Development of new biotin/streptavidin reagents for pretargeting.

The high affinity of biotin for streptavidin has made this pair of molecules very useful for in vivo applications. To optimize reagents for one potential in vivo application, antibody-based pretargeting of cancer, we have prepared a number of new biotin and streptavidin derivatives. The derivatives developed include new radiolabeled biotin reagents, new protein biotinylation reagents, and new biotin multimers for cross-linking and/or polymerization of streptavidin. We have also modified streptavidin by site-directed mutation and chemical modification to improve its in vivo characteristics, and have developed new reagents for cross-linking antibody fragments with streptavidin. A brief overview of these new reagents is provided.