DO ENDOGENOUS RETROVIRUSES HAVE ETIOLOGIC IMPLICATIONS IN INFLAMMATORY AND DEGENERATIVE NERVOUS-SYSTEM DISEASES

Vertebrates carry large numbers of endogenous retroviruses (ERVs) and related sequences in their genomes. These retroviral elements are inhe rited as Mendelian traits. Generally, ERVs are defective without the a bility of being expressed as viral particles. However, ERV sequences o ften have a potential for expression of at least some proteins. So far , the possible biological significance of ERVs is not clear. Nonethele ss, there are observations suggesting a connection between ERVs and va rious diseases. This is the case with murine lupus and a spinal cord d isease of certain mouse strains. In the present review, we discuss pos sible mechanisms by which ERVs could contribute to the development of human degenerative and inflammatory nervous system diseases, including direct effects on nervous system cells and immune cells. Interactions between ERVs and infectious viruses are also discussed. Finally, we r eview a possible retroviral etiology of multiple sclerosis.