Liv Bode

Learning deficiencies in borna disease virus-infected but clinically healthy rats☆

Borna disease (BD) virus, a still unclassified neurotropic agent, causes either fatal encephalomyelitis or persistent asymptomatic infection in a variety of animal species. We monitored the neuronal functions of intracerebrally infected but healthy rats with three types of learning experiments. Spatial discrimination learning, using the y maze and the hole board, was significantly less successful in BD virus-infected (I) compared with mock-infected (M) rats. Similarly, I rats tended to show a certain emotional disturbance (reduced resting behavior and less anxiety) as evaluated by open-field and neophobia tests. Furthermore, in two aversive learning experiments (taste aversion and reaction suppression via Skinner box), it appeared that the I rats expressed a significantly diminished ability to learn pain avoidance compared with M rats. In conclusion, we found specific learning deficiencies together with subtle behavioral alterations suggesting that BD virus causes certain modulations of high integrative brain functions which are only detectable under experimental conditions.

Borna Disease Virus Infection, a Human Mental-Health Risk

SUMMARY This article focuses on human Borna disease virus (BDV) infections, most notably on the development of valid diagnostic systems, which have arisen as a major research issue in the past decade. The significance of a novel modular triple enzyme-linked immunosorbent assay that is capable of specifically measuring anti-BDV antibodies as well as major structural proteins N (p40) and P (p24) in the blood, either as free antigens in the plasma or as antibody-bound circulating immune complexes (CICs), is explained. The impact of CICs and plasma antigen, which indicate periods of antigenemia in the course of BDV infection, along with other infection markers that are still in use is discussed. The review further provides new insight into possible links of BDV to human diseases, summarizing cross-sectional and longitudinal data which correlate acute depression with the presence and amount of antigen and CICs. Moreover, BDV prevalence in healthy people is reevaluated, suggesting that this was previously underestimated. Antiviral efficacy of amantadine, in vivo and in vitro, is outlined as well, with emphasis on wild-type (human and equine) versus laboratory strains. Finally, the pros and cons of the association of BDV with human disease, as detailed in the literature, are critically discussed and related to our data and concepts. This article supports existing correlative evidence for a pathogenic role of BDV infection in particular human mental disorders, in analogy to what has been proven for a variety of animal species.

Distribution of antibodies to porcine circovirus in swine populations of different breeding farms

SummaryAn enzyme linked immunosorbent assay (ELISA) was developed for mass antibody screening to porcine circovirus (PCV) in pig herds of different age groups and of different husbandries. Infection with PCV was found to be common in all swine herds tested, with only one exception, a herd at a small farm. Statistically, the percentage of PCV negative sera decreased and titer levels increased with increasing age of the pigs. Within individual age groups, differences were found to exist between different husbandries. No correlation was detected between antibody levels and reproductive disorders in the herds.

Presence of antibodies reacting with porcine circovirus in sera of humans, mice, and cattle

SummaryAntibodies reacting with porcine circovirus (PCV) were found in sera of humans, mice, and cattle by means of an indirect immunofluorescence assay (IFA) and an ELISA. In man, the highest seroprevalence (23.9% in IFA and 30.2% in ELISA) was found among hospitalized patients with fever of partially unclear etiology. Non-hospitalized “healthy” persons of the former German Democratic Republic showed a significantly higher number of positive sera (IFA=20%) than blood donors from Berlin-West (IFA=8.6%). Murine sera reacted positive with PCV in IFA between 12 to 69% in different breeding groups and about 35% of cattle sera were found reactive with PCV in IFA. Double-staining IFAs, immuno-electron microscopy and immunoblotting showed that non-porcine antibodies reacted with PCV structural antigen. Mathematical analysis releaved that in ELISA, non-porcine antibodies reacted specifically with PCV. Loss of binding specificity of non-porcine antibodies in ELISA after storage of sera and lower maximal optical densities obtained at equal titers in ELISA with non-porcine than with porcine sera suggest that antibodies in man, mice and cattle are caused by related species specific viruses sharing antigenic epitopes with PCV.

Amantadine and human Borna disease virus in vitro and in vivo in an infected patient with bipolar depression

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SEQUENCE CHARACTERIZATION OF HUMAN BORNA DISEASE VIRUS

Borna disease virus (BDV) causes a central nervous system disease in several vertebrate animal species, which is manifest by behavioral abnormalities. Seroepidemiologic data suggest that BDV might infect humans, possibly being associated with certain mental disorders. This is further supported by the detection of both BDV-specific antigens and RNA sequences in peripheral blood mononuclear cells (PBMCs) of psychiatric patients. For the first time the sequence characterization of human BDV is documented here. BDV was recovered by co-cultivation techniques from the PBMCs of three hospitalized psychiatric patients. BDV was unequivocally identified based on sequence identification of BDV open reading frames (ORFs) p24, p16 and p56, as well as of the predicted catalytic domain of the BDV L polymerase. Each human BDV isolate had an unique sequence, but they displayed a high degree of sequence conservation with respect of BDV isolates from naturally infected animals of different species.

Nitrocellulose-enzyme-linked immunosorbent assay (NC-ELISA) — A sensitive technique for the rapid visual detection of both viral antigens and antibodies

A modification of the enzyme-linked immunosorbent assay (ELISA) is described for sensitive and rapid direct visual detection of antigens of four adenoviruses (Ad) and anti-Ad antibodies using nitrocellulose (NC) membrane discs as high-capacity solid phase. The NC-ELISA was performed in microtitre plates containing NC-discs. Small amounts of crude supernatants from Ad-infected cells as antigen were bound to the discs. Additional binding capacity was blocked with an excess of bovine serum albumin. The subsequent reaction of virus antigen with specific rabbit antibody was visualized using alkaline phosphatase-conjugated anti-rabbit IgG and histochemical substrates. The sensitivity of the NC-ELISA for the detection of Ad-antigens was found to be 8-10-fold higher than a conventional ELISA using polystyrene solid phase supports. The sensitivity levels were estimated to be similar comparing NC-ELISA and tissue culture assay results. The quantitative determination of anti-Ad antibodies by NC-ELISA showed 8-fold higher sensitivity compared to microneutralization test. The NC-ELISA could detect purified immunoglobulin at a level of 1 ng using a direct test procedure and 10 ng using the indirect method. The detection limits are good compared to other highly sensitive assays. The use of crude antigen combined with high sensitivity and easy technical performance makes the NC-ELISA useful as a tool for rapid viral diagnosis.

Borna disease virus proteins in cerebrospinal fluid of patients with recurrent depression and multiple sclerosis

Evidence that human Borna disease virus (BDV) infection is aetiopathogenetically involved in some psychiatric disorders is accumulating, but direct proof for BDV activity in patients’ brains is still lacking. We report BDV proteins (N=40 kDa, P=24 kDa) and antibodies in cerebrospinal fluid (CSF) of 128 patients with psychiatric and 102 with neurological illnesses. Samples originated from a CSF bank (MPI Munich, 1992–1996) and a prospective collection in 1996. Corresponding serum or blood samples were not available. Antigens p40 and p24 (ref 5) were determined by an enzyme immunoassay with mixed specific monoclonal antibodies. These antigens were detected only in CSFs from patients with recurrent major depression and multiple sclerosis, but not in patients with other psychiatric (n=96) or neurological (n=83) disorders (table). Three of 32 patients with recurrent major depression (9·4%) had both proteins in equally high amounts, in the absence of other abnormal CSF findings; two of these had low antibody titres. Samples were collected during the first week in hospital, 6 weeks, 22 weeks, and 52 weeks after onset of their second or third depressive episodes. Two patients had a melancholic subtype and one RESEARCH LETTERS

Characterization and sequence of a 33-kDa enterohemolysin (Ehly1)-associated protein in Escherichia coli

The nucleotide sequence of the 2.1-kb EcoRI-AccI fragment of the enterohemolysin (Ehly)-associated plasmid, pEO21, has been determined. A third of this sequence encodes a 29.6-kDa protein, and coincides with the location of Tn1725 insertions which inactivate the production of Ehly. A protein of similar size (33-35 kDa) was found to be produced in large amounts by JM83[pEO21] and found to be immunologically related to the approximately 65-kDa protein made by the parental strain, C3888. DNA sequences coding for the 29.6-kDa protein of phi C3888, now designated Ehly 1, were found only in some enterohemolytic Escherichia coli indicating the existence of multiple, genetically different Ehlys.

Human Bornavirus infection – towards a valid diagnostic system

* Disclaimer: the article reflects the author’s but not the institution’s opinion (see also http://www.rki.de). This article is in part an evaluation and assessment of results which will be published elsewhere in detail. Contributions of unpublished raw data included here were from the Master Theses of Thomas Willemsen (epitopes on BDV Nand P-protein), Dennis Schmidt (BDV N-protein characterisation from plasma), and Steffen Zander (BDV P-protein). Corresponding author: E-mail (office): bodel/rki.de E-mail (Internet): Liv.Bode/web.de