CD55 and cancer: Figure 7E shows the expression of CD46, CD55 and CD59, membrane complement regulatory proteins, on SU-DHL cells. In fact, in Figure 7F, the capacity of TB5 to induce complement activation of cancer cells is clearly evident, in particular when CD46/CD55/CD59 were neutralized by specific blocking antibodies not directly able to activate the complement system, causing up to 70% of cell lysis.