PROPERTIES OF THE CAUSATIVE AGENT OF A CHICKEN TUMOR : II. THE INACTIVATION OF THE TUMOR-PRODUCING AGENT BY MONOCHROMATIC ULTRA-VIOLET LIGHT

THE ANTIGENIC POTENCY OF EPIDEMIC INFLUENZA VIRUS FOLLOWING INACTIVATION BY ULTRAVIOLET RADIATION

A study of the antigenic potency of influenza virus inactivated by ultraviolet radiation has been made. Virus so inactivated is still capable of functioning as an immunizing agent when given to mice by the intraperitoneal route. In high concentrations inactivated virus appears to be nearly as effective as active virus but when quantitative comparisons of the immunity induced by different dilutions are made, it is seen that a hundredfold loss in immunizing capacity occurs during inactivation. Virus in suspensions prepared from the lungs of infected mice is inactivated more rapidly than virus in tissue culture medium. A standard for the comparison of vaccines of epidemic influenza virus is proposed.

PROPERTIES OF THE CAUSATIVE AGENT OF A CHICKEN TUMOR : XIV. RELATION BETWEEN A TUMOR NUCLEOPROTEIN AND THE ACTIVE PRINCIPLE

1. The tumor-producing fraction, isolated from Chicken Tumor I by means of differential centrifugation at high speed, has been investigated as regards its power to absorb ultraviolet light. A characteristic absorption spectrum was found, with a maximum at λ2575. The absorbing power of the material in that region was largely due to the presence of nucleic acid, or of a closely related compound. 2. Inactivation of the purified tumor fraction with ultraviolet light depressed the absorbing power of the material, especially in the region of 2600–2500Å. These changes were those which nucleic acid would present under the same conditions. 3. Inactivation of the tumor agent with acid or alkali was accompanied by decomposition of the tumor nucleoprotein and passage of free nucleic acid into solution. 4. Partial or complete inactivation of the tumor agent by heat, at 50° or 65deg;C., was attended by liberation of nucleic acid of low molecular weight. 5. The parallelism between tumor-producing activity and the integrity of the tumor ribonucleoprotein suggests that the nucleoprotein may be an essential part of the active principle.

PROPERTIES OF THE CAUSATIVE AGENT OF A CHICKEN TUMOR : IV. ASSOCIATION OF AN INHIBITOR WITH THE ACTIVE PRINCIPLE

The presence of an inhibiting substance in the chicken tumor is shown by the fact that a desiccate of the tumor is more active after it has been washed two or three times with water, and that an extract of the tumor is more potent after some factor is removed by adsorption on aluminum hydroxide. When the tumor-producing factor in an extract of a slow-growing tumor has been destroyed by heating at 55 degrees C. it is found to have the property of neutralizing a highly active tumor extract. This inhibiting property is destroyed by heating over 65 degrees C.

PROPERTIES OF THE CAUSATIVE AGENT OF A CHICKEN TUMOR : III. ATTEMPTS AT ISOLATION OF THE ACTIVE PRINCIPLE

By two methods a protein fraction can be separated out from a Chicken Tumor I extract, which carries all the tumor-producing agent. The precipitate can be dissolved and reprecipitated a number of times without loss of activity. The agent can be largely dissociated from the protein as shown by the fact that aluminum hydroxide will adsorb the protein from an extract and leave the agent behind. This purified material has a very low protein content, if any, as shown by both chemical and biological tests.

Predicted inactivation of viruses of relevance to biodefense by solar radiation

UV radiation from the sun is the primary germicide in the environment. The goal of this study was to estimate inactivation of viruses by solar exposure. We reviewed published reports on 254-nm UV inactivation and tabulated the sensitivities of a wide variety of viruses, including those with double-stranded DNA, single-stranded DNA, double-stranded RNA, or single-stranded RNA genomes. We calculated D(37) values (fluence producing on average one lethal hit per virion and reducing viable virus to 37%) from all available data. We defined "size-normalized sensitivity" (SnS) by multiplying UV(254) sensitivities (D(37) values) by the genome size, and SnS values were relatively constant for viruses with similar genetic composition. In addition, SnS values were similar for complete virions and their defective particles, even when the corresponding D(37) values were significantly different. We used SnS to estimate the UV(254) sensitivities of viruses for which the genome composition and size were known but no UV inactivation data were available, including smallpox virus, Ebola, Marburg, Crimean-Congo, Junin, and other hemorrhagic viruses, and Venezuelan equine encephalitis and other encephalitis viruses. We compiled available data on virus inactivation as a function of wavelength and calculated a composite action spectrum that allowed extrapolation from the 254-nm data to solar UV. We combined our estimates of virus sensitivity with solar measurements at different geographical locations to predict virus inactivation. Our predictions agreed with the available experimental data. This work should be a useful step to understanding and eventually predicting the survival of viruses after their release in the environment.

