Fetal and Adult Hematopoietic Stem Cells Give Rise to Distinct T Cell Lineages in Humans

• Published in: Science (American Association for the Advancement of Science) Vol. 330; no. 6011; pp. 1695 - 1699
• Main Authors: Mold, Jeff E, Venkatasubrahmanyam, Shivkumar, Burt, Trevor D, Michaëlsson, Jakob, Rivera, Jose M, Galkina, Sofiya A, Weinberg, Kenneth, Stoddart, Cheryl A, McCune, Joseph M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 17-12-2010; The American Association for the Advancement of Science
• Subjects: Adult; Adult stem cells; Adult Stem Cells - cytology; Adult Stem Cells - physiology; Adults; Aging - immunology; Animals; Biological and medical sciences; Bone Marrow - embryology; Bone Marrow Cells; CD4-Positive T-Lymphocytes - immunology; Cell Lineage; Cytoprotection; Developmental Stages; Fetus; Fetus - cytology; Fetus - immunology; Fundamental and applied biological sciences. Psychology; Gene Expression; Hematopoietic Stem Cells - physiology; Humans; Immune Tolerance; Liver; Liver - cytology; Liver - embryology; Lymphocyte Activation; Lymphopoiesis; Medicin och hälsovetenskap; Mice; Mice, SCID; Molecular and cellular biology; Oligonucleotide Array Sequence Analysis; Phenotypes; Principal components analysis; Stem cells; T lymphocytes; T-Lymphocyte Subsets - immunology; T-Lymphocyte Subsets - physiology; T-Lymphocytes - immunology; T-Lymphocytes - physiology; T-Lymphocytes, Regulatory - immunology; T-Lymphocytes, Regulatory - physiology; Thymocytes; Thymus Gland - cytology; Thymus Gland - immunology; Young Adult; Human; Hematopoietic cell; Adult; Fetus; Stem cell; T-Lymphocyte
• ISSN: 0036-8075; 1095-9203; 1095-9203
• DOI: 10.1126/science.1196509

Although the mammalian immune system is generally thought to develop in a linear fashion, findings in avian and murine species argue instead for the developmentally ordered appearance (or "layering") of distinct hematopoietic stem cells (HSCs) that give rise to distinct lymphocyte lineages at different stages of development. Here we provide evidence of an analogous layered immune system in humans. Our results suggest that fetal and adult T cells are distinct populations that arise from different populations of HSCs that are present at different stages of development. We also provide evidence that the fetal T cell lineage is biased toward immune tolerance. These observations offer a mechanistic explanation for the tolerogenic properties of the developing fetus and for variable degrees of immune responsiveness at birth.