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The NK-92 cell line is an immortalised cell line that has the characteristics of a type of immune cell found in human blood called ’natural killer’ (NK) cells. Blood NK cells and NK-92 cells recognize and attack cancer cells as well as cells that have been infected with a virus, bacteria, or fungus. [1]
A more efficient way to obtain high numbers of NK cells is to expand NK-92 cells, an NK cell line with all the characteristics of highly active blood Natural Killer (NK) cells but with much broader and higher cytotoxicity. NK-92 cells grow continuously in culture and can be expanded to clinical-grade numbers in bags or bioreactors. [56]
Natural killer (NK) cells are a type of lymphocyte cell involved in the innate immune system's response to viral infection and tumor transformation of host cells. [20] [7] Like T cells, NK cells have many qualities characteristic of the adaptive immune system, including the production of “memory” cells that persist following encounter with antigens and the ability to create a secondary ...
Granzymes are serine proteases released by cytoplasmic granules within cytotoxic T cells and natural killer (NK) cells. They induce programmed cell death (apoptosis) in the target cell, thus eliminating cells that have become cancerous or are infected with viruses or bacteria. [1] Granzymes also kill bacteria [2] and inhibit viral replication.
Normal body cells are not recognized and attacked by NK cells because they express intact self MHC antigens. Those MHC antigens are recognized by killer cell immunoglobulin receptors (KIR) that slow the reaction of NK cells. The NK-92 cell line does not express KIR and is developed for tumor therapy. [11] [12] [13] [14]
Granzyme B is released with perforin which inserts into a target cell's plasma membrane forming a pore.Perforin has a radius of 5.5 nm and granzyme B has a stokes radius of 2.5 nm and can therefore pass through the perforin pore into the target to be destroyed.
In cancers, a Killer Activation Receptor (KAR), located on the surface of the NK cell, binds to certain molecules which only appear on cells that are undergoing stress situations. In humans, this KAR is called NKG2D and the molecules it recognizes MICA and MICB. This binding provides a signal which induces the NK cell to kill the target cell. [9]
Cytotoxic T-cell activity: Fas-induced apoptosis and the perforin pathway are the two main mechanisms by which cytotoxic T lymphocytes induce cell death in cells expressing foreign antigens. [ 13 ] Immune privilege : Cells in immune privileged areas such as the cornea or testes express Fas ligand and induce the apoptosis of infiltrating ...