title: Co-expression of an epitope on human free kappa-light chains and on a cytoplasmic component in activated T cells.
abstract: K-1-21 is a murine monoclonal antibody that reacts with human kappa-light chains in free form but not when they are associated with immunoglobulin heavy chains. K-1-21 was unexpectedly shown to bind to a determinant, STA (Sezary T cell antigen), detected by immunofluorescence in the cytoplasm but not on the surface of Sezary T cells isolated from peripheral blood (4/4 cases) and in Sezary T cells from lymph node and bone marrow (one patient). STA was detected in F2/F7, CCRF-CEM, Molt-4, and CCRF-HSB (four human T ALL cell lines), in JURKAT (a human T cell leukemia line), and in MLA144 (a Gibbon T cell lymphoma line). It also occurred in Leu-3a+ antigen-specific T cell clones (6/6 tested). Moreover, although STA was absent from freshly isolated normal T cells, its expression could be evoked in E+ cells from peripheral blood by in vitro culture with phytohemagglutinin. Thus, STA appears to be a cytoplasmic marker for activated T cells. Cytoplasmic inhibition immunofluorescence studies indicated that K-1-21 binding to STA in Sezary cells or T cell lines was inhibited by preincubation of the K-1-21 antibody with purified kappa-Bence Jones protein. STA from radiolabeled MLA144 cell lysates was immunoprecipitated by K-1-21 and was identified on polyacrylamide gel electrophoresis under reducing conditions as a protein of m.w. 57,000. Additional experiments are underway to define the molecular basis of the interesting cross-reactivity between a determinant in T cells and the K-1-21 reactive epitope on free kappa-light chains.
authors.forename: K Z
authors.initials: KZ
authors.lastname: Walker
authors.forename: G E
authors.initials: GE
authors.lastname: Hayden
authors.forename: C C
authors.initials: CC
authors.lastname: Goodnow
authors.forename: H A
authors.initials: HA
authors.lastname: Boux
authors.forename: E
authors.initials: E
authors.lastname: Adams
authors.forename: A
authors.initials: A
authors.lastname: Basten
authors.forename: R L
authors.initials: RL
authors.lastname: Raison
mesh_terms: D000937:Antigen-Antibody Reactions; D000954:Antigens, Surface / Q000032:analysis; D002460:Cell Line; D002999:Clone Cells / Q000276:immunology; D003593:Cytoplasm / Q000276:immunology*; D000939:Epitopes / Q000032:analysis* / Q000276:immunology; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000032:analysis*; D007145:Immunoglobulin kappa-Chains / Q000032:analysis* / Q000276:immunology; D007399:Interphase; D008213:Lymphocyte Activation; D010835:Phytohemagglutinins / Q000494:pharmacology; D011233:Precipitin Tests; D012751:Sezary Syndrome / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
chemical_list: D000954:Antigens, Surface; D000939:Epitopes; D007147:Immunoglobulin Light Chains; D007145:Immunoglobulin kappa-Chains; D010835:Phytohemagglutinins; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7