MOLECULAR ENGINEERING - APPLICATIONS TO THE CLINICAL LABORATORY

Advances in cellular and molecular biology methods have led to the mol ecular engineering of novel human biomolecules, some of which have bee n successfully applied to the documentation of clinical laboratory ass ays. Here I describe the use of engineered chimeric antibodies in the clinical immunology laboratory in three principal applications: (a) as reference proteins to document the specificity of clinical assay reag ents, be used as reagent-grade purified antigens, and facilitate the e pitope mapping of antibody reagents; (b) as calibration proteins to as sign mass/volume estimates to proposed antibody standards; and (c) as interference proteins to study the effects of naturally occurring auto antibodies on the accuracy and sensitivity of current clinical assays. The model recombinant proteins used for these illustrations are chime ric antibodies with a defined V-region specificity for one of two hapt ens (nitrophenyl or dansyl) and C-region domains covering a spectrum o f human isotypes. I also describe a panel of mutant human IgG1-4 anti- dansyl chimeric antibodies that have been genetically engineered with swapped, deleted, or point-mutated wild-type C-region exons and used a s specialized reagents for mapping the epitopes to which clinically us ed human IgG-specific monoclonal antibodies bind. Finally, the use of a recombinant human IgG1 anti-human IgE Fc chimeric antibody to simula te human IgG anti-IgE autoantibody interference in assays of total ser um IgE is investigated.