scholarly journals Comparison of the infectivity of influenza Viruses in two host Systems: the Allantois of infect Eggs and Surviving Allantois-on-Shell

1958 ◽  
Vol 56 (4) ◽  
pp. 535-546 ◽  
Author(s):  
S. Fazekas de St Groth ◽  
D. O. White
Keyword(s):  
Influenza Virus ◽  
Virus Particle ◽  
Host Resistance ◽  
Thermal Inactivation ◽  
Allantoic Fluid ◽  
Relative Sensitivity ◽  
Influenza Viruses ◽  
Critical Step ◽  
Test Systems ◽  
Intracellular Stage

It is shown that the assay for infectivity in bits of allantois-on-shell, which has been standardized on the BEL strain, is optimal also for nine representative strains of influenza virus tested.On the average, the sensitivity of the technique is the same as of orthodox allantoic infectivity tests; its precision is always higher. The relative sensitivity of the two tests varies from strain to strain, the log tray/egg differences being SW (+0.88), MEL (+0.51), CAM (+0.31), PR8 (0.28), WSE (+0.25), HUT (−0.02), BEL (−0.22), FMI (−0.35), LEE (−0.47), BON (−1.02). This gradient is the same for fully infective and incomplete forms of influenza virus.The tray/egg gradient of susceptibility is negatively correlated with the variation in host resistance.The differences in susceptibility are not due to any effect of the plastic trays, to thermal inactivation of the virus, to differences in adsorption or viropexis in the two test systems or to the effect of allantoic fluid on the virus particle. The critical step has been shown to occur during the intracellular stage of multiplication.

scholarly journals Variation of host resistance to influenza viruses in the allantois

1959 ◽  
Vol 57 (1) ◽  
pp. 123-134 ◽  
Author(s):  
D. O. White ◽  
S. Fazekas de St Groth
Keyword(s):  
Linear Function ◽  
Virus Particle ◽  
Host Resistance ◽  
Allantoic Fluid ◽  
Influenza Viruses ◽  
Natural Conditions ◽  
In Ovo ◽  
Permanent Damage

1. Methods are described for altering the susceptibility of the surviving allantois to infection by influenza viruses.2. Under natural conditions susceptibility is a linear function of age between 10 and 18 days of incubation. The drop is 0·11 log10 unit per day for all strains of influenza tested.3. In whole eggs this decline is masked by the effect of acid allantoic fluid which prevents infection when the pH falls below 6. The effect is not directed against the virus particle, nor does it do permanent damage to the cell, as surviving tissues are equally susceptible whatever the pH of the allantoic fluid that bathed them in ovo.4. Surviving membranes can be made less susceptible by incubating the eggs at 35° rather than 38° C.; by maintenance for 24 hr. in vitro; by use of deficient or inappropriate medium. These methods lower susceptibility more for some strains than for others.5. All treatments which lower susceptibility also increase its variation from egg to egg.

scholarly journals Development of an enzyme-linked immunosorbent assay (ELISA) for the detection of specific antibodies against an H7N7 and an H3N8 equine influenza virus

1984 ◽  
Vol 93 (3) ◽  
pp. 609-620 ◽  
Author(s):  
M. S. Denyer ◽  
J. R. Crowther ◽  
R. C. Wardley ◽  
R. Burrows
Keyword(s):  
Influenza Virus ◽  
Immunosorbent Assay ◽  
Solid Phase ◽  
Allantoic Fluid ◽  
Influenza Viruses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Equine Influenza Virus ◽  
Serum Samples ◽  
Specific Antibodies ◽  
Equine Influenza

SummaryThis paper describes a solid-phase microtitre plate enzyme-linked immunosorbent assay (ELISA) for the detection of antibodies to equine influenza viruses. Using egg-grown influenza viruses as the antigens attached to the solid phase, crossreactions were observed between an H7N7 equine virus (designated A1) and an H3N8 equine influenza virus (designated A2) when untreated antisera were tested. Absorption of antisera with egg-grown A/Porcine/Shope/1/33 influenza virus eliminated cross-reactive antibodies so that specific detection of anti-equine influenza A1 or A2 antibodies was possible.Examination of horse sera following vaccination with A1 and/or A2 isolates showed that antibodies were produced against antigen associated with egg allantoic fluid as well as against virus. Such antibodies were eliminated following the absorption of antisera with porcine influenza virus. Results using sera from horses with known vaccination histories confirmed that the ELISA preferentially detected antibodies homologous to the antigen attached to the solid phase and methods to evaluate the current serological state of individual horses by relating the titres of specific antibodies against equine influenza A1 and A2 isolates are shown. This ELISA provides a simple and rapid method of assessing specific antibodies from horse sera and offers advantages over the ‘routine’ HI and SRH assessments since it gives high precision, is economical of reagents and has the capacity to handle large numbers of serum samples.

