How alpha beta T cells deal with induced TCR alpha ablation.
On deletion of the gene encoding the constant region of the T cell antigen receptor (TCR)alpha chain in mature T cells by induced Cre-mediated recombination, the cells lose most of their TCR from the cell surface within 7--10 days, but minute amounts of surface-bound TCR beta chains are retained for long periods of time. In a situation in which cellular influx from the thymus is blocked, TCR-deficient naive T cells decay over time, the decay rates being faster for CD8(+) cells (t(1/2) approximately 16 days) than for CD4(+) cells (t(1/2) approximately 46 days). TCR(+) naïve cells are either maintained (CD8(+)) or decay more slowly (CD4(+); t(1/2) approximately 78 days.) Numbers of TCR-deficient memory T cells decline very slowly (CD8(+) cells; t(1/2) approximately 52 days) or not at all (CD4(+) cells), but at the population level, these cells fail to expand as their TCR(+) counterparts do. Together with earlier data on T cell maintenance in environments lacking appropriate major histocompatibility complex antigens, these data argue against the possibility that spontaneous ligand-independent signaling by the alpha beta TCR contributes significantly to T-cell homeostasis.
Polic
B
B
Department of Immunology, Institute for Genetics, University of Cologne, Weyertal 121, 50931 Cologne, Germany. bojanp@medri.hr
Kunkel
D
D
Scheffold
A
A
Rajewsky
K
K
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D013997:Time Factors
D016693:Receptors, Antigen, T-Cell, alpha-beta