title: The role of monocytes and natural killer cells in mediating antibody-dependent lysis of colorectal tumour cells.
abstract: Monocytes and natural killer (NK) cells are known to be important effector cell populations in mediating antibody-dependent cell-mediated cytotoxicity (ADCC). Purified monocyte and NK effector cell populations, from normal and colorectal cancer (CRC) patients, together with a number of murine (17-1A and 323/A3) and their chimaeric (c17-1A) or humanised (3622W94) equivalents, and chimaeric (c) SF25 were compared for their ability to mediate ADCC of colorectal tumour cells. The chimaeric and humanised antibodies were significantly better at mediating tumour lysis than their murine equivalents with all-effector populations. When effector cells from CRC patients were used the cSF25 antibody was significantly better than 3622W94 (P < 0.02) which, in turn, was significantly better than c17-1A (P < 0.03). Depletion of NK cells produced a decrease in specific tumour lysis with all antibodies. In addition a higher rate of NK cell death was observed in CRC patients during the assay than in normal controls. The chimaeric and humanised antibodies stained a similar percentage of the HT-29 target cells (>80%), but 3622W94 bound to significantly more cells from primary tumour biopsies than cSF-25 (P = 0.001). Together, the results suggest that NK cells are the most important effector cell type mediating ADCC in vitro, that there is some impairment of NK function in CRC patients, and that cSF25 is the most potent antibody. For use in vivo the anti-Ep-CAM antibody 3622W94 would appear to be the most suitable reagent for further study.
authors.affiliation: Academic Surgical Unit, Medical Research Laboratory, Wolfson Building, University of Hull, Hull, HU6 7RX.
authors.forename: N
authors.initials: N
authors.lastname: Abdullah
authors.forename: J
authors.initials: J
authors.lastname: Greenman
authors.forename: A
authors.initials: A
authors.lastname: Pimenidou
authors.forename: K P
authors.initials: KP
authors.lastname: Topping
authors.forename: J R
authors.initials: JR
authors.lastname: Monson
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology* / Q000473:pathology; D000328:Adult; D000368:Aged; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000912:Antibodies, Neoplasm / Q000276:immunology*; D000920:Antibody-Dependent Cell Cytotoxicity; D000951:Antigens, Neoplasm / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology*; D014408:Biomarkers, Tumor; D015815:Cell Adhesion Molecules / Q000276:immunology*; D015179:Colorectal Neoplasms / Q000276:immunology* / Q000473:pathology; D000071858:Epithelial Cell Adhesion Molecule; D005260:Female; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000209:etiology; D007694:Killer Cells, Natural / Q000276:immunology*; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D051379:Mice; D008875:Middle Aged; D009000:Monocytes / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D000912:Antibodies, Neoplasm; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D014408:Biomarkers, Tumor; D015815:Cell Adhesion Molecules; D000071858:Epithelial Cell Adhesion Molecule; D011993:Recombinant Fusion Proteins; C115012:human epithelial antigen-125