Peripheral selection of T cell repertoires: the role of continuous thymus output.
We investigated the role of continuous thymus output in the shaping of mature T cell repertoires by studying in vivo the survival of a single clone of mature Rag2-deficient T cell receptor (TCR) transgenic cells at different stages of activation in the absence or presence of thymus export. In the absence of thymus export, TCR-transgenic lymphocytes survived indefinitely in the peripheral pools. When new lymphocytes were produced in the thymus and migrated to the periphery, resident memory T cells were maintained in constant numbers, whereas naive and self-reactive T cells were replaced by recent thymus migrants. This T cell renewal ensured both the efficiency of recall responses to antigens as memory T cells persisted independently of thymus output, and the capacity of the immune system to respond to new antigen stimulation as the naive T cell pool was continuously renewed. Our results also indicate that thymus export is required to control the number of self-reactive peripheral T cells that may invade the peripheral pools if thymus output fails.
Tanchot
C
C
U345 Institut National de la Sante et de la Recherche Medicale, Institut Necker, 156, 75730 Paris Cedex 15, France.
Rocha
B
B
D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002470:Cell Survival; D016922:Cellular Senescence; D002678:Chimera / Q000276:immunology; D002999:Clone Cells; D004268:DNA-Binding Proteins; D005260:Female; D007108:Immune Tolerance / Q000276:immunology; D007156:Immunologic Memory; D008213:Lymphocyte Activation; D018655:Lymphocyte Count; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D018448:Models, Immunological; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology*
D004268:DNA-Binding Proteins; C499308:Rag2 protein, mouse; D016693:Receptors, Antigen, T-Cell, alpha-beta; C064655:V(D)J recombination activating protein 2