Cross reactive antigenicity in orally vaccinated foxes and raccoon dogs against European Bat Lyssavirus type 1 and 2.

For the first time, the effectiveness of oral rabies vaccines against European Bat Lyssaviruses Type 1 (EBLV-1) and Type 2 (EBLV-2) by means of cross-neutralization assays was investigated. Sera from orally vaccinated red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) with the Street Alabama Dufferin (SAD) B19 and SAD P5/88 live-modified vaccine viruses were used to study the cross reactive antigenicity against CVS-11 (genotype 1), EBLV-1 (genotype 5) and EBLV-2 (genotype 6). For comparison, similar crossneutralization assays with sera from EBLV-1 and EBLV-2 infected ferrets (Mustela putorius furo) and/or foxes were conducted. Sera from animals vaccinated with the two oral rabies vaccines were reactive against CVS-11 (homologous virus), EBLV-1 and EBLV-2 (heterologous virus). There was a positive relationship among the virus neutralising antibody titres (VNA); high VNA titres against CVS-11 also resulted in high VNA titres against each EBLV, whereas in general, the VNA-titres obtained with homologous virus were statistically higher than those with the heterologous virus except for SAD P5/88 vaccinated raccoon dogs. No significant difference was found between EBLV-1 and EBLV-2 VNA titres. A similar trend was observed when the results of the cross-neutralization data of the foxes and ferrets inoculated i.m. with EBLV-1 and/or EBLV-2 was analysed. Based on the similarity of the EBLV-VNA titres obtained in our study questions were raised on whether the genetic distance of genotype 5 & 6 within phylogroup 1 really does reflect their antigenetic characteristics or whether this is a feature of attenuated live vaccine viruses. This broad cross protection, however, demonstrated that the representatives of attenuated SAD strains of oral rabies vaccines currently used in Germany are most likely able to protect the reservoir species, red fox and raccoon dog, against EBLV-1 and EBLV-2 infection.

Glutathione levels and nerve cell loss in hippocampal cultures from trisomy 16 mouse--a model of Down syndrome.

The tripeptide glutathione (reduced state, GSH) is an important intracellular free radical scavenger protecting cells against oxidative stress. The trisomy 16 mouse is a model of the human trisomy 21 (Down syndrome). Here we demonstrate that cultured hippocampal neurons from trisomy 16 mouse exhibit decreased GSH levels and augmented cell death when compared to diploid cells. Additional lowering of GSH levels led to enhanced cell death in trisomy 16 cells. Based on these results we suggest that a GSH level which is decreased under a specific threshold by increased consumption, reduced synthesis or lack in precursor contributes to cell loss and neurodegeneration in Down syndrome.

The glutathione level of retinal Müller glial cells is dependent on the high-affinity sodium-dependent uptake of glutamate.

The dependence of intracellular glutathione, an important radical scavenger, on the extracellular glutamate and cystine concentration and the velocity of the high affinity sodium/glutamate transporter was studied in freshly-isolated Müller glial cells of the guinea-pig, kept in vitro for up to 11 h. To this end the relative Müller cell glutathione levels were measured using the fluorescent dye monochlorobimane, using different concentrations of glutamate and cystine in Ringer solution. In some experiments L-buthionine-[S,R]-sulfoximine, a blocker of glutathione synthesis, or L-trans-pyrrolidine-2,4-dicarboxylic acid and L-alpha-aminoadipic acid, inhibitors of glutamate uptake, were added. The Müller cells maintained about 80% of the normal glutathione level when maintained in Ringer solution containing 100 microM glutamate for 11 h. When under these conditions 100 microM cystine was added, the glutathione level increased to values, which were even higher than those at the beginning of the incubation period. Addition of cystine without glutamate caused a run down of the glutathione level to about 45% of the normal level, which is comparable to the run down in pure Ringer solution. Likewise, application of L-buthionine-[S,R]-sulfoximine (5 mM) lead to a strong run down of the glutathione level even in glutamate/cystine (100 microM)-containing solution. A similar suppressing effect was observed using L-trans-pyrrolidine-2,4-dicarboxylic acid and L-alpha-aminoadipic acid in the presence of 100 microM cystine and glutamate. We conclude that the intracellular glutamate concentration of the Müller cells is determined by the extracellular glutamate concentration and the velocity of the sodium/glutamate uptake. Consequently, cystine uptake into Müller cells, which is performed by the cystine/glutamate antiporter, is fueled by the sodium/glutamate transporter with intracellular glutamate. Both glutamate and cystine are also substrates for glutathione synthesis. The glutathione level is logically limited by the capacity of the sodium/glutamate transporter to provide glutamate intracellularly for, first, cystine uptake and, second, direct insertion into glutathione. Accordingly, the glutathione level is reduced when the sodium/glutamate transporter is blocked. Thus, a diminution of the glutathione level should be taken into consideration when the effects of sodium/glutamate uptake failure and reduced intracellular glutamate concentrations are discussed.

[Quality management in the serodiagnosis of European swine fever: results of comparative tests]. / Qualitätsmanagement bei der Serodiagnostik der Europäischen Schweinepest (ESP): Ergebnisse von Ringversuchen.

In the course of inter-laboratory quality management comparative serological tests on classical swine fever (CSF) are conducted once per year. Results from tests carried out in 1994 and 1995 indicate that most regional diagnostic laboratories were able to classify the test sera correctly as CSF-positive, bovine viral diarrhea (BVD)-positive and negative, respectively. Difficulties were encountered in the differential diagnosis of CSF and BVD in neutralisation tests. There is a need to improve the standardization of CSF serology on the basis of a well established method in order to ensure reliability of test results and to enable comparison of results obtained from different laboratories.

[Comparison of different BVD virus strains for their use in the differential diagnosis of classical swine fever--an attempt to standardize neutralization tests]. / Vergleich verschiedener BVDV-Stämme für Zwecke der Differentialdiagnose in der KSP-Serologie--ein Beitrag zur Standardisierung des Neutralisationstestes.

Six bovine virus diarrhoea (BVD) virus strains were tested in the neutralization test for their use in the differential diagnosis in classical swine fever (CSF) serology. The aim of the investigation was to find a suitable BVD virus strain guaranteeing a safe differentiation of CSF- and BVD virus induced antibodies using permanent cell cultures (PK-15, MDBK). For test purposes the neutralizing antibody titres of 73 defined test sera were titrated against the CSF virus strain Alfort/187 as well as the BVD virus strains Grub, Paplitz, NADL, 1138/69, Stendal, 10421/Han 94). Tests were repeated fivefold. The level of mean antibody titres, the differences in titre to the homologous pestivirus strain, the standard deviation and the variation coefficient served as test criteria. The BVD virus strains Grub and NADL yielded the best results. In view of harmonization and standardization the BVD virus strain NADL in connection with a standard protocol for neutralization tests is recommended for the differential diagnosis in CSF serology. Due to the adaptation of the permanent cell-lines PK-15 and MDBK to horse serum a further source of contamination with non cytopathogenic BVD viruses under routine conditions can be excluded.