Pre-registration efficacy study of a novel marker vaccine against classical swine fever on maternally derived antibody positive (MDA+) target animals.

Maternally Derived Antibodies (MDA) can have a negative effect on the efficacy of live attenuated vaccines against classical swine fever (CSF). For this reason, a marker vaccine candidate CP7_E2alf was tested for its efficacy in the presence of MDA. Pregnant sows were vaccinated four weeks before farrowing with CSF virus (CSFV) strain "Thiverval". A total of 40 piglets with MDAs were included in this study. At six weeks of age the piglets were allocated into three treatment groups using generalized randomized block design (GRBD) blocking on serological status and pen location. Of the 40 piglets with MDAs, 30 piglets were vaccinated either orally (n = 15) or intramuscularly (n = 15) with a single dose of vaccine candidate produced under Good Laboratory Practice (GLP) conditions. The ten remaining piglets were allocated into the untreated control group. All 40 piglets were oronasally challenged with 2 ml of the highly virulent CSFV strain "Koslov" 14 days after vaccination. It was revealed that presence of MDAs negatively influences the efficacy of the live marker vaccine candidate, however, the extent of this negative impact depends on the route of vaccine administration. Based on our observations, intramuscular vaccination is recommended during CSF control programs in order to develop superior immune protection.

Pre-registration efficacy study of a novel marker vaccine against classical swine fever on Maternally Derived Antibody negative (MDA-) target animals.

Classical swine fever (CSF) marker vaccine candidate CP7_E2alf produced under Good Laboratory Practice (GLP) conditions by Pfizer was tested on 40 six-week-old MDA-piglets according to the European Pharmacopoeia (Ph.Eur.) requirements. Single doses of CP7_E2alf were given to 15 piglets orally, while 15 other piglets were intramuscularly vaccinated. Ten additional animals were included as unvaccinated controls. All piglets were oronasally challenged with the highly virulent CSF virus (CSFV) strain "Koslov" 14 days after vaccination. CP7_E2alf administered i.m. provided a complete protection, while p.o. administratrion triggered only partial protection. The level of protection was determined by the development of clinical signs, viraemia and rate of mortality. The vaccine candidate met the criteria of Ph. Eur Monograph 0065, "Swine-fever vaccine (live, prepared in cell cultures), classical" 7th Edition, which claims the efficacy test is invalid if fewer than 50 per cent of the control piglets display typical signs of serious infection of CSF or die, and if fewer than 100 per cent of the control piglets show clinical signs of disease within 21 days following challenge. Fulfilling these validity criteria is a key step in the registration procedure for a vaccine candidate to become openly available.

Intense picosecond X-Ray pulses from laser plasmas by use of nanostructured "Velvet" targets

We describe the optical, radiative, and laser-plasma physics of a new type of nanostructured surface especially promising as a very high absorption target for high-peak-power subpicosecond laser-matter interaction. This oriented-nanowire material, irradiated by 1 ps pulses at intensities up to 10(17) W cm(-2), produces picosecond soft x-ray pulses 50x more efficiently than do solid targets. We compare this to "smoke" or metallic clusters, and solid nanogroove-grating surfaces; the "metal-velvet" targets combine the high yield of smoke targets with the brief emission of grating surfaces.

Persistently infected cattle stabilise bovine viral diarrhea virus leading to herd specific strains.

Animals persistently infected with BVDV are important in the epizootiology of the Bovine Viral Diarrhea (BVD) because they are a permanent source of contamination within a herd. These animals produce large quantities of virus and have, therefore, been proposed as responsible for generating antigenic variability. However, limited studies have failed to detect antigenic or genetic changes in viruses isolated at different time from persistently infected animals. One hypothesis to account for this stability is that the immunotolerance is accompanied by a selection against antigenic change. The presence of an immunotolerant persistently infected (IPI) animal in a herd would in turn lead to herd specific strains. To verify this hypothesis, we compared 17 BVDV strains isolated from IPI animals from 3 herds of Eastern Belgium. The comparison was based on the sequence of a 389 bp fragment of E2--a gene encoding for a highly variable glycoprotein. Sequences were strongly conserved within herds but were quite different between herds, indicating that BVDV herd-specific strains do exist and are associated with the presence of IPI animals.

Studies on the pathogenicity of bovine herpesvirus type 5 in sheep.

Four Merino lambs were intranasally inoculated with bovine herpesvirus type 5 (BHV-5) reference strain N569. Two lambs were mock-inoculated as negative controls. The virus-inoculated animals developed apathy, inappetence, rhinitis, nasal, ocular and genital discharge, slight diarrhea and neurological disorders, like tremor and salivation. BHV-5 was isolated from the nasal discharge in two of the animals, while the polymerase chain reaction (PCR) detected the virus in all the infected lambs. Two lambs died on post infection day (PID) 13, while the other two infected animals were euthanized on PID 15 and 30. Gross pathological changes were not observed, however, histopathological examinations revealed diffuse nonsuppurative meningo-encephalitis in all infected animals. Viral antigen was detected by immunohistochemistry and viral nucleic acid was revealed by in situ hybridization in the brain of the two lambs, which died on PID 13. The virus was demonstrated by virus isolation and by PCR from different organs of all the infected animals. Slight rise of antibodies was observed in the infected animals from PID 15. The results show that BHV-5 is able to cross the species barrier and may establish infection in sheep.

Apoptosis of tumor cells induced by substances of the circulatory system.

Despite global abnormalities of the immune system, such as in AIDS, the incidence of only a few kinds of tumor increases, and even in the development of these tumors the degree of immunosuppression seems not to be a critical factor. This means that the known immune system has no significant role in the tumor preventing mechanism. Thus, the fact that tumors do not develop in the majority of the population during their lifetime, indicates the existence of an additional defense mechanism of the immune system. We demonstrated previously that this defense is produced by the synergistic action of certain substances of the circulatory system. Here we report that the substances taking part in the defense induced, but only when they were used together, the apoptosis of tumor cells, but not normal cells, as was detected by different methods. Other substances of the circulatory system did not show similar effects. These results further support the existence of the mentioned defense mechanism called by us the Passive Antitumor Defense System.

Theoretical and literary evidence for the existence of the passive antitumor defence system.

It is well documented that despite global abnormalities of the immune system in AIDS and other immune deficiency diseases or in immunosuppressed patients the incidence of only a few kinds of tumour increases and even in the development of tumours in question the degree of immunosuppression seems not to be a critical factor. It results from this that the known immune system has no significant role in the mechanism that prevents the development of tumours. Consequently, the fact that tumours do not develop in the majority of the population during their lifetime, indicates the existence of other defence systems. We assumed that the defence is made by small substances of the circulatory system. Substantial evidence exists that the uptake of the majority of these substances is increased and unregulated by tumour cells and proportional to their availability. This feature of tumour cells may be fatal when the number of cells is still low and there are abundant substances in their environment because some substances may be toxic if their concentrations can reach high level in the cells. Thus, the arising cancer cells die in the majority of the population during their lifetime if the number of cells arisen is not too high, or the concentrations of the required substances are not too low. To our hypothesis, the above effects of the physiological mixture of the given molecules in the blood form the Passive Antitumor Defence System (PADS). This hypothesis is confirmed by our experiments and supported by epidemiological, clinical observations and other literary data.

Epidemiology of syphilis in Hungary between 1952 and 1996.

Trends in morbidity from syphilis in Hungary between 1952 and 1996 were analysed. The incidence of syphilis/100,000 inhabitants declined rapidly owing to the public health and therapeutic measures of the early 1950s (1952: total=73.6, early infections=60.2; 1962: total=13.7, early infections=8.7). After a temporary, slight increase until 1973 the number of reported syphilis cases declined continuously between 1978 and 1989 (1989: total=0.9, early infections=0.84). In 1994 a marked increase occurred when compared with 1993 (1993: total=early: 1.4. 1994: total=2.3, early infections=2.2). Incidence trends were statistically analysed using Chi-square test and linear regression. Chi-square analysis showed that the changes in the incidence of total and early syphilis are significant (P<0.00001) comparing the time intervals 1952-1962 with 1962-1966 and 1975-1979 with 1988-1992. The same trends were found using the linear regression test, except for the time interval of 1960-1973.

The decreased antibacterial activity of oral polymorphonuclear leukocytes coincides with the occurrence of virus-carrying oral lymphocytes and epithelial cells.

Patients suffering from periodontitis or periodontosis were selected for the study. Further subdivision of these groups was based on the presence or absence of herpes and/or adenoviruses in their oral lymphocytes and epithelial cells. The phagocytic and bactericidal activities of oral leukocytes isolated from the same individuals were compared with virus carriage. In the periodontitis group, 60.5%, and in the periodontosis group 61.5% of patients carried viruses, while this was established only in 21.1% of control cases. On the other hand, emigration and sulcular gathering of the less viable polymorphonuclear leukocytes was elevated but their phagocytotic activity was decreased among periodontitis patients. Bactericidal capacity was significantly lowered among those subjects who carried viruses in their cells, as compared with virus-free persons, especially in the periodontitis group. The functions of the polymorphonuclear leukocytes accumulated in the sulcus gingivalis may be modified by mediators released from the virus-carrying cells. These mediators could achieve a greater concentration locally, and the damaged leukocytes would not be able to eliminate the microbes continuously so that the accumulation of bacterial products, among them endotoxins, could lead to periodontal inflammation.

