Antibodies and genetically engineered related molecules: production and purification

Antibodies and antibody derivatives constitute 20 % of biopharmaceutical products currently in development, and despite early failures of murine products, chimeric and humanized monoclonal antibodies are now viable therapeutics. A number of genetically engineered antibody constructions have emerged, including molecular hybrids or chimeras that can deliver a powerful toxin to a target such as a tumor cell. However, the general use in clinical practice of antibody therapeutics is dependent not only on the availability of products with required efficacy but also on the costs of therapy. As a rule, a significant percentage (50-80%) of the total manufacturing cost of a therapeutic antibody is incurred during downstream processing. The critical challenges posed by the production of novel antibody therapeutics include improving process economics and efficiency, to reduce costs, and fulfilling increasingly demanding quality criteria for Food and Drug Administration (FDA) approval. It is anticipated that novel affinity-based separations will emerge from the development of synthetic ligands tailored to specific biotechnological needs. These synthetic affinity ligands include peptides obtained by synthesis and screening of peptide combinatorial libraries and artificial non-peptidic ligands generated by a de novo process design and synthesis. The exceptional stability, improved selectivity, and low cost of these ligands can lead to more efficient, less expensive, and safer procedures for antibody purification at manufacturing scales. This review aims to highlight the current trends in the design and construction of genetically engineered antibodies and related molecules, the recombinant systems used for their production, and the development of novel affinity-based strategies for antibody recovery and purification.