Recombinant Human Complement C5 Protein (C-His)

Measured by functional ELISA. Immobilized recombinant human C5 binds reference anti-C5 antibodies eculizumab/ravulizumab with EC50 values in the ng/mL range.

Complement component C5 is the fulcrum of the complement system: cleavage of its alpha chain releases C5a, the most potent anaphylatoxin and neutrophil chemoattractant of the cascade, while the remaining C5b initiates assembly of the membrane attack complex that lyses pathogens and, in disease, host cells. Blocking C5 with eculizumab and its longer-acting successor ravulizumab transformed paroxysmal nocturnal hemoglobinuria and atypical hemolytic-uremic syndrome into manageable diseases, and C5-pathway inhibition now spans myasthenia gravis, geographic atrophy and transplant research. Two-chain recombinant C5 presented here enables anti-C5 screening, complement assay standardization and terminal-pathway research.