title: MHC class II expression in human basophils: induction and lack of functional significance.
abstract: The antigen-presenting abilities of basophils and their role in initiating a Th2 phenotype is a topic of current controversy. We aimed to determine whether human basophils can be induced to express MHC Class II and act as antigen presenting cells for T cell stimulation. Isolated human basophils were exposed to a panel of cytokines and TLR-ligands and assessed for MHC Class II expression. MHC Class II was expressed in up to 17% of isolated basophils following incubation with a combination of IL-3, IFN-γ and GM-CSF for 72 hours. Costimulatory molecules (CD80 and CD86) were expressed at very low levels after stimulation. Gene expression analysis of MHC Class II-positive basophils confirmed up-regulation of HLA-DR, HLA-DM, CD74 and Cathepsin S. However, MHC Class II expressing basophils were incapable of inducing antigen-specific T cell activation or proliferation. This is the first report of significant cytokine-induced MHC Class II up-regulation, at both RNA and protein level, in isolated human basophils. By testing stimulation with relevant T cell epitope peptide as well as whole antigen, the failure of MHC Class II expressing basophils to induce T cell response was shown not to be solely due to inefficient antigen uptake and/or processing.
authors.affiliation: Department of Immunology, Monash University, Melbourne, Victoria, Australia ; Department of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital and Monash University, Melbourne, Victoria, Australia.
authors.forename: Astrid L
authors.initials: AL
authors.lastname: Voskamp
authors.affiliation: Department of Immunology, Monash University, Melbourne, Victoria, Australia ; Department of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital and Monash University, Melbourne, Victoria, Australia.
authors.forename: Sara R
authors.initials: SR
authors.lastname: Prickett
authors.affiliation: Department of Immunology, Monash University, Melbourne, Victoria, Australia.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Mackay
authors.affiliation: Department of Immunology, Monash University, Melbourne, Victoria, Australia ; Department of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital and Monash University, Melbourne, Victoria, Australia.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Rolland
authors.affiliation: Department of Immunology, Monash University, Melbourne, Victoria, Australia ; Department of Allergy, Immunology and Respiratory Medicine, The Alfred Hospital and Monash University, Melbourne, Victoria, Australia.
authors.forename: Robyn E
authors.initials: RE
authors.lastname: O'Hehir
mesh_terms: D017951:Antigen Presentation; D000944:Antigens, Differentiation, B-Lymphocyte / Q000235:genetics* / Q000276:immunology; D018122:B7-1 Antigen / Q000235:genetics / Q000276:immunology; D051940:B7-2 Antigen / Q000235:genetics / Q000276:immunology; D001491:Basophils / Q000166:cytology* / Q000187:drug effects / Q000276:immunology; D002403:Cathepsins / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D018920:Coculture Techniques; D015870:Gene Expression; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006681:HLA-D Antigens / Q000235:genetics* / Q000276:immunology; D006684:HLA-DR Antigens / Q000235:genetics* / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000235:genetics* / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D007377:Interleukin-3 / Q000494:pharmacology; D018418:Th2 Cells / Q000166:cytology* / Q000187:drug effects / Q000276:immunology
chemical_list: D000944:Antigens, Differentiation, B-Lymphocyte; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D006681:HLA-D Antigens; C084245:HLA-DM antigens; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D007377:Interleukin-3; C045084:invariant chain; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D002403:Cathepsins; C028217:cathepsin S