title: Evaluation of CD4+ T cells proliferating to grass pollen in seasonal allergic subjects by flow cytometry.
abstract: Our objective was to characterize T-cell responses to Phleum pratense in grass pollen allergic individuals and healthy controls using the fluorescent dye PKH26. Peripheral blood mononuclear cells were stimulated with P. pratense, or with recall antigens, and CD3+/CD4+ and CD3+/CD8+ T-cells that had proliferated were analysed by flow cytometry. In the presence of P. pratense CD4+/CD3+ T-cells proliferated more in grass pollen sensitive atopic patients than in nonallergic controls or in nongrass pollen sensitive atopic subjects. PPD and TT recall antigens elicited uniformly high proliferation in all T-cell subsets. Only half of pollen sensitive patients also had an increased proliferation of CD3+/CD8+ T-cells in response to P. pratense. We determined precursor frequency of CD4+ T cells in the original population that responded to P. pratense and found values ranging from 1 x 10-3 to 0.6 x 10-1, in the same range as those measured for PPD and TT. In conclusion, grass pollen sensitive atopic patients show enhanced CD4+ T-cell reactivity to P. pratense, and this could be related to the presence of elevated numbers of circulating allergen-specific CD4+ T cells. This flow cytometric method should allow the identification of other phenotypic markers such as intracellular cytokines in allergen specific responding CD4+ T cells.
authors.affiliation: Service de Pneumologie UPRES EA2705, INSERM U 31, Institut Paris-Sud sur les Cytokines, Hôpital Antoine Béclère, Assistance Publique Hôpitaux de Paris, Université Paris-Sud, Clamart, France.
authors.forename: A C
authors.initials: AC
authors.lastname: Rimaniol
authors.forename: G
authors.initials: G
authors.lastname: Garcia
authors.forename: S J
authors.initials: SJ
authors.lastname: Till
authors.forename: F
authors.initials: F
authors.lastname: Capel
authors.forename: G
authors.initials: G
authors.lastname: Gras
authors.forename: K
authors.initials: K
authors.lastname: Balabanian
authors.forename: D
authors.initials: D
authors.lastname: Emilie
authors.forename: M
authors.initials: M
authors.lastname: Humbert
mesh_terms: D000485:Allergens / Q000276:immunology*; D017252:CD3 Complex; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D016022:Case-Control Studies; D002455:Cell Division; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D006801:Humans; D008213:Lymphocyte Activation; D018655:Lymphocyte Count; D009930:Organic Chemicals; D031784:Phleum; D011058:Pollen / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology*
chemical_list: D000485:Allergens; D017252:CD3 Complex; D005456:Fluorescent Dyes; D009930:Organic Chemicals; C070080:PKH 26