Affinity purification of novel bispecific antibodies recognising carcinoembryonic antigen and doxorubicin

Hydrophobic interaction chromatography at low salt concentration for the capture of monoclonal antibodies

We evaluated hydrophobic interaction chromatography (HIC) at low salt concentration for the capture of proteins from feed stocks by using monoclonal antibodies as model samples. It was indicated that the HIC at low salt concentration on critical hydrophobicity supports has a potential for capturing hydrophobic monoclonal antibodies directly from large volumes of feed stocks and recovering bound monoclonal antibodies in high yield. On the other hand, the HIC at low salt concentration did not seem so useful for the capture of weakly hydrophobic monoclonal antibodies. The recovery of weakly hydrophobic monoclonal antibodies from columns packed with critical hydrophobicity supports was not quantitative and significantly decreased as the residence time of the monoclonal antibodies in the columns became longer.

Optimizing expression and purification from cell culture medium of trispecific recombinant antibody derivatives

Antibody fragments offer the possibility to build multifunctional manifolds tailored to meet a large variety of needs. We optimized the production of a manifold consisting of one (bibody) or two (tribody) single-chain variable fragments coupled to the C-terminus of Fab chains. Different strong mammalian promoters were compared and the influence of expression media on production and recovery was investigated. Since the physical and chemical nature of these molecules largely depends on the nature of the antibody building blocks incorporated, a generally applicable process for the purification of recombinant antibody derivatives from serum containing mammalian cell culture medium was designed. To this end we compared protein L, hydroxyapatite, immobilized metal affinity chromatography, cation-exchange chromatography and hydrophobic charge induction chromatography.

Bispecific antibody targeting of doxorubicin to carcinoembryonic antigen-expressing colon cancer cell linesin vitro andin vivo

A bispecific monoclonal antibody (BsMAb) recognising carcinoembryonic antigen (CEA) and doxorubicin (Dox) was used in colorimetric microcytotoxicity assays with 3 human colon cancer cell lines (COLO320DM, SKCO1 and LS174T) showing no, high or medium CEA expression, respectively. The IC50 values for Dox with COLO320DM, SKCO1 and LS174T were 1,163, 28.5 and 324 ng/ml, respectively. BsMAb caused statistically significant reductions in Dox IC50 values at 1, 0.1 and 0.01 microg/ml with the CEA-expressing cell lines SKCO1 and LS174T but not with COLO320DM. BsMAb or control antibody alone had no significant effect on the cell viability of any of the cell lines and did not reduce Dox IC50 values. In vivo, there was a statistically significant inhibition of the growth of CEA-expressing LS174T cells growing as xenografts in nude mice treated with BsMAb and Dox compared to control mice. This effect was not seen with COLO320DM xenografts. Our results demonstrate that a BsMAb that recognises CEA and Dox can reduce the IC50 for Dox in vitro and inhibit growth in vivo in a CEA-specific manner.