title: A monoclonal antibody reactive with a 15-kDa cytoplasmic granule-associated protein defines a subpopulation of CD8+ T lymphocytes.
abstract: We have recently described a novel method for the production and characterization of mAb reactive with T cell-restricted intracellular antigens. From a panel of antibodies that react specifically with permeabilized T lymphocytes but not with permeabilized B lymphocytes or native T cells, we have selected one, designated TIA-1, that reacts with 20 to 36% of digitonin permeabilized peripheral blood T lymphocytes. Flow cytometric analysis of purified CD4+ and CD8+ subsets showed TIA-1 to recognize a subpopulation of 49 to 64% of CD8+ lymphocytes. Little or no reactivity with CD4+ resting T lymphocytes was observed. TIA-1 did not react with any of a panel of T cell lines, B cell lines, or monocytoid cell lines. TIA-1 reacted strongly with NK cell clones and CD8+ cytolytic T cell clones, and less strongly with CD4+-activated T cell clones, suggesting a preferential expression in cells possessing cytolytic potential. Cell fractionation experiments showed TIA-1 to be membrane associated. Furthermore, Percoll gradient fractionation of a cytolytic T cell clone (T4T8C1) showed the majority of TIA-1 to be contained in a low density membrane fraction that also contained serine protease activity. Immunoelectron microscopy showed TIA-1 to decorate the membranes of electron lucent and electron dense cytoplasmic granules in this same cytolytic T cell clone. Biochemical analysis showed TIA-1 to be a 15-kDa protein in unstimulated T cells. Upon activation with Con A or anti-CD3 antibodies. TIA-1 was induced to form disulfide linked dimers, trimers, and tetramers of the basic 15-kDa unit. Taken together, our data suggest that TIA-1 is a cytolytic granule associated protein that may define a subpopulation of resting CD8+ T lymphocytes possessing cytolytic potential.
authors.affiliation: Division of Tumor Immunology, Dana-Farber Cancer Institute, Boston, MA 02115.
authors.forename: P
authors.initials: P
authors.lastname: Anderson
authors.forename: C
authors.initials: C
authors.lastname: Nagler-Anderson
authors.forename: C
authors.initials: C
authors.lastname: O'Brien
authors.forename: H
authors.initials: H
authors.lastname: Levine
authors.forename: S
authors.initials: S
authors.lastname: Watkins
authors.forename: H S
authors.initials: HS
authors.lastname: Slayter
authors.forename: M L
authors.initials: ML
authors.lastname: Blue
authors.forename: S F
authors.initials: SF
authors.lastname: Schlossman
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology*; D000941:Antigens / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D015153:Blotting, Western; D016827:CD8 Antigens; D002451:Cell Compartmentation; D003594:Cytoplasmic Granules / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D005434:Flow Cytometry; D006801:Humans; D007111:Immunity, Cellular; D007150:Immunohistochemistry; D007694:Killer Cells, Natural / Q000276:immunology*; D008213:Lymphocyte Activation; D013601:T-Lymphocytes / Q000276:immunology* / Q000648:ultrastructure; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000941:Antigens; D000945:Antigens, Differentiation, T-Lymphocyte; D016827:CD8 Antigens