A novel screening system for claudin binder using baculoviral display

<jats:sec><jats:label /><jats:p>Recently, it became clear that claudin (CL) plays a pivotal role in tight junction (TJ) barrier function in epithelial cell, and we previously proved that CL can be a target for pharmaceutical therapy. Despite the presence of more than 20 CL family members, few ligands for CL have been identified because it is difficult to prepare CL in an intact form. In this study, we developed a method to screen for CL binders by using the budded baculovirus (BV) display system. CL4‐displaying BV interacted with a CL4 binder, the C‐terminal fragment of Clostridium perfringens enterotoxin (C‐CPE), but it did not interact with mutated C‐CPE that lost CL4‐binding region. C‐CPE did not interact with BV and CL1‐displaying BV. We used CL4‐displaying BV to select CL4‐binding phage in a mixture of a scFv‐phage and C‐CPE‐phage. The percentage of C‐CPE‐phage in the phage mixture increased after the selection, indicating that CL‐displaying BV may be useful for the selection of CL binders. We prepared a C‐CPE phage library by mutating the functional amino acids, and screened the library with CL4‐displaying BV. Then we found that the newly obtained CL4 binders also modulated the TJ barrier. These finding indicate that the CL‐displaying BV system may be a promising method to produce a novel CL binder and modulator.</jats:p></jats:sec>