CD59 glycoprotein (CD59)

Potent inhibitor of the complement membrane attack complex (MAC) action. Acts by binding to the C8 and/or C9 complements of the assembling MAC, thereby preventing incorporation of the multiple copies of C9 needed for complete formation of the osmolytic pore.

This inhibitor seems to be species-specific. Involved in signal transduction for T-cell activation complexed to a protein tyrosine kinase.