Anton Mayr

Genetic and Antigenic Heterogeneity of Different Parapoxvirus Strains

Six stomatitis papulosa and three Orf virus strains were compared by serology and by DNA restriction analysis. A neutralization kinetic study revealed extensive serological cross-reactivity between all strains, but did not allow their classification. Restriction analysis of viral DNAs revealed two distinct groups among the stomatitis papulosa strains while the Orf virus strains formed a third, more heterogeneous group. The large heterogeneity of restriction patterns of parapoxvirus DNAs as compared to those orthopoxviruses is discussed.

Characterization of a small Porcine DNA virus

Characteristics of a small DNA virus isolated from kidney cell cultures of healthy 3 week-old pigs are described. The virus isolate multiplies in kidney cell cultures of pig origin, produces intranuclear inclusion bodies, and hemagglutinates guinea pig, human group 0, chicken, cat, rat and mouse red blood cells. It multiplies in pigs resulting in antibody production, but is not pathogenic for newborn hamsters and mice. The virus particle is 20–22 mμ in size, hexagonal in shape and without a lipid containing envelope. Buoyant density is between 1.37 and 1.38g/ml. This virus is stable within a wide range of pH, resistant to heat (56°C), against treatment with trypsin, and lipid solvents. The porcine virus was proposed as a member of the picodna virus group, and named “Porcine Picodna Virus (PPV)”.

Smallpox vaccination and bioterrorism with pox viruses.

Bioterrorist attacks occupy a special place amongst the innumerable potential types of terrorist attack, with the intentional release of pox viruses being especially feared in this connection. Apart from the variola virus, the agent responsible for smallpox in humans, the monkeypox virus and numerous other animal pox viruses pose potential risks for humans and animals. This risk scenario also includes recombinations between the various pox viruses, changes in hosts and genetically engineered manipulations of pox viruses. For over 200 years, the method of choice for combatting smallpox was via vaccination with a reproductive, original vaccinia virus. Worldwide eradication of smallpox at the end of the 1970s and the discontinuation of routine smallpox vaccination in 1980 can be credited to such vaccination. Unfortunately, these vaccinations were associated with a large number of postvaccinal impairments, sometimes resulting in death (e.g. postvaccinal encephalitis). The only way to restrict such postvaccinal complications was to carry out initial vaccination within the first 2 postnatal years. Initial vaccination at a later age led to such a sharp increase in the number of vaccines with complications that vaccination had to be discouraged. The dilemma of the smallpox vaccine stocks stems from the fact that a large portion of these stocks are produced with the same vaccinia strains as before. This is irresponsible, especially as the percentage of immune-suppressed persons in the population, for whom vaccination-related complications pose an especial threat, is increasing. One solution to the dilemma of the smallpox vaccine stocks is the MVA strain. It is harmless, protects humans and animals equally well against smallpox and can be applied parenterally.

Physical characterization of a stomatitis papulosa virus genome: A cleavage map for the restriction endonucleasesHindIII andEcoRI

SummaryThe genome of stomatitis papulosa virus (aparapoxvirus) was cleaved with the restriction endonucleasesHindIII andEcoRI, each giving rise to 6 fragments respectively. Double digestion with both enzymes resulted in 8 bands, two of which contained DNA fragments in double molar concentrations as revealed by reciprocal digests of isolated DNA fragments. The genome size, estimated by summation of the molecular weights of the fragments, is approximately 86×106 daltons, some 30×106 daltons smaller than vaccinia virus (anorthopoxvirus) DNA.The cleavage sites ofHindIII andEcoRI endonucleases were mapped on the genome by analysis of reciprocal digests of isolated DNA fragments and by cross-hybridization experiments. This yielded two mapped segments which were then oriented relative to one another by cleavage of isolated partial digestion products.The terminal restriction fragments show rapid renaturation after alkali denaturation and subsequent neutralization, indicating that stomatitis papulosa virus DNA contains terminal cross-links analogous to those found in vaccinia virus DNA.

Highly attenuated poxviruses induce functional priming of neutrophils in vitro

SummaryHighly attenuated poxvirus samples were used to examine the influence of potential poxvirus expression vector systems on neutrophil function. Exposure to the viruses alters the number of membrane bound complement-and Fcγ-receptors and led to functional priming of neutrophils to subsequent stimuli.

Production of Borna virus in tissue culture.

Summary This is the first report on the cultivation of Borna virus in tissue culture. In subcultures of lamb kidneys, the virus reproduces with a latent period of several weeks. At 48–72 hr postinfection, the infectivity of the subcultures for rabbits disappears but recurs after 5–10 weeks. The infectivity is not lost by subcultivation of the cells, and the infected cultures show an enhanced growth rate. After several weeks, plaque-like areas with enlarged cells and nuclei can be observed in the infected cultures. Nuclear inclusion bodies are found, but very rarely, and show no correlation to the infectivity of the cells for rabbits. The behavior of Borna virus in cell cultures is typical of a slow virus infection, and thus, the Borna infection of tissue cultures offers itself as a new model for the study of slow viruses.

