MAP-2:CD55 chimeric construct effectively modulates complement activation.

Area of Science:

• Immunology
• Protein Engineering

Background:

• The complement system is crucial for innate immunity but also implicated in inflammatory diseases.
• Current treatments for complement-mediated pathologies are limited.
• MAP-2 inhibits the lectin pathway, and CD55 regulates C3/C5 convertase activity.

Purpose of the Study:

• To develop a novel chimeric inhibitor, MAP-2:CD55^1-4, targeting multiple complement cascade levels.
• To evaluate the in vitro and in vivo efficacy of the chimeric inhibitor compared to its parent molecules.

Main Methods:

• Fusion of enzymatically inactive MAP-2 with the N-terminal domains of CD55.
• In vitro assessment of complement inhibition across classical, lectin, and alternative pathways.
• Hemolytic assays and neutrophil activation studies using Aspergillus fumigatus conidia.

Main Results:

• MAP-2:CD55^1-4 demonstrated significantly enhanced inhibition of all three complement pathways compared to MAP-2 or CD55 alone.
• The chimeric inhibitor's potency was further increased when complexed with mannose-binding lectin.
• MAP-2:CD55^1-4 protected erythrocytes in hemolytic assays and reduced neutrophil activation and phagocytosis.

Conclusions:

• Engineered fusion proteins represent a promising strategy for developing potent complement inhibitors.
• MAP-2:CD55^1-4 is a highly effective inhibitor with potential therapeutic applications for complement-mediated diseases.