title: Increased expression of a novel early activation surface membrane receptor in cutaneous T cell lymphoma cells.
abstract: Using a newly generated monoclonal antibody we identified the 96 kDa transmembrane receptor SC5 expressed simultaneously on a human Sezary cell line and a minor T cell subset in normal individuals. SC5 antigen was detected mostly on CD45RO+ lymphocytes from both CD4+ and CD8+ subsets as well as on natural killer and B lineage cells. SC5 surface expression increased very early after polyclonal stimulation of CD3+ cells due to the transfer of intracellular SC5 molecules to the cell membrane. Engagement of SC5 receptor by its monoclonal antibody inhibited the anti-CD3-induced proliferation and cytokine secretion of peripheral blood T cells and cell clones, whereas SC5 monoclonal antibody did not affect the cytotoxic activity of CD8+ T cell clones. Extensive phenotypic analysis revealed that the percentage of SC5+ CD4+ circulating lymphocytes in Sezary syndrome patients was significantly increased in comparison with controls (p < 0.01) and correlated with the morphologically detected percentage of Sezary syndrome cells in peripheral blood (p < 0.001). In one patient we clearly demonstrated that the circulating malignant T cells coexpress SC5 molecules. Importantly, ligation of SC5 receptor in a cutaneous T cell lymphoma cell line profoundly inhibited the anti-CD3-induced proliferation. Consequently, the expression of SC5 receptor in the peripheral blood of Sezary syndrome patients may serve not only to detect the presence of circulating malignant CD4+ cells but also as a target for immunotherapy.
authors.affiliation: INSERM 448, Hôpital Henri Mondor, Créteil, France.
authors.forename: M
authors.initials: M
authors.lastname: Nikolova
authors.forename: A
authors.initials: A
authors.lastname: Tawab
authors.forename: A
authors.initials: A
authors.lastname: Marie-Cardine
authors.forename: M
authors.initials: M
authors.lastname: Bagot
authors.forename: L
authors.initials: L
authors.lastname: Boumsell
authors.forename: A
authors.initials: A
authors.lastname: Bensussan
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D001773:Blood Cells / Q000378:metabolism; D017252:CD3 Complex / Q000276:immunology; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D006801:Humans; D008214:Lymphocytes / Q000473:pathology; D016399:Lymphoma, T-Cell / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D012751:Sezary Syndrome / Q000378:metabolism; D012878:Skin Neoplasms / Q000276:immunology / Q000378:metabolism* / Q000473:pathology
chemical_list: D000911:Antibodies, Monoclonal; D017252:CD3 Complex; D011956:Receptors, Cell Surface; C429763:SC5 receptor, human