An object of the present invention is to provide a
monoclonal antibody which is useful as a
diagnostic agent or a therapeutic agent for a
disease relating to a polypeptide encoded by
Claudin-4 (hereinafter referred to as “CLDN4”)
gene or a polypeptide encoded by a
Claudin-3 (hereinafter referred to as “CLDN3”)
gene, or a method for using the same. Accordingly, the present invention provides a
monoclonal antibody or an
antibody fragment thereof, which specifically recognizes three-dimensional structure of an
extracellular region of CLDN4 and binds to the
extracellular region; a
monoclonal antibody or an antibody fragment thereof, which specifically recognizes three-dimensional structure of both of
extracellular regions of CLDN3 and CLDN4 and binds to the extracellular regions; a hybridoma which produces the antibody;
a DNA which encodes the antibody; a vector which comprises the
DNA; a transformant obtained by transforming the vector; a process for producing an antibody or an antibody fragment thereof using the hybridoma or the transformant; and a
diagnostic agent or a therapeutic agent for a
disease relating to a polypeptide encoded by CLDN4
gene and / or CLDN3 gene using the antibody or the antibody fragment.