In vitro-labeled DNA for detecting viral genomes in multiple sclerosis: I. Papovaviruses.

Papovaviruses appear to be neurotropic and one, JC virus, is implicated as the cause of one type of demyelinating disease, progressive multifocal leukoencephalopathy. To investigate whether human papovaviruses play a role in multiple sclerosis, radioactively labeled DNA from BK virus, human papilloma virus, and simian virus 40 was used as a probe in order to detect related unlabeled DNA sequences in DNA isolated from multiple sclerosis brain and/or spinal cord. Labeled viral probes were denatured and DNA allowed to reassociate in the presence of excess unlabeled DNA from multiple sclerosis tissue or from controls. The reassociation rate of the probe is proportional to the concentration of viral DNA present, and an increase in the reassociation rate of the probe over that of control reactions would indicate the presence of unlabeled viral DNA in multiple sclerosis cellular DNA. However, addition of DNA derived from multiple sclerosis patients did not increase rates of reassociation of viral probes. Known human papovaviruses probably have no role in the pathogenesis of multiple sclerosis.