Biosynthetically lipid-modified human scFv fragments from phage display libraries as targeting molecules for immunoliposomes.

A human anti-CD22 single chain (sc) Fv antibody fragment from a synthetic phage antibody display library was biosynthetically lipid-tagged by using Escherichia coli lipoprotein sequences. The purified anti-CD22 scFv lipoprotein was incorporated into liposomes by detergent dilution. Anti-CD22 immunoliposomes were shown to bind specifically in a dose- and time-dependent manner to CD22+ cell lines and CD22+ B-lymphocytes present in freshly isolated samples of blood mononuclear cells. The immunoliposomes were demonstrated to accumulate in intracellular compartments. Biosynthetically lipid-tagged human scFv antibody fragments isolated from phage display libraries may facilitate the construction of immunoliposomes with improved properties.