title: Monoclonal Lym-1 antibody-dependent cytolysis by neutrophils exposed to granulocyte-macrophage colony-stimulating factor: intervention of FcgammaRII (CD32), CD11b-CD18 integrins, and CD66b glycoproteins.
abstract: Murine monoclonal antibody (MoAb) Lym-1 is an IgG2a able to bind HLA-DR variants on malignant B cells and suitable for serotherapeutic approaches in B-lymphoma patients. We have previously shown that Lym-1 can synergize with granulocyte-macrophage colony-stimulating factor (GM-CSF) to trigger neutrophil cytolysis towards Raji cells used as a model of B-lymphoma targets. Here we provide evidence for the intervention of certain neutrophil receptors or surface molecules in this model of cell-mediated lysis. The lysis was completely inhibited by the anti-FcgammaRII MoAb IV.3 and unaffected by the anti-FcgammaRIII MoAb 3G8. This suggests that neutrophil cytolysis involves FcgammaRII without cooperation of this receptor with FcgammaRIII. Moreover, the lysis was inhibited by an anti-CD18 MoAb (MEM48) and by a MoAb specific for carcinoembryonic antigen (CEA)-like and glycophosphatidyl inositol (GPI)-linked glycoproteins (CD66b). Using an immunofluorescence staining procedure, cross-linking of CD66b induced the redistribution of CD11b on neutrophils with distinct areas of CD11b clustering via a process susceptible of inhibition by D-mannose. This is consistent with the ability of CD11b-CD18 and CD66b to undergo lectin-like physical interactions on the neutrophil surface. Such a type of interaction is presumably instrumental for neutrophil cytolytic activity in that the lysis was inhibited by D-mannose and enhanced by the MoAb VIM-12, which mimics the cooperation between CD11b and GPI-anchored molecules by specifically interacting with CD11b lectin-like sites. Therefore, the present results prove the absolute requirement for FcgammaRII in neutrophil GM-CSF/Lym-1-mediated cytolysis and, on the other hand, define the crucial role of CD66b and CD11b/CD18 in the expression of the cell lytic potential.
authors.affiliation: Department of Internal Medicine, University of Genova Medical School, Genova, Italy. otto@csita.unige.it
authors.forename: L
authors.initials: L
authors.lastname: Ottonello
authors.forename: A L
authors.initials: AL
authors.lastname: Epstein
authors.forename: P
authors.initials: P
authors.lastname: Dapino
authors.forename: P
authors.initials: P
authors.lastname: Barbera
authors.forename: P
authors.initials: P
authors.lastname: Morone
authors.forename: F
authors.initials: F
authors.lastname: Dallegri
mesh_terms: D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D000920:Antibody-Dependent Cell Cytotoxicity; D015703:Antigens, CD; D000951:Antigens, Neoplasm / Q000502:physiology; D001402:B-Lymphocytes / Q000276:immunology*; D018821:CD18 Antigens / Q000502:physiology*; D015815:Cell Adhesion Molecules; D058851:GPI-Linked Proteins; D017261:Glycosylphosphatidylinositols / Q000502:physiology; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G; D008214:Lymphocytes / Q000276:immunology; D016393:Lymphoma, B-Cell / Q000276:immunology*; D016177:Macrophage-1 Antigen / Q000502:physiology*; D008562:Membrane Glycoproteins / Q000502:physiology*; D009504:Neutrophils / Q000187:drug effects / Q000276:immunology*; D017452:Receptors, IgG / Q000502:physiology*; D011994:Recombinant Proteins; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000951:Antigens, Neoplasm; D018821:CD18 Antigens; C504120:CEACAM8 protein, human; D015815:Cell Adhesion Molecules; D058851:GPI-Linked Proteins; D017261:Glycosylphosphatidylinositols; D006684:HLA-DR Antigens; D007074:Immunoglobulin G; D016177:Macrophage-1 Antigen; D008562:Membrane Glycoproteins; D017452:Receptors, IgG; D011994:Recombinant Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor