The Role of the Thymus in the Immune Response

Thorac Surg Clin. 2019 May;29(2):123-131. doi: 10.1016/j.thorsurg.2018.12.001. Epub 2019 Mar 7.


The thymus is a primary lymphoid organ essential for the development of T lymphocytes, which orchestrate adaptive immune responses. T-cell development in the thymus is spatially regulated; key checkpoints in T-cell maturation and selection occur in cortical and medullary regions to eliminate self-reactive T cells, establish central tolerance, and export naïve T cells to the periphery with the potential to recognize diverse pathogens. Thymic output is also temporally regulated due to age-related involution of the thymus accompanied by loss of epithelial cells. This review discusses the structural and age-related control of thymus function in humans.

Keywords: Epithelial cells; Immunosenescence; T lymphocytes; T-cell development.

Publication types

  • Review

MeSH terms

  • Aging / immunology
  • Aging / physiology
  • Homeostasis / physiology
  • Humans
  • Immune System / physiology
  • T-Lymphocytes / physiology
  • Thymus Gland / embryology
  • Thymus Gland / immunology*
  • Thymus Gland / physiology*