title: Induction of class I antigen processing components in oligodendroglia and microglia during viral encephalomyelitis.
abstract: Glia exhibit differential susceptibility to CD8 T cell mediated effector mechanisms during neurotropic coronavirus infection. In contrast to microglia, oligodendroglia are resistant to CD8 T cell perforin-mediated viral control in the absence of IFN gamma. Kinetic induction of MHC Class I expression by microglia and oligodendroglia in vivo was thus analyzed to assess responses to distinct inflammatory signals. Flow cytometry demonstrated delayed Class I surface expression by oligodendroglia compared with microglia. Distinct kinetics of Class I protein upregulation correlated with cell type specific transcription patterns of genes encoding Class I heavy chains and antigen processing components. Microglia isolated from naïve mice expressed high levels of these mRNAs, whereas they were near detection limits in oligodendroglia; nevertheless, Class I protein was undetectable on both cell types. Infection induced modest mRNA increases in microglia, but dramatic transcriptional upregulation in oligodendroglia coincident with IFN alpha or IFN gamma mRNA increases in infected tissue. Ultimately mRNAs reached similar levels in both cell types at their respective time points of maximal Class I expression. Expression of Class I on microglia, but not oligodendroglia, in infected IFN gamma deficient mice supported distinct IFN requirements for Class I presentation. These data suggest an innate immune preparedness of microglia to present antigen and engage CD8 T cells early following infection. The delayed, yet robust, IFN gamma dependent capacity of oligodendroglia to express Class I suggests strict control of immune interactions to avoid CD8 T cell recognition and potential presentation of autoantigen to preserve myelin maintenance.
authors.affiliation: Department of Pathology, University of Southern California Keck School of Medicine, Los Angeles, CA, USA.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Malone
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Stohlman
authors.forename: Chandran
authors.initials: C
authors.lastname: Ramakrishna
authors.forename: Wendy
authors.initials: W
authors.lastname: Macklin
authors.forename: Cornelia C
authors.initials: CC
authors.lastname: Bergmann
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004679:Encephalomyelitis / Q000473:pathology* / Q000821:virology*; D005434:Flow Cytometry; D015870:Gene Expression / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D006801:Humans; D007371:Interferon-gamma / Q000172:deficiency; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D017628:Microglia / Q000378:metabolism*; D018991:Myelin Proteolipid Protein / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009836:Oligodendroglia / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013116:Spinal Cord / Q000473:pathology / Q000821:virology; D013997:Time Factors; D014162:Transfection / Q000379:methods
chemical_list: D015395:Histocompatibility Antigens Class I; D018991:Myelin Proteolipid Protein; D009419:Nerve Tissue Proteins; C047516:Plp1 protein, mouse; D012333:RNA, Messenger; D049452:Green Fluorescent Proteins; D007371:Interferon-gamma