title: 4-1BB is expressed on CD45RAhiROhi transitional T cell in humans.
abstract: Murine 4-1BB is an approximately 30-kDa glycoprotein expressed on activated T cells and plays a role in T-cell-mediated proliferative response. To date the majority of work on 4-1BB has been conducted in the mouse. To assess the role of 4-1BB in humans, mAbs were made against the recombinant human (rh) 4-1BB protein. One such mAb 4B4-1 specifically binds SF-21 insect cells expressing rh4-1BB but not irrelevant control protein as measured by flow cytometry (FCM). 4B4-1 mAb stains PMA- and ionomycin-stimulated CEM (human T lymphoma) cells and PHA-stimulated peripheral blood T cells, but not resting cells. 4B4-1 mAb immunoprecipitates both approximately 32 and approximately 80 kDa protein from rh4-1BB expressing SF-21 cells and an approximately 39- and approximately 85-kDa protein from PMA-stimulated CEM cells under reducing conditions by SDS-PAGE. As added proof of its specificity, binding of FITC-labeled 4B4-1 mAb to PHA-stimulated T cells was blocked by rh4-1BB protein. Together these data demonstrate that 4B4-1 is specific for 4-1BB in humans. Unlike in the mouse, 4-1BB is expressed much earlier (within 24 hr) peaking around 2-3 days following PHA stimulation. As in the mouse 4-1BB is induced on both CD4+ and CD8+ T cell subsets. 4-1BB expression is induced upon PHA stimulation in both the naive (CD45RAhi-CD45ROlo/-) and the memory (CD45RAlo/-ROhi) T cell populations. Virtually all CD45RAhiROlo/- cells upon culture in PHA give rise to an intermediate CD45RAhiROhi 4-1BB+ transitional cell and subsequently CD45RAlo/-ROhi 4-1BBlo/- and CD45RAlo/-ROhi 4-1BBhi cells. In contrast, approximately 27% of CD45RAlo/-ROhi 4-1BB- cells when cultured in PHA for 24 hr acquire 4-1BB expression and all remain CD45RAlo/-ROhi.
authors.affiliation: Department of Microbiology and Immunology, Walther Oncology Center, Indiana University School of Medicine, Indianapolis, 46202-5120, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Garni-Wagner
authors.forename: Z H
authors.initials: ZH
authors.lastname: Lee
authors.forename: Y J
authors.initials: YJ
authors.lastname: Kim
authors.forename: C
authors.initials: C
authors.lastname: Wilde
authors.forename: C Y
authors.initials: CY
authors.lastname: Kang
authors.forename: B S
authors.initials: BS
authors.lastname: Kwon
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D015703:Antigens, CD; D002478:Cells, Cultured; D006801:Humans; D017493:Leukocyte Common Antigens / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D017475:Receptors, Nerve Growth Factor / Q000096:biosynthesis* / Q000276:immunology; D018124:Receptors, Tumor Necrosis Factor / Q000096:biosynthesis* / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D017475:Receptors, Nerve Growth Factor; D018124:Receptors, Tumor Necrosis Factor; C505714:TNFRSF9 protein, human; C505715:Tnfrsf9 protein, mouse; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9; D017493:Leukocyte Common Antigens