Decreasing the threshold for thymocyte activation biases CD4+ T cells toward a regulatory (CD4+CD25+) lineage.
Thymus-derived CD4(+)CD25(+) regulatory T (T(r)) cells play a critical role in suppressing aberrant responses to self in vivo. The factors that influence a CD4(+) T cell's decision to commit to an immunoregulatory T(r) cell lineage are currently unknown. In the present study, we found that in mice, abundantly expressing a few or one peptide(s) bound to MHC class II molecules, a large portion of conventional CD4(+) T cells could be biased towards the commitment to a T(r) lineage by reducing the threshold required for thymocyte activation. This occurred in the presence of either an antisense glucocorticoid receptor transgene or a pharmacological inhibitor of glucocorticoid synthesis. These results demonstrate a novel in vivo pathway for the generation of T(r) cells, and raise the possibility that therapeutic enhancement of the T(r) cell repertoire through pharmacological manipulation of TCR signaling thresholds may provide a feasible means of ameliorating autoimmunity.
Stephens
Geoffrey L
GL
Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, 30912-2600, USA.
Ignatowicz
Leszek
L
D000818:Animals; D015704:CD4 Antigens / Q000032:analysis*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D019070:Cell Lineage; D005938:Glucocorticoids / Q000037:antagonists & inhibitors / Q000494:pharmacology; D016130:Immunophenotyping; D008213:Lymphocyte Activation; D008297:Male; D008797:Metyrapone / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D015375:Receptors, Interleukin-2 / Q000032:analysis*; D013601:T-Lymphocytes / Q000276:immunology*
D015704:CD4 Antigens; D005938:Glucocorticoids; D011948:Receptors, Antigen, T-Cell; D015375:Receptors, Interleukin-2; D008797:Metyrapone