Human borna disease virus infection
A study to find borna disease (BD) virus (BDV)-specific serum antibodies in psychiatric patients with major depression but not in healthy controls suggested a possible causal relationship between BDV infection and depressive disorders. Serological assay including such as IFA, WBA and ELISA are discussed. BDV antigen was first detected in peripheral blood mononuclear cells (PBMCs) of psychiatric patients by fluorescence-activated cell sorting (FACS) using monoclonal antibodies against P and N. To measure BDV antigen in the cerebrospinal fluid (CSF) and blood, researchers developed an antigen capture ELISA which uses monoclonal antibodies and polyclonal antiserum to capture and detect the antigen, respectively. When researchers first described the new technology of PCR in 1986 it took 6 more years before this method was used for detection of BDV-specific nucleic acid in human brain tissue specimens. Using RT-nested PCR and in situ hybridization, BDV-specific RNA (N) was detected in autopsy brain samples from four out of five patients with a diagnosis of hippocampus sclerosis and astrocytosis. In summary, since most of the RT-PCR products or virus isolates from brain tissue are identical in sequence to laboratory strains, one might be tempted to speculate that laboratory contaminations occurred in almost all cases of positive BDV results from human samples. The use of valid and unambiguous laboratory methods is essential for BDV diagnosis, in a general setting of lack of knowledge about etiology and pathogenesis of psychiatric disorders.