Activation of T Lymphocytes and the role of adapter LAT (Linker for the activation of T cells)

ACTIVATION OF T LYMPHOCYTES

INTRODUCTION

T lymphocytes are white blood cells that play a major role in the innate immune system of a biological species . These white blood cells are also called T cell and can be easily differentiated from other kinds of lymphocytes , including the B lymphocytes and the natural killer (NK cells through their characteristic feature of a unique protein receptor that is displayed on its cell membrane . This unique protein has been designated as the T cell receptor (TCR . The letter T of T lymphocytes designates the source

of these cells , the thymus , which is recognized as the main organ of origin of T lymphocytes

TYPES OF T LYMPHOCYTES

Different types of T lymphocytes exist and each type performs a specialized function . Helper T cells , also known as TH cells , serve as messengers of the immune system . When helper T cells are activated these cells proliferate and produce cytokines , which are small proteins that control the extent of immune response that a biological organism will express . Several types of cytokines exist and each cytokine triggers the maturation of helper T cells into specific subtypes such as helper T cell subtype 1 , 2 and 17 (Balandina et al , 2005 . Another type of T lymphocyte is the cytotoxic T cell (CTL , which is also known as the TC cell . Cytotoxic T cells are responsible for the destruction of cells that were infected by viruses , as well as for the annihilation of tumor cells . These cells also play a major role in determining whether a cell is normally part of the system or a foreign cell Cytotoxic T cells are known to be the first in line to react and reject if an organ transplanted into a recipient is not compatible in terms of tissue compatibility . The cytotoxic T cells that are associated with tissue rejection are designated at CD8 T cells , based on the idea that these cytotoxic T cells produce a specific CD8 glycoprotein that is displayed on its cell membrane . These CD8 glycoproteins interact with helper T lymphocytes , of which may trigger its transformation into regulatory T cells . The major role of regulatory T cells is to inhibit the onset of an autoimmune dis within the system of the organism

Another type of T lymphocyte is the memory T cell which is produced as soon as an infection occurs in an individual . These specific T cells continue to circulate in the blood system for several months even when the infection has been stopped . Memory T cells further differentiate into effector T cells when they find the same antigen that was associated with the previous infection , hence the term memory is appropriate to apply to this type of function . Two general types of memory T cells include the central and effector cells . Memory T cells are known to carry either the CD4 or the CD8 glycoprotein on its plasma membrane (Wildin et al , 2001

Regulatory T cells are another type of T lymphocytes that play a crucial role...