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81.
Target antigens for H-2-restricted vesicular stomatitis virus-specific cytotoxic T cells. 总被引:13,自引:0,他引:13
R M Zinkernagel A Althage J Holland 《Journal of immunology (Baltimore, Md. : 1950)》1978,121(2):744-748
Cytotoxic thymus-derived lymphocytes from mice infected with vesicular stomatitis virus (VSV) are H-2 restricted and virus specific for the Indiana and New Jersey strains of VSV. VSV-Indiana-immune T cells can lyse target cells infected with the temperature sensitive (ts) mutant ts 045 about 30 times better when target cell infection occurs at the permissive rather than the non-permissive temperature. Since this mutant fails to express the glycoprotein at the cell surface when grown at the nonpermissive temperature, our results support the view that the viral glycoprotein is involved in defining the major target antigen for VSV-specific T cells. However, the tl 17 mutant that expresses a mutant glycoprotein at the cell surface was lysed, suggesting that the expressed mutated glycoprotein can cross-react with Indiana wild-type glycoprotein. Targets infected at the nonpermissive temperature with VSV ts G31 (mutant in the matrix protein) are still susceptible to T cell-mediated lysis but at a lower level of sensitivity. These results are compatible with the interpretation that for VSV-specific T cell lysis of infected target cells, the viral glycoprotein is a major target antigen and must be expressed, and that the matrix protein plays a lesser role, probably by indirectly influencing glycoprotein configuration at the cell surface. 相似文献
82.
Reciprocal radiation bone-marrow chimeras were produced between the standard C57BL/6 (=B6) and the mutant B6.C-H-2
ba
(=Hz1) strain. When infected with vaccinia virus, these chimeras, as well as an (Hz1 × B6)= Hz1 chimera, produced cytotoxic cells that killed vaccinia-infected H-2KkH-2Db target cells but failed to kill virus-infected H-2KbH-2Dd cells. Virus-infected (Hz1 × B6)F1 B6 chimeras, however, killed both types of target. These experiments demonstrate strict T-cell specificity capable of differentiating between two molecules that apparently differ by a single amino acid substitution. 相似文献
83.
Rico Frigg Michael A. Klein Ivan Hegyi Rolf M. Zinkernagel Adriano Aguzzi 《Journal of virology》1999,73(11):9584-9588
Prion infections can present without clinical manifestations. B-cell deficiency may be a model for subclinical transmissible spongiform encephalopathy, since it protects mice from disease upon intraperitoneal administration of scrapie prions; however, a proportion of B-cell-deficient mice accumulate protease-resistant prion protein in their brains. Here, we have characterized this subclinical disease. In addition, we have studied the possibility that a neurotoxic factor secreted by B cells may contribute to pathogenesis. 相似文献
84.
85.
R Quintero‐Torres HA Castillo‐Matadamas Jeff F Young RM Bermúdez Cruz 《Luminescence》2014,29(5):440-444
Relaxation dynamics is universal in science and engineering; its study serves to parameterize a system's response and to help identify a microscopic model of the processes involved. When measured data for a phenomenon cannot be fitted using one exponential, the choice of an alternative function to describe the decay becomes nontrivial. Here, we contrast two different, but fundamentally related approaches to fitting nontrivial decay curves; exponential decomposition and the gamma probability density function. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
86.
Harris NL Spoerri I Schopfer JF Nembrini C Merky P Massacand J Urban JF Lamarre A Burki K Odermatt B Zinkernagel RM Macpherson AJ 《Journal of immunology (Baltimore, Md. : 1950)》2006,177(9):6256-6262
Following an abrupt transition at birth from the sterile uterus to an environment with abundant commensal and pathogenic microbes, neonatal mammals are protected by maternal Abs at mucosal surfaces. We show in mice that different Ab isotypes work in distinct ways to protect the neonatal mucosal surface. Secretory IgA acts to limit penetration of commensal intestinal bacteria through the neonatal intestinal epithelium: an apparently primitive process that does not require diversification of the primary natural Ab repertoire. In contrast, neonatal protection against the exclusively luminal parasite Heligmosomoides polygyrus required IgG from primed females. This immune IgG could either be delivered directly in milk or retrotransported via neonatal Fc receptor from the neonatal serum into the intestinal lumen to exert its protective effect. 相似文献
87.
