Thymic and Postthymic Regulation of Naïve CD4(+) T-Cell Lineage Fates in Humans and Mice Models.
Our understanding of how thymocytes differentiate into many subtypes has been increased progressively in its complexity. At early life, the thymus provides a suitable microenvironment with specific combination of stromal cells, growth factors, cytokines, and chemokines to induce the bone marrow lymphoid progenitor T-cell precursors into single-positive CD4(+) and CD8(+) T effectors and CD4(+)CD25(+) T-regulatory cells (Tregs). At postthymic compartments, the CD4(+) T-cells acquire distinct phenotypes which include the classical T-helper 1 (Th1), T-helper 2 (Th2), T-helper 9 (Th9), T-helper 17 (Th17), follicular helper T-cell (Tfh), and induced T-regulatory cells (iTregs), such as the regulatory type 1 cells (Tr1) and transforming growth factor-β- (TGF-β-) producing CD4(+) T-cells (Th3). Tregs represent only a small fraction, 5-10% in mice and 1-2% in humans, of the overall CD4(+) T-cells in lymphoid tissues but are essential for immunoregulatory circuits mediating the inhibition and expansion of all lineages of T-cells. In this paper, we first provide an overview of the major cell-intrinsic developmental programs that regulate T-cell lineage fates in thymus and periphery. Next, we introduce the SV40 immortomouse as a relevant mice model for implementation of new approaches to investigate thymus organogenesis, CD4 and CD8 development, and thymus cells tumorogenesis.
Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, SP, Brazil.
José E
JE
Belizário
Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, SP, Brazil.
Wesley
W
Brandão
Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, SP, Brazil.
Cristiano
C
Rossato
Department of Immunology, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, SP, Brazil.
Jean Pierre
JP
Peron
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D008221:Lymphoid Tissue / Q000166:cytology; D051379:Mice; D050378:T-Lymphocytes, Regulatory / Q000166:cytology* / Q000276:immunology*; D018417:Th1 Cells / Q000166:cytology / Q000276:immunology; D058504:Th17 Cells / Q000166:cytology / Q000276:immunology; D018418:Th2 Cells / Q000166:cytology / Q000276:immunology; D060168:Thymocytes / Q000166:cytology / Q000276:immunology
D053645:Interleukin-2 Receptor alpha Subunit