scholarly journals The effects of UK 2054 on the multiplication of influenza viruses

1970 ◽  
Vol 68 (1) ◽  
pp. 151-158 ◽  
Author(s):  
R. D. Barry ◽  
Patricia Davies
Keyword(s):  
Influenza Virus ◽  
Chick Embryo ◽  
Inhibitory Effect ◽  
Virus Multiplication ◽  
Influenza Viruses ◽  
Host Cells ◽  
Virus Infectivity ◽  
Virus Growth ◽  
Virus Particles ◽  
Embryo Fibroblasts

SummaryThe isoquinoline compound UK 2054 prevents the uptake of influenza virus by susceptible cells. Pre-incubation of virus particles with 500μg./ml. UK 2054 at 37°C. for 2 hr. does not reduce virus infectivity. Host cells vary in their responsiveness to the inhibitory effect of UK 2054; virus multiplication is inhibited in chick allantoic cells by lower concentrations than those required to inhibit virus growth in chick embryo fibroblasts. The effectiveness of UK 2054 is reduced by the presence of serum.It is concluded that inhibition of influenza virus multiplication by UK2054 might result from interaction of the inhibitor with both virus and cells. Any direct combination between inhibitor and virus is completely reversible.

scholarly journals STUDIES ON HOST-VIRUS INTERACTIONS IN THE CHICK EMBRYO-INFLUENZA VIRUS SYSTEM

1949 ◽  
Vol 90 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Werner Henle
Keyword(s):  
Influenza Virus ◽  
Chick Embryo ◽  
Active Agent ◽  
Allantoic Fluid ◽  
Inhibitory Effect ◽  
Influenza Viruses ◽  
Host Cells ◽  
Active Virus ◽  
Homologous Virus ◽  
Host Virus Interactions

Experiments have been reported on the propagation of influenza viruses in the allantoic membrane of the developing chick embryo during the first infectious cycle. After adsorption of the seed virus onto the host cells, only a small percentage of it remains demonstrable by infectivity titrations. This amount remains constant for 4 hours in the case of infection with PR8 virus, and for 6 hours in that of infection with Lee virus. Thereafter, a sharp rise in infectivity occurs 2 to 3 hours before liberation of the new generations of active virus into the allantoic fluid can be detected. Injection of homologous virus, inactivated by ultraviolet irradiation, following infection prevents or delays the production of virus in the tissues, depending to some extent upon the number of ID50 of active virus used as inoculum. The smaller the dose, the more pronounced the inhibitory effect. With increasing delay in the injection of the inhibitor, progressively more virus is produced and liberated 6 and 9 hours after infection with PR8 and Lee virus, respectively. Thus, production of virus may be interrupted by the homologous inhibitor when given up to 3 hours after infection with PR8, and up to4½ hours after infection with Lee virus. Since no increase in infectivity can bedetected during these 3 and 4½ hour periods in the tissues, it is suggested that influenza virus propagates in at least two major stages: first, non-infectious, immature virus material is produced which, subsequently, is converted into the fully active agent. Presumably the first step can be interrupted by the homologous inhibitor, while the second cannot. Heterologous irradiated virus, injected after infection of the tissue, exerts only a slight inhibitory effect on the production of virus.

scholarly journals INHIBITION OF RELEASE OF VACCINIA VIRUS BY N1-ISONICOTINOYL-N2-3-METHYL-4-CHLOROBENZOYLHYDRAZINE

1969 ◽  
Vol 129 (4) ◽  
pp. 795-808 ◽  
Author(s):  
Nobuo Kato ◽  
Hans J. Eggers ◽  
Heinrich Rolly
Keyword(s):  
Chick Embryo ◽  
Vaccinia Virus ◽  
Inhibitory Effect ◽  
Virus Multiplication ◽  
Kidney Cells ◽  
Virus Release ◽  
Single Cycle ◽  
Infected Cells ◽  
Embryo Fibroblasts ◽  
Intracellular Virus

N1-isonicotinoyl-N2-3-methyl-4-chlorobenzoylhydrazine (IMCBH) is a selective inhibitor of vaccinia virus multiplication. In concentrations up to 50 µg/ml, IMCBH causes neither toxic morphologic changes, nor does it inhibit the multiplication of cells. Viruses other than vaccinia are not affected by IMCBH. The virus-inhibitory effect of IMCBH is dependent on the type of host cell used, i.e., the compound is effective in chick embryo fibroblasts and monkey kidney cells but not in L cells. IMCBH does not exhibit any protecting effect on vaccinia virus-infected mice or rabbits. IMCBH interferes with virus release: in single cycle experiments in chick embryo fibroblasts, IMCBH strongly blocks the release of vaccinia virus at concentrations as low as 3 µg/ml, while intracellular virus synthesis is hardly affected. Viral cytopathic changes are completely suppressed by IMCBH within the span of a single cycle infection, although extensive changes eventually occur. By inhibiting virus release from initially infected cells, IMCBH markedly inhibits the multiplication of vaccinia virus in cell cultures infected at low virus/ cell multiplicities. IMCBH does not inhibit the early toxic cytopathic changes induced by large inocula of vaccinia virus in BHK21 cells.

scholarly journals INFLUENZA VIRUS MULTIPLICATION IN THE CHORIOALLANTOIC MEMBRANE IN VITRO: KINETIC ASPECTS OF INHIBITION BY 5, 6-DICHLORO-1-ß-D-RIBOFURANOSYLBENZIMIDAZOLE

1954 ◽  
Vol 100 (6) ◽  
pp. 541-562 ◽  
Author(s):  
Igor Tamm ◽  
David A. J. Tyrrell
Keyword(s):  
Influenza Virus ◽  
Chorioallantoic Membrane ◽  
Inhibitory Effect ◽  
Virus Multiplication ◽  
Benzimidazole Derivatives ◽  
Similar Degree ◽  
Virus Concentration ◽  
Virus Particles ◽  
Rate Of Increase

A procedure is described for kinetic studies on the multiplication of Lee virus in the chorioallantoic membrane in vitro employing the hemagglutination technique for measurement of virus concentration. A linear relationship was found between the logarithm of virus adsorbed and the amount of membrane used. Of the virus adsorbed less than 10 per cent could be recovered from the membrane. Of the recoverable virus 90 per cent was eliminated by specific immune serum. Lee virus was adsorbed by the allantoic and chorionic layers of the membrane to a similar degree. Multiplication occurred in both layers and to a similar extent. When 107.66 EID50 of Lee virus was inoculated per 2.9 cm.2 of chorioallantoic membrane, the ratio of infectivity to hemagglutination titer in the yield was low, although the rate of appearance of virus particles was not diminished despite the large inocula. Virus produced in membranes was liberated rapidly and continually into the medium. 5,6-Dichloro-1-ß-D-ribofuranosylbenzimidazole (DRB), 0.000055 M, prolonged the latent period by more than 100 per cent. The rate of increase during the period of rapid rise was similar in the presence or absence of DRB, but the yield was markedly reduced at the end of this period in the presence of DRB. The amount of the virus in the membranes continued to rise in the presence of DRB and eventually approached the maximal levels reached much earlier in the controls. Measurement of the amount of virus in the media indicated a greater degree of inhibition than did measurement in the membranes. Comparative studies with two benzimidazole derivatives on the dependence of the inhibitory effect on the time of addition of the compound showed that processes which could be inhibited by DRB were of shorter duration than those inhibited by 2,5-dimethylbenzimidazole (MB). With MB the relationship between the time of addition and the inhibitory effect was similar both for virus and for soluble complement-fixing antigen; with DRB the inhibitable processes were of shorter duration for the complement-fixing antigen than for virus particles. DRB was not only 35 times more active on a molar basis but also was more selective in its action than MB. DRB interfered with processes which preceded the emergence of either soluble complement-fixing antigen or virus particles. Some of the implications of these findings are discussed in relation to the mechanism of inhibition of influenza virus multiplication by benzimidazole derivatives.

scholarly journals ON THE ROLE OF RIBONUCLEIC ACID IN ANIMAL VIRUS SYNTHESIS

1960 ◽  
Vol 111 (3) ◽  
pp. 339-349 ◽  
Author(s):  
Igor Tamm ◽  
Marjorie M. Nemes ◽  
Suydam Osterhout
Keyword(s):  
Influenza Virus ◽  
Chorioallantoic Membrane ◽  
Inhibitory Effect ◽  
Virus Multiplication ◽  
Point Of View ◽  
Host Cells ◽  
Animal Virus ◽  
Host Cell Proteins

Adenosine, but not guanosine, was capable of blocking the inhibitory effect of 5,6-dichloro-1-ß-D-ribofuranosylbenzimidazole (DRB) on influenza virus multiplication in the chorioallantoic membrane in vitro. At virus inhibitory concentrations DRB caused marked inhibition in uptake of adenosine-8-C14 into RNA of uninfected host cells, but it had little effect on uptake of C14-L-alanine into host cell proteins or on cellular oxygen consumption. The activity of DRB in inhibiting multiplication of the DNA-containing adenovirus was similar to its inhibitory activity on multiplication of the RNA-containing influenza virus. These and earlier results are discussed from the point of view of the important role of RNA in the reproduction of DNA-containing viruses.

scholarly journals Functional Analysis of PA Binding by Influenza A Virus PB1: Effects on Polymerase Activity and Viral Infectivity

2001 ◽  
Vol 75 (17) ◽  
pp. 8127-8136 ◽  
Author(s):  
Daniel R. Perez ◽  
Ruben O. Donis
Keyword(s):  
Amino Acids ◽  
Influenza Virus ◽  
Amino Acid ◽  
Viral Replication ◽  
Influenza A Virus ◽  
Influenza A ◽  
Amino Acid Sequences ◽  
Influenza Viruses ◽  
Virus Growth ◽  
Transcription And Replication

ABSTRACT Influenza A virus expresses three viral polymerase (P) subunits—PB1, PB2, and PA—all of which are essential for RNA and viral replication. The functions of P proteins in transcription and replication have been partially elucidated, yet some of these functions seem to be dependent on the formation of a heterotrimer for optimal viral RNA transcription and replication. Although it is conceivable that heterotrimer subunit interactions may allow a more efficient catalysis, direct evidence of their essentiality for viral replication is lacking. Biochemical studies addressing the molecular anatomy of the P complexes have revealed direct interactions between PB1 and PB2 as well as between PB1 and PA. Previous studies have shown that the N-terminal 48 amino acids of PB1, termed domain α, contain the residues required for binding PA. We report here the refined mapping of the amino acid sequences within this small region of PB1 that are indispensable for binding PA by deletion mutagenesis of PB1 in a two-hybrid assay. Subsequently, we used site-directed mutagenesis to identify the critical amino acid residues of PB1 for interaction with PA in vivo. The first 12 amino acids of PB1 were found to constitute the core of the interaction interface, thus narrowing the previous boundaries of domain α. The role of the minimal PB1 domain α in influenza virus gene expression and genome replication was subsequently analyzed by evaluating the activity of a set of PB1 mutants in a model reporter minigenome system. A strong correlation was observed between a functional PA binding site on PB1 and P activity. Influenza viruses bearing mutant PB1 genes were recovered using a plasmid-based influenza virus reverse genetics system. Interestingly, mutations that rendered PB1 unable to bind PA were either nonviable or severely growth impaired. These data are consistent with an essential role for the N terminus of PB1 in binding PA, P activity, and virus growth.

Sodium Deoxycholate Exerts a Direct Destructive Effect on HIV and Influenza Viruses in vitro and Inhibits Retrovirus-Induced Pathology in An Animal Model

1994 ◽  
Vol 5 (3) ◽  
pp. 176-181 ◽  
Author(s):  
J. S. Oxford ◽  
M. A. Zuckerman ◽  
E. Race ◽  
R. Dourmashkin ◽  
K. Broadhurst ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Bile Salts ◽  
Lipid Membrane ◽  
Sodium Deoxycholate ◽  
Influenza Viruses ◽  
Virus Infectivity ◽  
Destructive Effect ◽  
Leukaemia Virus ◽  
Point Of Entry

The bile salt sodium deoxycholate had a virucidal effect on influenza, Rauscher leukaemia and HIV-1 viruses, reducing virus infectivity by a maximum of 6 logs TCID50 ml−1 after 1 h incubation at 37 °C with 50 μg ml−1 of the compound. Electron microscopy demonstrated directly that sodium deoxycholate and other bile salts perturbed influenza virus structure causing partial or complete disruption of the virion lipid membrane, thus allowing entry of phosphotungstate dye to the virion interior. Parenteral administration of sodium deoxycholate (14 mg kg−1) to Balb/C mice abrogated pathology caused by Rauscher leukaemia virus replicating in the spleen and influenza virus replicating in the lung. Bile salts may also have clinical potential as topical virucidal agents at the point of entry of enveloped viruses and particularly against HIV.

scholarly journals Cleavage of Influenza A Virus Hemagglutinin in Human Respiratory Epithelium Is Cell Associated and Sensitive to Exogenous Antiproteases

2002 ◽  
Vol 76 (17) ◽  
pp. 8682-8689 ◽  
Author(s):  
Oleg P. Zhirnov ◽  
Mine R. Ikizler ◽  
Peter F. Wright
Keyword(s):  
Molecular Weight ◽  
Influenza Virus ◽  
Serine Proteases ◽  
Influenza A ◽  
Extracellular Fluid ◽  
Respiratory Epithelium ◽  
Influenza Viruses ◽  
Secretory Cells ◽  
Low Molecular Weight ◽  
Virus Growth

ABSTRACT Proteolytic cleavage of the hemagglutinin (HA) of human influenza viruses A/Aichi/2/68 (H3N2) and A/WSN/34 (H1N1) from HA0 to HA1/HA2 was studied in primary human adenoid epithelial cells (HAEC). HAEC contain a mixture of ciliated and nonciliated secretory cells and mimic the epithelium membrane of the human respiratory tract. Pulse-chase labeling with [35S]methionine and Western blot analysis with anti-HA antibodies of cellular and virion polypeptides showed that HAEC cleaved newly synthesized HA0 to HA1/HA2 (“cleavage from within”) and significant amounts of cleaved HA accumulated within cells. It was also shown that HAEC was able to cleave HA0 of incoming virions (“cleavage from without”), whereas the HA0 of nonabsorbed virions free in extracellular fluid were not cleaved, supporting the conclusion that HA0 cleavage in HAEC is cell associated. Low-molecular-weight inhibitors of serine proteases, aprotinin and leupeptin, when added to influenza virus-infected HAEC suppressed HA0 cleavage and reduced the amount of cleaved HA1/HA2 both in cells and in progeny virions and thus diminished the infectivity of the virus. In contrast, the addition of fetal bovine serum, containing a number of high-molecular-weight antiproteases that compete for proteases in the extracellular environment, did not inhibit influenza virus growth in HAEC. These data suggest that in human respiratory epithelium the cleavage of influenza virus HA containing a single arginine in the proteolytic site (i) is a cell-associated process accomplished by serine-type protease(s) and (ii) is sensitive to low-molecular-weight exogenous inhibitors of serine proteases.

scholarly journals INHIBITION OF INFLUENZA VIRUS MULTIPLICATION BY N-GLYCOSIDES OF BENZIMIDAZOLES

1954 ◽  
Vol 99 (3) ◽  
pp. 227-250 ◽  
Author(s):  
Igor Tamm ◽  
Karl Folkers ◽  
Clifford H. Shunk ◽  
Frank L. Horsfall
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Benzimidazole Derivative ◽  
Chorioallantoic Membrane ◽  
Inhibitory Effect ◽  
Virus Multiplication ◽  
Cellular Growth ◽  
Tissue Proliferation ◽  
Fresh Culture Medium

Chloro derivatives of benzimidazole were found to be 2 to 3 times more active than corresponding methyl derivatives in causing inhibition of Lee virus multiplication in chorioallantoic membrane cultures in vitro. The most active benzimidazole derivative thus far tested is 5,6-dichloro-1-ß-D-ribofuranosylbenzimidazole (DRB); it caused 75 per cent inhibition of Lee virus multiplication in membrane cultures at a concentration of 0.38 x 10–4 M. On the other hand, 5,6-dimethyl-1-alpha;-D-ribofuranosylbenzimidazole, the moiety present in vitamin B12, failed to inhibit Lee virus multiplication at a concentration of 35 x 10–4 M. Other N-glycosides of 5,6-dichlorobenzimidazole were considerably less active than DRB. In single cycle experiments, the degree of inhibition of Lee virus multiplication by DRB in membrane cultures was not dependent on the amount of virus in the inoculum. This compound did not inactivate the infectivity of extracellular Lee virus, had no effect on virus-erythrocyte interaction, did not interfere with the adsorption of the virus by the host tissue, nor affect the release of newly formed virus from the membrane. The inhibitory effect of DRB on Lee virus multiplication, in contrast to that of 2,5-dimethylbenzimidazole, persisted after transfer of infected membranes into fresh culture medium not containing the compound. Both DRB and the 2,5-dimethyl compound caused 99 per cent inhibition of Lee virus multiplication without affecting oxygen uptake of the membrane. Tissue proliferation of membrane pieces in roller tube culture was not significantly affected by DRB at inhibitory concentration, whereas at equivalent concentration the 2,5-dimethyl compound did restrict cellular growth. At higher concentrations, both compounds caused retardation of cell proliferation. This effect was reversible on removal of either compound from the medium. The multiplication of several strains of influenza A and B viruses, i.e. Lee, MB, PR8, and FM1, was inhibited to the same degree by each of the two compounds; DRB was 35 times more active than the 2,5-dimethyl compound relative to each of the strains. DRB caused inhibition of Lee virus multiplication in intact embryonated chicken eggs and in mice without causing significant signs of toxicity in either host. Some of the implications of these findings are discussed in relation to the mechanism of the inhibition of influenza virus multiplication.

scholarly journals Identification of Stabilizing Mutations in an H5 Hemagglutinin Influenza Virus Protein

2015 ◽  
Vol 90 (6) ◽  
pp. 2981-2992 ◽  
Author(s):  
Anthony Hanson ◽  
Masaki Imai ◽  
Masato Hatta ◽  
Ryan McBride ◽  
Hirotaka Imai ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Avian Influenza ◽  
Conformational Change ◽  
Receptor Binding ◽  
Heat Stability ◽  
Influenza Viruses ◽  
Virus Infectivity ◽  
Highly Pathogenic ◽  
Human Type ◽  
Droplet Transmission

ABSTRACTHighly pathogenic avian influenza viruses of the H5N1 subtype continue to circulate in poultry in Asia, Africa, and the Middle East. Recently, outbreaks of novel reassortant H5 viruses have also occurred in North America. Although the number of human infections with highly pathogenic H5N1 influenza viruses continues to rise, these viruses remain unable to efficiently transmit between humans. However, we and others have identified H5 viruses capable of respiratory droplet transmission in ferrets. Two experimentally introduced mutations in the viral hemagglutinin (HA) receptor-binding domain conferred binding to human-type receptors but reduced HA stability. Compensatory mutations in HA (acquired during virus replication in ferrets) were essential to restore HA stability. These stabilizing mutations in HA also affected the pH at which HA undergoes an irreversible switch to its fusogenic form in host endosomes, a crucial step for virus infectivity. To identify additional stabilizing mutations in an H5 HA, we subjected a virus library possessing random mutations in the ectodomain of an H5 HA (altered to bind human-type receptors) to three rounds of treatment at 50°C. We isolated several mutants that maintained their human-type receptor-binding preference but acquired an appreciable increase in heat stability and underwent membrane fusion at a lower pH; collectively, these properties may aid H5 virus respiratory droplet transmission in mammals.IMPORTANCEWe have identified mutations in HA that increase its heat stability and affect the pH that triggers an irreversible conformational change (a prerequisite for virus infectivity). These mutations were identified in the genetic background of an H5 HA protein that was mutated to bind to human cells. The ability to bind to human-type receptors, together with physical stability and an altered pH threshold for HA conformational change, may facilitate avian influenza virus transmission via respiratory droplets in mammals.

scholarly journals THE INHIBITORY EFFECT OF POLYSACCHARIDE ON MUMPS VIRUS MULTIPLICATION

1948 ◽  
Vol 87 (5) ◽  
pp. 385-410 ◽  
Author(s):  
Harold S. Ginsberg ◽  
Walther F. Goebel ◽  
Frank L. Horsfall
Keyword(s):  
Chick Embryo ◽  
Inhibitory Effect ◽  
Virus Multiplication ◽  
Mumps Virus ◽  
Viral Multiplication ◽  
Chemical Studies ◽  
Structural Configurations ◽  
Serological Activity

Polysaccharides derived from type-specific Friedländer bacilli cause inhibition of the multiplication of mumps virus in the allantoic sac of the chick embryo. As little as 5 µg. of polysaccharide is effective as an inhibitor. Inhibition of multiplication is obtained when polysaccharide is injected as long as 4 days after inoculation of virus. Chemical studies have shown that the structural configurations of the polysaccharide responsible for specific serological activity are not identical with those which determine the inhibitory effect relative to mumps virus. The possible mechanisms of the inhibition of viral multiplication by means of polysaccharides are discussed.

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