title: Generation and preliminary characterization of an antibody library with preferential reactivity to human colorectal cancer cells as compared to normal human blood cells.
abstract: We are developing recombinant polyclonal antibody libraries (PCALs) reactive to human colorectal cancer cells as an anti-cancer therapeutic approach. To test the hypothesis that PCALs with preferential recognition of tumor cells as compared to normal cells could be generated, a Fab phage display library reactive to human colorectal cancer cell lines was absorbed with normal human blood cells. ELISA analysis of the absorbed Fab phage display library showed that 70% of tested clones reacted to colorectal cancer cells. Reactivity of the library to blood cells was reduced 4-10-fold, with many clones unreactive to one or more of the blood cell types. DNA fingerprint analysis of colorectal cancer-binding clones showed that the absorbed library remained polyclonal. The H and L chain V region gene pairs of the absorbed library were transferred in mass from the Fab phage display vector to a mammalian vector and expressed as IgG following transfection into Sp2/0 myeloma cells. ELISA analysis showed that 79% of transfectants expressed IgG and of those 74% were positive for binding to the SW480 human colorectal cancer cell line. A template of 95 SW480-reactive wells was assembled, designated Lib-Col2.1, and IgG purified from a consolidated mass culture. The purified Lib-Col2.1 IgG was compared to the clinically used anti-colorectal cancer mAb 17-1A, by ELISA and flow cytometry, for binding density on SW480 colorectal cancer cells and on normal human blood cells. The results showed that Lib-Col2.1 bound to SW480 cells at higher density than mAb 17-1A and that its binding to normal human blood cells was reduced 2.4-24-fold relative to an unabsorbed anti-SW480 serum. Furthermore, Lib-Col2.1 was more effective than mAb 17-1A at inhibiting the growth of SW480 cells in culture. These results suggest that a polyclonal antibody library with preferential reactivity to cancer cells as compared to normal cells could be generated.
authors.affiliation: Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Room K707, 715 Albany Street, MA 02118, USA.
authors.forename: Meredith A
authors.initials: MA
authors.lastname: Liebman
authors.forename: Brent R
authors.initials: BR
authors.lastname: Williams
authors.forename: Kylle M
authors.initials: KM
authors.lastname: Daley
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Sharon
mesh_terms: D000906:Antibodies / Q000235:genetics / Q000276:immunology*; D000918:Antibody Specificity / Q000276:immunology*; D001773:Blood Cells / Q000276:immunology*; D002455:Cell Division; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000276:immunology* / Q000473:pathology; D016172:DNA Fingerprinting; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000235:genetics / Q000276:immunology; D019151:Peptide Library
chemical_list: D000906:Antibodies; D007140:Immunoglobulin Fab Fragments; D019151:Peptide Library