T-cells are MHC-Restricted - Essay Example

Only on StudentShare

Extract of sample
T-cells are MHC-Restricted

T-helper cells are so named because they produce and secrete protein molecules called cytokines that perform various functions within the immune system that direct and 'help' the immune response. Within the Helper T-cell group are two further subsets known as Th1 (or type 1) and Th2 (or type 2). Cytotoxic T-cells play a central role in the destruction of tumour cells and virally-infected cells, and are also thought to have an important role in transplant rejection.
Differentiation of T-cells into CD4+ and CD8+ cells begins in the thymus during T-cell development. However, cells only become fully differentiated mature cells in the peripheral lymphoid system, during an active immune response.
All T-cells originate in the marrow of long bones (such as the femur), and are derived from hematopoetic stem cells. Hematopoetic progenitors that derive from these stem cells travel to the thymus via the lymphatic system. Upon reaching the thymus they divide to generate T-cell precursors known as immature thymocytes (Schwarz B A, Bhandoola A. 2006). Approximately 98% of these precursor cells die in the thymus without becoming fully-differentiated T-cells, due to selection processes called positive and negative selection. The 2% of cells that survive selection eventually leave the thymus to become mature T-cells.
At the beginning of the selection process, all thy ...
Download paper


T-cells are a member of the subset of white blood cells called lymphocytes. These cells, which originate in the thymus, play a vital role in cell-mediated immunity. The T-cell can be distinguished from other lymphocytes such as Natural Killer (NK) cells and B-cells due to the presence of the T-cell receptor (TCR) which is found only on the surface of T-cells.
Author : demetris98

Related Essays

Structure of The Major Histocompatibiltiy Complex (MHC)
The functions performed by the complex are: binding of peptide fragments from invading pathogens and then displaying these peptide fragments on the cell surface so that it should be recognized by T-cells fro further degradation....
8 pages (2008 words) Essay
Eukaryotic and Prokaryotic cells
DNA as we know tells us about our family structure and passes on from one generation to another. The large number of cells and their network helps in differentiating the DNA structure. The DNA keeps of replicating with the help of template polymerization. The Eukaryotic and Prokaryotic cells are made up of similar basic chemicals like carbohydrates, proteins, nucleic acid, minerals, fats and vitamins, while making use of proteins as catalysts. The hereditary information is transformed into RNA, which in turn is translated into proteins. Therefore these two cells are similar in nature in many...
2 pages (502 words) Essay
Prokaryotic and Eukaryotic Cells
4). While prokaryotes are single-celled, most eukaryotes are multi-celled which influences the cells mobility and defines their function. The simplicity and specialization of the prokaryotic cells and the complexity of the multi-celled structure of the eukaryotic cells limit and allow for the unique functions of each classification....
2 pages (502 words) Essay
Costimulatory activity of dendritic cells
T cell activation is a highly regulated event involving complex receptor-ligand interactions, ultimately leading to downstream signaling events (Annu Rev Immunol. 2002). Optimal activation of naïve T cells requires at least two signals, antigen recognition and co-stimulation (Bretscher and Cohn 1970).The first signal requires engagement of an antigen receptor by foreign antigen. Professional antigen presenting cells (APCs) such as dentritic cells, macrophages and B-lymphocytes play a major role in this. They present different sets of antigens and serve to activate T cells at different points...
3 pages (753 words) Essay
Stem Cells
Most other cells in our bodies are capable of either no replication at all, or only limited multiplication. Stem cells however can continue to replicate mitotically in an endless series of cell divisions in which a single progenitor call can give rise to populations of several million cells....
5 pages (1255 words) Research Paper
Describe in Molecular Detail the Biological Function of Langerhans Cells
The antigen presenting cells move in and out of lymph nodes to initiate immune responses. The interaction of Langerhans cells with immuno competent cells initiates the formation of a number of antibodies in various parts of the human body....
6 pages (1506 words) Essay
Got a tricky question? Receive an answer from students like you! Try us!