Immunocytochemical search for JC papovavirus large T-antigen in multiple sclerosis brain tissue.

The large T-antigens of papovaviruses JC (JCV) and BK share a C-terminal subsequence with myelin basic protein (MBP). Since this sequence functions as a phosphate acceptor site in MBP, expression of a competing T-antigen sequence in oligodendroglia might adversely affect their ability to post-translationally process MBP and thus to maintain myelin. We have used techniques which demonstrate JCV T-antigen in small oligodendroglial cells from progressive multifocal leukoencephalopathy tissue to search for a possible latent JCV infection expressing T-antigen in nine cases of multiple sclerosis (MS) and three normal brains. No cells expressing T-antigen were detected in plaque or periplaque regions of the MS brains or in control CNS tissue.