The invention relates to an antibody which inhibits the binding between u-PA and u-PAR to an extent of at least 90% in an assay as defined in the specification, or an active fragment or immunological equivalent of said antibody. Examples of such antibodies are deposited 7 July 1994 at Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSM) with accession numbers DSM ACC2178 and DSM ACC2179 under the terms and conditions of the Budapest Treaty. The invention furthermore relates to a method for detecting or quantifying u-PAR or a glycosylation variant of u-PAR in a sample by use of an antibody according to the invention. Furthermore, the invention relates to a method for the manufacture of a therapeutic agent for preventing or counteracting localized proteolytic activity using of an antibody of the invention as well as to use of an antibody according to the invention for the preparation of a diagnostic agent which is capable of targeting a diagnostic to a cell that contains a u-PAR on the surface.