title: Expression of both B7-1 and CD28 contributes to the IL-2 responsiveness of CTLL-2 cells.
abstract: The CTLL-2 bioassay is used frequently to determine interleukin-2 (IL-2) concentrations in experimental samples, including samples that contain reagents which affect the CD28-B7 interaction. We therefore evaluated whether the CD28-B7 pathway plays a role in the growth of CTLL-2 cells. Flow cytometry demonstrated that CTLL-2 cells express both CD28 and B7-1. CTLA4-immunoglobulin (CTLA4-Ig) inhibited the growth of CTLL-2 cells over a range of IL-2 concentrations, suggesting that the CD28-B7 interaction plays an important role in the growth of CTLL-2 cells. Anti-B7-1 antibody also inhibited CTLL-2 proliferation at all concentrations of IL-2. These results indicate that the CTLL-2 bioassay may not be a reliable means of determining IL-2 levels in experimental samples containing reagents that affect the CD28-B7 interaction. They also suggest that co-expression of CD28 and B7 may contribute to the growth of malignant T cells.
authors.affiliation: University of Iowa, Iowa City, 52242, USA.
authors.forename: R
authors.initials: R
authors.lastname: Belani
authors.forename: G J
authors.initials: GJ
authors.lastname: Weiner
mesh_terms: D000069594:Abatacept; D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000276:immunology; D018122:B7-1 Antigen / Q000032:analysis* / Q000276:immunology; D001681:Biological Assay; D018106:CD28 Antigens / Q000032:analysis* / Q000276:immunology; D060908:CTLA-4 Antigen; D002455:Cell Division / Q000276:immunology; D002460:Cell Line; D004306:Dose-Response Relationship, Immunologic; D005434:Flow Cytometry; D018796:Immunoconjugates; D007136:Immunoglobulins / Q000276:immunology; D007376:Interleukin-2 / Q000276:immunology*; D051379:Mice; D015375:Receptors, Interleukin-2 / Q000378:metabolism; D013601:T-Lymphocytes / Q000737:chemistry / Q000166:cytology / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D018122:B7-1 Antigen; D018106:CD28 Antigens; D060908:CTLA-4 Antigen; C556707:Ctla4 protein, mouse; D018796:Immunoconjugates; D007136:Immunoglobulins; D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D000069594:Abatacept