title: Human CD4+ T cell responses to the dog major allergen Can f 1 and its human homologue tear lipocalin resemble each other.
abstract: Lipocalin allergens form a notable group of proteins, as they contain most of the significant respiratory allergens from mammals. The basis for the allergenic capacity of allergens in the lipocalin family, that is, the development of T-helper type 2 immunity against them, is still unresolved. As immunogenicity has been proposed to be a decisive feature of allergens, the purpose of this work was to examine human CD4+ T cell responses to the major dog allergen Can f 1 and to compare them with those to its human homologue, tear lipocalin (TL). For this, specific T cell lines were induced in vitro from the peripheral blood mononuclear cells of Can f 1-allergic and healthy dog dust-exposed subjects with peptides containing the immunodominant T cell epitopes of Can f 1 and the corresponding TL peptides. We found that the frequency of Can f 1 and TL-specific T cells in both subject groups was low and close to each other, the difference being about two-fold. Importantly, we found that the proliferative responses of both Can f 1 and TL-specific T cell lines from allergic subjects were stronger than those from healthy subjects, but that the strength of the responses within the subject groups did not differ between these two antigens. Moreover, the phenotype of the Can f 1 and TL-specific T cell lines, determined by cytokine production and expression of cell surface markers, resembled each other. The HLA system appeared to have a minimal role in explaining the allergenicity of Can f 1, as the allergic and healthy subjects' HLA background did not differ, and HLA binding was very similar between Can f 1 and TL peptides. Along with existing data on lipocalin allergens, we conclude that strong antigenicity is not decisive for the allergenicity of Can f 1.
authors.affiliation: Department of Clinical Microbiology, Institute of Clinical Medicine and Biocenter Kuopio, University of Eastern Finland, Kuopio, Finland.
authors.forename: Aino L K
authors.initials: AL
authors.lastname: Liukko
authors.affiliation: Department of Clinical Microbiology, Institute of Clinical Medicine and Biocenter Kuopio, University of Eastern Finland, Kuopio, Finland.
authors.forename: Tuure T
authors.initials: TT
authors.lastname: Kinnunen
authors.affiliation: Department of Clinical Microbiology, Institute of Clinical Medicine and Biocenter Kuopio, University of Eastern Finland, Kuopio, Finland; Institute of Dentistry, School of Medicine, University of Eastern Finland, Kuopio, Finland.
authors.forename: Marja A
authors.initials: MA
authors.lastname: Rytkönen-Nissinen
authors.affiliation: Department of Clinical Microbiology, Institute of Clinical Medicine and Biocenter Kuopio, University of Eastern Finland, Kuopio, Finland.
authors.forename: Anssi H T
authors.initials: AH
authors.lastname: Kailaanmäki
authors.affiliation: Department of Pulmonary Diseases, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Jukka T
authors.initials: JT
authors.lastname: Randell
authors.affiliation: Commissariat à l'Energie Atomique, Institut de Biologie et de Technologies, Service d'Ingénierie Moléculaire des Protéines, Gif Sur Yvette, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Maillère
authors.affiliation: Department of Clinical Microbiology, Institute of Clinical Medicine and Biocenter Kuopio, University of Eastern Finland, Kuopio, Finland.
authors.forename: Tuomas I
authors.initials: TI
authors.lastname: Virtanen
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000276:immunology*; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D016022:Case-Control Studies; D002460:Cell Line; D016207:Cytokines / Q000096:biosynthesis; D004285:Dogs; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000737:chemistry / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000276:immunology; D054835:Lipocalin 1 / Q000737:chemistry / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D010455:Peptides / Q000737:chemistry / Q000276:immunology; D010641:Phenotype; D011485:Protein Binding; D018417:Th1 Cells / Q000276:immunology / Q000378:metabolism; D018418:Th2 Cells / Q000276:immunology / Q000378:metabolism
chemical_list: D000485:Allergens; D016207:Cytokines; D018984:Epitopes, T-Lymphocyte; D000949:Histocompatibility Antigens Class II; C518443:LCN1 protein, human; D054835:Lipocalin 1; D010455:Peptides; C091462:allergen Can f I