What does IL-7 do to T cells?
IL-7 promotes T-cell survival by up-regulating the expression of anti-apoptotic genes; the anti-apoptotic genes Bcl-2 and Mcl-1 (myeloid-cell-leukemia sequence-1) are the major targets in naïve T-cells. The protein products encoded by these genes inhibit the pro-apoptotic proteins Bax and Bak.
Do T cells develop in the thymus?
Precursors of T cells migrate from the bone marrow and mature in the thymus. This process is similar to that for B cells, including the sequential rearrangement of antigen receptor gene segments.
What are the 3 stages of T cell development in the thymus?
The thymus consists of three major regions: the cortex, the medulla, and the corticomedullary junction. Progenitor cells enter the thymus at the corticomedullary junction. Most immature T cells, termed thymocytes, are found in the cortex.
Which of the following is the function of IL-7?
IL-7 is essentially involved in T-cell homeostasis at various developmental stages. This cytokine is required for the development of mature T cells in the thymus and also prompts the survival of naïve and memory T cells in the periphery.
Where does the thymus develop from?
According to the classical view, the thymus derives from the endoderm of the 3rd pharyngeal pouch on both sides. The 3rd pharyngeal pouch gives origin ventrally to the thymus and dorsally to the 3rd parathyroid gland, whereas the 4th pharyngeal pouch gives origin to the 4th parathyroid and the ultimo- branchial body.
What kind of immune system cells develop in the thymus?
Before birth and throughout childhood, the thymus is instrumental in the production and maturation of T-lymphocytes or T cells, a specific type of white blood cell that protects the body from certain threats, including viruses and infections.
What are the stages of T cell development?
T cell progenitors originate in the bone marrow and, through a series of defined and coordinated developmental stages, enter the thymus, differentiate, undergo selection, and eventually mature into functional T cells.
At what stage of T cell development is the pre TCR expressed?
Cells that undergo in-frame rearrangement to assemble a functional TCRβ will express a pre-TCR, composed of TCRβ and pre-Tα, and will then progress to the CD4−CD8− double-positive (DP) stage. It is during the DP stage when thymocytes undergo TCRα rearrangement to produce a mature αβTCR.
Where is IL-7 produced?
thymus
IL-7 is produced by mesenchymal and epithelial cells in lymphoid organs. In the thymus, IL-7 mRNA is detected in thymic epithelial cells (TECs) by in situ hybridization, especially at the corticomedullary junction (12). Additionally, IL-7 is expressed in the mesenchymal stromal cell lines isolated from thymus (13).
How does IL-7 affect thymus function?
IL-7 functions at all stages of T-cell differentiation and homeostasis. IL-7 treatment has been shown to increase the peripheral naïve and central memory T-cell pool making it a potential treatment for patients with impaired T-cell populations. The IL-7 effect on thymus function is unclear.
Is Interleukin 7 required for T cell development?
Interleukin (IL)-7 is required for T-cell development as well as for the survival and homeostasis of mature T-cells. In the thymus, the double negative (DN) CD4(-) CD8(-) thymocyte progenitor transition into double positive CD4+ CD8+ cells requires Notch and IL-7 signaling.
What is the role of IL-7 in T-cell differentiation and homeostasis?
Conclusion IL-7 functions at all stages of T-cell differentiation and homeostasis. IL-7 treatment has been shown to increase the peripheral naïve and central memory T-cell pool making it a potential treatment for patients with impaired T-cell populations.
What is the role of IL-7 in the pathogenesis of lymphopenia?
IL-7 is critical for homeostatic proliferation and survival of naive T-cells. Proc Natl Acad Sci USA. 2001;98:8732–8737. [PMC free article][PubMed] [Google Scholar] von Freeden-Jeffry U, Vieira P, Lucian LA, McNeil T, Burdach SEG, Murray R. Lymphopenia in IL-7 gene-deleted mice identifies Il-7 as a non-redundant cytokine.