COMPLEMENT RECRUITMENT USING BISPECIFIC DIABODIES

We describe the engineering of antibody fragments produced in bacteria for recruitment of complement effector functions. From a phage displa y repertoire we isolated human antibody fragments directed against com plement Clq, and linked these to lysozyme-specific antibody fragments, creating bispecific antibodies (diabodies). One diabody was able to r ecruit Clq, resulting in efficient lysis of lysozyme-coated sheep eryt hrocytes, and also induced rosette-formation of erythrocytes with huma n monocytes and phagocytosis after phorbol ester stimulation. These di abodies may have therapeutic applications requiring the activation of complement.