Development of claudin‐1‐specific ligand

Abstract

Claudins (CLs) are a family of tetratransmembrane proteins consisting of 27 members and are potential targets for enhancing mucosal drug absorption, treating cancer, and mucosal vaccination using the C‐terminal fragment of Clostridium perfringens enterotoxin (C‐CPE), a CL‐3/‐4 binder. The development of efficient CL binders is important for their future clinical application. We previously developed a broadly specific CL binder by using C‐CPE as a prototype; however, we did not successfully generate a CL subtype‐specific binder. Here, we focused on developing a CL subtype‐specific antibody. Because of the low antigenicity of CLs, we performed three different immunization procedures. BXSB mice with an autoimmune disorder were immunized with CL‐1‐displayed budded baculovirus, CL‐1‐expressing cells, or plasmid DNA encoding CL‐1. The DNA‐based immunization showed the highest production of serum anti‐CL‐1 antibodies. Therefore, B cells were isolated from the DNA‐immunized mice, and the B cells were fused with myeloma cells to form hybridomas. Hybridomas were screened for the production of the anti‐CL‐1 antibody. The antibodies bound to CL‐1‐expressing cells, but not to CL‐2, ‐4 or ‐5‐expressing cells. These results indicate that immunization of BXSB mice with CL DNA is a potentially useful method for the development of specific CL ligands.