scholarly journals N2Gas Plasma Inactivates Influenza Virus by Inducing Changes in Viral Surface Morphology, Protein, and Genomic RNA

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Akikazu Sakudo ◽  
Naohiro Shimizu ◽  
Yuichiro Imanishi ◽  
Kazuyoshi Ikuta
Keyword(s):  
Influenza Virus ◽  
Plasma Treatment ◽  
Influenza A ◽  
Allantoic Fluid ◽  
High Voltage Pulse ◽  
Influenza Viruses ◽  
Blue Staining ◽  
Enzyme Linked Immunosorbent Assay ◽  
Gas Plasma ◽  
Electron Microscopy Analysis

We have recently treated with N2gas plasma and achieved inactivation of bacteria. However, the effect of N2gas plasma on viruses remains unclear. With the aim of developing this technique, we analyzed the virucidal effect of N2gas plasma on influenza virus and its influence on the viral components. We treated influenza virus particles with inert N2gas plasma (1.5 kpps; kilo pulses per second) produced by a short high-voltage pulse generated from a static induction thyristor power supply. A bioassay using chicken embryonated eggs demonstrated that N2gas plasma inactivated influenza virus in allantoic fluid within 5 min. Immunochromatography, enzyme-linked immunosorbent assay, and Coomassie brilliant blue staining showed that N2gas plasma treatment of influenza A and B viruses in nasal aspirates and allantoic fluids as well as purified influenza A and B viruses induced degradation of viral proteins including nucleoprotein. Analysis using the polymerase chain reaction suggested that N2gas plasma treatment induced changes in the viral RNA genome. Scanning electron microscopy analysis showed that aggregation and fusion of influenza viruses were induced by N2gas plasma treatment. We believe these biochemical changes may contribute to the inactivation of influenza viruses by N2gas plasma.

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 ANTIBODY RESPONSE OF HUMAN BEINGS FOLLOWING VACCINATION WITH INFLUENZA VIRUSES

1942 ◽  
Vol 75 (5) ◽  
pp. 495-511 ◽  
Author(s):  
G. K. Hirst ◽  
E. R. Rickard ◽  
Loring Whitman ◽  
F. L. Horsfall
Keyword(s):  
Influenza Virus ◽  
Antibody Response ◽  
Influenza A ◽  
Geometric Mean ◽  
Allantoic Fluid ◽  
Influenza Viruses ◽  
Human Beings ◽  
Significant Difference ◽  
Antibody Levels

Eleven different preparations of influenza virus were used to vaccinate large groups of human beings. The antibody response to these vaccines was measured by means of the in vitro agglutination inhibition test, and the geometric mean titers of sera taken 2 weeks after vaccination were compared. From these comparisons the following conclusions were drawn: 1. There was a wide individual variation in the antibody response of human beings to the same preparation of influenza virus administrated subcutaneously. The amount of antibody produced by a group with a low prevaccination antibody level was very nearly the same as the amount produced by groups that had higher initial levels. 2. The use of the X strain of distemper virus in the preparation of an influenza vaccine did not enhance the antigenicity of the influenza virus present. 3. Within certain limits the mean antibody response of human beings increased as the amount of virus injected was increased. When large amounts of influenza A virus were given, the antibody response was of the same order of magnitude as that which occurred following actual infection by this virus. 4. When the vaccine was prepared from allantoic fluid, there was no significant difference in the antibody response of human beings given active virus, formalin-inactivated virus, heat-inactivated virus, or virus inactivated by the drying process. 5. Ground infected chick embryos, when diluted with infected allantoic fluid, gave a greater antibody response than allantoic fluid alone (when the virus remained active). The antigenicity of such a preparation was diminished when the virus was inactivated by formalin. 6. Antibody levels 6 and 9 weeks after vaccination showed a marked drop from the 2-week postvaccination levels. In a small group the antibody levels at 5 months were still further reduced. Those individuals who possessed the higher titers tended to lose their antibodies faster than did those at a lower level.

scholarly journals A SEDIMENTABLE COMPONENT OF ALLANTOIC FLUID AND ITS RELATIONSHIP TO INFLUENZA VIRUSES

1944 ◽  
Vol 80 (2) ◽  
pp. 83-100 ◽  
Author(s):  
C. A. Knight
Keyword(s):  
Influenza Virus ◽  
Rabbit Antiserum ◽  
Allantoic Fluid ◽  
Influenza Viruses ◽  
Red Cell ◽  
Serological Tests ◽  
Cell Agglutination ◽  
Small Component ◽  
Serum Dilution ◽  
Neutralizing Capacity

Macromolecular material was isolated from normal allantoic fluid by a centrifugation procedure comparable to that currently employed for the concentration and purification of influenza viruses. The yield of material was found to vary with the age of the embryo, reaching a maximum average value after 14 days of incubation at 39°C. of about 0.02 mg. per ml. of allantoic fluid. The purified material was found to contain protein, carbohydrate, and lipid and to have a general composition similar to purified preparations of PR8 influenza virus. A typical preparation of normal material had an isoelectric point at pH 2.3. Sedimentation studies indicated that the normal material can give a variety of sedimentation constants depending upon the concentration and viscosity of the preparations. The sedimentation constant, corrected for viscosity, of the major component of a fresh preparation was 170 S. The diameters of the predominant particles shown in electron micrographs of the normal material and of preparations of PR8 influenza virus were about 40 and 100 mµ, respectively. Serological tests indicated that the normal material is a good antigen and that preparations of both A and B types of influenza virus obtained from allantoic fluids by centrifugation show a strong serological relationship to the normal material. Freezing and thawing of allantoic fluid, and repeated adsorption of virus on red cells, failed to provide a practical basis for the separation of normal protein from the virus entity in the case of PR8 virus. In the cases of similar preparations of F12 and of Lee viruses, a partial separation of a small component was accomplished by fractional centrifugation and this component and the normal protein were shown to be identical or very closely related. Antiserum to the purified normal material inhibited red cell agglutination by A and B types of influenza virus at serum dilutions of 600 to 700, but failed to show significant neutralizing capacity in chick embryo and in mouse tests at a serum dilution of 100. Rabbit antiserum to purified preparations of PR8 virus gave a 50 per cent red cell agglutination inhibition endpoint at a serum dilution of 112,000. Some of the implications of the findings are discussed.

scholarly journals THE IMMUNOLOGICAL RESPONSE TO INFLUENZA VIRUS INFECTION AS MEASURED BY THE COMPLEMENT FIXATION TEST

1943 ◽  
Vol 78 (5) ◽  
pp. 347-366 ◽  
Author(s):  
William F. Friedewald
Keyword(s):  
Influenza Virus ◽  
Red Blood Cells ◽  
Virus Particle ◽  
Blood Cells ◽  
Complement Fixation Test ◽  
Complement Fixation ◽  
Allantoic Fluid ◽  
Mouse Lung ◽  
Soluble Antigen ◽  
Strain Specificity

A quantitative complement fixation test with influenza immune sera and virus antigens obtained from allantoic fluid is described. The method utilizes a photoelectric densitometer which provides a simple, objective, and accurate determination of the hemolytic reaction. The enhancement of the hemolytic activity of complement in the presence of serum or allantoic fluid necessitates a preliminary titration of complement in the presence of these agents. An accurate appraisal of the activity of the complement under the conditions of the actual test permits the selection of an optimal amount of complement and greatly increases the sensitivity of the test. The substance (or substances) responsible for the enhanced hemolytic activity of complement has been found in human and many animal sera and in allantoic fluids obtained from the developing chick embryo. It requires the presence of both complement and hemolysin, resists heating at 100°C. for 2 hours, and is dialyzable. Allantoic fluid or mouse lung preparations of influenza virus contain a complement-fixing antigen which is intimately associated with the virus particle. It sediments in the high speed centrifuge at the same rate as the hemagglutinin and infective particle and, like the latter, is adsorbed by fowl red blood cells and eluted from the cells on standing at room temperature or 37°C. It cannot be separated from the virus particle by repeated washings in the centrifuge or repeated adsorptions with red blood cells; the hemagglutinin and complement-fixing antigen titers remain roughly proportional. This antigen shows a high degree of strain specificity in cross complement fixation tests with PR8, W.S., and swine ferret antisera, and, as found with the neutralization test, it shows little or no strain specificity with human sera. A soluble antigen is also present in influenza virus preparations which can be readily separated from the virus particle by centrifugation. It is not adsorbed by red blood cells. Furthermore, it reacts in lower titer with ferret antisera and usually shows less strain specificity in cross complement fixation tests. In general, allantoic fluid virus preparations contain much less of the soluble antigen than mouse lung extracts.

AFM Investigation of Avian Influenza Viruses

2010 ◽  
Author(s):  
Balaji Srinivasan ◽  
Husein Rokadia ◽  
Steve Tung ◽  
Ronghui Wang ◽  
Yanbin Li
Keyword(s):  
Influenza Virus ◽  
Electrical Properties ◽  
Avian Influenza ◽  
Avian Influenza Virus ◽  
Virus Particle ◽  
Complex Impedance ◽  
Electrical Characterization ◽  
Influenza Viruses ◽  
Complex Impedance Spectrum ◽  
Virus Strains

The present paper describes a direct label-free diagnostic method that uses atomic force microscopy (AFM) to identify avian influenza virus strains through their electrical properties. In this method, a single virus particle is sandwiched between a rigid, conductive substrate and a conductive AFM tip (radius ∼ 8nm). Electrical characterization is achieved by probing the complex impedance spectrum of the sandwiched virus while mechanical characterization is achieved through nanoindentation. A total of three virus strains (inactivated) with different combinations of glycoprotein subtypes (H2N2, H3N5 and H4N6) were tested. Results from the electrical characterization indicate that the impedance spectra of different virus strains are indeed different. While the average electrical capacitance of a virus particle is about 17pF, the variation from one strain to another can be as high as 70%. A COMSOL Multiphysics™ simulation was carried out to estimate the electrical properties of the glycoproteins on the virus particle by comparing the simulated capacitance to the experimentally obtained values. The result indicates that the electrical conductivity of the glycoproteins is in the range of 9 to 14 mS and the dielectric constant value is around 2. The present results strongly suggest the possibility of using AFM as a diagnostic tool for direct recognition of avian influenza virus strains.

scholarly journals PRECIPITIN REACTIONS OF HIGHLY PURIFIED INFLUENZA VIRUSES AND RELATED MATERIALS

1946 ◽  
Vol 83 (4) ◽  
pp. 281-294 ◽  
Author(s):  
C. A. Knight
Keyword(s):  
Influenza Virus ◽  
Normal Mouse ◽  
Allantoic Fluid ◽  
Influenza Viruses ◽  
Antigenic Structure ◽  
Mouse Lung ◽  
Structure Characteristic ◽  
Virus Activity ◽  
Mouse Lungs

Antisera to purified PR8 virus, to purified protein from normal allantoic fluid, and to purified normal mouse lung particles were obtained from hyper-immunized rabbits and used in quantitative precipitin tests employing various purified preparations of influenza virus and related materials as antigens. The results of those tests indicated that the most highly purified preparations of PR8 or of Lee influenza virus obtained from infectious allantoic fluid contain an antigen characteristic of normal allantoic fluid and likewise that highly purified mouse lung PR8 virus contains an antigen characteristic of normal mouse lungs. Since the infectivity of virus preparations which were ultracentrifugally and electrochemically homogeneous was precipitated by the appropriate antisera to normal antigens, it was concluded that the normal antigens constitute a part of the 100 mµ particles with which influenza virus activity is at present deemed to be associated. It was estimated from quantitative precipitin data that the most highly purified preparations of PR8 and of Lee influenza viruses obtained from infectious allantoic fluid contain at least about 20 and 30 per cent, respectively, of an antigenic structure characteristic of the sedimentable protein of normal allantoic fluid.

A Study on Host Tropism Determinants of Influenza Virus Using Machine Learning

2020 ◽  
Vol 15 (2) ◽  
pp. 121-134 ◽  
Author(s):  
Eunmi Kwon ◽  
Myeongji Cho ◽  
Hayeon Kim ◽  
Hyeon S. Son
Keyword(s):  
Machine Learning ◽  
Amino Acids ◽  
Influenza Virus ◽  
Random Forest ◽  
Physicochemical Properties ◽  
Protein Sequences ◽  
Influenza Viruses ◽  
Host Tropism ◽  
Post Hoc ◽  
Ha Protein

Background: The host tropism determinants of influenza virus, which cause changes in the host range and increase the likelihood of interaction with specific hosts, are critical for understanding the infection and propagation of the virus in diverse host species. Methods: Six types of protein sequences of influenza viral strains isolated from three classes of hosts (avian, human, and swine) were obtained. Random forest, naïve Bayes classification, and knearest neighbor algorithms were used for host classification. The Java language was used for sequence analysis programming and identifying host-specific position markers. Results: A machine learning technique was explored to derive the physicochemical properties of amino acids used in host classification and prediction. HA protein was found to play the most important role in determining host tropism of the influenza virus, and the random forest method yielded the highest accuracy in host prediction. Conserved amino acids that exhibited host-specific differences were also selected and verified, and they were found to be useful position markers for host classification. Finally, ANOVA analysis and post-hoc testing revealed that the physicochemical properties of amino acids, comprising protein sequences combined with position markers, differed significantly among hosts. Conclusion: The host tropism determinants and position markers described in this study can be used in related research to classify, identify, and predict the hosts of influenza viruses that are currently susceptible or likely to be infected in the future.

Sign in / Sign up

Export Citation Format

Share Document