Narayan P Subramaniyam Outi RM Väisänen Katrina E Wendel Jaakko AV Malmivuo 《Nonlinear biomedical physics》2010,4(Z1):S4
Background
The electroencephalography (EEG) is an attractive and a simple technique to measure the brain activity. It is attractive due its excellent temporal resolution and simple due to its non-invasiveness and sensor design. However, the spatial resolution of EEG is reduced due to the low conducting skull. In this paper, we compute the potential distribution over the closed surface covering the brain (cortex) from the EEG scalp potential. We compare two methods – L-curve and generalised cross validation (GCV) used to obtain the regularisation parameter and also investigate the feasibility in applying such techniques to N170 component of the visually evoked potential (VEP) data.Methods
Using the image data set of the visible human man (VHM), a finite difference method (FDM) model of the head was constructed. The EEG dataset (256-channel) used was the N170 component of the VEP. A forward transfer matrix relating the cortical potential to the scalp potential was obtained. Using Tikhonov regularisation, the potential distribution over the cortex was obtained.Results
The cortical potential distribution for three subjects was solved using both L-curve and GCV method. A total of 18 cortical potential distributions were obtained (3 subjects with three stimuli each – fearful face, neutral face, control objects).Conclusions
The GCV method is a more robust method compared to L-curve to find the optimal regularisation parameter. Cortical potential imaging is a reliable method to obtain the potential distribution over cortex for VEP data.88.
Bacillus pumilus was isolated from surface-sterilized tissues of the medicinal plant Ocimum sanctum. Scanning electron microscopic (SEM) imaging confirmed the presence of a rod shaped bacterium within the plant tissues. The bacterium was identified as B. pumilus by biochemical analyses and 16S rRNA gene sequencing. In vitro analyses indicate that the isolated strain of B. pumilus was endowed with multiple plant growth promotion (PGP) traits such as phosphate solubilization and the production of indole acetic acid (IAA), siderophore and hydrogen cyanide (HCN). Phosphate solubilization (37.3 μg ml?1) and IAA production (36.7 μg ml?1) by the isolate was found to reach a maximum after 60 h of incubation. Siderophore mediated iron sequestration by B. pumilus may confer a competitive advantage to the host with respect to pathogen inhibition. Siderophore produced by the isolate was found to be of a trihydroxamate type with hexadentate nature. The B. pumilus isolate also exhibited cellulolytic, proteolytic and chitinolytic activity. Cell free supernatant, culture filtrates of the isolate were found to suppress the growth of fungal phytopathogens. The culture filtrate retained its antifungal activity even after exposure to heat. In addition to PGP, the isolate exhibited probiotic properties such as acid tolerance (pH2), bile salt tolerance (2 %), auto-aggregation, antibiotic resistance and the absence of haemolytic activity. These finding suggest the possibility of utilizing this endophytic strain of B. pumilus as a bioinoculant to enhance plant growth and also as a probiotic. 相似文献
89.
RM Christie 《Biotechnic & histochemistry》2013,88(2):51-56
Although the color of indigo is strongly dependent on its environment, it is blue in most commonly encountered situations. Indigo's absorption at such long wavelengths for such a small molecule is unique, and I provide here an overview of the concepts advanced to account for this feature. A traditional valence–bond approach may be used to provide a reasonable qualitative explanation. A more rigorous, quantitative explanation is provided by molecular orbital methods of varying degrees of sophistication and several explanations have been proposed based on these models. Commonly, it is suggested that the important structural unit in determining color is based on the cross-conjugated “H-chromophore” concept. A second closely related explanation describes it as two symmetrically coupled merocyanine chains. Another proposal suggests that the basic chromophore may be interpreted as the aza analogue of two coupled anti aromatic-cyclopentadienyl ions. PiSYSTEM, a commercially available quantum mechanics program, has been used to provide a successful quantitative account of the colors of indigo and indirubin, a red isomer. 相似文献
90.
da Silva FH Pereira VG Yasumura EG Tenório LZ de Carvalho LP Lisboa BC Matsumoto PK Stilhano RS Samoto VY Calegare BF Brandão Lde C D'Almeida V Filippo TR Porcionatto M Toma L Nader HB Valero VB Camassola M Nardi NB Han SW 《Genetic vaccines and therapy》2012,10(1):2-11