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1.
2.
Interleukin 2 and concanavalin A stimulate interferon-gamma production in a murine cytolytic T cell clone by different pathways 总被引:1,自引:0,他引:1
D E Dunn K C Herold G R Otten D W Lancki T Gajewski S N Vogel F W Fitch 《Journal of immunology (Baltimore, Md. : 1950)》1987,139(12):3942-3948
We identified a variant murine cytolytic T lymphocyte (CTL) clone which, in contrast to the parent clone and all other murine T cell populations tested, was found to have acquired spontaneously the ability to produce interferon-gamma (IFN-gamma) in response to recombinant interleukin 2 (rIL-2). IFN-gamma production in response to concanavalin A (Con A), which was characteristic of all T cell populations tested, was preserved in this variant. The IFN produced by the variant in response to either stimulus was active in both a macrophage-activating factor assay and an anti-viral assay. Both activities induced by either stimulus could be blocked by monoclonal anti-IFN-gamma antibodies. Upon Northern blot analysis using an IFN-gamma-specific cDNA probe, the IFN-gamma RNA isolated from variant cells stimulated with Con A or IL-2 were found to migrate equivalently. The unusual pattern of responsiveness in this variant CTL was exploited to compare the mechanisms involved in induction of IFN-gamma production by Con A or IL-2. Striking differences were observed. Unlike IFN-gamma production induced by Con A, IFN-gamma production induced by IL-2 was not accompanied by an elevation of intracellular Ca2+ levels, did not require physiologic extracellular Ca2+ levels, and was not inhibited by the immunosuppressive agent cyclosporin A. Thus, in this variant CTL clone, conditions that have ordinarily been associated in an obligate manner with lymphokine gene expression were found instead to be related to the specific mode of stimulation. 相似文献
3.
The aim of this study was to investigate circadian variation in concentrations of arachidonic acid (AA) metabolites in relation to the circadian pattern in bronchial patency. Blood samples were obtained at 4-hr intervals from 2000 of 1 day until 1400 of the next from 12 diurnally active asthmatic and six diurnally active non-asthmatic patients. Bloods were analyzed for the prostanoids thromboxane A2 (measured as stable metabolite 6-keto-PGF1a), PGE2 and PGF2a. Airways patency was assessed by self-measurement of peak expiratory flow (PEF). In asthmatics, circadian variation was detected in PEF as well as PGE2 and TXB2. The circadian trough of the PEF rhythm closely coincided with the circadian peak of the PGE2 and TXB2 rhythms. In the controls, the PEF was not circadian rhythmic. Of the AA metabolites only 6-keto-PGF1a exhibited 24-hr bioperiodicity in the controls. The controls exhibited a significantly higher circadian mean of PEF (P less than 0.001), while the asthmatics had a lower 24-hr average PGE2 but greater mean TXB2/PGE2 ratio. The obstructive effect caused by the overall 24-hr deficiency of PGE2 in asthmatics is possibly amplified by the increased of TXB2 during the early morning hours. This dissociation of the temporal patterns in TXB2 and PGE2 levels over the 24 hr is discussed as a characteristic finding for asthmatics. 相似文献
4.
Differential Dialysis Culture for Separation and Concentration of a Macromolecular Product 总被引:4,自引:0,他引:4
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A differential dialysis flask, constructed with three chambers and two membranes of different porosity, was used to effect the separation and concentration of enterotoxin B produced extracellularly by a culture of Staphylococcus aureus. Variables were examined that affected the diffusion of glucose, as measured by half-equilibration time and permeability coefficient; the relative chamber volume, type of membrane, membrane masking, and mixing all exerted a substantial influence on diffusion rates. A number of membrane filters were tested for usefulness; one type, made with vinylidene fluoride, had desirable physical and diffusional properties, but neither it nor others consistently withheld the bacteria for more than a marginally useful period of about 50 hr. In ordinary two-chambered dialysis culture, the amount of enterotoxin reached 10 times that in control culture; in differential, three-chambered dialysis culture the comparable factor of increase was about 7, with about two-thirds of this amount being separated from cells in the product chamber of the flask. 相似文献
5.
Characterization of a human coronavirus (strain 229E) 3C-like proteinase activity. 总被引:15,自引:8,他引:7
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The RNA polymerase gene of human coronavirus (HCV) 229E encodes a large polyprotein that contains domains with motifs characteristic of both papain-like cysteine proteinases and proteinases with homology to the 3C proteinase of picornaviruses. In this study, we have, first, expressed the putative HCV 229E 3C-like proteinase domain as part of a beta-galactosidase fusion protein in Escherichia coli and have shown that the expressed protein has proteolytic activity. The substitution of one amino acid within the predicted proteinase domain (His-3006-->Asp-3006) abolishes, or at least significantly reduces, this activity. Amino-terminal sequence analysis of a purified, 34-kDa cleavage product shows that the bacterial fusion protein is cleaved at the dipeptide Gln-2965-Ala-2966, which is the predicted amino-terminal end of the putative 3C-like proteinase domain. Second, we have confirmed the proteolytic activity of a bacterially expressed polypeptide with the amino acid sequence of the predicted HCV 229E 3C-like proteinase by trans cleavage of an in vitro translated polypeptide encoded within open reading frame 1b of the RNA polymerase gene. Finally, using fusion protein-specific antiserum, we have identified a 34-kDa, 3C-like proteinase polypeptide in HCV 229E-infected MRC-5 cells. This polypeptide can be detected as early as 3 to 5 h postinfection but is present in the infected cell in very low amounts. These data contribute to the characterization of the 3C-like proteinase activity of HCV 229E. 相似文献
6.
