Since the advent of hybridoma technology more than two decades ago, numerous antibodies have entered the clinical setting as potent therapeutic agents. Their repeated application in humans, however, is limited by the development of human antimouse antibodies (HAMA) in the recipient, leading to allergic re- tions against the foreign murine protein and rapid neutralization. To circumvent these limitations many new antibodies have recently been tailored through recombinant antibody technology. The initial clinical data show encouraging results, thus demonstrating the potential of these new...