title: Functional effects of a monoclonal antibody directed against a distinct epitope on 4F2 molecular complex in human peripheral blood mononuclear cell activation.
abstract: The 4F2 antigenic complex is expressed on most human cell lines in culture, on monocytes and activated lymphocytes, but not on resting T and B lymphocytes. Monoclonal antibody (mAb) CB43 recognizes an epitope of the 4F2 heterodimer either located on the light chain or dependent on the conformation of the molecule. The binding of CB43 mAb to peripheral blood mononuclear cells (PBMC) induced a dose-dependent comitogenic effect in the presence of submitogenic concentrations of anti-CD3 mAb. Significant amounts of interleukin (IL)-1 beta but not IL-2 or interferon-gamma were released in the supernatant. Pretreatment of monocytes with CB43 mAb increased the phytohemagglutinin-induced T lymphocyte proliferation. However, CB43 mAb did not exert agonistic effects on activated T lymphocytes. Depletion of CB43+ cells from PBMC decreased the proliferation and generation of cytotoxic effector cells induced by a mannoprotein (MP) derived from Candida albicans cell wall but not by recombinant IL-2. Furthermore, depletion of CB43+ cells from PBMC preactivated with MP or rIL-2 led to a significant decrease in their cytotoxic activity. CB43 mAb did not inhibit the growth of cell lines nor the proliferation of T cells. Thus CB43 mAb identifies a distinct functional epitope on the 4F2 molecular complex and might be useful in further studying the role of this molecule in cellular activation.
authors.affiliation: Istituto CNR Tipizzazione Tissutale e Problemi della Dialisi, L'Aquila, Italy.
authors.forename: G C
authors.initials: GC
authors.lastname: Spagnoli
authors.forename: C
authors.initials: C
authors.lastname: Ausiello
authors.forename: C
authors.initials: C
authors.lastname: Palma
authors.forename: G
authors.initials: G
authors.lastname: Bellone
authors.forename: G
authors.initials: G
authors.lastname: Ippoliti
authors.forename: M
authors.initials: M
authors.lastname: Letarte
authors.forename: F
authors.initials: F
authors.lastname: Malavasi
mesh_terms: D000911:Antibodies, Monoclonal / Q000502:physiology*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology / Q000502:physiology*; D017252:CD3 Complex; D002460:Cell Line; D016207:Cytokines / Q000096:biosynthesis; D003602:Cytotoxicity, Immunologic; D000939:Epitopes / Q000276:immunology*; D027261:Fusion Regulatory Protein-1; D006801:Humans; D007519:Isoantigens / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D008213:Lymphocyte Activation; D009000:Monocytes / Q000502:physiology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D017252:CD3 Complex; D016207:Cytokines; D000939:Epitopes; D027261:Fusion Regulatory Protein-1; D007519:Isoantigens; D011948:Receptors, Antigen, T-Cell