Harry M. Rose

The effect of hydroxyurea on virus development. II. Vaccinia virus.

Abstract Hydroxyurea in appropriate concentration inhibits the formation of mature infectious particles of vaccinia virus without preventing the synthesis of viral protein. Development of the virus is arrested at the “immature” or single-membrane stage, and the viral particles lack the internal body or “nucleoid” that is normally present. Hydroxyurea appears to act by inhibiting the synthesis of viral DNA.

Collocalia mucoid: A substrate for myxovirus neuraminidase☆

Abstract A potent inhibitor of myxovirus hemagglutination has been derived by aqueous extraction from the nest-cementing substance (salivary secretions) of the Oriental swiftlet (genus Collocalia ). The active material contains about 50% carbohydrate, is susceptible to the neuraminidase of influenza virus of all strains thus far tested, and lacks detectable blood group antigens. Observations on the relation between viral hemagglutinin, neuraminidase activity, and the conversion of myxoviruses to “indicators” are presented and discussed. Evidence is presented to indicate that the enzymic and hemagglutinative properties of myxovirus may be separate and dissociable functions.

An Electron Microscopic Study of Changes at the Surface of Influenza-Infected Cells as revealed by Ferritin-Conjugated Antibodies.

The sequence of events associated with liberation of the PR8 strain of influenza virus at the surface of chorioallantoic membranes (CAM) was studied by means of ferritin-conjugated antibodies, one of which was specific for the V antigen of the virus and the other for host cell antigen. With an input multiplicity of approximately 0.001 per cell, viral progeny were first detected by infectivity titrations and electron-microscopy after 12 and 13 hours, respectively. As infection proceeded, viral antigen progressively accumulated at the cell surface, while host cell antigen diminished in amount. It was concluded that normal host cell protein did not constitute an integral part of the surface structure of the virus.

Ionization of Sulfonamides

A recent quantitative analysis of bacteriostasis by sulfanilamide, sulfapyridine, sulfadiazine and sulfathiazole showed that for inhibition of Es. coli decreasing amounts of each drug in the order named were required. 1 Actually over six hundred times more sulfanilamide is required than sulfathiazole or sulfadiazine, and similar results have also been obtained with a variety of other microörganisms, 2 indicating that this regular increasing order of bacteriostatic potency is characteristic of these N1 sulfonamides (Col. A, Table I) and not attributable to the selective action of one drug against a certain organism. Furthermore, the quantitative relationships between these sulfonamides and para aminobenzoic acid (PAB) differ just as widely; e. g., over 600 times more PAB is needed to block sulfathiazole and sulfadiazine than to block sulfanilamide. (Col. F.) When the minimum effective concentration of each drug was tested, the same amount of PAB was required to block each drug. (Col. E.) In other words, going from sulfanilamide to sulfadiazine a progressively larger proportion of each drug actually present in the cultures appears to possess activity against either bacteria or PAB; the active moiety presumably being similar for each drug. It seems possible that such a partition into active and inactive portions might be controlled by the extent to which the drugs are ionized in the cultures. Accordingly the dissociation constants were measured∗ (Col. B) and the percent of each drug ionized at pH 7.0 (Col. C) was computed. (Some shift in the apparent pK may be expected to occur in complex biological media.) Based on these values and using the minimum effective amounts of drug added to the culture (Col. A), the concentration of ionized drug was estimated (Col. D).

Adenoviral Infection in Military Recruits

Field studies were made at Fort Dix, NJ, in 1966 and 1967 of the protective effect of oral live type 4 adenovirus vaccine against severe, incapacitating acute respiratory disease (ARD) in military recruits. The vaccine largely or completely eliminated type 4 adenovirus as the cause of such disease, but the suppression of type 4 by immunization was associated with replacement ARD that was caused by type 7 adenovirus in 1966 and by both type 7 and type 21 in 1967. The outbreak of ARD caused by type 21 was the first of its kind in the western hemisphere. The results of these studies show that adenoviral infection in military recruits cannot be controlled with a monovalent type 4 vaccine and that additional vaccines containing type 7 and probably other antigenic types will be required.

Serial sections of vaccinia virus examined at one stage of development in the electron microscope

Abstract Two clusters of intracytoplasmic viral particles are illustrated in eight consecutive serial sections. The sections average 30–33 mμ in thickness. The viral particles are spherical with diameters varying from 200–240 mμ. They possess a dense, limiting membrane 9–12 mμ thick. All particles sectioned five or more times can be shown to contain a nucleoid at one stage of development.

Enzymic Action of Influenza Virus on Human Erythrocyte Stroma Components.

Summary The presence in human erythrocyte stroma of a chromogenic substance giving absorption spectra (direct Ehrlich and Bial reactions) identical with those of crystalline sialic acid has been confirmed. A potent water-soluble inhibitor of viral hemagglutination, containing 7–11% by weight of this chromogen, has been isolated by partition dialysis from concentrated human erythrocyte stroma. 30–40% of the chromogen in the crude stroma concentrate and up to 56% of that in the purified inhibitor was rendered dialyzable following treatment with concentrated infective influenza virus, which in most instances also destroyed receptors for indicator viruses. Limited chromatographic analysis indicated that the dialyzable chromogen is most probably sialic acid. These observations represent the first direct demonstration of split products resulting from enzymic action of influenza virus on human erythrocyte components.

Concentration of Influenza Virus (PR8 Strain) by a Cation Exchange Resin.

Summary A simple method has been described for the rapid concentration and partial purification of the PR8 strain of influenza virus by means of an ion exchange resin.

Multiplication of Visna Virus in Bovine and Porcine Cell Lines

Summary Continuous cell lines derived from embryo bovine trachea (EBTr), pig kidney (PK(15)) and calf kidney (MDBK) were tested for their ability to support the multiplication of visna virus. Visna virus multiplied to a significant degree in EBTr and PK(15) cells and produced distinctive cytopathic changes in EBTr cells, but not in PK(15) cells. Serial passage was successful in EBTr cells, and virus from a late passage was immunologically similar to visna virus propagated in cell cultures prepared from sheep choroid plexus cells. Inoculation of EBTr monolayers with concentrated visna virus at high virus/cell multiplicities resulted in widespread polykaryocyte formation within 6 hr. EBTr cells may furnish a more convenient in vitro system for the study of visna virus than the cell culture systems now in use.

Metabolic effects of phenethyl alcohol on mammalian cells

Abstract In baby hamster kidney (BHK 21) cells, phenethyl alcohol interferes primarily with RNA synthesis. The effects of the compound on DNA and protein synthesis appear to derive from its primary effect on RNA metabolism. This conclusion was supported by the finding that phenethyl alcohol did not inhibit protein synthesis in rabbit reticulocytes which do not synthesize new RNA. The DNA isolated from phenethyl alcohol-treated cells was undegraded; this is at variance with the report of other investigators.