title: Cell adhesion molecules: detection with univalent second antibody.
abstract: Identification of cell surface molecules that play a role in cell-cell adhesion (here called cell adhesion molecules) has been achieved by demonstrating the inhibitory effect of univalent antibodies that bind these molecules in an in vitro assay of cell-cell adhesion. A more convenient reagent, intact (divalent) antibody, has been avoided because it might agglutinate the cells rather than blocking cell-cell adhesion. In this report, we show that intact rabbit immunoglobulin directed against certain cell surface molecules of Dictyostelium discoideum blocks cell-cell adhesion when the in vitro assay is performed in the presence of univalent goat anti-rabbit antibody. Under appropriate experimental conditions, the univalent second antibody blocks agglutination induced by the rabbit antibody without significantly interfering with its effect on cell-cell adhesion. This method promises to be useful for screening monoclonal antibodies raised against potential cell adhesion molecules because: (a) it allows for the screening of large numbers of antibody samples without preparation of univalent fragments; and (b) it requires much less antibody because of the greater affinity of divalent antibodies for antigens.
mesh_terms: D000888:Antibodies, Anti-Idiotypic; D000908:Antibodies, Fungal; D002448:Cell Adhesion; D004023:Dictyostelium / Q000032:analysis* / Q000276:immunology / Q000502:physiology; D005656:Fungal Proteins / Q000032:analysis*; D006023:Glycoproteins / Q000032:analysis; D007118:Immunoassay; D007140:Immunoglobulin Fab Fragments; D037102:Lectins / Q000032:analysis*
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000908:Antibodies, Fungal; D005656:Fungal Proteins; D006023:Glycoproteins; D007140:Immunoglobulin Fab Fragments; D037102:Lectins