serum complement activity or increase susceptibility to infection at effective therapeutic doses.

Conclusions:

• CR2-mediated targeting of complement inhibitors enhances bioavailability and efficacy for treating intestinal I/R injury.
• This targeted approach preserves host resistance to infection, offering a significant advantage over systemic complement inhibition.