NK & TC CELLS

Compare and contrast the functions and mechanisms of action of NK cells and TC Cells

NK cells and TC Cells

The paper will present a comparison between Natural Killer Cells also known as NK Cells and Cytotoxic T lymphocyte Cells which are known as TC Cells.

NK Cells - Natural Killer Cells

NK cells (natural killer) are a lymphocyte belonging to the immune system. They are also known as null cells. These cells are virtually indistinguishable morphologically large lymphocytes except for the granules they contain. NK Cells are also called third population as well when they met T lymphocytes and B marker, NK cells do not attach these markers (B or T).

NK cells are important components in nonspecific immune defense. They share a common progenitor with T lymphocytes. Originate in the bone marrow and are large and granular. These cells do not destroy the pathogens directly, taking a more related to the destruction of infected cells or may be carcinogenic. They are phagocytic cells, destroy other cells throughout the attack on their plasma membrane causing diffusion of ions and water inside the cell to increase its internal volume to a breaking point in which case the analysis. NK cells are chemically characterized by the presence of the marker CD56 and absence of CD3.

NK cells kill target cells are nonspecific and respond from the outset. NK cells also kill tumor or infected by virus by a programmed death (apoptosis). It is believed that these cells detected by the target cell recognition of glycocalyx anomalous. It is also believed to recognize when infected cells or tumor cells lose MHC class I, which inhibit the action of NK cells (Bambard 2008, pp. 143-159).

Characteristics

They are also known as LGG cells because they are large cells filled with cytoplasmic granules. No express a membrane receptor specifically lymphocytes, the TCR or T cell receptor (the Ig typical membrane B lymphocytes, CD3, etc.). They also have a great quality that distinguishes them from other T cells, not mature in the thymus. Neither cell markers expressed phenotypic traditionally identified with the rest of the subpopulations of lymphocytes. In membranes expressing only CD2, CD16 and LFA-1, differentiating T cells that are always CD3 + and CD16 -. They are located mainly in circulating blood and the spleen, rarely in other tissues.

Functions

Killer cells have the ability to differentiate the cells infected by a virus, or cell tumor who have undergone malignant transformation. They can identify which cells are characteristic of the host and which are foreign. This happens due to membrane receptors of the killer cell detected the absence of MHC or MHC molecules in these damaged cells and inhibitory receptors on healthy cells. This simple system to recognize healthy cells from damaged cells is very effective. In addition to this release interferon and other cytokines, to trigger non-specific response and destroy the cell which has driven the substance, to be attacked by viral action (Colonna 2000, pp. 123-129). The recognition of target cells induces the mobilization of granules to the site ...