What is the function of thymic epithelial cells?

Thymic Epithelial Cells Contribute to Thymopoiesis and T Cell Development. The thymus is the primary lymphoid organ responsible for the generation and maturation of T cells. Thymic epithelial cells (TECs) account for the majority of thymic stromal components.

Where are thymic epithelial cells?

thymic stroma
Thymic epithelial cells (TECs) are specialized cells with high degree of anatomic, phenotypic and functional heterogeneity that are located in the outer layer (epithelium) of the thymic stroma. The thymus, as a primary lymphoid organ, mediates T cell development and maturation.

Are thymocytes T cells?

A Thymocyte is an immune cell present in the thymus, before it undergoes transformation into a T cell. Thymocytes are produced as stem cells in the bone marrow and reach the thymus via the blood.

What is thymic stroma?

Thymus stromal cells, which can include all non-T lineage cells, such as thymic epithelial cells, endothelial cells, mesenchymal/fibroblast cells, dendritic cells, and B cells, provide signals that are essential for thymocyte development as well as for the homeostasis of the thymic stroma itself.

Where do thymic epithelial cells come from?

They are formed from both epithelial and mesenchymal components, and collectively they support a stepwise program of thymocyte development. Of these stromal cells, cortical, and medullary thymic epithelial cells represent functional components of thymic microenvironments in both the cortex and medulla.

What happens to T cells in the thymus?

In the thymus, T cells develop their specific T cell markers, including TCR, CD3, CD4 or CD8, and CD2. T cells also undergo thymic education through positive and negative selection. The thymus is a multi-lobed organ composed of cortical and medullary areas surrounded by a capsule.

What is the relationship between the thymus and T cells?

THE THYMUS IS A SPECIALIZED ORGAN THAT DIRECTS THE DEVELOPMENT AND SELECTION OF T CELLS WHICH DIRECT ADAPTIVE IMMUNITY.

How do thymocytes enter thymus?

During their lifetime, thymocytes are in constant motion. Originally developing in the bone marrow, early progenitor cells circulate in the blood until they enter the thymus through blood vessels located at the CMJ.

Why do we lose our thymus?

A peculiar feature of the thymus is that it disappears as we get older. The thymus starts deteriorating after birth but the process speeds up after puberty and, by age 65, we are basically unable to make new T cells. As the organ shrinks, the T cell areas are replaced with fatty tissue, in a process called involution.

What are thymic epithelial cells?

The thymic epithelial cells are endodermal derivatives of the third pharyngeal pouch that further differentiates into specialized epithelium within the cortex and medulla. Overall, these cells are characterized by an eosinophilic cytoplasm containing intermediate filament bundles with pale, ovoid nuclei.

What is the thymus?

The thymus is a soft organ located behind the breastbone and between the lungs. In relation to the organs in the human body, the thymus is a two-lobed structure that lies almost on top of the heart and traces up along the trachea.

What is the thymus cell lymphocyte?

Within the thymus, thymus cell lymphocytes or T cells mature. T cells are critical to the adaptive immune system, where the body adapts specifically to foreign invaders.

Where is thymic tissue found in the body?

Thymic tissue may be found scattered on or around the gland, and occasionally within the thyroid. The thymus in children stretches variably upwards, at times to as high as the thyroid gland. Scheme showing development of branchial epithelial bodies from the thoracic cavity of the foetus.