Abstract: The invention relates to binding agents which can be induced to aggregate in response to a specific stimulus. In preferred embodiments the binding agents comprise at least a binding member for a binding partner and the binding partner. At least one of the binding member and binding partner are reversibly masked such that a plurality of binding agents are not able to aggregate with one another until the masked moiety is unmasked. Preferred mechanisms to induce aggregation include irradiation and enzyme action. Applications of the invention include signal amplification in biochemical assays and provision of high local concentrations of therapeutic agents in vivo.

Abstract: The invention relates to assays in which complexes between an analyte and a binding agent specific for the analyte are detected by a reporter molecule, which is capable of binding to the binding agent when the binding agent is complexed with analyte but not when the binding agent is complexed with an analyte analogue. The invention provides a method of modifying such a binding agent in order to create a tailored site where the reporter molecule may bind to the binding agent. This provides control over the location and nature of the reporter binding site. Antibodies, including bispecific antibodies, are preferred binding agents. The invention also provides novel methods for labelling antibodies close to their antigen binding site using bi- and tri-functional reagents. Modified binding agents produced by the methods described are also provided.

Abstract: The invention relates to a method of selectively coating a molecule, in a reversible and random fashion, with a plurality of electromagnetically labile compounds so as to modulate the activity and/or availability of said molecule, and to reverse this modulation on exposure to electromagnetic energy. The invention also concerns the provision of a molecule having reversibly and randomly attached thereto a plurality of electromagnetically labile compounds with a view to modulating the activity/availability of said molecule.