CHARACTERIZATION OF A RECOMBINANT FV FRAGMENT OF ANTI-MUC1 ANTIBODY HMFG1

A recombinant Fv (variable fragment) has been produced for the murine monoclonal antibody HMFG1. This antibody was raised against human milk fat globules and reacts with an epitope (PDTR) in the protein core of MUC1 mucins, which are up-regulated in human breast and other carcino mas. Binding specificity of the Fv fragment has been demonstrated thro ugh immunoaffinity purification, and by radioimmunoassay. The affinity constants for this Fv fragment and for the proteolytically produced F ab (antigen binding fragment) of the related humanised antibody HuHMFG 1 were determined by monitoring the fluorescence quenching of the anti body fragments whilst adding aliquots of MUC1 related antigenic peptid es KAPDTRPAPG and VTSAPDTRPAPG. Using these techniques it has been dem onstrated that the products of these different methods of antibody fra gmentation are comparable, and suitable for solution structure analysi s using nuclear magnetic resonance (NMR) spectroscopy.