Viral stimulation

Viral stimulant. Smoke of the leaf, administered by inhalation to mice at variable doses twice daily for 5 days followed by 2 nontreatment days, dosed for two to six cycles, was inactive on encephalomyo-carditis virus. Herpes virus type 1, and influenza virus APR-8 b Vitamins A and C concentrations influence. Methyl chloride extract of the leaf, administered intragastrically to rats at a dose... 

In 1961 it was reported that human leukocytes were capable of producing IFN in response to viral infections [8,9]. This viral stimulation of white blood cells was initially used to produce leukocyte IFN for clinical applications. Identification of a number of varied IFN inducers such as mycoplasma or other microorganisms in cell cultures, lipopolysaccharides (LPS, derived from bacteria membranes), tumor-derived or virus-transformed cells, and synthetic chemical compounds such as polyanions and poly I C (poly inosine-cytosine) suggested that different IFN mixtures could be derived from interaction of various inducing agents and appropriate target cells [10-16]. Another pH-labile, nonvirus-induced IFN termed immune-IFN (induced by immune effector cells) was discovered in 1965. It was produced by... 

Acetylcysteine The N-acetyl derivative of cysteine. It is used as a mucolytic agent to reduce the viscosity of mucous secretions. It has also been shown to have antiviral effects in patients with HIV due to inhibition of viral stimulation by reactive oxygen intermediates, [nih]... 

Interleukin-1 OC and (3. IL-1 has radioprotective activity toward BM and other tissues (151,164). IL-1 is produced in response to endotoxin, other cytokines, and microbial and viral agents, primarily by monocytes and macrophages. Other nucleated cells can also produce it. IL-1 appears to play an important role in the regulation of normal hemopoiesis directly by stimulating the most primitive stem cells and indirectly by stimulating other hemopoietic factors, including G-CSF, GM-CSF, M-CSF, and IL-6. 

FIAC also strongly inhibits HCMV and Epstein-Barr vims (EBV) in vitro the two vimses known not to induce a specific viral thymidine kinase for their repHcation. However, HCMV may stimulate cellular kinases that can anabolize FIAC to its 5 -triphosphate, which specifically inhibits the HCMV-encoded DNA polymerase. This selective activity suggests that FIAC should be evaluated against HCMV infections. FIAC-ttiphosphate incorporated into DNA has shown strong in vitro activity against the DNA polymerases of human hepatitis B vims (HBV) and of woodchuck hepatitis vims (WHV) (37). 

Interferons [alFN, piFN and ylFN]. Interferons are a family of glycosylated proteins and are cytokines which are produced a few hours after cells have been infected with a virus. Interferons protect cells from viral infections and have antiviral activities at very low concentrations ( 3 x 10 M, less than 50 molecules are apparently sufficient to protect a single cell). Double stranded RNA are very efficient inducers of IFNs. There are three main types of IFNs. The aIFNs are synthesised in lymphocytes and the piFNs are formed in infected fibroblasts. The a and P families are fairly similar consisting of ca 166 to 169 amino acids. Although ylFNs are also small glycosylated proteins (ca 146 amino acids), they are different because they are not synthesised after viral infections but are produced by lymphocytes when stimulated by mitogens (agents that induced cell division). 

Viral infections continue to be significant causes of morbidity and mortality and at the same time continue to be resistant to treatment by small molecules. Avridine (6) is an antiviral compound which has shown some activity in a variety of animal tests apparently based upon its ability to stimulate a number of cells to produce the high molecular weight endogenous antiviral substance interferon. Thus, the compound is believed to operate indirectly by stimulating the body s own natural defenses against viral penetration into host cells. Avridine is synthesized by... 

On the other hand, EFN-a may also be involved in the activation of autoreactive T-cells as has been proposed for type I diabetes. An DFN-a inducible superantigen, encoded by the truncated envelope gene of a human endogenous retrovirus and specifically activating V 37 T-cells, has been detected in pancreatic lesions from type I diabetes patients, infiltrated by V 37 T-cells. Since IFN-a expression could be detected in pancreatic (3 cells in conceit with persistent viral infections, there is a clear link between viral infections and autoimmunity via IFN-a-stimulated superantigen expression. 

Virally infected host cells, and also tissue grafts from a genetically dissimilar donor, have been shown to stimulate the formation of T cells that are cytotoxic for these cells (Tc cells). Tc cells express CDS on their cell surface. 

Reaction against virally infected or transplanted cells results in stimulated lymphocytes transforming into Tc cells which can eliminate target cells bearing the sensitizing antigen. 

The selective stimulation of these cells is of importance because they are the most active effector cells in host defense mechanisms against bacterial and viral infections. 

A recent report has demonstrated that the proteolytic activity of NS3 plays an additional role in viral infection, beyond polyprotein processing. An important mediator of the cellular immune response is the transcription factor interferon regulatory factor 3 (IRF-3), which becomes activated on infection and then stimulates production of type-1 interferon and other antiviral genes [46]. It was found that expression of heterodimeric NS3/4A... 

Generation of antibodies that can recognize and bind to specific viruses is straightforward. A sample of live or attenuated virus, or a purified component of the viral caspid, can be injected into animals to stimulate polyclonal antibody production (or to facilitate monoclonal antibody production by hybridoma technology). Harvested antibodies are then employed to develop specific immunoassays that can be used to screen test samples routinely for the presence of that specific virus. Immunoassays capable of detecting a wide range of viruses are available commercially. The sensitivity, ease, speed and relative inexpensiveness of these assays render them particularly attractive. 

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