title: Expression of the myelin proteolipid protein gene in the human fetal thymus.
abstract: We have analyzed human fetal thymus and spleen for expression of the proteolipid protein (PLP) gene. We demonstrate that the PLP gene is transcribed in both tissues, and that both the PLP and DM-20 mRNAs are produced. Western blot analyses revealed that both the PLP and DM-20 protein isoforms were present in the fetal thymus and spleen. Immunohistochemical analyses indicated that the PLP/DM-20 proteins were detected in cells which have the distribution and morphology of thymic macrophages. These results provide further evidence that the PLP and DM-20 proteins are expressed in cell types other than myelin forming cells and possess function(s) unrelated to myelin structure. Furthermore, these data demonstrate that the PLP and DM-20 proteins are not shielded from the immune system behind the blood-brain barrier. These observations directly impinge upon the debate concerning acquisition of tolerance and the recognition that the encephalitogenic nature of PLP in diseases, such as Multiple Sclerosis, may not simply be related to its 'sequestration' from a 'naive' immune system.
authors.affiliation: Mental Retardation Research Center, U.C.L.A. School of Medicine 90095, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Pribyl
authors.forename: C W
authors.initials: CW
authors.lastname: Campagnoni
authors.forename: K
authors.initials: K
authors.lastname: Kampf
authors.forename: T
authors.initials: T
authors.lastname: Kashima
authors.forename: V W
authors.initials: VW
authors.lastname: Handley
authors.forename: J
authors.initials: J
authors.lastname: McMahon
authors.forename: A T
authors.initials: AT
authors.lastname: Campagnoni
mesh_terms: D017398:Alternative Splicing / Q000502:physiology; D015152:Blotting, Northern; D015153:Blotting, Western; D005333:Fetus / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry; D018991:Myelin Proteolipid Protein / Q000032:analysis / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D013154:Spleen / Q000737:chemistry / Q000502:physiology; D013601:T-Lymphocytes / Q000737:chemistry / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000196:embryology*
chemical_list: D018991:Myelin Proteolipid Protein; D012333:RNA, Messenger