Characterization of V beta-bearing cells in athymic (nu/nu) mice suggests an extrathymic pathway for T cell differentiation.
In the present article, the expression of the T cell receptor (TcR) beta chain and other T cell molecules was evaluated in surface immunoglobulin-negative spleen cell populations of young and old BALB/c and C57BL/6 nude mice, using a panel of monoclonal antibodies. The results obtained show that in young nude mice, most Thy-1high cells do not express other T cell markers. These mice have, however, a sizable population of Thy-1low cells with the same phenotype of alpha/beta+, CD4-CD8- thymocytes or MRL/lpr peripheral T cells, expressing predominantly genes of the V beta 8 family. The evolution of alpha/beta+ cells in aging nudes is strongly suggestive of an extrathymic pathway of differentiation of these cells since (a) the acquisition of high density TcR and CD3, as well as Thy-1 or CD4CD8 antigens at the cell surface of nude V beta+ T cells is not simultaneous; (b) alpha/beta+ cells in nude mice co-express other T cell markers at random and, even in old mice, they never completely resemble to the predominant high Thy-1+ CD3+ TcR alpha/beta+, CD4+CD8+ cells of euthymic controls; and (c) BALB/c nude T cells express V beta 11 genes, that are deleted in euthymic BALB/c mice. This latter finding may also indicate differences in the mechanisms of selection of T cells specificities in the thymus vs. the peripheral pools.
Rocha
B
B
Unité INSERM U25, Hôpital Necker, Paris, France.
D000367:Age Factors; D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis; D017252:CD3 Complex; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens; D002454:Cell Differentiation; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D010641:Phenotype; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D011948:Receptors, Antigen, T-Cell / Q000032:analysis*; D016693:Receptors, Antigen, T-Cell, alpha-beta; D013601:T-Lymphocytes / Q000276:immunology*; D018800:Thy-1 Antigens
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D011947:Receptors, Antigen, B-Cell; D011948:Receptors, Antigen, T-Cell; D016693:Receptors, Antigen, T-Cell, alpha-beta; D018800:Thy-1 Antigens