title: Evidence for extrinsic origin of Ia positive cells in embryonic murine thymus.
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D004622:Embryo, Mammalian / Q000166:cytology / Q000276:immunology*; D004847:Epithelial Cells; D004848:Epithelium / Q000276:immunology; D005260:Female; D005802:Genes, MHC Class II; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology; D008099:Liver / Q000166:cytology / Q000276:immunology; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D010641:Phenotype; D011247:Pregnancy; D013950:Thymus Gland / Q000166:cytology* / Q000196:embryology / Q000276:immunology