| 1. |
- Annacker, O, et al.
(author)
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Essential role for CD103 in the T cell-mediated regulation of experimental colitis
- 2005
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In: Journal of Experimental Medicine. - : Rockefeller University Press. - 1540-9538 .- 0022-1007. ; 202:8, s. 1051-1061
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Journal article (peer-reviewed)abstract
- The integrin CD103 is highly expressed at mucosal sites, but its role in mucosal immune regulation remains poorly understood. We have analyzed the functional role of CD103 in intestinal immune regulation using the T cell transfer model of colitis. Our results show no mandatory role for CD103 expression on T cells for either the development or CD4(+)CD25(+) regulatory T (T reg) cell-mediated control of colitis. However, wild-type CD4(+)CD25(+) T cells were unable to prevent colitis in immune-deficient recipients lacking CD103, demonstrating a nonredundant functional role for CD103 on host cells in T reg cell-mediated intestinal immune regulation. Non-T cell expression of CD103 is restricted primarily to CD11c(high) MHC class IIhigh dendritic cells (DCs). This DC population is present at a high frequency in the gut-associated lymphoid tissue and appears to mediate a distinct functional role. Thus, CD103(+) DCs, but not their CD103(-) counterparts, promoted expression of the gut-homing receptor CCR9 on T cells. Conversely, CD103(-) DCs promoted the differentiation of IFN-gamma-producing T cells. Collectively, these data suggest that CD103(+) and CD103(+) DCs represent functionally distinct subsets and that CD103 expression on DCs influences the balance between effector and regulatory T cell activity in the intestine.
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| 2. |
- Fergusson, J. R., et al.
(author)
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CD161(int)CD8+T cells : a novel population of highly functional, memory CD8+T cells enriched within the gut
- 2016
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In: Mucosal Immunology. - : Elsevier BV. - 1933-0219 .- 1935-3456. ; 9:2, s. 401-413
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Journal article (peer-reviewed)abstract
- The C-type lectin-like receptor CD161 is expressed by lymphocytes found in human gut and liver, as well as blood, especially natural killer (NK) cells, T helper 17 (Th17) cells, and a population of unconventional Tcells known as mucosalassociated invariant T (MAIT) cells. The association of high CD161 expression with innate T-cell populations including MAITcells is established. Here we show that CD161 is also expressed, at intermediate levels, on a prominent subset of polyclonal CD8+ T cells, including antiviral populations that display a memory phenotype. These memory CD161(int)CD8+ Tcells are enriched within the colon and express both CD103 and CD69, markers associated with tissue residence. Furthermore, this population was characterized by enhanced polyfunctionality, increased levels of cytotoxic mediators, and high expression of the transcription factors T-bet and eomesodermin (EOMES). Such populations were induced by novel vaccine strategies based on adenoviral vectors, currently in trial against hepatitis C virus. Thus, intermediate CD161 expression marks potent polyclonal, polyfunctional tissue-homing CD8+ T-cell populations in humans. As induction of such responses represents a major aim of T-cell prophylactic and therapeutic vaccines in viral disease and cancer, analysis of these populations could be of value in the future.
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| 3. |
- Musil, C F, et al.
(author)
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Spatial and temporal changes in South African solar ultraviolet-B exposure: Implications for threatened taxa
- 1999
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In: Ambio: a Journal of Human Environment. - 0044-7447. ; 28:5, s. 450-456
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Journal article (peer-reviewed)abstract
- Spatial and temporal changes in South African solar UV-B (280-315 nm) exposure were modeled and mapped at 2.5 km2 resolution using ozone, relative humidity, cloud amount and elevation data. Computations indicated large natural gradients in UV-B exposure ranging from a 34.2% change over 14o of latitude to a 44.2% change over 16o of longitude. Modelling of future scenarios in annual UV-B exposure indicated small increases ranging from 2.5% in the year 2003 (best-case ozone depletion scenario) to 8.1% in the year 2051 (worst-case ozone-depletion scenario). Notable were substantial increases in intra-annual variability in UV-B radiation with ozone depletion. Exposure exhibits a 12% increase during late autumn (May) in the year 2003 and a 35% increase during this season in the year 2051. Taxonomic, life form and functional attributes were analyzed in 2146 threatened (rare, endangered, vulnerable) species representing 468 genera and 103 families, and their distributions compared with modeled spatial and temporal UV-B distribution patterns. The high fractions of evergreen and succulent life forms and geophytes, present among threatened taxa, indicate a high degree of physiological resilience to increased solar UV-B stress, though some life forms, e.g. trees, appear relatively less resistant. Conceivable reductions in per capita reproductive output and overall plant fitness were indicated in some plant functional types, e.g. herbaceous annuals, which may lead to altered patterns of species coexistence, floristic composition and diversity.
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