title: Interferon-gamma-induced intercellular adhesion molecule-1: expression on human tumor cells enhances bifunctional antibody-mediated lysis through a lymphocyte function-associated antigen-1 dependent mechanism.
abstract: Antitumor x anti-CD3 bifunctional antibodies (BFAs) affect tumor cell lysis by activating and physically linking T-cells and tumor cells. Since tumor target antigen expression does not correlate with susceptibility to BFA-mediated tumor cytotoxicity, we investigated the role of cell adhesion molecules as accessory molecules. In 3 human colon tumor cell lines (LS174T, WIDR, and COLO205), recombinant interferon-gamma (rIFN-gamma) consistently increased BFA-mediated tumor cell lysis by cultured peripheral blood lymphocytes and consistently increased tumor cell expression of intercellular adhesion molecule-1 (ICAM-1). Using cell conjugation assays, we demonstrated that ICAM-1 and lymphocyte function-associated antigen-1 (LFA-1) interactions were important for effector-to-target cell conjugate formation and demonstrated that tumor cell pretreatment with rIFN-gamma enhanced cell conjugate formation. Whereas anti-LFA-1 blocked all BFA-mediated tumor lysis and conjugate formation, anti-ICAM-1 blocked only the enhancing effects of rIFN-gamma for both cytolysis and conjugate formation. Although BFAs were shown to provide effector-to-target cell bridging, LFA-1 was found to be a common critical element required for BFA-mediated cell conjugation and lysis. ICAM-1, which was augmented by rIFN-gamma, appears to be only one of several ligands interacting with LFA-1. These results provide one explanation as to why high expression of tumor-associated antigen alone does not predict the susceptibility to BFA-mediated lysis and provides further support for the concept of combined modality immune therapies.
authors.affiliation: Department of Surgery, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: P S
authors.initials: PS
authors.lastname: Ramsey
authors.forename: P A
authors.initials: PA
authors.lastname: Dean
authors.forename: A
authors.initials: A
authors.lastname: Tasimowicz-Alpini
authors.forename: J H
authors.initials: JH
authors.lastname: Donohue
authors.forename: H
authors.initials: H
authors.lastname: Nelson
mesh_terms: D018033:Antibodies, Bispecific / Q000276:immunology* / Q000494:pharmacology; D015815:Cell Adhesion Molecules / Q000096:biosynthesis*; D003110:Colonic Neoplasms / Q000276:immunology* / Q000473:pathology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma / Q000494:pharmacology*; D007376:Interleukin-2 / Q000494:pharmacology; D016169:Lymphocyte Function-Associated Antigen-1 / Q000276:immunology / Q000502:physiology*; D016853:Muromonab-CD3 / Q000276:immunology / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D018033:Antibodies, Bispecific; D015815:Cell Adhesion Molecules; D007376:Interleukin-2; D016169:Lymphocyte Function-Associated Antigen-1; D016853:Muromonab-CD3; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma