Destruction Of Virus Research Articles

Photoinactivation of measles virus

Measles virus in the fluid state is rapidly inactivated by exposure to visible light. Vaccinia and poliovirus exposed under the same conditions retained their infectivity. There is a relationship between the rate of inactivation, the intensity of illumination, and the wavelength. It appears that the shorter the wavelength, the more rapid is virus destruction. Certain proteinaceous materials had a protective effect on the irradiated virus and reducing substances also decreased the photoinactivation. It is suggested that flavoproteins, possibly derived from the cell substrate, may serve as the sensitizing agents for measles virus.

The antigenicity of ultra-violet irradiated vaccinia virus.

SummaryVaccinia virus which has been inactivated by exposure to ultra-violet irradiation under strictly controlled conditions produces an immunity response in rabbits and monkeys. This can be measured by relative insusceptibility to challenge with living virus and by the titration of circulating antibody.Experiments with small doses of living virus in excess of those that might have been given accidentally indicate that the immune response to the irradiated material was not due to traces of living virus that had escaped detection.There is a logarithmic relationship between exposure to irradiation and destruction of virus. The exposure necessary to produce complete inactivation can be deduced from a knowledge of this relationship. Excessive exposure destroys the antigenicity of the preparations.The antigenicity of irradiated virus can be preserved for at least 6 months at 4°C. and at least 2 months at 37°C. by drying from the frozen state.Circulating antibody is detectable in rabbits for at least 22 weeks following immunization, and a single subsequent reinforcing dose is followed by a secondary immune response.The possibility that preliminary immunization with irradiated virus may diminish the risk of complications and reduce the severity of the reaction to subsequent Jennerian vaccination with living virus is discussed. This material may provide a basal immunity in those individuals in which vaccination is contraindicated.

Inactivation of virus by mustard at varying hydrogen ion concentrations.

SummaryA more complete destruction of virus occurred at acid reactions (pH 6.2) as opposed to alkaline reactions. The results with 5 × 10−3 M mustard also indicated that at alkaline reactions destruction of viral infectivity was completed during the first half minute of mustard-virus interaction. In contrast, at pH 6.2 the action of mustard upon virus extended beyond this half minute and led to complete inactivation of virus which survived the initial period of reaction. 2. A comparison of the interfering capacity of virus inactivated with 5 × 10−3 M mustard at pH 8.0 with that of virus treated with 5 × 10−4 M mustard at pH 6.2 revealed a marked interfering effect for the latter. This observation would appear to suggest a convenient procedure for preparation of interfering suspensions of virus for studies of the interference phenomenon.

Effect of Sodium Thiosulfate Upon Mustard-Virus Interaction.

Discussion and SummaryThe present studies would appear to indicate that the rate of reaction of mustard with virus was extremely rapid and that there were chemical groups in influenza virus which rendered them highly susceptible to mustard action. The rapidity of reaction at room temperature was attested by the observation that the greatest portion of the viral population was inactivated during the first minute of mustard-virus interaction. The inability of sodium thiosulfate, a substance reputedly having marked affinity for mustard molecules, to influence the course of events during the first minute of reaction seemingly supported the second of the above premises; presumably thiosulfate failed to compete successfully with virus for the molecules of mustard, thus accounting for the rapid initial destruction of virus. The partially “protective” action of thiosulfate upon destruction of virus by mustard, as reported herein, was confined to events after the first minute of reaction, and was probably related ...

INFLUENCE OF EXTRANEOUS PROTEIN AND VIRUS CONCENTRATION ON THE INACTIVATION OF THE RABBIT PAPILLOMA VIRUS BY X-RAYS

The pronounced resistance to the x-rays manifested by the papilloma virus in ordinary suspensions is due to the protecting influence of extraneous matter and also in considerable degree to the amount of virus present in the preparation. Two to 4 million r were required to inactivate the virus contained in the crude papilloma extracts prepared for the present work, whereas 100,000 r or less was enough to inactivate comparable concentrations of virus after extraneous matter had been excluded by repeated differential centrifugation. The addition of normal rabbit serum or crystalline egg albumin to purified suspensions of virus was found to increase greatly the amount of irradiation required to inactivate the virus. Furthermore the percentage destruction of virus by a given amount of irradiation increases as the concentration is decreased by dilution with saline or buffer solutions. As little as 3,000 r will inactivate much of the virus in very dilute suspensions. The complement-binding antigen of papilloma virus suspensions is also inactivated by x-rays, but requires a somewhat larger amount of irradiation than necessary to destroy the infectivity of the suspensions. The effects of irradiation on the antiviral antibody present in the blood of animals which have become immune to the virus-an antibody that specifically fixes complement in mixture with the papilloma virus-are also conditioned by extraneous material. 250,000 to 500,000 r had only a slight effect on the antibody in whole serum, while this amount of irradiation completely inactivated comparable amounts of antibody in preparations partially purified by precipitation with ammonium sulfate. As a whole the findings indicate that under certain conditions of purity and concentration most of the radiation does not act by direct hits on virus or antibody particles, but indirectly by ionizing or exciting some other molecules present in the exposed suspension, which then react with the virus or antibody molecules.

INFLUENCE OF NITROGEN SUPPLY ON THE RATE OF MULTIPLICATION OF TOBACCO-MOSAIC VIRUS

In a former paper the writer (10) reported experiments which showed that the virus activity of juice expressed from tobacco plants diseased with tobacco mosaic was correlated with the amount of nitrogen supplied to the plants. No conclusions could be drawn from these experiments as to whether this increased activity was due to an increase in the rate of virus multiplication or to some other factor, such as greater accumulation of virus particles over a longer period of time, less destruction of virus, or greater dispersion of aggregates of virus particles. Further studies have now been completed which suggest that the variation in virus activity resulting from a change in nitrogen supply may be brought about by a change in the rate of virus multiplication. Results obtained from several repetitions of the experiments to be described below agree closely with those reported in this paper. Materials and methods

The Destruction of the Virus of Foot-and-Mouth Disease in Manure

The Destruction of the Virus of Foot-and-Mouth Disease in Manure