title: Increased density of ecto 5' nucleotidase antigen on leukemic T cells from patients with cutaneous T-cell lymphoma and adult T-cell leukemia/lymphoma.
abstract: Malignant CD4+ T cells in adult T-cell leukemia/lymphoma (ATL) and cutaneous T-cell lymphoma (CTCL) express a number of cell surface molecules that are upregulated on normal T cells activated by foreign antigen. In this report we describe an interesting exception to the parallel phenotypic features of activated T cells and malignant CD4+ T cells. A monoclonal antibody (MoAb; termed 27.2) that was raised to HTLV-1+, CD4+25+ leukemic T cells stained weakly 25% of peripheral T cells, including approximately 50% of CD8+ T cells and 20% of CD4+ T cells. Flow cytometry analysis indicated that the surface density of the 27.2 antigen was unchanged or diminished when normal T cells were activated by antigen. However, 3/4 Sezary cases and 4/8 cases of ATL had relatively high densities of the 27.2 antigen. Immunoprecipitation and sodium dodecylsulfate polyacrylamide gel electrophoresis of the NP-40-solubilized membranes of surface-iodinated ATL cells indicated that MoAb 27.2 reacted with a 75 Kd molecule. The size and distribution of the 27.2 antigen on T cell subsets suggested that it might be the enzyme ecto-5' nucleotidase (NT), a phosphatidylinositol-linked enzyme that catalyzes dephosphorylation of monophosphate nucleotides to their respective nucleosides. This was confirmed by demonstrating that lymphocyte ecto-5'NT activity was blocked partially and inhibited completely by preincubating cells with MoAb 27.2 for 1 hour at 4 degrees C and 24 hours at 37 degrees C, respectively. When used with a second MoAb (27.1) to a novel T cell activation antigen found on all CTCL and ATL leukemias examined, 27.2 was found to discriminate between normal and leukemic T cells in two patients with ATL. These studies suggest that ecto-5'NT has diagnostic value in T cell malignancies and may be aberrantly expressed in some cases of ATL and CTCL.
authors.affiliation: Department of Pediatrics, Nippon Medical School Hospital, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Fukunaga
authors.forename: S S
authors.initials: SS
authors.lastname: Evans
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Ueda
authors.forename: K
authors.initials: K
authors.lastname: Tamura
authors.forename: T
authors.initials: T
authors.lastname: Takakuwa
authors.forename: D
authors.initials: D
authors.lastname: Gebhard
authors.forename: J
authors.initials: J
authors.lastname: Allopenna
authors.forename: S
authors.initials: S
authors.lastname: Demaria
authors.forename: B
authors.initials: B
authors.lastname: Clarkson
mesh_terms: D015720:5'-Nucleotidase / Q000276:immunology / Q000378:metabolism*; D000911:Antibodies, Monoclonal / Q000276:immunology; D000951:Antigens, Neoplasm / Q000032:analysis; D000954:Antigens, Surface / Q000276:immunology; D006801:Humans; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000276:immunology* / Q000473:pathology; D007962:Leukocytes / Q000276:immunology; D008213:Lymphocyte Activation; D008970:Molecular Weight; D012751:Sezary Syndrome / Q000276:immunology*; D012878:Skin Neoplasms / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D015720:5'-Nucleotidase