Where do NK cells differentiate?

NK cells are known to differentiate and mature in the bone marrow, lymph nodes, spleen, tonsils, and thymus, where they then enter into the circulation.

How are NK cells formed?

NK cells, like B and T cells, are a lymphocyte lineage derived from the CLP [1], and like B cells, are thought to develop primarily in the bone marrow [2], although other sites of development, such as the liver and thymus, have also been proposed (reviewed in [3]).

What do NK cells use to distinguish between self and nonself?

NK cells utilize inhibitory receptors to differentiate “self” from “missing self”. The lack of expression of MHC class I molecules (missing self) promotes the activation of NK cells and the lysis of the target cell.

How do natural killer cells recognize their targets?

Furthermore, NK cells express the low-affinity IgG receptor CD16, which enables them to recognize and kill target cells opsonized with antibodies by antibody-dependent cell-mediated cytotoxicity.

How does NK cells recognize abnormal cells?

NK cells recognize abnormal or infected cells with activating receptors and inhibitory receptors. All normal cells in the body express MHC I to signal that those cells are part of the body.

How do NK cells distinguish between healthy cells and infected unhealthy cells?

Figure: Lymphocytes: Lymphocytes, such as NK cells, are characterized by their large nuclei that actively absorb Wright stain and, therefore, appear dark colored under a microscope. An infected cell (or a tumor cell) is often incapable of synthesizing and displaying MHC I molecules appropriately.

What do NK cells recognize?

However, NK cells can recognize and kill cells that have down-regulated MHC class I molecules from their cell surface. The MHC class I molecules are recognized by NK cell inhibitory receptors and the ligation of these receptors inhibits the activation of NK cells.

What are characteristics of natural killer cells?

NK (natural killer) cells comprise 10%-15% of peripheral blood mononuclear cells and have morphology of large, granular lymphocytes with the central role of killing the virus-infected and malignantly transformed cells, without prior sensitization.

What distinguishes NK cells from cytotoxic T?

NK cells were first noticed for their ability to kill tumour cells without any priming or prior activation (in contrast to cytotoxic T cells, which need priming by antigen presenting cells). They are named for this ‘natural’ killing.