Demethylated CD8 gene in CD4+ T cells suggests that CD4+ cells develop from CD8+ precursors.
Mature T cells and medullary thymocytes bear either the CD4 or CD8 differentiation antigen. Precursor cells in the thymus express neither CD4 nor CD8 (CD4-8-), but most cortical thymocytes are CD4+8+. Whether CD4+ and CD8+ mature T cells arise directly from CD4-8- precursors or from a CD4+8+ intermediate remains unresolved. In this study, methylation of the CD8 gene in murine T cells and thymocytes was examined. There was progressive demethylation of the CD8 gene in the thymus during the transition from CD4-8- to CD4+8+. A similar pattern of demethylation of the CD8 gene was seen in CD4+ mature T cells, suggesting previous expression of CD8 in the CD4+ lineage.
Carbone
A M
AM
Department of Medicine, National Jewish Center for Immunology and Respiratory Medicine, Denver, CO.
Marrack
P
P
Kappler
J W
JW
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000235:genetics*; D004247:DNA / Q000378:metabolism*; D015245:Deoxyribonuclease BamHI / Q000378:metabolism; D019003:Deoxyribonuclease HpaII; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D005091:Exons; D006412:Hematopoietic Stem Cells / Q000276:immunology*; D006825:Hybridomas / Q000276:immunology; D007438:Introns; D008745:Methylation; D051379:Mice; D008806:Mice, Inbred AKR; D013601:T-Lymphocytes / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D004247:DNA; D015245:Deoxyribonuclease BamHI; D019003:Deoxyribonuclease HpaII; D015252:Deoxyribonucleases, Type II Site-Specific; C037130:GCGC-specific type II deoxyribonucleases