title: Frequency analysis of the T cell precursors in the thymus.
abstract: A frequency determination of the T cell precursors in murine adult and fetal thymuses as well as in the bone marrow and fetal liver was made. Cells were serially diluted and injected into deoxyguanosine-treated fetal thymus lobes with a microinjector, and the lobes were cultured for 12 to 21 days. The lobes in which T cell development did not occur were discriminated from those in which T cells developed, and the precursor frequency was determined by Poisson probability distribution analysis. The precursor cell frequencies in adult bone marrow cells (2.4 x 10(-5)) and fetal liver cells (1.7 x 10(-4)) were comparable to those determined previously in in vivo intrathymus transfer experiments. The present study further shows that only a small fraction of fetal thymus cells (0.9-5.0 x 10(-2)), CD4-8- adult thymocytes (1.6 x 10(-2)), and Thy-1 low positive adult thymocytes (3.3 x 10-4)) retain the precursor activity.
authors.affiliation: Department of Immunology, Kyoto University, Japan.
authors.forename: Y M
authors.initials: YM
authors.lastname: Dou
authors.forename: W T
authors.initials: WT
authors.lastname: Germeraad
authors.forename: J
authors.initials: J
authors.lastname: Gyotoku
authors.forename: Y
authors.initials: Y
authors.lastname: Katsura
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000032:analysis; D001854:Bone Marrow Cells; D005260:Female; D005865:Gestational Age; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D008099:Liver / Q000166:cytology; D008562:Membrane Glycoproteins / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D011247:Pregnancy; D013601:T-Lymphocytes / Q000502:physiology*; D018800:Thy-1 Antigens; D013950:Thymus Gland / Q000166:cytology*
chemical_list: D000954:Antigens, Surface; D008562:Membrane Glycoproteins; D018800:Thy-1 Antigens