Synthesis of high avidity antibody fragments (scFv multimers) for cancer imaging.

Multivalent antibody fragments (scFv dimers, trimers and tetramers) provide high avidity and ideal pharmacokinetics for tumour targeting applications. This protocol describes our optimised protocol for high-level bacterial synthesis of soluble antibody scFv fragments, as either monomers or multimers, using the heat-inducible bacterial expression vector pPOW3. Our protocol is rapid, which minimizes protein degradation, and utilises inexpensive reagents for cost-effective product synthesis. The strong, temperature-regulated promoters in pPOW3 provide efficient production of either monomeric or multimeric single-chain antibody fragments as dictated by the gene construct design.