Inhibition of complement dependent cytotoxicity by anti-CD20 aptamers

Abstract

Complement dependent cytotoxicity (CDC) plays a vital role in human immunity and is important for the action of therapeutic antibodies. In addition, the deregulation of complement dependent cytotoxicity is a main contributor to autoimmune diseases and inflammatory pathologies, including, rheumatoid arthritis, lupus and transplant rejection. In this work, we developed DNA aptamers inhibiting complement dependent cytotoxicity in vitro. Aptamer clones selected by differential cell-SELEX and next-generation sequencing technologies possessed strong affinity (K_d < 75 nM) and selectively to B-lymphocyte antigen CD20 and showed good results in competitive displacement of CD20 antibodies. More importantly, the anti-CD20 aptamers protected and increased the viability of cells in the presence of CD20 antibodies and complement factors from human serum. These shielding aptamers can serve as drug candidates for inhibition of complement activation in the treatment of autoimmune diseases and organ transplantation.