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排序方式: 共有357条查询结果,搜索用时 15 毫秒
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3.
Protective cytotoxic T lymphocyte responses against paramyxoviruses induced by epitope-based DNA vaccines: involvement of IFN-gamma 总被引:1,自引:0,他引:1
Hsu SC; Obeid OE; Collins M; Iqbal M; Chargelegue D; Steward MW 《International immunology》1998,10(10):1441-1447
Plasmid DNA vectors have been constructed with minigenes encoding a single
cytotoxic T lymphocyte (CTL) epitope from either the M2 protein of
respiratory syncytial virus (RSV) or from the nucleoprotein of measles
virus (MV) with or without a signal sequence (also called secretory or
leader sequence). Following intradermal immunization, plasmids in which the
CTL epitopes were expressed in-frame with the signal sequence were more
effective at inducing peptide- and virus- specific CTL responses than
plasmids expressing CTL epitopes without the signal sequence. This
immunization resulted in protection against MV-induced encephalitis and a
significant reduction in viral load following RSV challenge. The reduction
of viral load following RSV challenge was abrogated by prior injection with
anti-IFN-gamma antibodies. These results highlight the ability of
epitope-based DNA immunization to induce protective immune responses to
well-defined epitopes and indicate the potential of this approach for the
development of vaccines against infectious diseases.
相似文献
4.
Rabbit trace eyeblink conditioning is a hippocampus-dependent task in which the auditory conditioned stimulus (CS) is separated from the corneal airpuff unconditioned stimulus (US) by a 500-ms empty trace interval. Young rabbits are able to associate the CS and US and acquire trace eyeblink conditioned responses (CRs); however, a subset of aged rabbits show poor learning on this task. Several studies have shown that CA1-hippocampal activity is altered by aging; however, it is unknown how aging affects the interaction of CA1 single neurons within local ensembles during learning. The present study examined the extracellular activity of CA1 pyramidal neurons within local ensembles in aged (29-34 mo) and young (3-6 mo) rabbits during 10 daily sessions (80 trials/session) of trace eyeblink conditioning. A single surgically implanted nonmovable stereotrode was used to record ensembles ranging in size from 2 to 12 separated single neurons. A total of six young and four aged rabbits acquired significant levels of CRs, whereas five aged rabbits showed very few CRs similar to a group of five young pseudoconditioned rabbits. Pyramidal cells (2,159 total) were recorded from these four groups during training. Increases in CA1 pyramidal cell firing to the CS and US were diminished in the aged nonlearners. Local ensembles from all groups contained heterogeneous types of pyramidal cell responses. Some cells showed increases while others showed decreases in firing during the trace eyeblink trial. Hierarchical clustering was used to isolate seven different classes of single-neuron responses that showed unique firing patterns during the trace conditioning trial. The proportion of cells in each group was similar for six of seven response classes. Unlike the excitatory modeling patterns reported in previous studies, three of seven response types (67% of recorded cells) exhibited some type of inhibitory decrease to the CS, US, or both. The single-neuron response classes showed different patterns of learning-related activity across training. Several of the single-neuron types from the aged nonlearners showed unique alterations in response magnitude to the CS and US. Cross-correlation analyses suggest that specific single-neuron types provide more correlated single-neuron activity to the ensemble processing of information. However, aged nonlearners showed a significantly lower level of coincident pyramidal cell firing for all cell types within local ensembles in CA1. 相似文献
5.
MW Lieberman R Barrios G Kala SV Kala ED Lykissa CN Ou 《Environmental health perspectives》1999,107(9):A444-A445
Respond on comments on Lieberman's article: Cyclosiloxanes Produce Fatal Liver and Lung Damage in Mice. Environ Health Perspect 107:161-165 相似文献
6.
Differential inotropic and chronotropic effects of various protein kinase C activators on isolated guinea pig atria 总被引:2,自引:0,他引:2
1,2-Dioctanoylglycerol (10-100 microM) produced a positive inotropic effect on electrically stimulated left guinea pig atria and increased the frequency of spontaneously beating atria. Various phorbol esters and mezerein induced heterogeneous responses of the left atria. Phorbol dibutyrate and phorbol didecanoate decreased the force of contraction to different extents, whereas phorbol myristate acetate and mezerein had dual actions: an initial enhancement followed by a decline in force. None of these compounds changed the spontaneous atrial rate. 相似文献
7.
