Natural killer T cell
noun, plural: natural killer T cells
A T cell capable of destroying infected cells and infective particles upon recognizing CD1 protein presenting lipid antigen with its T-cell receptor
Natural killer T cell is a type of T lymphocyte that "kills" foreign pathogens and cancer cells upon recognizing CD1 protein that presents lipid antigens on the surface of an antigen-presenting cell with its T-cell receptor. This activates the natural killer T cell to produce cytokines.
Natural killer T cell should not be confused with another T lymphocyte with similar function, i.e. cytotoxic T cell. The cytotoxic T cell (also called killer T cell) is a T cell that has CD8+ receptor on its cell surface. This receptor is essential for binding with MHC class I molecule for recognition of an antigen-presenting cell. The natural killer T cell does not express this receptor and therefore does not associate with MHC class I molecule.
Natural killer T cell should not also be confused with a natural killer cell (NK cell). The former has antigen-specific receptors. This means that the natural killer T cell is more specific in its immune response. The NK cell is less specific and therefore attacks a wider range of pathogens.
- NKT cell