Monoclonal antibodies labeled with polymeric paramagnetic ion chelates

Polymeric paramagnetic ion chelate molecules were synthesized and covalently linked to monoclonal antibodies. The labeled antibodies retained their antigen binding capacity in vitro while carrying up to an average of 50 paramagnetic ion chelates, enabling specifically bound antibody concentrations less than 2.0 microM to significantly reduce proton longitudinal relaxation times.