Measles virus nucleic acid sequences in human brain.

We constructed a measles virus genomic recombinant DNA library, and used clones coding for portions of the viral P, M and H proteins to probe for measles virus nucleic acid sequences in post-mortem multiple sclerosis, SSPE and control brains. By dot blot hybridization, the probes detected measles virus nucleic acid sequences in as little as 3 nanograms of total RNA extracted from measles virus-infected cells and also in highly diluted RNA extracted from SSPE brain, but did not detect measles virus sequences in RNA extracted from 11 multiple sclerosis or 8 control brains, even at a 1 000-fold higher concentration of RNA. By in situ hybridization, these probes detected measles virus nucleic acid sequences in virtually every cell and the surrounding neuropile of SSPE brain, but again did not detect such sequences in multiple sclerosis or control brains. Our findings using these highly specific probes confirm that measles virus is found in SSPE brains and indicate that measles virus genome is unlikely to be present in multiple sclerosis or normal brains.