A novel format of TNF-α binding affibody molecule ameliorate coronary artery endothelial injury in a mouse model of Kawasaki disease.

Kawasaki disease (KD) is a disease characterized by systemic immune vasculitis that often involves coronary arteries and can result in long-term cardiovascular sequelae. Different strategies for treatment of KD-and KD-induced coronary artery lesions are currently under investigation, including passive immunization with anti-TNFα monoclonal antibodies (mAbs). Herein, we examine the potential therapeutic capabilities of a novel type of TNFα-targeting agent based on an affibody molecule possessing fundamentally different properties than mAbs. Using phage display technology, we successfully screened and obtained three TNF-α binding affibody molecules and confirmed their high binding affinity and specificity for recombinant and native TNF-α by surface plasmon resonance (SPR), confocal double immunofluorescence and coimmunoprecipitation assays. Moreover, by binding to TNF-α, the affibody molecules could effectively neutralize TNFα-induced L929 cytotoxicity. To increase the targeting properties and serum half-life, one preferred affibody molecule ZTNF-α263 was redesigned to assemble drugs with bivalent TNFα binding with added specificity for serum albumin (ZTNF-α263-ABD035-ZTNF-α263, hereinafter denoted ZTAT). We further determined its binding ability, TNF-α signal blocking and neutralizing capacity, serum half-life and immunogenicity. Most importantly, our study provides strong evidence that the engineered ZTAT protein was therapeutically effective against KD induced-endothelial injury, as judged by both in vitro and in vivo assessments. These data suggested that because of the flexibility inherent, low-molecular weight anti-TNFα affibody construct ZTAT, can be developed into a potent therapeutic agent that can be produced and purified cost-effectively.