Toxicity of microbial products in cell culture.

Cytotoxicity of a mixed pyrogen preparation and its components as well as native and radiodetoxified lipopolysacharides (LPS) was determined with established HEp-2 cell cultures and by measuring plating efficiency. This proved to be more sensitive to the damaging effect of both microbe-containing LPS (Escherichia coli) and purified LPS. Microorganisms without this compound (Lactobacillus casei, Streptococcus faecalis) seem to be more infifferent on cells, even Saccharomyces cerevisiae has a marked augmenting effect on cell plating. Divergence in null-toxicity between the established cultures and plating efficiency makes it possible to presume that the primary effect of microorganisms on epithelial cells is medited by LPS, and the subsequent liberation of lysosomal proteinases is responsible for major biological effects.

Immune studies by the use of Multitest-Merieux in patients with kidney tumours.

Responsiveness to recall antigens was studied by the use of Multitest-Merieux in 20 cases of kidney tumour with and without deposits. The patients of either group, compared with the controls, had depressed scores of immunoreactivity. After surgical removal of the tumour-bearing kidney, immunoreactivity increased, regardless of the presence or absence of deposits. The number of reacting antigens also increased in every case. Lymphocyte transformation in vitro was also depressed, in comparison with the controls before surgery, but after the intervention the transformed blast cells increased in number. Multitest was found suitable for studies of delayed-type sensitivity.

Study of antibodies to adenoviruses in patients with tumors of the urogenital system.

The presumable relationship between viruses and malignant disease has been studied. Approximately 4000 assays for antibodies to adenovirus were carried out with sera of patients with malignant and nonmalignant diseases of the urogenital organs and other organic diseases. The search was directed in the first place at antibodies to the early non-virion antigens of adenovirus-12 of oncogenic properties. On the evidence of the complement fixation reaction antibodies to adenoviruses were found to be less frequent in malignant tumors and in hypertrophy of the prostate than in the control group. Antibody to the non-virion antigen of adenoviruses was found in 53 per cent of patients with neoplastic diseases and prostatic hypertrophy, in 18 per cent of patients with urogenital diseases other than tumors and in 4 per cent of those with other organic diseases. The results point to a possible role of adenoviruses in tumors of the urogenital organs.

Suspected adverse drug reactions in the Hungarian veterinary practice between 1982 and 1992.

The most characteristic adverse drug reactions observed after the use of home-manufactured or imported veterinary medicinal products in Hungary between 1982 and 1992 included toxicosis, severe local reaction, lack of efficacy, and presence of residues in the edible tissues of food animals. The causes of adverse drug reactions comprised manufacturing defects, lack of chemical or microbiological stability, misuse or extra label use, and neglecting the warnings in the directions for use. Collection and analysis of data relating to adverse drug reactions are indispensable for the prevention of similar cases. The authorities can facilitate data collection by supplying veterinary practitioners with the necessary report forms.

Pathogenicity of a bovine viral diarrhoea virus strain in pregnant sows: short communication.

The biological properties of bovine viral diarrhoea virus (BVDV) strain Oregon C24V were studied after intranasal and subcutaneous infection of pregnant sows. This virus strain is widely used in Hungary for immunising cattle against bovine viral diarrhoea (BVD). Based upon the results of the clinical, gross pathological, histopathological and virological examinations it can be established that the given strain caused asymptomatic infection and serological conversion in sows that were in the second third of gestation. The virus caused clinically apparent disease in some of the piglets born at term, which indicates that it had crossed the placenta. More than half (57%) of the live-born piglets died within 60 days of birth. The sows and their progeny did not shed the virus. BVDV infection has great differential diagnostic importance in pigs, as classical swine fever (CSF) virus strains of reduced virulence cause similar clinical symptoms and gross and histopathological changes.

Occurrence of atypical myxomatosis in Central Europe: clinical and virological examinations.

