title: CD26 antigen is a surface dipeptidyl peptidase IV (DPPIV) as characterized by monoclonal antibodies clone TII-19-4-7 and 4EL1C7.
abstract: In this study we investigated the binding of three different monoclonal antibodies (MoAb), TII 19-4-7, 4EL1C7, and B1.19.2, which are clustered in CD26 to the ectoenzyme dipeptidyl peptidase IV (DPP IV) and to T lymphocytes. We found that all three MoAb bind to both unstimulated and mitogen-stimulated T lymphocytes. Further results indicated an inconsistency within the CD26-clustered MoAb: TII 19-4-7 and 4EL1C7, but not B1.19.2, recognized DPP IV on the surface o T lymphocytes and immobilized on solid-phase ELISA or Western blot. There was competition of binding to DPP IV between TII 19-4-7 and 4EL1C7. From these results we conclude that CD26 antigen is represented by the ectoenzyme DPP IV. TII 19-4-7 and 4EL1C7 recognize the same or partly identical epitopes on DPP IV, whereas B1.19.2 recognizes a different antigen. TII 19-4-7 and 4EL1C7, but not B1.19.2, should be clustered in CD26.
authors.affiliation: Department of Immunology and Cell Biology, Forschungsinstitut Borstel, FRG.
authors.forename: A J
authors.initials: AJ
authors.lastname: Ulmer
authors.forename: T
authors.initials: T
authors.lastname: Mattern
authors.forename: A C
authors.initials: AC
authors.lastname: Feller
authors.forename: E
authors.initials: E
authors.lastname: Heymann
authors.forename: H D
authors.initials: HD
authors.lastname: Flad
mesh_terms: D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000032:analysis*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis* / Q000276:immunology; D001667:Binding, Competitive; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000032:analysis* / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; D018819:Dipeptidyl Peptidase 4