Characterization of a BHK(TK-) cell clone resistant to postattachment entry by herpes simplex virus types 1 and 2. 总被引:1,自引:0,他引:1
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BHK(TK-) cells selected for resistance to polyethylene glycol-mediated fusion give rise to clones that are resistant to herpes simplex virus (HSV) infection. We have characterized one such clone, designated 95-19, and found that it is resistant to entry of HSV type 1 (HSV-1), HSV-2, and the related alphaherpesvirus pseudorabies virus (PRV). Single-step growth experiments show no detectable replication of multiple strains of HSV-1 and HSV-2 on 95-19 cells. Three lines of evidence suggest that these cells are resistant to postattachment entry. (i) Measurements of binding of radiolabeled virus show that heparin-sensitive binding of HSV-1 and HSV-2 to 95-19 cells is identical to binding to BHK(TK-) cells, suggesting that the block to replication occurs after attachment to heparan sulfate proteoglycan. (ii) 95-19 cells exposed to HSV-1 or HSV-2 at high multiplicity show no detectable immediate-early (IE) mRNA expression. (iii) Exposure of attached virus and cells to polyethylene glycol results in partial recovery of both IE gene expression and virus yield in single-step growth. The degrees of recovery of single-step yield and IE gene expression are similar, suggesting that the only block to single-step replication is at the point of virus entry and that these cells are deficient in some cellular factor required for efficient postattachment entry of free virus. 95-19 cells are also highly resistant to entry by cell-to-cell spread, suggesting that the same cellular factor participates in both types of entry. 相似文献
7.
The effect of placebo and ACTH-1-17 (Synchrodyn®, Hoechst) upon urinary free cortisol was examined at 5 different circadian stages on 10 men with Steinbrocker Stage II–III rheumatoid arthritis. A mean cosinor analysis of urinary cortisol data from the subjects prior to treatment with either ACTH or placebo revealed a statistically highly-significant rhythm. A circadian variation in a response of urinary free cortisol to a placebo was also seen. Moreover, the response of the midline-estimating statistic of rhythm (rhythm-adjusted circadian average) of urinary free cortisol to ACTH-1-17 by patients with rheumatoid arthritis is circadian rhythmic. This reactivity rhythm is out of phase with the spontaneous rhythm in urinary cortisol acrophases—in the tests limited thus far to midsummer. The further assessment of the circadian component in the context of broader interactions by rhythms with other frequencies in various conditions in health and disease is warranted by the demonstration of rhythms here presented for men with rheumatoid arthritis. 相似文献
8.
Suresh K. Aggarwal Michael Kinter David A. Herold 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1992,576(2)
A gas chromatographic—mass spectrometric method for the determination of cobalt in biological materials employing stable enriched 62Ni as an internal standard and using lithium bis(trifluoroethyl)dithiocarbamate as a chelating agent is described. The method involves the addition of a known amount (1 μg) of 62Ni to the sample, the formation of the chelate and the determination by selected-ion monitoring of the m/z
ratio, which corresponds to
. No appreciable memory effect was observed, and an acceptable dynamic range of 100 was found. There was good agreement between the cobalt concentration values determined by gas chromatography—mass spectrometry and electrothermal atomic absorption spectrometry. The present method has high sensitivity and can be used for the quantitation of cobalt at concentrations as low as 1 μg/l. The use of enriched 62Ni circumvents the problem caused by endogenous nickel and simultaneously provides data on the nickel concentration in the biological sample without any additional experimental effort. 相似文献
9.
Summary Hindgut epithelial cells of the aquatic isopod,Asellus communis, and the terrestrial isopod,Armadillidium vulgare, possess annulate lamellae. The organelle is present in non-dividing cells of intermolt adult organisms. The lamellae exhibit dense pore areas traversed by diaphragms, and the lamellae are associated with elements of endoplasmic reticulum.This research was supported in part by a grant to E. R. Witkus from the Irene Heinz and John La Porte Given Foundation. 相似文献
10.
The interactions of butanol and mixtures of butanol and ethanol with dipalmitoylphosphatidyl choline (DPPC) liposomes have been investigated by both spectrophotometric measurements and Fourier transform 13C nuclear magnetic resonance spectroscopy. The spectrophotometric experiments indicate that butanol exhibits the same effects on the thermotropic properties of DPPC as the other short chain alcohols, methanol, ethanol and propanol, which have been shown to be characteristic of the alcohol induced transition of the lipid to the interdigitated state. An additive effect of butanol and ethanol on the induction of the interdigitated phase in DPPC was also observed. A decrease in line width and increase in T1 of the choline methyl signal were observed in the 13C-NMR experiments conducted at 32 degrees C when butanol was added to DPPC in increasing amounts suggesting an increase of disorder in the head group region of the lipid. Addition of ethanol to the NMR sample containing butanol produced hysteresis in the heating and cooling curves characteristic of the interdigitated state. In the interdigitated state, the choline methyl signal exhibited a T1 value equal to that when the lipid is in the fluid state. The increase of mobility in the head group region in the interdigitated gel state relative to the bilayer gel can be rationalized by the increase in surface area in that site when the lipid interdigitates. 相似文献