Med. Weter. 68 (5), 274-279, 2012

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Wyszyńska Z., Szulc L., Struzik J., Niemiałtowski M.
Immunobiology of NK cells
NK (natural killer) cells are lymphoid, often granular, cells that are an important component of natural immunity, along with the complement system and phagocytic activity. NK cells are defined as cells of the innate immune response. Recent studies, however, demonstrate that specific subsets of mouse NK cells can develop specific immunological “memory” to a variety of antigens. NK cells do not require prior contact with foreign (i.e. viral or tumor) antigens and are not MHC-restricted. NK cells are involved in antibody-dependent cell-mediated cytotoxicity (ADCC) and are thus able to destroy target cells coated with antibodies. NK cells express strong cytotoxicity against neoplastic and virus-infected cells after the activation of the perforin/granzyme system. They express stimulatory and inhibitory receptors on cell surface that recognize self-MHC proteins and regulate their activation. Mice NK cells express a large number of receptors, such as Ly49 receptors, which can inhibit the activity of MHC class I molecules. This short review shows an important role of NK cells as the effector arms of the immune system.
Keywords: NK cells, immunobiology, receptors