Electron optical and buoyant density studies of hog cholera virus

Virus particles with a buoyant density between 1.14 and 1.20 g/ml, with a peak density of 1.15 to 1.16 g/ml were shown to cause hog cholera disease in pigs. In electron microscopic studies particles of two distinct sizes were demonstrated in these fractions. A lipid enveloped particle with an outer diameter of 39–40 mμ and an inner (core) diameter of 28–29 mμ was proposed to be hog cholera virus.

Charakterisierung eines Stutenabortvirus aus Polen und Vergleich mit bekannten Rhinopneumonitisvirus-Stämmen des Pferdes

Ein in Polen aus einem abortierten Pferdefötus isolierter Erreger, Stamm RAC, wurde auf Grund seiner Eigenschaften als Rhinopneumonitisvirus der Pferde charakterisiert. Das Rhinopneumonitisvirus gehört zur Gruppe der Herpesviren, Auffällig ist das breite kulturelle Wirtsspektrum des Rhinopneumonitisvirus, das sich in Pferde-, Kälber- und Schweinenieren-Zellkulturen züchten läßt, wobei vor allem den leicht erhältlichen Schweinenierenkulturen der Vorzug gegeben werden soll. Nach Adaptierung ist eine Züchtung auch in Schafnieren-, Bullenhoden- und Hühnerembryofibroblasten-Kulturen möglich. Alle untersuchten Stämme gehören zu einem einheitlichen Serotyp. Mit der Neutralisationsreaktion lassen sich zwei Subtypen unterscheiden (Subtyp 1: der Stamm Kentucky-D, Subtyp 2: die Stämme RAC, Army 183, Hannover 1835 und V 100/64). Der Subtyp 2 scheint in Europa vorherrschend zu sein. Mit Hilfe der Präzipitationsreaktion ist eine Unterscheidung der Subtypen nicht möglich. In Rekonvaleszentenseren von Stuten, die abortiert hatten, konnten neutralisierende Antikörper nachgewiesen werden. Präzipitierende Antikörper konnten jedoch, wohl aus zeitlichen Gründen, nicht nachgewiesen werden. An agent isolated in Poland from an aborted horse fetus has been characterized as the equine rhinopneumonitis virus (RAC strain). The equine rhinopneumonitis virus belongs to the herpes group. The cultural spectrum is remarkably large. The virus can be cultivated in horse, calf and hog kidney cultures. The readily available ho kidney cultures are preferable. After an adaptation a cultivation is also possible in sheep kidney, bovine testis and chick embryo fibroblast cultures. All examined strains belong to a uniform serotype. With the neutralization test two serotypes can be distinguished: Subtype 1 (the Kentucky strain) and subtype 2 (the strains RAC Army 183, Hannover 1835 and V 100/64). The subtype 2 seems to be prevalent in Europe. The precipitation test allows no distinction of subtypes. Reconvalescent serum of mares having aborted contains neutralizing antibodies. Precipitating antibodies could not be demonstrated, probably because too much time had elapsed.

A monoclonal blocking-ELISA for detection of orthopoxvirus antibodies in feline sera

A double sandwich blocking-ELISA using a genus-specific neutralizing monoclonal antibody (MAb) against the vaccinia virus 32 kD adsorption protein (D8L open reading frame: ORF) was developed to detect orthopoxvirus (OPV) antibodies in sera. A collection of 2173 feline serum samples was examined in an epidemiological study. The blocking-ELISA revealed 44 (2%) sera with positive titres of 1:2-1:256. ELISA results were confirmed by the plaque-reduction test. A close correlation between titres of both assays could be observed (r = 0.986). In general, the sensitivity of the blocking ELISA was two to four times higher. Neutralizing OPV-antibodies were found in nine sera with ELISA-titres > 1:4. Antibody specificity to OPV was also demonstrated by Western blotting analysis with selected feline sera. The epidemiographical distribution of the ELISA-positive sera and case histories of 37 seropositive cats available from the referring veterinarians are demonstrated. The blocking-ELISA enables a rapid serological diagnosis and can be used in veterinary and human medicine. It allows OPV-antibody screening in human and other animal species.

More than one component of the Newcastle disease virus particle is capable of interferon induction.

Abstract The interferon (IFN)-inducing capacities of intact NDV virions, β-propiolactone-inactivated particles and several structural components were compared, using human PBML as the IFN producing cells. Intact and inactivated virions as well as the nucleocapsid fraction did not differ significantly in their IFN-inducing capacity. In contrast, genomic RNA as well as M protein fraction and envelopes induced IFN titres to a level of about 10% of those achieved with virions. NDV-induced IFN production could be blocked specifically by incubation with polychonal anti-NDV-monoclonal antibodies (mAbs) and with two of three anti-HN-mAbs, but not with anti-NDV-mAbs directed against the F, M or NP protein. In addition, IFN induction by fixed MDBK cells, expressing NDV surface proteins after infection with NDV Ulster, was inhibited by one of two anti-F-mAbs. The results suggest that the induction of IFN synthesis in human PBML is a complex process involving not only the HN protein but also the uncleaved F protein precursor, a component of the M protein fraction and — once having entered the cell — the genomic RNA.