Objective: To study the potentially practical use of C3 inactive fragment in anti-inflammation.
Methods: A vector expressing RGD polypeptide derived from the alpha chain segment of human C3 was constructed by using PCR and genetic engineering methods and a recombinant protein (namely C 33) was expressed with high efficiency in E. coli.
Results: The analysis of SDS-PAGE showed the molecular weight of C 33 was about 15 KD. Its purity was above 95% after purification. The amino acid composition was inconsistent with the theoretical values. U937 cells stimulated by low dosage PMA adhered with coated C 33, and the adhesion was blocked by anti-CD 11b monoclonal antibody. After injection of purified C 33 into mice which were consequently challenged by dead E. coli, the mortality of the endotoxic shock was significantly reduced.
Conclusion: C 33 can specifically bind to CD 11b/CD 18. C 33 as a ligand for CD 11b/CD 18 might be potentially used as an anti-inflammatory agent.