title: Reactivation of a major histocompatibility complex class II gene in mouse plasmacytoma cells and mouse T cells.
abstract: Terminally differentiated plasma cells and mouse T cells do not express major histocompatibility complex (MHC) class II genes although class II gene expression is observed in pre-B and mature B cells as well as in activated human T cells. Transient heterokaryons were prepared and analyzed to investigate the mechanisms of inactivation of MHC class II gene in mouse plasmacytoma cells and mouse T cells. The endogenous MHC class II genes in both mouse plasmacytoma cells and mouse T cells can be reactivated by factors present in B cells. This reactivation of class II gene is also observed by fusion with a human T cell line which expresses MHC class II genes, but not with a class II negative human T cell line. It appears that the loss of MHC class II gene expression during the terminal differentiation of B cells or T cell lineage is due to absence of positive regulatory factor(s) necessary for class II transcription.
authors.affiliation: Howard Hughes Medical Institute, Section of Immunobiology, Yale University School of Medicine, Connecticut 06510.
authors.forename: C H
authors.initials: CH
authors.lastname: Chang
authors.forename: W L
authors.initials: WL
authors.lastname: Fodor
authors.forename: R A
authors.initials: RA
authors.lastname: Flavell
mesh_terms: D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D004247:DNA / Q000378:metabolism; D005786:Gene Expression Regulation; D005802:Genes, MHC Class II; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010954:Plasmacytoma / Q000235:genetics / Q000276:immunology*; D013154:Spleen / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D004247:DNA