Search results
Results from the WOW.Com Content Network
A critical step in T cell maturation is making a functional T cell receptor (TCR). Each mature T cell will ultimately contain a unique TCR that reacts to a random pattern, allowing the immune system to recognize many different types of pathogens. This process is essential in developing immunity to threats that the immune system has not ...
The purpose of thymocyte development is to produce mature T cells with a diverse array of functional T cell receptors, through the process of TCR gene rearrangement. Unlike most genes, which have a stable sequence in each cell which expresses them, the T cell receptor is made up of a series of alternative gene fragments. In order to create a ...
The remaining 96–98% of T cells die by apoptosis and are phagocytosed by macrophages in the thymus. So many thymocytes (T cells) die during the maturation process because there is intensive screening to make sure each thymocyte can recognize self-peptide:self-MHC complex [12] and for self-tolerance. Having experienced apoptosis, the thymocyte ...
The beginning of the cleavage process is marked when the zygote divides through mitosis into two cells. This mitosis continues and the first two cells divide into four cells, then into eight cells and so on. Each division takes from 12 to 24 hours.
This process is error-prone, and some thymocytes fail to make functional T-cell receptors, whereas other thymocytes make T-cell receptors that are autoreactive. [14] If a functional T cell receptor is formed, the thymocyte will begin to express simultaneously the cell surface proteins CD4 and CD8 .
At the end of G2, the cell transitions into mitosis, where the nucleus divides. The G2 to M transition is dramatic; there is an all-or-nothing effect, and the transition is irreversible. This is advantageous to the cell because entering mitosis is a critical step in the life cycle of a cell.
Mitosis in an animal cell (phases ordered counter-clockwise), with G 1 labeled at left. The G 1 phase, gap 1 phase, or growth 1 phase, is the first of four phases of the cell cycle that takes place in eukaryotic cell division. In this part of interphase, the cell synthesizes mRNA and proteins in
Two opposite types of gametes (e.g., male and female) from these individuals or cells fuse to become a zygote. In the whole cycle, zygotes are the only diploid cell; mitosis occurs only in the haploid phase. The individuals or cells as a result of mitosis are haplonts, hence this life cycle is also called haplontic life cycle. Haplonts are: