Enhancement by Poly-d-Lysine of Poly I: C-Induced Interferon Production in Mice

Poly-d-lysine of high molecular weight enhances interferon induction in mice by the double-stranded complex of polyinosinic and polycytidylic acids and is superior to diethylaminoethyl-dextran in this respect.     

Anomalous Effects of Heterologous Normal Serum on Interferon Production in Mice

WHILE studying the inhibitory effect of burro anti-mouse lymphocyte serum on the production of interferon in mice¹, we investigated whether rabbit anti-mouse lymphocyte serum (ALS) had similar activity. There was some inhibition of interferon production after intraperitoneal injection of polyinosinic/polycytidylic acid (poly IC) in NIH Swiss strain mice pretreated with three doses of potent rabbit anti-mouse lymphocyte serum. Animals treated with normal rabbit serum, however, showed a similar inhibition of interferon production (Table 1), although normal burro serum had no effect¹.     

Interferon Production in Mice by Cell Wall Mutants of Salmonella typhimurium

The interferon response elicited by Salmonella typhimurium mutants in mice is not dependent on the presence of a complete cell wall lipopolysaccharide. In fact, a mutant (G30/C21) which has lost all the polysaccharide side chains and sugars of the O antigen and contains only 2-keto-3-deoxyoctonate and lipid is indistinguishable in its interferon-stimulating ability from the wild type which possesses a complete O antigen with polysaccharide side chains.     

The Germination of Avena fatua under Different Gaseous Environments

The atmosphere in which seeds germinate can profoundly affect the level of germination and dormancy. Seeds were germinated in atmospheres containing various concentrations of carbon dioxide and oxygen. At the same time the effect of light on these systems was examined. The germination of partially dormant populations of wild oat seed is inhibited by white light. This response to light is most apparent when the curyopsis is enclosed in the pales. Investigations into the effect of the ambient atmosphere on germination have indicated that, while oxygen is a necessary factor in the germination of tliis species, carbon dioxide also has an effect. A lack of carbon dioxide increases the degree of light inhibition of germination; 3 per cent carbon dioxide (by volume) allows germination in light; 20 per cent carbon dioxide inhibits germination in light and darkness at all tested oxygen concentrations.     

Visualizing Production of Beta Interferon by Astrocytes and Microglia in Brain of La Crosse Virus-Infected Mice

Beta interferon (IFN-β) is a major component of innate immunity in mammals, but information on the in vivo source of this cytokine after pathogen infection is still scarce. To identify the cell types responsible for IFN-β production during viral encephalitis, we used reporter mice that express firefly luciferase under the control of the IFN-β promoter and stained organ sections with luciferase-specific antibodies. Numerous luciferase-positive cells were detected in regions of La Crosse virus (LACV)-infected mouse brains that contained many infected cells. Double-staining experiments with cell-type-specific markers revealed that similar numbers of astrocytes and microglia of infected brains were luciferase positive, whereas virus-infected neurons rarely contained detectable levels of luciferase. Interestingly, if a mutant LACV unable of synthesizing the IFN-antagonistic factor NSs was used for challenge, the vast majority of the IFN-β-producing cells in infected brains were astrocytes rather than microglia. Similar conclusions were reached in a second series of experiments in which conditional reporter mice expressing the luciferase reporter gene solely in defined cell types were infected with wild-type or mutant LACV. Collectively, our data suggest that glial cells rather than infected neurons represent the major source of IFN-β in LACV-infected mouse brains. They further indicate that IFN-β synthesis in astrocytes and microglia is differentially affected by the viral IFN antagonist, presumably due to differences in LACV susceptibility of these two cell types.     

Chemical Carcinogenesis in Mice inhibited by Interferon

SEVERAL experiments have demonstrated that the anti-viral substance, interferon, can inhibit the growth of spontaneous^1,2, transplanted³ and virus-induced neoplasms in mice^4–7. Lieberman et al.⁵ reported that interferon treatment partially suppressed X-radiation-induced leukaemia in C57B1/6 mice. As they pointed out, the inhibitory effect provided additional evidence for the theory that X-rays cause lymphoma through the activation of a leukaemogenic type C RNA viral intermediate. In this communication, we report studies with CF-1 mice (Carworth Farms, New York City) to determine the effects of interferon on SC tumour induction by 3-methylcholanthrene (3-MC). These mice were previously shown to harbour high levels of type C RNA gs antigen and.infectious virus in normal spleens and in induced tumours, while spontaneous tumours rarely develop until late in life^8–10.     

Cellular Mechanisms of Interferon Production

Rabbit kidney cell cultures stimulated with either double-stranded polyinosinate-polycytidylate (poly I:poly C) or with ultraviolet-irradiated Newcastle disease virus (UV-NDV) produce two types of interferon response, designated "early" and "late," respectively. The early response is suppressed by inhibitors of RNA or protein synthesis and is therefore thought to represent de novo synthesis of interferon. Circumstantial evidence suggested that this interferon response is regulated by a translation control mechanism. Late interferon production with poly I:poly C only took place in the presence of inhibitors of RNA or protein synthesis. The late interferon is therefore likely to be derived by the activation of an interferon precursor. The stimulation of late poly I:poly C-induced interferon production by cycloheximide suggested the existence of a second, posttranslational level of control of interferon production. This posttranslation control seems to be activated by interferon. UV-NDV can probably suppress the synthesis of the posttranslation inhibitory protein, and therefore it stimulates a late interferon response in the absence of inhibitors of RNA or protein synthesis. It is postulated that both the translation and posttranslation inhibitor participate in the development of a cellular refractory state to repeated interferon stimulation. The picture of interferon which emerges from this study is one of a heterogenous class of proteins whose production is controlled by cellular repressors acting at various levels.     

Effect of Antilymphocytic Serum on Circulating Interferon in Mice as a Function of the Inducer

MOST investigators concerned with interferon synthesis in vivo have used the experimental procedure described by Baron and Buckler¹, in which circulating interferon is induced by intravenous administration of viruses. When interpreting results, however, it is difficult to know which cells are responsible for circulating interferon synthesis in the animal. Using a radiobiological approach, we have shown that after an intravenous injection of virus, interferon released into the blood stream of mice originates in cell populations of varying radiosensitivities, depending on the virus inoculated². Myxo-virus-induced circulating interferon production is characterized by high radiosensitivity, for serum interferon titres are decreased by more than 90% in C3H/He mice after one total body X-irradiation of 250 r. Moreover, the species specificity of interferon has enabled us to show that circulating interferon induced by Newcastle disease virus (NDV) is of donor type in xenogeneic radiochimaeras, from which we concluded that cells responsible for interferon synthesis with this virus originate from haemopoietic stem cells^3,4. Both granulocytes and lymphocytes fulfil the criteria of very radiosensitive elements derived from haemopoietic stem cells^5,6. We wish to report that myxovirus-induced circulating interferon production is selectively depressed after administration of antilymphocyte serum (ALS).     

Herbivore Body Condition Response in Altered Environments: Mule Deer and Habitat Management

The relationships between habitat, body condition, life history characteristics, and fitness components of ungulates are interwoven and of interest to researchers as they strive to understand the impacts of a changing environment. With the increased availability of portable ultrasound machines and the refinement of hormonal assays, assessment of ungulate body condition has become an accessible monitoring strategy. We employed body condition scoring, estimation of % ingesta-free body fat (%IFBF), assessment of free thyroid hormones (FT4 and FT3), and assessment of pregnancy, as metrics to determine if landscape-level habitat treatments affected body condition of adult (≥1.5 years old) female mule deer (Odocoileus hemionus). All body condition related metrics were measured on 2 neighboring study areas — a reference area that had received no habitat treatments and a treatment study area that had received mechanical removal of pinyon pine (Pinyus edulis) - Utah juniper (Juniperus osteosperma) forest, chemical control of weeds, and reseeding with preferred mule deer browse species. A consistent trend of higher %IFBF was observed in the treatment study area than in the reference study area , although variation of estimates was larger than hypothesized. A similar pattern was observed with higher thyroid hormones concentrations being observed in the treatment study area, but large amounts of variation within concentration estimates were also observed. The consistent pattern of higher body condition related estimates in our treatment study area provides evidence that large mammalian species are sensitive to landscape change, although variation within estimates underlie the challenge in detecting population level impacts stemming from environmental change.     

Discerning Pig Screams in Production Environments

Pig vocalisations convey information about their current state of health and welfare. Continuously monitoring these vocalisations can provide useful information for the farmer. For instance, pig screams can indicate stressful situations. When monitoring screams, other sounds can interfere with scream detection. Therefore, identifying screams from other sounds is essential. The objective of this study was to understand which sound features define a scream. Therefore, a method to detect screams based on sound features with physical meaning and explicit rules was developed. To achieve this, 7 hours of labelled data from 24 pigs was used. The developed detection method attained 72% sensitivity, 91% specificity and 83% precision. As a result, the detection method showed that screams contain the following features discerning them from other sounds: a formant structure, adequate power, high frequency content, sufficient variability and duration.     

Mengovirus-Induced Cytopathic Effect in L-Cells: Protective Effect of Interferon

The effect of interferon on mengovirus-induced cytopathic effect (CPE) in L cells, the cut-off of host-cell protein synthesis, and production of mature virus were found to be dependent on the concentration of interferon. CPE and inhibition of host protein synthesis were not affected until the concentration of interferon was increased 100-fold over that required to reduce viral yields by 90%.     

Production of Interferon in Serum-Free Human Leukocyte Suspensions

The recovery of interferon from Sendai-infected suspensions of purified human leukocytes is dependent on the serum concentration in the incubation medium. Very little interferon is obtained from serum-free suspensions. The data reported demonstrate that the critical macromolecular, age-independent, and species-unspecific serum principle can be omitted from the suspensions if the medium is supplemented with a combination of crystalline serum albumin and high concentrations of any one of five studied dipolar ionic buffers [N,N-bis(2-hydroxyethyl) glycine (Bicine), N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES), 2-(N-morpholino)ethanesulfonic acid (MES), N-tris(hydroxymethyl)methyl-2-amino-ethanesulfonic acid (TES), and N-tris(hydroxymethyl)methylglycine (Tricine)]. The optimal combination [TES (1.0%, w/v) and bovine serum albumin (0.8%, w/v)] allows the production of potent preparations of serum-free human interferon.     

Relationship between Immunity and Interferon Production in Macrophages

In vitro interferon (IF) production in peritoneal macrophages of normal and Newcastle disease virus (NDV)-immunized mice was studied. Of ascites cells used, 80% were macrophages, 14% lymphocytes, and 6% polymorphonuclear leukocytes. It was indicated that IF was produced mainly in the macrophages after NDV inoculation. IF production in the macrophages derived from immunized mice was more enhanced than that in those from normal mice. It is not clear at present, however, whether this enhancement is based on immunological specificity. The IF production in the culture of macrophages reached its maximum value in 6 to 9 hr after inoculation of the inducer. After 12 hr, the IF titer in the culture fluid decreased gradually. A possible explanation of this fact is that there may be partial inactivation of IF by some cellular components.     

Adaptation of Enterovirus 71 to Adult Interferon Deficient Mice

Non-polio enteroviruses, including enterovirus 71 (EV71), have caused severe and fatal cases of hand, foot and mouth disease (HFMD) in the Asia-Pacific region. The development of a vaccine or antiviral against these pathogens has been hampered by the lack of a reliable small animal model. In this study, a mouse adapted EV71 strain was produced by conducting serial passages through A129 (α/β interferon (IFN) receptor deficient) and AG129 (α/β, γ IFN receptor deficient) mice. A B2 sub genotype of EV71 was inoculated intraperitoneally (i.p.) into neonatal AG129 mice and brain-harvested virus was subsequently passaged through 12 and 15 day-old A129 mice. When tested in 10 week-old AG129 mice, this adapted strain produced 100% lethality with clinical signs including limb paralysis, eye irritation, loss of balance, and death. This virus caused only 17% mortality in same age A129 mice, confirming that in the absence of a functional IFN response, adult AG129 mice are susceptible to infection by adapted EV71 isolates. Subsequent studies in adult AG129 and young A129 mice with the adapted EV71 virus examined the efficacy of an inactivated EV71 candidate vaccine and determined the role of humoral immunity in protection. Passive transfer of rabbit immune sera raised against the EV71 vaccine provided protection in a dose dependent manner in 15 day-old A129 mice. Intramuscular injections (i.m.) in five week-old AG129 mice with the alum adjuvanted vaccine also provided protection against the mouse adapted homologous strain. No clinical signs of disease or mortality were observed in vaccinated animals, which received a prime-and-boost, whereas 71% of control animals were euthanized after exhibiting systemic clinical signs (P<0.05). The development of this animal model will facilitate studies on EV71 pathogenesis, antiviral testing, the evaluation of immunogenicity and efficacy of vaccine candidates, and has the potential to establish correlates of protection studies.     

Bridging the Species Divide: Transgenic Mice Humanized for Type-I Interferon Response

We have generated transgenic mice that harbor humanized type I interferon receptors (IFNARs) enabling the study of type I human interferons (Hu-IFN-Is) in mice. These “HyBNAR” (Hybrid IFNAR) mice encode transgenic variants of IFNAR1 and IFNAR2 with the human extracellular domains being fused to transmembrane and cytoplasmic segments of mouse sequence. B16F1 mouse melanoma cells harboring the HyBNAR construct specifically bound Hu-IFN-Is and were rendered sensitive to Hu-IFN-I stimulated anti-proliferation, STAT1 activation and activation of a prototypical IFN-I response gene (MX2). HyBNAR mice were crossed with a transgenic strain expressing the luciferase reporter gene under the control of the IFN-responsive MX2 promoter (MX2-Luciferase). Both the HyBNAR and HyBNAR/MX2-Luciferase mice were responsive to all Hu-IFN-Is tested, inclusive of IFNα2A, IFNβ, and a human superagonist termed YNSα8. The mice displayed dose-dependent pharmacodynamic responses to Hu-IFN-I injection, as assessed by measuring the expression of IFN-responsive genes. Our studies also demonstrated a weak activation of endogenous mouse interferon response, especially after high dose administration of Hu-IFNs. In sharp contrast to data published for humans, our pharmacodynamic readouts demonstrate a very short-lived IFN-I response in mice, which is not enhanced by sub-cutaneous (SC) injections in comparison to other administration routes. With algometric differences between humans and mice taken into account, the HyBNAR mice provides a convenient non-primate pre-clinical model to advance the study of human IFN-Is.     

Smad3基因剔除小鼠血清酶活性的变化

目的　探讨Smad3基因对剔除小鼠血清酶活性的影响。方法　采用荷兰半自动生化分析仪对 35日龄、70日龄、6月龄的三种不同基因型的小鼠的ALP、AST、ALT、CK、LDH L进行测定。结果　纯合型小鼠各项指标较野生型高 ,且表现出ALP随着年龄的增长而降低 ;AST、ALT、CK、LDH L随着年龄的增长而增高。结论　Smad3基因的剔除对小鼠的血清酶活性有一定的影响 ,为该小鼠的进一步研究提供基础。