Virus resistance

Gubareva LV (2004) Molecular mechanisms of influenza virus resistance to neuraminidase inhibitors, Virus Res 103 199-203... 

Schinazi RF, Lloyd RM Jr, Nguyen M-H, Cannon DL, McMillan A, Ilksoy N, Chu CK, Liotta DC, Bazmi HZ, Mellors JW. Characterization of human immunodeficiency viruses resistant to oxathiolane-cytosine nucleosides. Antimicrob Agents Chemother 1993 37 875-881. 

DAWSON, W.O., Gene silencing and virus resistance a common mechanism, Trends Plant Sci., 1996,1,107-108. 

Drug resistance Viruses resistant to ganciclovir can arise after prolonged treatment with valganciclovir. 

Resistant virus Resistant virus emerges rapidly and uniformly when nevirapine is administered as monotherapy. Therefore, always administer nevirapine in... 

The reverse transcriptase enzyme (RT) is the primary enzyme responsible for the conversion of the viral single-strand RNA to the double-strand DNA. The reverse transcriptase enzyme is a component of the virion and is encoded by the pol gene. The RT is manufactured in the HIV-infected cells as a gag-pol fusion polyprotein. The RT is not the only enzyme necessary for the translation of RNA to DNA. The other enzymes for this conversion include RNA-dependent DNA polymerase, DNA-dependent DNA polymerase, and RNase H (Gilboa and Mitra, 1978 Prasad and Gogg, 1990). The reverse transcriptase enzyme has a high error rate (1 in 2000 bases), which produces higher incidents of mutation. Some of these mutations make the virus resistant to NNRTI treatment. 

Influenza virus resistant to oseltamivir has not been found in naturally acquired isolates but has been isolated from influenza patients who have undergone treatment with this drug. These resistant strains contain mutations in the active site of neuraminidase and are generally less virulent and infective than nonresistant virus. In vitro passage of influenza virus in the presence of oseltamivir carboxylate can produce mutations in hemagglutinin that decrease the overall dependence of viral replication on neuraminidase however, the clinical relevance of this resistance mechanism is unknown. 

Two mutant lines of yellow mosaic virus resistant barley were found in ca. 50,000 M2 families. The character of the resistance in a field was not changed over three generations [114]. 

Thach, N. Q. F., U., Wenzel, G. (1993). Somatic fusion for combining virus resistances in Solanum tuberosum L. Theoretical and Applied Genetics 85, 863-867. 

Gu Z, Gao Q, Fang H, Salomon H, Pamiak MA, Goldberg E, et al. Identification of a mutation of codon 65 in the IKKK motif of reverse transcriptase that encodes human immunodeficiency virus resistance to 2, 3 -dideoxycytidine and 2, 3 -dideoxy-3 -thiacytidine. Antimicrob Agents Chemother 1994 38 275-281. 

Gianinazzi, S. Kassanis, B. (1974). Virus resistance induced in plants by polyacrylic acid. Journal of General Virology 23, 1-9. 

Luria, S.E., and M. Delbruck. Mutations of bacteria from virus sensitivity to virus resistance. Genetics 28 491-511, 1943. 

TABLE 8-3. Activities of Calanolides Against Viruses Resistant to HIV-l-Specific Inhibitors... 

Activated carbons of high absorptivity show high ability to remove organic pollutants. Carbons give good effects in removal of refractional compounds (resistant to conventional methods). It was stated, that carbons may adsorb metals and inorganic compounds such as antimony, arsenic, bismuth, chromium, cobalt, fluorine, chlorine as well as viruses resistant to chlorination [11—14]. 

Choose cultivars that are adapted to local growing conditions. Many are resistant to one or more problems. Resistant cultivars are usually denoted in seed catalogs as follows F = Fusarium-resistant, V = Verticillium-resistant, T = tobacco mosaic virus-resistant, and N = nematode-resistant. 

If you expect a virus problem, you may able to plant a virus-resistant cultivar. For example, many peas and beans have been rred for resistance to bean mosaic, and breeder have developed tomatoes that resist tobacco mosaic virus. In some cases, a cultivar may be susceptible to a virus, but not prone to getting It because it is resistant to insects that transmit the virus. Such is the case with Royalty purple raspberry, which, though prone to mosaic, is resistant to aphids that spread the disease. 

Type I interferons induce a virus-resistant state in human cells, whereas type II are more active in inhibiting growth of tumour cells. 

Allen M, Deslauriers M, Andrews C, Tipples G, Walters K, Tyrrell D, et al. Identification and characterization of mutations in hepatitis B virus resistant to lamivudine. Lainivudine Clinical Investigation Group. Hepatology 1998 27 1670-7. 

Acyclovir is the drug of choice for herpes simplex encephalitis. In patients with normal renal function, acyclovir is usually administered as 10 mg/kg intravenously every 8 hours for 2 to 3 weeks. Herpes virus resistance to acyclovir has been reported with increasing incidence, particularly from immunocompromised patients with prior or chronic exposures to acyclovir. The alternative treatment for acyclovir-resistant herpes simplex virus is foscarnet. The major toxicity of foscarnet is renal impairment, and doses must be individualized for renal function. The dose for patients with normal renal function is 40 mg/kg infused over 1 hour every 8 to 12 hours for 2 to 3 weeks. Ensuring adequate hydration is imperative. In addition, patients receiving foscarnet should be monitored for seizures related to alterations in plasma electrolyte levels. 

Nonetheless, some activities may be mentioned, ranging from phytosanitary improvement to genetic manipulations mainly of fruit trees with the aim of inducing pathogen (virus) resistance [101,102]. Examples are viruses of stone and pome fruit trees (e.g. plum pox virus [103]) and of vine. The complete nucleotide sequence of plum poxvirus has been determined [104]. A second aim is to revitalize old strains of fruit trees and other cultured plants. 

This approach has received more attention because the protected cells have a selective advantage over the non-transduced ones. Therefore, the requirement for a very high efficient transduction rate is less critical. Protected T cells should be used to repopulate the immune system with virus-resistant cells, and gene transfer to hematopoietic stem cells (HSC) is a promising approach to achieve this goal [34] (see also Part II, Chapter 8). However, it is still unclear whether the repopulated immune system would be able to generate a diversity of anti-... 

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