2621. |
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2622. |
- Johansson, C, et al.
(författare)
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Critical test of the validity of Monin-Obukhov similarity during convective conditions
- 2001
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Ingår i: Journal of the Atmospheric Sciences. - 0022-4928 .- 1520-0469. ; 58:12, s. 1549-1566
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Tidskriftsartikel (refereegranskat)abstract
- A recent study of convective boundary layer characteristics performed with large eddy simulation technique (LES) has demonstrated unexpected influence of the depth of the boundary layer on surface layer characteristics. The present study tests some of the
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2623. |
- Johansson, C, et al.
(författare)
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Differential expression of chemokine receptors on human IgA+ and IgG+ B cells.
- 2005
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Ingår i: Clinical and experimental immunology. - : Oxford University Press (OUP). - 0009-9104 .- 1365-2249. ; 141:2, s. 279-87
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Tidskriftsartikel (refereegranskat)abstract
- Organ-specific lymphocyte homing is dependent on the expression of tissue-specific homing receptors and selected chemokine receptors. During the effector phase of an immune response, IgA and IgG antibody-secreting cells (ASC) are differently distributed in the body. Still, B cell expression of L-selectin and the mucosal homing receptor integrin alpha4beta7 is not related to the isotype produced, but only to the site of antigen encounter. In this study, we examined if differences in chemokine responsiveness between IgA+ and IgG+ B cells could explain their different tissue localization. Circulating CD19+ B cells were isolated and their expression of IgA, IgG, and selected chemokine receptors was determined by flow cytometry. Few Ig+ cells expressed CCR2, CCR3, or CCR9, and there was no difference in the expression of these receptors between IgA+ and IgG+ cells. In contrast, CCR4, CCR5, and CXCR3 was expressed on significantly more IgG+ than IgA+ cells. The function of chemokine receptors on memory B cells and ASC was then tested in the transwell system. IgG+ memory cells migrated to a higher extent than IgA+ cells towards the CXCR3 ligand CXCL11/I-TAC, while there was only a small migration towards the CCR4 ligand CCL17/TARC and the CCR9 ligand CCL25/TECK. ASC migrated poorly to all chemokines tested. In conclusion, this study shows that IgG+ and IgA+ memory B cells have a differential expression of the Th1 associated chemokine receptor CXCR3, as well as of CCR4 and CCR5. In contrast, none of the studied chemokine receptors was preferentially expressed by IgA+ cells.
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2624. |
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2625. |
- Johansson, C, et al.
(författare)
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Elevated levels of IgG and IgG4 to Malassezia allergens in atopic eczema patients with IgE reactivity to Malassezia
- 2004
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Ingår i: International archives of allergy and immunology. - : S. Karger AG. - 1018-2438 .- 1423-0097. ; 135:2, s. 93-100
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Tidskriftsartikel (refereegranskat)abstract
- <i>Background:</i> The opportunistic yeast <i>Malassezia</i> is considered to be one of the factors that can contribute to atopic eczema (AE). Elevated serum IgE levels, T-cell proliferation and positive skin prick test (SPT) and atopy patch test (APT) reactions to <i>Malassezia</i> are found among AE patients. <i>Methods:</i> Sera from 127 AE patients, 14 patients with seborrheic dermatitis (SD) and 33 healthy controls were investigated for IgE and IgG4 to <i>M. sympodialis </i>extract and four recombinant <i>Malassezia</i> allergens; rMala s 1, rMala s 5, rMala s 6, and rMala s 9. In addition, IgG to the recombinant allergens was analyzed. The IgG and IgG4 levels were compared to IgE levels and in vivo reactions (SPT and APT) to <i>Malassezia</i>.<i> Results:</i> AE patients with serum IgE levels >0.35 kU/l to <i>M. sympodialis</i> extract had significantly higher IgG4 levels to <i>M. sympodialis</i> extract than AE patients without detectable serum IgE to <i>M. sympodialis</i> extract, SD patients and healthy controls. Among the AE patients with and without detectable serum IgE to <i>M. sympodialis</i> extract, respectively, there were no differences in IgG4 levels between patients with positive or negative in vivo reactions to <i>M. sympodialis</i> extract. IgG4 to the rMala s allergens was almost exclusively found among patients with IgE to the same allergen. Within the four tested rMala s allergens, most IgG4 reactions were found to rMala s 6, an allergen with homology to cyclophilin. <i>Conclusions:</i> Elevated serum IgG4 to<i> M. sympodialis</i> extract accompanies elevated serum IgE to the extract. This is further confirmed by the association between IgG/IgG4 and IgE to recombinant <i>Malassezia</i> allergens.
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2626. |
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2627. |
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2628. |
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2629. |
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2630. |
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