title: Two differential pathways from double-negative to double-positive thymocytes.
abstract: Murine thymocytes are divided into four major populations on the basis of expression of CD4 and CD8 antigens. The bulk of evidence favours the view that CD4-CD8- cells can develop into CD4-CD8+ and CD4+CD8- cells via the CD4+CD8+ stage in the thymus. However, CD4-CD8+ and CD4+CD8- thymocyte subsets contain not only CD3+ mature cells but also CD3- immature cells, which seem to be intermediate cells between CD4-CD8- and CD4+CD8+ cells. Here we demonstrate mouse strain differences in the proportion of immature single-positive thymocyte subsets in thymus at the steady or developing state. In C3H mice, immature CD4+CD8- is dominant in proportion over CD4-CD8+ in foetal thymus and in donor-derived thymocytes at an early stage of bone marrow transplantation. On the other hand, immature CD4-CD8+ is dominant over CD4+CD8- during T-cell development in the case of B10.BR mice. An intermediate pattern was shown in the case of F1 mice. Both of these immature single-positive subsets gave rise to double-positive cells after 24 hr culture. These results suggest that there exist two distinct differential pathways; one is from CD4-CD8- cells to CD4+CD8+ cells via CD4-CD8+ cells, and another is via CD4+CD8- cells, and that an application of the 'CD8 pathway' or 'CD4 pathway' seems to be genetically destined by BM-derived cells but not by thymic stromal cells.
authors.affiliation: Department of Immunology, Kyushu University, Fukuoka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshikai
authors.forename: Y
authors.initials: Y
authors.lastname: Moroi
authors.forename: T
authors.initials: T
authors.lastname: Asano
authors.forename: T
authors.initials: T
authors.lastname: Ando
authors.forename: K
authors.initials: K
authors.lastname: Nomoto
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis*; D017252:CD3 Complex; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens; D005260:Female; D051379:Mice; D008815:Mice, Inbred Strains; D011828:Radiation Chimera / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000032:analysis; D013045:Species Specificity; D013950:Thymus Gland / Q000166:cytology / Q000196:embryology / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D011948:Receptors, Antigen, T-Cell