The effects of recombinant-DNA-derived interferons on the growth of myeloid progenitor cells 总被引:5,自引:0,他引:5
Interferons (IFNs) have been shown to have significant effects on hematopoietic cell growth. Previous studies defining these effects have utilized mouse and human alpha-, beta-, and gamma-IFN isolated from supernatants of stimulated cells. Despite purification, the possible presence of other lymphokines and soluble factors remains a concern. In this study, the effects of gene-cloned alpha- and gamma-IFN on colony- forming units of granulocyte/macrophage (CFU-GM) progenitors cultured from the peripheral blood of normal volunteers were examined. In addition, blast cell colonies from one patient with acute myelogenous leukemia (AML) were studied. The growth of normal CFU-GM and AML blast cell colonies was inhibited in a dose-dependent manner by gamma- and alpha-IFN. gamma-IFN was ten to 100 times more potent than alpha-IFN in that this species of IFN reduced colony formation by greater than 50% at concentrations of less than 15 antiviral U/mL. The effects of gamma- IFN were neutralized by a monoclonal antibody specific for gamma-IFN. These in vitro studies indicate that human gamma-IFN may be an important modulator of myelopoiesis. Although these data indicate a possible efficacy of gamma-IFN in the treatment of AML, the in vitro results should be considered for their in vivo significance. 相似文献
8.
Peter A. Jaques Selcen Kilinc-Balci Lee Portnoff Robyn Weible Matthew Horvatin 《Journal of occupational and environmental hygiene》2016,13(11):881-893
Gowns and coveralls are important components of protective ensembles used during the management of known or suspected Ebola patients. In this study, an Elbow Lean Test was used to obtain a visual semi-quantitative measure of the resistance of medical protective garments to the penetration of two bodily fluid simulants. Tests were done on swatches of continuous and discontinuous regions of fabrics cut from five gowns and four coveralls at multiple elbow pressure levels (2–44 PSI). Swatches cut from the continuous regions of one gown and two coveralls did not have any strike-through. For discontinuous regions, only the same gown consistently resisted fluid strike-through. As hypothesized, with the exception of one garment, fluid strike-through increased with higher applied elbow pressure, was higher for lower fluid surface tension, and was higher for the discontinuous regions of the protective garments. 相似文献
9.
Phosphatidylinositol 3-kinase (PI3-kinase) and phosphatidylinositol 4-kinase (PI4-kinase) enzymes are an important family of signaling molecules that have been implicated in the regulation of intracellular vesicle trafficking. It has previously been shown that PI3-kinase and PI4-kinase enzymes regulate neuronal survival and the retrograde axonal transport of nerve growth factor in sympathetic and sensory neurons. We have extended these studies to examine the role these enzymes play in the regulation of the retrograde axonal transport of neurotrophin-3 (NT-3) and neurotrophin-4 (NT-4) in sympathetic and sensory neurons in vivo. Wortmannin (0.1 nmol/eye), a PI3-kinase and PI4-kinase antagonist, reduced the amount of (125)I-NT-3 retrograde transport in sympathetic neurons by approximately 50% and (125)I-NT-4 in sympathetic neurons by approximately 40% and sensory neurons by approximately 20%. The PI3-kinase antagonist LY294002 (100 nmol/eye) reduced the retrograde axonal transport of (125)I-NT-4 in sympathetic and sensory neurons, and (125)I-NT-3 in sympathetic neurons. Phenylarsine oxide (PAO), a PI4-kinase antagonist, significantly inhibited (125)I-NT-4 retrograde axonal transport in sympathetic and sensory neurons. These results show that wortmannin-sensitive PI3-kinases and PI4-kinases may be involved in NT-3 and NT-4 retrograde axonal transport. The retrograde axonal transport of neurotrophic factors in sympathetic and sensory neurons in vivo appears to depend upon the activation of different receptors and second messenger cascades at the nerve terminal. 相似文献
10.
A DNA endonuclease, isolated from the nuclei of normal human and xeroderma
pigmentosum complementation group A (XPA) cells, which recognizes
predominately pyrimidine dimers, was examined for the mechanism by which it
locates sites of damage on UVC-irradiated DNA. In reaction mixtures with
low ionic strengths (i.e. lacking KCl), the normal and XPA endonuclease
locate sites of UV damage on both naked and reconstituted nucleosomal DNA
by different mechanisms. On both of these substrates, the normal
endonuclease acts by a processive mechanism, meaning that it binds
non-specifically to DNA and scans the DNA for sites of damage, whereas the
XPA endonuclease acts by a distributive one, meaning that it randomly
locates sites of damage on DNA. However, while both the normal and XPA
endonucleases can incise UVC irradiated naked DNA, they differ in ability
to incise damaged nucleosomal DNA. The normal endonuclease showed increased
activity on UVC treated nucleosomal DNA compared with naked DNA, whereas
the XPA endonuclease showed decreased activity on the damaged nucleosomal
substrate. Since a processive mechanism of action is sensitive to the ionic
strength of the micro-environment, the KCl concentration of the reaction
was increased. At 70 mM KCI, the normal endonuclease switched to a
distributive mechanism of action and its ability to incise damaged
nucleosomal DNA also decreased. These studies show that there is a
correlation between the ability of these endonucleases to act by a
processive mechanism and their ability to incise damaged nucleosomal DNA;
the normal endonuclease, which acts processively, can incise damaged
nucleosomal DNA, whereas the XPA endonuclease, which acts distributively,
is defective in ability to incise this substrate.
相似文献