Predicted inactivation of viruses of relevance to biodefense by solar radiation

UV radiation from the sun is the primary germicide in the environment. The goal of this study was to estimate inactivation of viruses by solar exposure. We reviewed published reports on 254-nm UV inactivation and tabulated the sensitivities of a wide variety of viruses, including those with double-stranded DNA, single-stranded DNA, double-stranded RNA, or single-stranded RNA genomes. We calculated D(37) values (fluence producing on average one lethal hit per virion and reducing viable virus to 37%) from all available data. We defined "size-normalized sensitivity" (SnS) by multiplying UV(254) sensitivities (D(37) values) by the genome size, and SnS values were relatively constant for viruses with similar genetic composition. In addition, SnS values were similar for complete virions and their defective particles, even when the corresponding D(37) values were significantly different. We used SnS to estimate the UV(254) sensitivities of viruses for which the genome composition and size were known but no UV inactivation data were available, including smallpox virus, Ebola, Marburg, Crimean-Congo, Junin, and other hemorrhagic viruses, and Venezuelan equine encephalitis and other encephalitis viruses. We compiled available data on virus inactivation as a function of wavelength and calculated a composite action spectrum that allowed extrapolation from the 254-nm data to solar UV. We combined our estimates of virus sensitivity with solar measurements at different geographical locations to predict virus inactivation. Our predictions agreed with the available experimental data. This work should be a useful step to understanding and eventually predicting the survival of viruses after their release in the environment.

Predicted inactivation of viruses of relevance to biodefense by solar radiation

UV radiation from the sun is the primary germicide in the environment. The goal of this study was to estimate inactivation of viruses by solar exposure. We reviewed published reports on 254-nm UV inactivation and tabulated the sensitivities of a wide variety of viruses, including those with double-stranded DNA, single-stranded DNA, double-stranded RNA, or single-stranded RNA genomes. We calculated D(37) values (fluence producing on average one lethal hit per virion and reducing viable virus to 37%) from all available data. We defined "size-normalized sensitivity" (SnS) by multiplying UV(254) sensitivities (D(37) values) by the genome size, and SnS values were relatively constant for viruses with similar genetic composition. In addition, SnS values were similar for complete virions and their defective particles, even when the corresponding D(37) values were significantly different. We used SnS to estimate the UV(254) sensitivities of viruses for which the genome composition and size were known but no UV inactivation data were available, including smallpox virus, Ebola, Marburg, Crimean-Congo, Junin, and other hemorrhagic viruses, and Venezuelan equine encephalitis and other encephalitis viruses. We compiled available data on virus inactivation as a function of wavelength and calculated a composite action spectrum that allowed extrapolation from the 254-nm data to solar UV. We combined our estimates of virus sensitivity with solar measurements at different geographical locations to predict virus inactivation. Our predictions agreed with the available experimental data. This work should be a useful step to understanding and eventually predicting the survival of viruses after their release in the environment.

Rhinoviruses: kinetics of ultraviolet inactivation and effects of UV and heat on immunogenicity

The kinetics of ultraviolet inactivation for two human rhinoviruses and poliovirus were compared. No major differences in the rates of ultraviolet inactivation were detectable. All viral preparations inactivated by ultraviolet irradiation induced neutralizing antibody in guinea pigs. In contrast, when guinea pigs were immunized with a heat inactivated rhinovirus preparation, little or no neutralizing antibody was elicited. Immune electron microscopy of the heated rhinovirus preparations revealed the presence of particles resembling empty capsids. These results suggest that rhinoviruses and enteroviruses are affected in a similar manner when subjected to ultraviolet or heat inactivation.