Discovery of a novel claudin 6 (CLDN6) specific monoclonal antibody

Claudin 6 (CLDN6) is a tight junction molecule that is involved in cell to cell adhesion of epithelial and endothelial cell sheets. CLDN6 is considered an oncofetal protein which is not expressed in normal human tissue but is expressed in some cancers such as endometrial, ovarian and testis cancer. Expression of CLDN6 in endometrial and urothelial cancer leads to a poor prognosis. The problem of developing antibodies against CLDN6 is that the family member claudin 9 (CLDN9) is highly homologous, only varying by 2 amino acids in the extracellular domain. To address this need, Integral Molecular has developed the MPS Discovery Engine ® to enable the isolation, characterization, and engineering of monoclonal antibodies for tight junction proteins, GPCRs, ion channels, and transporters. MPS utilizes a collection of technologies to address each of the barriers to monoclonal antibody development against the native extracellular epitopes of multispan membrane proteins. These include, antigen engineering to attain high levels of surface expression, DNA and Lipoparticle immunization to present native epitopes to the immune system, diverse immunization host species to deal with highly conserved proteins, Lipoparticles (high concentration native membrane proteins) to enable phage display, microfludic B-cell isolation to isolate rare MAbs, and shotgun mutagenesis (comprehensive alanine scanning) for epitope mapping. Using the MPS Discovery Engine ® we were able to successfully screen a large panel of clones for claudin 6 specificity. From these clones there were 72 potential antibodies that reacted with either claudin 6 or 6/9. A subset of these antibodies reacted only to claudin 6 and not to claudin 9 which has led to our lead drug candidate. With our MPS Discovery Engine ® platform, we have the ability to target intact, conformationally specific, and functional antibodies to multipass membrane proteins. Citation Format: Lewis J. Stafford, Brad Screnci, Chidananda Sulli, Erin Rosenberg, Nicholas Molino, David Tucker, Jonathan Sullivan, Trevor Barnes, Jennifer Pfaff, Tanmayee Hazarika, Thomas Charpentier, Samantha Gilman, Rebecca Rimkunas, Rona Wilf, Sharon Willis, Benjamin Doranz, Joseph Rucker, Ross Chambers. Discovery of a novel claudin 6 (CLDN6) specific monoclonal antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5759.