An outbreak of the atypical form of myxomatosis struck a rabbit farm in Hungary. The animals had previously been vaccinated with a vaccine containing Shope rabbit fibroma virus strain. The disease appeared in winter when the presence of mosquitoes and fleas is not common. The virus was isolated from an eyelid specimen of a naturally infected rabbit. The surviving animals were observed for four weeks, blood samples were collected and, after euthanasia, organ specimens were also examined by morphological methods including pathology and electron microscopy. Serum samples were examined by virus neutralisation for antibodies. Genetic analysis of the isolated virus was carried out by polymerase chain reaction (PCR) and direct sequencing. The primers were designed on the basis of the major envelope gene (Env) of the Lausanne reference strain in the GenBank. The viral proteins were examined by SDS-PAGE. The isolated virus (ref. no.: BP04/2001) was able to infect the susceptible animals directly, by contact. The disease was characterised by respiratory symptoms of the upper tracheal tract, conjunctivitis and high mortality by the 11th-14th day. Aerogenic infection with strain BP04/2001 resulted in 100% morbidity among the susceptible animals. Sequencing of the amplified 400-bp-long DNA revealed 97% homology with the Env gene of the Lausanne strain, which proves that strain BP04/2001 is a variant of the Lausanne strain having been enzootic throughout Europe. The live vaccine strain used in Hungary against myxomatosis, which is also a Lausanne-derived strain, protected the animals. According to the protein analysis a protein of 200 kDa in size is not expressed in strain BP04/2001. This is the first report on atypical myxomatosis in Central Europe. The virus spreads by airborne transmission and may cause severe losses in the rabbit population.

[Detection of the virus-specific antigens of adenoviruses and herpes simplex virus in patients with malignant genital diseases]. / Obnaruzhenie virusspetsificheskikh antigenov adenovirusov i virusa prostogo gerpesa u bol'nykh so zlokachestvennymi zabolevaniiami genitalii.

The possibility of detecting virus-specific antigens in women with various pathological changes of the genitalia (cancer and pre-cancer conditions) was demonstrated. Comparative examinations of specimens from patients with cancer diseases of the genitalia for the presence of structural and virus-induced early antigens of HSV-2 demonstrated immunofluorescence test (IFT) to be the diagnostic test for the detection of HSV antigens in patients with cervical carcinoma. The rate of virus-induced antigen findings in the group of patients with cervical carcinoma was 51.6%, in precancer conditions, 31.7%, in recurrent genital herpes, 78.5%, in the control group of healthy women, 5%, by the IFT. The detection of virus-specific adenovirus and herpes antigens in human tumors is of interest for further investigation of a possible role of these viruses in the generation of malignant neoplasias and for the development of methods for specific immunodiagnosis.

[Persistence of herpes simplex virus and adenoviruses in lymphocytes of patients with urogenital tumors]. / Persistentsiia virusa prostogo gerpesa i adenovirusov v limfotsitakh bol'nykh s opukholiami urogenital'nogo trakta.

Certain viruses with neoplastic potential are known to be capable of participating in tumor formation to impair the immune system. In the present study, this association was investigated in patients with urogenital tract tumors. In studies of latent virus carrier state by means of immunofluorescence techniques using specimens from 118 patients with malignant tumors and 70 control persons it was found that in more than 50% of the patients, latent antigens of herpes simplex virus or adenoviruses were present in 1-3% of circulating lymphocytes. In the control group, virus carrier state in lymphocytes was demonstrated in only few patients. Using lymphocyte blastogenesis test, the effect of nonspecific mitogen (phytohemagglutinin) induced transformation of only 10-50% lymphocytes to lymphoblast cells in patients with malignant tumors, the percentage of transformation being also dependent on the stage of the tumor process. In the control group, treatment of lymphocytes with phytohemagglutinin resulted in transformation of 55-85% of lymphocytes into lymphoblasts. The lymphocytes of the majority of patients with tumors became sensitive to specific herpes-virus and adenovirus antigens, mainly the lymphocytes of the patients whose blood cells were also virus carriers.

Cytokine and immunoglobulin isotype profiles during CP7_E2alf vaccination against a challenge with the highly virulent Koslov strain of classical swine fever virus.

CP7_E2alf is a promising marker vaccine candidate against classical swine fever (CSF). To better understand the mechanisms of protection, cytokine and isotype-specific antibody profiles were investigated in CP7_E2alf vaccinated pigs before and after challenge with the highly virulent CSFV strain "Koslov" at 14 days or 6 months post-vaccination. The interference of vaccination with CSFV pathogeny-related cytokine responses, previously described following a moderately virulent challenge, was confirmed. However, the levels of additional cytokines, TNF-α and IL-6, were significantly attenuated by vaccination following highly virulent challenge. This vaccine interference with cytokine response was not dependent on the immunization route or the consequence of competition between vaccine and challenge strain. Interestingly, IFN-γ enhancement and persistent high IgG2 levels suggested an important role of cell-mediated immunity in long-term protection against CSFV induced by CP7_E2alf vaccination. IgA production also revealed a stimulation of mucosal immunity, especially after oral administration of the vaccine.