170 research outputs found
Data management study. Appendix Q - Contractor data requirements advanced missions /AM/ Final report
Contractor data requirements relating to advanced missions and potential follow-up programs of Voyager projec
Data management study. Appendix O - Contractor data requirements science integration /SI/ Final report
Contractor data requirements for integration of scientific experiments aboard Voyager spacecraf
Immunologic abnormalities of mice bearing the gld mutation suggest a common pathway for murine nonmalignant lymphoproliferative disorders with autoimmunity.
Spontaneous murine lupus-like syndromes. Clinical and immunopathological manifestations in several strains.
Fas-Mediated Apoptosis Regulates the Composition of Peripheral αβ T Cell Repertoire by Constitutively Purging Out Double Negative T Cells
BACKGROUND: The Fas pathway is a major regulator of T cell homeostasis, however, the T cell population that is controlled by the Fas pathway in vivo is poorly defined. Although CD4 and CD8 single positive (SP) T cells are the two major T cell subsets in the periphery of wild type mice, the repertoire of mice bearing loss-of-function mutation in either Fas (lpr mice) or Fas ligand (gld mice) is predominated by CD4(-)CD8(-) double negative alphabeta T cells that also express B220 and generally referred to as B220+DN T cells. Despite extensive analysis, the basis of B220+DN T cell lymphoproliferation remains poorly understood. In this study we re-examined the issue of why T cell lymphoproliferation caused by gld mutation is predominated by B220+DN T cells. METHODOLOGY AND PRINCIPAL FINDINGS: We combined the following approaches to study this question: Gene transcript profiling, BrdU labeling, and apoptosis assays. Our results show that B220+DN T cells are proliferating and dying at exceptionally high rates than SP T cells in the steady state. The high proliferation rate is restricted to B220+DN T cells found in the gut epithelium whereas the high apoptosis rate occurred both in the gut epithelium and periphery. However, only in the periphery, apoptosis of B220+DN T cell is Fas-dependent. When the Fas pathway is genetically impaired, apoptosis of peripheral B220+DN T cells was reduced to a baseline level similar to that of SP T cells. Under these conditions of normalized apoptosis, B220+DN T cells progressively accumulate in the periphery, eventually resulting in B220+DN T cell lymphoproliferation. CONCLUSIONS/SIGNIFICANCE: The Fas pathway plays a critical role in regulating the tissue distribution of DN T cells through targeting and elimination of DN T cells from the periphery in the steady state. The results provide new insight into pathogenesis of DN T cell lymphoproliferation
The effector T cell response to influenza infection
Influenza virus infection induces a potent initial innate immune response, which serves to limit the extent of viral replication and virus spread. However, efficient (and eventual) viral clearance within the respiratory tract requires the subsequent activation, rapid proliferation, recruitment, and expression of effector activities by the adaptive immune system, consisting of antibody producing B cells and influenza-specific T lymphocytes with diverse functions. The ensuing effector activities of these T lymphocytes ultimately determine (along with antibodies) the capacity of the host to eliminate the viruses and the extent of tissue damage. In this review, we describe this effector T cell response to influenza virus infection. Based on information largely obtained in experimental settings (i.e., murine models), we will illustrate the factors regulating the induction of adaptive immune T cell responses to influenza, the effector activities displayed by these activated T cells, the mechanisms underlying the expression of these effector mechanisms, and the control of the activation/differentiation of these T cells, in situ, in the infected lungs
Tumor Necrosis Factor Sustains the Generalized Lymphoproliferative Disorder (gld) Phenotype
Estudo do reprocessamento de polietileno de baixa densidade (PEBD) reciclado do processamento de extrusão de filmes tubulares
Differential expression of murine autoimmunity and lymphoid hyperplasia determined by single genes.
The tropospheric distribution of carbon monoxide as observed during the TROPOZ II Experiment
As part of the TROPOZ II large-scale measurement campaign in January 1991 we deployed a Four Laser Airborne Infra Red (FLAIR) tunable diode laser spectrometer on board a Caravelle 116 research aircraft. We report here in situ CO measurements which were obtained with one of the four channels of the FLAIR instrument at a time resolution of either one or two minutes. The flight route of the TROPOZ II campaign followed the Atlantic coasts of North America, the Pacific and Atlantic coasts of South America and the Atlantic coasts of West Africa and Europe. A total of 48 CO vertical profiles extending from the surface to 10.5 km altitude were obtained. In the meridional direction adjacent profiles were separated by less than 10° latitude. Polewards of 30°S the CO distribution was very homogeneous with a mean mixing ratio of 55 ppbv. Between 30°S and the equator, the CO mixing ratio above 8 km altitude ranged up to 130 ppbv and was 20–60 ppbv higher than in the mid free troposhere. Three day backward trajectories for these CO rich airmasses originated over Amazonia. Earlier trace gas measurements as well as circulation studies suggested that these airmasses were of Northern Hemispheric origin and had been rapidly convected to the upper troposphere over central South America. The influence of biomass burning is clearly apparent from the measurements performed at 10°N on the African side of the Atlantic with CO mixing ratios being 100–300% higher than on the Central American side. CO mixing ratios further north ranged from 80 to 130 ppbv in the free troposphere and increased to 130–150 ppbv at lower altitudes
- …