Differential postselection proliferation dynamics of αβ T cells, Foxp3+ regulatory T cells, and invariant NKT cells monitored by genetic pulse labeling

TY - JOUR

T1 - Differential postselection proliferation dynamics of αβ T cells, Foxp3+ regulatory T cells, and invariant NKT cells monitored by genetic pulse labeling

AU - Föhse, Lisa

AU - Reinhardt, Annika

AU - Oberdörfer, Linda

AU - Schmitz, Susanne

AU - Förster, Reinhold

AU - Malissen, Bernard

AU - Prinz, Immo

PY - 2013/9/1

Y1 - 2013/9/1

N2 - The thymus generates two divergent types of lymphocytes, innate and adaptive T cells. Innate T cells such as invariant NKT cells provide immediate immune defense, whereas adaptive T cells require a phase of expansion and functional differentiation outside the thymus. Naive adaptive T lymphocytes should not proliferate much after positive selection in the thymus to ensure a highly diverse TCR repertoire. In contrast, oligoclonal innate lymphocyte populations are efficiently expanded through intrathymic proliferation. For CD4(+)Foxp3(+) regulatory T cells (Tregs), which are thought to be generated by agonist recognition, it is not clear whether they proliferate upon thymic selection. In this study, we investigated thymic and peripheral T cell proliferation by genetic pulse labeling. To this end, we used a mouse model in which all developing αβ thymocytes were marked by expression of a histone 2B-enhanced GFP (H2BeGFP) fusion-protein located within the Tcrd locus (TcrdH2BeGFP). This reporter gene was excised during TCR α-chain VJ-recombination, and the retained H2BeGFP signal was thus diluted upon cell proliferation. We found that innate T cells such as CD1d-restricted invariant NKT cells all underwent a phase of intense intrathymic proliferation, whereas adaptive CD4(+) and CD8(+) single-positive thymocytes including thymic Tregs cycled, on average, only once after final selection. After thymic exit, retention or loss of very stable H2BeGFP signal indicated the proliferative history of peripheral αβ T cells. There, peripheral Tregs showed lower levels of H2BeGFP compared with CD4(+)Foxp3(-) T cells. This further supports the hypothesis that the Treg repertoire is shaped by self-Ag recognition in the steady-state.

AB - The thymus generates two divergent types of lymphocytes, innate and adaptive T cells. Innate T cells such as invariant NKT cells provide immediate immune defense, whereas adaptive T cells require a phase of expansion and functional differentiation outside the thymus. Naive adaptive T lymphocytes should not proliferate much after positive selection in the thymus to ensure a highly diverse TCR repertoire. In contrast, oligoclonal innate lymphocyte populations are efficiently expanded through intrathymic proliferation. For CD4(+)Foxp3(+) regulatory T cells (Tregs), which are thought to be generated by agonist recognition, it is not clear whether they proliferate upon thymic selection. In this study, we investigated thymic and peripheral T cell proliferation by genetic pulse labeling. To this end, we used a mouse model in which all developing αβ thymocytes were marked by expression of a histone 2B-enhanced GFP (H2BeGFP) fusion-protein located within the Tcrd locus (TcrdH2BeGFP). This reporter gene was excised during TCR α-chain VJ-recombination, and the retained H2BeGFP signal was thus diluted upon cell proliferation. We found that innate T cells such as CD1d-restricted invariant NKT cells all underwent a phase of intense intrathymic proliferation, whereas adaptive CD4(+) and CD8(+) single-positive thymocytes including thymic Tregs cycled, on average, only once after final selection. After thymic exit, retention or loss of very stable H2BeGFP signal indicated the proliferative history of peripheral αβ T cells. There, peripheral Tregs showed lower levels of H2BeGFP compared with CD4(+)Foxp3(-) T cells. This further supports the hypothesis that the Treg repertoire is shaped by self-Ag recognition in the steady-state.

KW - Adoptive Transfer

KW - Animals

KW - Cell Differentiation/immunology

KW - Cell Proliferation

KW - Flow Cytometry

KW - Forkhead Transcription Factors/immunology

KW - Mice

KW - Mice, Inbred C57BL

KW - Natural Killer T-Cells/cytology

KW - Receptors, Antigen, T-Cell, alpha-beta/immunology

KW - T-Lymphocyte Subsets/cytology

KW - T-Lymphocytes, Regulatory/cytology

U2 - 10.4049/jimmunol.1301359

DO - 10.4049/jimmunol.1301359

M3 - SCORING: Journal article

C2 - 23894200

VL - 191

SP - 2384

EP - 2392

JO - J IMMUNOL

JF - J IMMUNOL

SN - 0022-1767

IS - 5

ER -